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Agilent Vapor Generation Accessory VGA 77 User Guide

1. Agilent Vapor Generation Accessory VGA 77 User s Guide 45 Operation You can do this by filling a suitable measuring cylinder to a convenient reference mark with distilled water then placing the sample capillary into the cylinder and observing the volume of water pumped out of the cylinder over a timed interval With a 50 Hz power supply the uptake rate should be about 7 mL per minute with a 60 Hz power supply it should be about 8 mL per minute Note the exact flow rates for future reference in the AA performance log in Appendix A at the end of this manual 8 Similarly measure the uptake rate for each of the other pump tubes The uptake rate for each should be within the range 0 8 1 2 mL min Note the exact flow rates for future reference in the AA performance log in Appendix A at the end of this manual If you are using the VGA 77 with an ICP system you must now adjust the speed of the instrument peristaltic pump until liquid is being pumped out of the gas liquid separator faster than it is being pumped in by the VGA 77 Set the spectrometer Pump speed to a minimum of 35 rpm 46 Your VGA 77 is now ready for use You should now either e Proceed to AA Setup on the following page if you are using the VGA 77 with an AA system e Proceed to ICP setup on Page 49 if you are using the VGA 77 with an ICP system or e Carry out the instructions for closing down the VGA 77 on Page 53 Agilent Vapor Gener
2. Frequency 50 60 1 Hz Consumption approx 20 VA Connections Mains inlet coupler 6 A 250 VAC IEC type Mains power cord connector Australia 10 A 250 VAC Complies with AS3112 USA 10 A 125 VAC Complies with NEMA 5 15P Europe 6 A 250 VAC Complies with CEE7 sheet vii or NFC61 303VA Gas Supplies Argon or nitrogen 99 99 pure minimum Only argon gas can be used when the VGA 77 is coupled with an ICP spectrometer The inert gas must be dry and dust free otherwise you must insert a suitable filter in the supply line Agilent Vapor Generation Accessory VGA 77 User s Guide 15 Introduction 16 Permissible pressure range Recommended pressure Nominal flow rate Gas connections inert gas inlet 6 mm 1 4 in ID reinforced PVC hose 3 meters 10 ft long Weights and Dimensions 300 to 400 kPa 43 to 57 psi 350 kPa 50 psi 90 mL minute System unit Width Depth Height Weight VGA 77 for AA and Vista Series ICP OES 320 mm 210 mm 270 mm 5 5 kg 13 in 8 in 11 in 12 Ib Shipping dimensions 590 mm 475 mm 320 mm 11 kg 23 in 19 in 13 in 24 Ib VGA 77 for 700 Series ICP OES with bracket 385 mm 340 mm 195 mm 6 kg 13 in 14 in 8 in 13 Ib Shipping dimensions 590 mm 490 mm 320 mm 10 kg 23 in 19 in 13 in 22 Ib Agilent Vapor Generation Accessory VGA 77 User s Guide Getting Started 00 Q 9 3 Getting Started Q eo Unpacking 17 e Installation 18 gt Installation Checklist 19 j Gas Supply Re
3. About the VGA 77 The Vapor Generation Accessory 77 VGA 77 is a vapor generation system for Atomic Absorption AA and Inductively Coupled Plasma Optical Emission Spectrometer ICP OES applications Vapor generation is an extremely sensitive procedure used for determining the level of mercury arsenic selenium and a range of other hydride forming elements in samples The sample capillary is placed in the solution to be measured and the VGA 77 pumps the sample through a reaction coil where it is automatically acidified and mixed with a suitable reductant The resulting vapor is transferred to an atomization cell for determination by the spectrometer The VGA 77 is supplied in a modular form with a pump unit and separate reagent module Since ICP and AA applications use different gas liquid separators using separate plumbing assemblies for different reagents enables e Flexibility the VGA 77 can be used with both AAs and ICPs e Quick and simple change of applications for example from AA to ICP or between different types of analyses Agilent Vapor Generation Accessory VGA 77 User s Guide 13 Introduction e Cleaner operation there is no chance of cross contamination between applications e Ease of operation there is no need to clean reagent bottles and tubing between applications as each application has a dedicated reagent module Similarly you can change from AA to ICP applications by changing reagent modules Part numbers f
4. approved safety glasses warranted to protect the eyes Never pump concentrated sulfuric acid through the VGA 77 system Warning and Caution Messages A Warning message is used in the text when failure to observe instructions or precautions could result in death or injury A Caution message is used when failure to observe instructions could result in damage to equipment Agilent supplied and or associated equipment A Note is used to give advice or information The following is a list of symbols that appear in conjunction with warnings in this manual and on the spectrometer The hazard they describe is also shown The beginning of the warning text is noted by a warning icon A triangular symbol indicates a warning The meanings of the symbols that may appear alongside warnings in the documentation or on the instrument itself are as follows Agilent Vapor Generation Accessory VGA 77 User s Guide 9 Safety Practices and Hazards A A A Corrosive liquid Electrical shock Explosion hazard Eye hazard Fire hazard Heavy weight danger to feet Heavy weight Hot surface Magnetic hazard danger to hands A A A Moving parts Noxious gas Sharp object Information Symbols Mains power on 0 Mains power off Fuse Single phase alternating current When attached to the rear of the instrument indicates that the product complies with the requirements of one or more EU Directives When attached to the rear of t
5. approved safety glasses warranted to protect the eyes Never pump concentrated sulfuric acid through the VGA 77 system In the VGA 77 system the vapor is generated continuously while solutions are being pumped This provides the convenience and advantages of a continuous analytical signal Agilent Vapor Generation Accessory VGA 77 User s Guide 43 Operation Setup General Setup 1 Check you have the correct module installed 2 Ensure that the inert gas supply to the VGA 77 is on with the cylinder regulator set to the recommended pressure of 350 kPa 50 psi 3 Ensure that the peristaltic pump is adjusted correctly as detailed in the following section 4 Setup any other accessories you require for example printers or autosamplers according to their instruction manuals 5 Set the instrument parameters for the element to be determined Use the integration mode with Agilent AA or ICP OES systems Agilent AA users can also use PROMT mode 6 Fill the reagent container s with the required reagent s Refer to Section 5 Pump Adjustment To adjust the pump 1 Set the regulator to the recommended pressure and turn on the inert gas supply Ensure that the inert gas supply is turned on before switching on the VGA 77 power If you start to pump solutions through the system before the inert gas is turned on the signal will be unreliable 2 Select the appropriate power lead and connect the VGA 77 to the mains power su
6. by a flow of argon gas into the spectrometer Nitrogen gas can be used with the AA reagent module 56 The following figure shows a schematic diagram of the VGA 77 To spectrometer Peristaltic Gas liquid Reaction coil pump separator Sample L d Acid Reductant Flow controller Argon 13 The peristaltic pump maintains a constant flow of analytical solutions into the accessory Figure 19 Schematic of the VGA 77 Agilent Vapor Generation Accessory VGA 77 User s Guide Analytical Notes The sample and acid are allowed to merge first before the reductant usually sodium borohydride NaBH enters the stream For mercury analysis SnCl solution is recommended Argon is then introduced into the liquid stream and the reaction proceeds while the mixture is flowing through the reaction coil Vigorous evolution of hydrogen assists the stripping of the hydride or mercury vapor from the liquid into the argon The gas is then separated from the liquid in the separator The liquid drains away to waste At this point a second stream of argon is introduced to ensure that the gas stream is not saturated with water vapor and does not condense in the sample introduction system The gas containing the element of interest then passes out of the separator into the spectrometer where it is analyzed As the VGA 77 produces a continuous signal you should use the integration mode with Agilent
7. cell becomes devitrified or not and even with meticulous cleaning the inside surface may deteriorate to the extent that the analytical signal will be suppressed You should regularly monitor the performance of the cell using absorbance measurements obtained from standard solutions Discard the cell as soon as the results of this monitoring become unacceptable When a significant number of samples are being analyzed the use of a Drierite trap inserted between the absorption cell and the output of the gas liquid separator will protect the absorption cell and extend its lifetime Refer to Use of Drierite Trap to Extend the Lifetime of Vapor Generation Absorption Cell 1986 October No 65 on www agilent com Under some circumstances the center section of the cell may gradually soften in the flame and sag If uncorrected this may become so severe that alignment of the cell within the optical path is impossible When sagging is first noticed it can be corrected by simply turning the cell over so that it will return to its normal shape the next time it is heated Gas Liquid Separator As with the cell the gas liquid separator must be cleaned immediately if contamination is suspected during conditioning or whenever the system has been left unused for some time Do not allow hydrochloric acid solutions to remain in the separator Agilent Vapor Generation Accessory VGA 77 User s Guide 73 Maintenance and Spare Parts Corrosive Chem
8. from the sample compartment 1 Disconnect the black fluoro elastomer tubing from the cell inlet 2 Release the spring clips and remove the absorption cell from the cell support 3 Soak the absorption cell in dilute nitric acid for at least 30 minutes 4 Rinse thoroughly with distilled water and allow it to air dry ina dust free location 5 Ifthe cell has been exposed to contamination with potassium iodide soak the cell in sodium hydroxide solution 0 5 w v for at least 30 minutes Wash thoroughly with dilute hydrochloric acid and then wash thoroughly with distilled water Allow to air dry in a dust free location Do not leave the cell in the sodium hydroxide for too long because this solution may accelerate cell devitrification Avoid handling the central part of the quartz cell with bare hands after it has been cleaned or while it is in use 72 Agilent Vapor Generation Accessory VGA 77 User s Guide Maintenance and Spare Parts The working life of the cell will depend on the type of analytical programs carried out At some stage the glass will start to turn white indicating the onset of devitrification Initially devitrification will not degrade the analytical performance but eventually the devitrified area will extend over most of the cell at which point it may be necessary to discard the cell If devitrification is excessive the cell will eventually crack spontaneously or fail through thermal shock Whether the
9. in the following table Table 1 6 Loss of analyte signal due to element interferences Analyte gt 50 10 50 10 As Au Ge Ni Pt Pd Rh Ag Bi Co Cu Sb Se Al B Ba Be Ca Cd Cr Cs Fe Ga Hf Hg Ru Sn Te In Ir K La Li Mg Mn Mo Na Pb Rb Re Si Sr Ti TI V W Y Zn Zr Bi Ag Au Co Cu Ni Pd As Cd Cr Fe Ge Ir Al B Ba Be Ca Cs Ga Hf Hg In K La Pt Rh Ru Se Te Mo Sb Sn Li Mg Mn Na Pb Rb Re Si Sr Ti TI V W Y Zn Zr Ge As Au Cd Co Fe Ni Bi Cu Ir Te Ag Al B Ba Be Ca Cr Cs Ga Hf Hg In Pd Pt Rh Ru Sb Se K La Li Mg Mn Mo Na Pb Rb Re Si Sn Sr Ti TI V W Y Zn Zr Sb Au Co Ge Ni Pt Pd As As Cr Cu Re Se AI B Ba Bi Ca Cd Cs Fe Be Ga Hf Hg Rh Ru n In Ir K La Li Mg Mn Mo Na Pb Rb Si Sr Te Ti TI V W Y Zn Zr Se Ag Cu Ni Pd Pt Rh Au As Cd Co Fe Ge Al B Ba Be Bi Ca Cr Cs Ga Hf Hg In Ru Sn Pb Sb Zn Ir K La Li Mg Mn Mo Na Rb Re Si Sr Te Ti TI V W Y Zr Te Ag Au Cd Co Cu Fe As Bi Ir Mo Sb Si Al B Ba Be Ca Cr Cs Ga Hf Hg K La Ge In Ni Pb Pd Pt W Li Mg Mn Na Rb Sr Ti V Y Zn Zr Re Rh Ru Se Sn 58 Agilent Vapor Generation Accessory VGA 77 User s Guide Analytical Notes Contamination When first establishing your analytical method you must always check for contamination before carrying out your program Traces of pot
10. s Guide Analytical Notes Se is not quantitatively recovered by hydride generation and must be reduced to Se by warming with concentrated hydrochloric acid Prepare the samples in 6 7 M hydrochloric acid use of a lower acid concentration will result in greater inter element interferences heat at 70 90 C for at least 10 minutes Cool to room temperature before analysis Reductant container NaBH 0 6 w v NaOH 0 5 w v Acid container 10 M HCl Tellurium The presence of potassium iodide will severely suppress the analytical response Always ensure that the VGA 77 system is completely free of potassium iodide before performing tellurium determinations To avoid contamination it is recommended that you dedicate a separate module to the analysis of those elements requiring pre reduction with KI ie As or Sb Te is not quantitatively recovered by hydride generation and must be reduced to Te Prepare the samples in 6 7 M hydrochloric acid heat at 70 90 C for at least 10 minutes and cool to room temperature before analysis Reductant container NaBH 0 6 w b NaOH 0 5 w v Acid container 5 M HCI Higher acid concentrations will reduce the analytical signal Agilent Vapor Generation Accessory VGA 77 User s Guide 67 Analytical Notes Tin The best results for tin will generally be obtained from solutions prepared in 1 w v tartaric acid Also a study has shown that the addition of L cysteine greatly improve
11. s Guide 71 Maintenance and Spare Parts Shock Hazards To prevent reduced safety protection or unwanted fusing always ensure that the marking on the fuse matches the screening shown adjacent to the voltage selector switches Check the fuses as follows 1 2 Disconnect the unit from the mains power supply Undo the fuse cap by pressing the cap and turning it counter clockwise Pull the cap out carefully The fuse should be held in the fuseholder in the fuse cap Check that the fuse is the correct type and that it is not damaged If necessary replace the fuse in the holder Place the fuse into the cap push the cap in and turn the cap clockwise Reconnect the unit to the mains power supply If a fuse blows repeatedly it may indicate other problems with the accessory You should contact your local Agilent sales office and arrange a service call 78 Agilent Vapor Generation Accessory VGA 77 User s Guide Maintenance and Spare Parts Spare Parts Use only Agilent supplied parts unless otherwise indicated The following spare parts are available from Agilent for your VGA 77 Module for AA includes reagent module tubing and connectors 9910062100 Module for ICP includes module tubing and connectors 9910062200 Absorption cell for AA 2 cells separator to cell tubing 9910040000 fluoro elastomer Flow through mercury cell kit Includes cell and separator to cell 9910040700 tubing fluoro elastomer
12. the instrument and carrying out the analytical program Dispose of waste in accordance with relevant safety practices Agilent Vapor Generation Accessory VGA 77 User s Guide Analytical Notes Standards Prepare your calibration standards from stock solutions For some samples it will be necessary to compare the calibration slopes using the normal calibration method with those obtained using the standard additions method If the slope is not the same you should use the standard additions technique for the analysis Reductant Sodium Borohydride The recommended sodium borohydride NaBH concentration is 0 6 w v However better results will be obtained for difficult samples containing high concentrations of metals if the sodium borohydride concentration is reduced to 0 3 w v Stannous chloride reductant is recommended for mercury determinations See Page 64 Always stabilize the solution by first adding sodium hydroxide NaOH 0 5 w v Since sodium borohydride will decompose significantly in one or two days you should not prepare more than 500 mL at a time At a flow rate of about 1 mL per minute this should be enough for continuous operation over a typical working day Stability may be improved by passing the solution through a 5 micron filter You can also extend the working life of the solution by storing at 5 C The solution should remain stable for approximately one week if stored at 5 C Allow the solution to re
13. to Page 79 for ordering information To install the burner clamp for the Mark V burner 1 Slacken the two clamping screws on the underside of the clamp The front of the air acetylene burner carries the identification label Orient the clamp so that the two mounting pegs are at the front of the burner This will ensure that the burner identification label is still visible through the open portion of the clamp 32 2 Fitthe clamp over the burner so that the two positioning lugs at each end of the clamp rest on top of the burner on either side of the burner slot 3 Tighten the clamping screws Agilent Vapor Generation Accessory VGA 77 User s Guide Getting Started Figure 11 Mark V burner with burner clamps installed The clamp can be left permanently installed since it will not interfere with normal flame analyses Installation of Zeeman Adapter for 240Z 280Z AA The VGA for Zeeman Adapter allows the VGA to be used with the Agilent 2407 28027 AA The adapter allows installation of the following cells in the sample compartment e Mercury flow through cell e Standard hydride absorption cell e ETC 60 Cell Mk 2 Assembly The following instructions outline the steps required to assemble and change cell holders of the VGA 77 for Zeeman Adapter When assembled the adapter is hooked over the sample compartment The VGA 77 for Zeeman Adapter is shipped with the Standard Cell Holder and a bracket for the ETC 6
14. 0 22 24 24 25 27 29 33 36 39 42 42 43 44 44 44 47 49 51 52 53 54 55 56 57 Agilent Vapor Generation Accessory VGA 77 User s Guide Contents Acid Concentration 57 Oxidation State 57 Interferences 58 Contamination 59 Memory Effects 59 Background Absorption AA only 59 Laboratory Procedures 60 General 60 Standards 61 Reductant Sodium Borohydride 61 Pump Tubing 61 Sources AA only 62 Basic Methods 62 Antimony 62 Arsenic 63 Bismuth 64 Mercury 64 Selenium 66 Tellurium 67 Tin 68 Additional Notes 69 References 69 Additional References 69 Agilent Vapor Generation Accessory VGA 77 User s Guide 5 Contents 6 Maintenance and Spare Parts Cleaning Procedures General Absorption Cell Gas Liquid Separator Tubing Replacement Procedures Pump Tubes Reaction Coil Uptake Capillary Tubes Fuses Spare Parts 7 Appendix AA Performance Log 71 71 71 72 73 75 76 76 76 7 7 79 81 Agilent Vapor Generation Accessory VGA 77 User s Guide Safety Practices and Hazards Q e 1 Safety Practices and Hazards amp E General 7 e P Hazard Warnings 8 Electrical Hazards 8 Chemical Hazards 8 Warning and Caution Messages 9 Information Symbols 10 Color Coding 11 Electromagnetic Compatibility 11 General Agilent Vapor Generation Accessory VGA 77 User s Guide Operation of the VGA 77 with an Atomic Absorption spectrometer AA or Inductively Coupled Plasma Optical Emis
15. 0 Workhead Mk 2 Agilent Vapor Generation Accessory VGA 77 User s Guide 33 Getting Started Standard Cell Holder ETC 60 Figure 12 Standard cell holder rear view and ETC 60 bracket side view Adapter and Standard Cell Holder Installation It is necessary to remove the Zeeman workhead to install the adapter To install the adapter 1 Remove the sampler and the Zeeman workhead from the instrument refer to your sampler and instrument manuals for detailed instructions WARNING Heavy Weight The workhead weighs approximately 16 kg 35 Ibs To avoid injury or damage always handle carefully The VGA 77 can be fitted to the front of the instrument as described in the instrument operation manual 2 Make sure that the sample compartment is empty Now is a good time to develop a method and align the lamps 34 Agilent Vapor Generation Accessory VGA 77 User s Guide Getting Started Adapter Standard Cell Holder Pivot point al Vertical adjustment Horizontal adjustment Figure 13 Adapter and standard cell holder 3 Attach the Standard Cell Holder to the adapter outside the sample compartment Lower the hooks of the Standard Cell Holder onto the pivot points of the adapter 4 Pass the adapter fitted with the Standard Cell Holder under the crossbar of the sample compartment 5 Hook the adapter on the top rear edge of the sample compartment Standard Cell Holder Figure 14 Adapte
16. AA or ICP OES systems Agilent AA users can also use PROMT mode Factors Affecting the Formation of Hydrides Acid Concentration The concentration of acid will affect the efficiency of hydride formation in the VGA 77 You must ensure that the acid concentrations of blank standard and sample solutions are the same For multi element analysis a compromise acid concentration will be required The use of oxidizing acids e g H2S04 HCIO4 should be avoided Oxidation State The hydride forming elements may exist in more than one oxidation state in samples and standards This can have dramatic effects on the measured signal For example for Te and Se a 10x or more increase in the signal intensity is observed if the lower oxidation state is prepared Agilent Vapor Generation Accessory VGA 77 User s Guide 57 Analytical Notes Solutions containing H SO and HCLO acids may give little or no signal for any hydride forming elements The use of H SO and HCIO is to be avoided as these are very strong oxidizing agents Sample and standard and blank solutions must be prepared by a similar method to obtain the lower oxidation state Interferences The measurement of some elements by VGA can be affected by the presence of other elements or molecules in the sample matrix These reduce the amount of element detected by the spectrometer by adversely affecting the amount of hydride formed A list of observed interferences is given
17. Agilent Vapor Generation Accessory VGA 77 User s Guide E Agilent Technologies Notices Agilent Technologies Inc 1993 1994 1996 1997 1999 2000 2003 2004 2010 and 2012 No part of this manual may be reproduced in any form or by any means including electronic storage and retrieval or translation into a foreign language without prior agreement and written consent from Agilent Technologies Inc as governed by United States and international copyright laws Manual Part Number 8510104700 Edition Tenth edition April 2012 Agilent Technologies Inc Warranty The material contained in this document is provided as is and is subject to being changed without notice in future editions Further to the maximum extent permitted by applicable law Agilent disclaims all warranties either express or implied with regard to this manual and any information contained herein including but not limited to the implied warranties of merchantability and fitness for a particular purpose Agilent shall not be liable for errors or for incidental or consequential damages in connection with the furnishing use or performance of this document or of any information contained herein Should Agilent and the user have a separate written agreement with warranty terms covering the material in this document that conflict with these terms the warranty terms in the separate agreement shall control Technology Licenses The h
18. Analytical Notes You should establish whether background absorption is occurring before carrying out your analytical program This can be done by analyzing a sample with background correction on and then repeating the analysis with it off Remember to do an instrument zero before each measurement If a significant difference is found between the two measurements then perform your analyses with background correction on If there is none leave the background correction off Laboratory Procedures General The vapor generation technique demands a particularly high standard of care in all of the activities which affect the accuracy and precision of the analytical result Scrupulous cleanliness is essential in all laboratory procedures standards and samples must be meticulously prepared and carefully handled Strict precautions must be taken to avoid contamination of apparatus and even though laboratory ware is stored under ideal conditions it should be thoroughly re washed before use Strict care should also be taken to avoid contamination of all reagents and distilled water Ideally reagents should be entirely free of the element of interest but this is obviously impossible for all analyte elements in all reagents Consequently you must always establish the level of the analytical signal attributable to analyte in the reagents It is of course standard practice to check the analytical signal from the blank solution before calibrating
19. Cell holder for Mark 7 burner 0110654990 Cell holder mounting kit for Mark VI burner 0110375990 Cell holder for Mark V burner mount 0110317790 Cell holder mounting kit for Mark V burner 0410117300 Tubing kit for AA 9910061900 Tubing kit for ICP 9910061800 Gas liquid separator kit for AA includes separator and rubber 9910071100 mounting strap Gas liquid separator kit for ICP includes separator tubing and 9910056900 rubber mounting strap Fuse T0 2AH0250V IEC sheet 5 5 x 20 mm 0 8 in 1910009300 Pump tubes black black pack of 12 3710027200 Pump tubes purple black pack of 12 3710027300 Polyethylene capillary tubing 1 m 3 3 ft lengths 2410020500 Fluoro elastomer tubing small 1 m 3 3 ft lengths 3710026800 Fluoro elastomer tubing AA 0 66 m 2 2 ft lengths 2 8 mm 3710026390 0 110 in ID Drain tubing from gas liquid separator 2 meter length required 3710009200 2 m 6 6 ft length 10 mm 0 4 in ID Reagent vessel 500 mL 6610011600 Replacement drip tray 7010017200 Agilent Vapor Generation Accessory VGA 77 User s Guide 79 Maintenance and Spare Parts This page is intentionally left blank Agilent Vapor Generation Accessory VGA 77 User s Guide Appendix AA Performance Log x d e e e 7 Appendix AA Performance Log 12 e e e e Date Operator Uptake rate Element Concentration Abs Agilent Vapor Generation Ac
20. ach room temperature prior to analysis Pump Tubing The pump tubing should be checked regularly by checking the flow rate see Page 44 Pump adjustment When concentrated acid is first pumped through the acid tube the inside of the tubing may turn white but this does not impair the efficiency of the tube Agilent Vapor Generation Accessory VGA 77 User s Guide 61 Analytical Notes Ensure samples reagents and standards are at room temperature prior to analysis The VGA 77 pump will not operate correctly with hot or cold solutions as the pumping rate may vary with solution temperature Sources AA only Hollow cathode lamps or UItrAA lamps can be used for all VGA 77 methods for AA analysis Basic Methods 62 The hydride forming elements may exist in more than one oxidation state in samples and standards See Page 57 The following analytical methods for sample and standard have been developed to ensure samples and standards are present in the correct oxidation state Antimony Prepare samples in at least 1 M hydrochloric acid and ensure that any analyte present as Sb is reduced to Sb by the action of potassium iodide at a concentration of 1 w v Reduction is spontaneous and heating should not be required Reductant container NaBH 0 6 w v NaOH 0 5 w v Acid container 5 to 10 M HCl Agilent Vapor Generation Accessory VGA 77 User s Guide Analytical Notes Arsenic If arsenic and selenium are b
21. antes de abrir 23 Getting Started 24 Installing the Pump Unit To install the VGA 77 on an Agilent AA Insert the hooks on the back of the unit into the slots located on either side of the Agilent AA sample compartment To install the VGA 77 on an Agilent 700 Series ICP OES instrument 1 Insert the four stainless steel thumbscrews into the four holes towards the front of the instrument sample compartment two on each side 2 Hook the four grooves in the VGA 77 mounting bracket over the four thumbscrews in the sample compartment For an instrument other than an Agilent AA or Agilent 700 Series ICP OES you should place the VGA 77 flat on a bench close to the sample compartment of the instrument When the VGA 77 is in position fit the drip tray to the front of the pump unit by positioning the large holes over the studs on the front of the VGA 77 and sliding the tray downwards Installing a Reagent Module To install a reagent module into the VGA 77 1 Loosen the locking screw at the lower rear left hand corner of the pump unit 2 Lower the reagent module into the space adjacent to the left side of the pump unit ensuring the reagent module locating studs are fully home in the slots 3 Wind the locking screw in until it holds the module firmly in place 4 Fitthe end of the tube from the pump unit marked Inert gas A the top tube on the front of the VGA to the nipple near the bottom of the reagent manifold
22. ardware and or software described in this document are furnished under a license and may be used or copied only in accordance with the terms of such license Restricted Rights Legend If software is for use in the performance of a U S Government prime contract or subcontract Software is delivered and licensed as Commercial computer software as defined in DFAR 252 227 7014 June 1995 or as a commercial item as defined in FAR 2 101 a or as Restricted computer software as defined in FAR 52 227 19 June 1987 or any equivalent agency regulation or contract clause Use duplication or disclosure of Software is subject to Agilent Technologies standard commercial license terms and non DOD Departments and Agencies of the U S Government will receive no greater than Restricted Rights as defined in FAR 52 227 19 c 1 2 June 1987 U S Government users will receive no greater than Limited Rights as defined in FAR 52 227 14 June 1987 or DFAR 252 227 7015 b 2 November 1995 as applicable in any technical data Safety Notices A CAUTION notice denotes a hazard It calls attention to an operating procedure practice or the like that if not correctly performed or adhered to could result in damage to the product or loss of important data Do not proceed beyond a CAUTION notice until the indicated conditions are fully understood and met A WARNING notice denotes a hazard It calls attention to an operating procedur
23. arted Figure 6 Close up view of the cut outs 2 Pullthe holder forward so that the cut outs hook around the burner edge Figure 7 Cell holder pulled forward with cut outs hooked around burner edge 3 Lower the holder into position Figure 8 Lowering the cell holder into position on the Mark 7 burner 30 Agilent Vapor Generation Accessory VGA 77 User s Guide Getting Started m Figure 9 Mark 7 burner with holder in position Mark VI and VI A Burners If you have a Mark VI or Mark VI A burner you will need a cell holder and suitable mounting brackets for these burners Refer to Page 79 for ordering information To install these mounting brackets on the burner 1 Align the burner clamps at either end of the burner with the mounting peg pointing inward and the hole in the end of the plate aligned over the hole in the end of the burner 2 Use the screws provided to fix the burner clamps in position NOTE The clamps can be left permanently installed since they will not interfere with normal flame analyses Agilent Vapor Generation Accessory VGA 77 User s Guide 31 Getting Started Figure 10 Mark VI burner with burner clamps installed The Mark VI A burner looks different to the Mark VI burner however the procedure for installing the clamps is the same Mark V Burner If you have a Mark V burner or earlier version you will need a cell holder and burner mount for this burner Refer
24. assium iodide KI will interfere severely with determinations for bismuth mercury selenium and tellurium You must always ensure that the VGA 77 system is completely free of residual iodide ions e g KI before attempting to determine these elements The most practical way of minimizing contamination problems is to provide a separate module including the reagent containers and pump tubes for these elements Page 79 lists spares and part numbers Another form of contamination can occur when changing from a high level standard to a low level standard You must make sure that all tubing in the module is thoroughly rinsed Memory Effects Because the VGA 77 uses a chemical reaction to produce the elemental hydrides some memory effects can be encountered in the reaction products when changing between low and high level standards Always allow several minutes when moving from a high to a low level standard You should also ensure that the standards are prepared at the same concentration as the samples Certain types of plastic can cause memory effects for mercury Keep mercury top standard concentration as low as practicable Background Absorption AA only In general background correction is not necessary for vapor generation work Occasional exceptions may be encountered For example when determining low level arsenic in the presence of another hydride forming element Agilent Vapor Generation Accessory VGA 77 User s Guide 59
25. ation Accessory VGA 77 User s Guide Operation AA Setup 1 Remove the cell in its holder from the burner and place it at the front of the reagent module 2 Lower the burner so that it is clear of the optical path Agilent recommends using reduced slit height 0 5 in all methods 3 Fitthe required hollow cathode lamp and set up the spectrometer as described in your instrument operation manual Select Optimize gt Optimize Lamp Position the cell in its holder on top of the burner Align the cell in the optical path as follows a Hold a piece of white card between the right hand end of the absorption cell and the sample compartment window b Using the burner positioning controls adjust the position of the cell until the light from the hollow cathode lamp passes through the cell onto the card Remove the card c Use the burner positioning controls to adjust the position of the cell for maximum transmission For mercury determinations proceed to Conditioning the System on Page 48 Lighting the Flame To light the flame 1 Carry out any safety checks described in your spectrometer operation manual Follow all instructions and observe all warnings 2 Setthe acetylene flow rather higher than normal in order to obtain a fuel rich air acetylene flame This is required for igniting the flame Agilent Vapor Generation Accessory VGA 77 User s Guide 47 Operation Some instruments may automatically set a fuel rich m
26. cess nitric acid is present e For the determination of arsenic and selenium in many practical samples containing high concentrations of metals such as copper iron or nickel fewer interferences have been observed using 0 3 w v NaBH solution concentration rather than 0 6 w v Use of the lower reductant concentration may be less sensitive e You can minimize interferences of transition metals such as cobalt copper iron and nickel on arsenic and selenium by preparing samples in 6 7 M HCl With lower acid concentrations greater inter element interferences are present e Co precipitation methods using lanthanum compounds have also been found to be useful References 1 Smith A E Interferences in the determination of elements that form volatile hydrides with NaBH using AAS and Ar H flame Analyst May 1975 100 300 306 2 Determination of tin by hydride generation AA 1992 October No 107 Additional References The following references are recommended e Spectroscopy 1985 Vol 1 0 60 e Appl Spectrosc 1985 Vol 39 1 48 e Jiri Dedina and Dimiter L Tsalev Hydride Generation Atomic Absorption Spectrometry Published by John Wiley and Sons Edited by J D Winefordner ISDN 0 471 953644 Agilent Vapor Generation Accessory VGA 77 User s Guide 69 Analytical Notes This page is intentionally left blank 70 Agilent Vapor Generation Accessory VGA 77 User s Guide Cleaning Procedures General Maintenanc
27. cessory VGA 77 User s Guide 81 Appendix AA Performance Log This page is intentionally left blank 82 Agilent Vapor Generation Accessory VGA 77 User s Guide www agilent com In This Book The manual describes the following e Introduction e Site Requirements and Specifications e Hardware Installation e Operation of Hardware and Software e Analytical Notes e Laboratory Procedures e Maintenance Procedures e Instrument Cleaning e Spare Parts e Performance Log Agilent Technologies 1993 1994 1996 1997 1999 2000 2003 2004 2010 and 2012 04 12 AVIAN 8510104700 Issue 10 GE Agilent Technologies
28. ction and the pump tubing connector out of their slots You will find it easier if you remove all of the T pieces and pump connectors 5 Hold the upper T piece and sleeve firmly with one hand and pull the reaction coil out of the sleeve Agilent Vapor Generation Accessory VGA 77 User s Guide 9 10 Maintenance and Spare Parts Fit the new reaction coil into the sleeve then replace all of the pump tube connections and T connections into their slots Wind the reaction coil around the channels and out through the hole in the manifold block Ensure that there are no kinks in the tubing Fit the black fluoro elastomer sleeve onto the end of the reaction coil Replace the manifold cover Replace the separator Uptake Capillary Tubes To replace an uptake capillary tube 1 ao cm c N Remove the separator and manifold cover as described previously Slide the pump tubing connector out of its slot Pull the capillary out of its sleeve Push the end of the new capillary into its sleeve Replace the connector into its slot Replace the cover Fuses FS1 FS2 TO 2 AH 250 V IEC60127 2 Sheet 5 5x20 mm Littelfuse 0215200 or equivalent Fuse information on the rear of the instrument is the most up to date For safety reasons any other internal fuse or circuit breaker is not operator accessible and should only be replaced by Agilent authorized representatives Agilent Vapor Generation Accessory VGA 77 User
29. device may not cause harmful interference 2 This device must accept any interference received including interference that may cause undesired operation Agilent Vapor Generation Accessory VGA 77 User s Guide 11 Safety Practices and Hazards 12 If this equipment does cause harmful interference to radio or television reception which can be determined by turning the equipment off and on the user is encouraged to try one or more of the following measures 1 2 3 Relocate the radio or antenna Move the device away from the radio or television Plug the device into a different electrical outlet so that the device and the radio or television are on separate electrical circuits Make sure that all peripheral devices are also certified Make sure that appropriate cables are used to connect the device to peripheral equipment Consult your equipment dealer Agilent Technologies or an experienced technician for assistance Changes or modifications not expressly approved by Agilent Technologies could void the user s authority to operate the equipment ICES NMB 001 This ISM device complies with Canadian ICES 001 Cet appareil ISM est conforme a la norme NMB 001 du Canada Agilent Vapor Generation Accessory VGA 77 User s Guide Introduction 00 Q 2 Introduction amp eo About the VGA 77 13 cT e m About this Manual 14 Specifications 14 Environmental 14 Power 15 Gas Supplies 15 Weights and Dimensions 16
30. dition the system 1 Allow the pump to operate for three or four minutes to stabilize the flow rates 2 Make sure the instrument is in Abs mode with a suitably short integration period 3 Aspirate your highest standard monitor the signal and measure the time taken for the signal to rise from zero to its stable value The time you measure for this interval will be the pre read delay that you should enter into your system software When presenting solutions to the system always wait until this period has elapsed before taking a reading 4 Aspirate your analytical blank Continue to aspirate the standard and analytical blank in turn until a consistent response is obtained for the standard solution and then proceed to Operation on Page 51 If a consistent response cannot be obtained within a reasonable time contamination is the likely cause Even slight contamination of the system can suppress production of hydride or mercury vapor In this circumstance you must suspend the conditioning procedure and clean the system thoroughly before continuing Refer to Page 71 for cleaning instructions ICP Setup The following procedure conditions the ICP system for the vapor generation analysis This procedure should be carried out e When the system is first installed e After the system has been completely flushed and cleaned Agilent Vapor Generation Accessory VGA 77 User s Guide 49 Operation e When new pump tubes a
31. e practice or the like that if not correctly performed or adhered to could result in personal injury or death Do not proceed beyond a WARNING notice until the indicated conditions are fully understood and met Agilent Vapor Generation Accessory VGA 77 User s Guide Contents Contents 1 Safety Practices and Hazards 7 General 7 Hazard Warnings 8 Electrical Hazards 8 Chemical Hazards 8 Warning and Caution Messages 9 Information Symbols 10 Color Coding 11 Electromagnetic Compatibility 11 EN55011 CISPR11 11 ICES NMB 001 12 2 Introduction 13 About the VGA 77 13 About this Manual 14 Specifications 14 Environmental 14 Power 15 Gas Supplies 15 Weights and Dimensions 16 3 Getting Started 17 Unpacking 17 Installation 18 Agilent Vapor Generation Accessory VGA 77 User s Guide 3 Contents 4 Operation Setup Installation Checklist Gas Supply Requirements Power Supply Requirements Installing the Pump Unit Installing a Reagent Module Installing the Drain Tubing Installing the VGA 77 Pump Tubing Installing the Burner Clamp Installation of Zeeman Adapter for 240Z 280Z AA Installing the Cell Connecting the Gas liquid Separator Outlet Connecting a Mercury Trap Connection to the Autosampler General Setup Pump Adjustment AA Setup ICP Setup Operation Automatic Operation Shutting Down Changing Modules 5 Analytical Notes Background Factors Affecting the Formation of Hydrides 19 2
32. e and Spare Parts 6 Maintenance and Spare Parts Cleaning Procedures General Absorption Cell Gas Liquid Separator Tubing Replacement Procedures Pump Tubes Reaction Coil Uptake Capillary Tubes Fuses Spare Parts 71 71 72 73 75 76 76 76 7 71 79 The VGA 77 uses high concentrations of HCl Continual exposure to HCl fumes may damage the instrumentation Maintain an efficient exhaust system during VGA determinations and remove HCl solutions from the VGA 77 and the spectrometer when you finish your analyses Always clean up any spilt liquids immediately The front of the spectrometer the burner torch compartment and the VGA 77 should be cleaned daily with a soft cloth If necessary use a cloth dampened with distilled water Observe the shut down procedure as described on Page 53 Agilent Vapor Generation Accessory VGA 77 User s Guide 71 Maintenance and Spare Parts Absorption Cell This section applies to AA modules only Always clean the absorption cell thoroughly immediately after use when contamination is suspected while conditioning the system or whenever the system has been left unused for some time Throughout the cleaning procedure remember that the cell is fragile and must be handled with appropriate care Hot surface Before touching the cell remember that it may be very hot and could cause serious burns Always turn the flame off and allow the cell to cool before attempting to remove it
33. ection to the VGA 77 The VGA 77 gas supply may be taken from the main argon gas line to ICP spectrometers if you use the following precautions 1 Insert a suitable T piece into the main argon gas supply to divert some of the gas to the VGA 77 2 Attach a regulator to control the flow of argon to the VGA 77 3 Place a tap in the argon supply to the VGA 77 The tap is required to shut off the argon supply to the vapor generator as gas can flow through the VGA 77 even when it is switched off Within the VGA 77 the inert gas supply is divided into two branches The first branch is controlled by a solenoid stop valve It supplies gas to the inlet side of the reaction coil The second branch supplies inert gas directly through the gas liquid separator Inert gas will flow through the separator even with the VGA 77 switched off When the VGA 77 is switched on it will flow through both branches To reduce gas consumption when the VGA 77 is not in use a shut off valve in the inlet gas supply is recommended The gas supply can then be shut off when the VGA 77 is switched off During operation the gas supply pressure is automatically monitored by a built in sensor If the gas supply is interrupted or if the supply pressure falls below the specified minimum the indicator light will be illuminated and the gas supply to the reaction coil is shut off Operator intervention is required to fix the low gas pressure Agilent Vapor Generat
34. ed to 240 volts the table tells you that the switch setting should be AD This means the left switch should be up position A and the right switch should be down position D Agilent Vapor Generation Accessory VGA 77 User s Guide Voltage Switch setting Getting Started Switch positions Left Right 240 10 230 14 6 230 6 14 220 10 120 10 100 10 Figure 2 Side of the VGA AD AD BD BD AC BC se only a fuse of the correct Type am current rating Up Down Up Down Down Down Down Down MODEL VGA 77 Utiliser uniquement un fusible de puissance et sensibilit ad quat Benutzen Sie nur eine Sicherung der vorgeschriebenen Bauart und Stromst rke Usare solo fusibili dello stesso tipo e con le stesse caratteristiche Utilizar solamente un fusible del tipo e intensidad correctos MADE IN AUSTRALIA BY VARIAN AUSTRALIA PTY LTD NON PATIENT EQUIPMENT Z V SELECTOR 240 10 IEC 127 FS1 SHEET 5 FS2 e e WARNING Disconnect supply before servicing ATTENTION D connecter ou couper l alimentation avant toute intervention 20VA 49 61Hz ATTENZIONE SCOLLEGARE L Alimentazione prima di operare Agilent Vapor Generation Accessory VGA 77 User s Guide 230 14 6 230 6 14 220 10 120 10 100 10 WARNUNG Ziehen Sie vor jedem Eingriff das Netzkabel ATENCION Desconectar de la red
35. ent Vapor Generation Accessory VGA 77 User s Guide 51 Operation Automatic Operation Operation of the VGA 77 is not interlocked to the system In the event of gas supply failure pumping faults or if the reagent containers are emptied the program will not be automatically stopped and results from the program will not be analytically valid For ICP systems At the end of an automatic run the VGA 77 pump continues to run and gas continues to flow To avoid waste liquid flooding the system set the Pump rate at end of sequence on the Preferences page to a rate that ensures the removal of all waste liquid from the gas liquid separator typically 40 45 rpm 52 Observe the following general rules but refer to the appropriate instrument operation or system manual for specific operating instructions e The VGA 77 technique requires the use of acids at high concentrations You must therefore ensure that the sample probe on the autosampler is corrosion resistant The Agilent SPS 3 is fitted with a corrosion resistant probe This probe should always be used for VGA 77 applications e When connecting the autosampler to the VGA 77 uptake capillary ensure that the joint is leak free and offers minimal dead volume by keeping the connecting tube as short as possible The uptake from the autosampler to the vapor generator is the only connection required between VGA 77 and other system components no electrical interconnection is r
36. equired e Remember to enter a suitable delay time to allow for the extra time needed for the solution to emerge from the autosampler tubing Also check the stabilization times e Inthe software select the required number of replicate measurements to be taken and select the appropriate re calibration and reslope frequencies Agilent Vapor Generation Accessory VGA 77 User s Guide Operation e Load the autosampler with your analytical blank standard solutions and samples in the correct locations e Save your revised method e Before starting the analytical program carefully check all sampling parameters to ensure that they are correct Also check that the reagent containers are full Shutting Down 1 Turn off the flame torch as described in your instrument operation manual Leave the VGA 77 switched on You will also need to leave the ICP pump running 2 Run a concentrated hydrochloric acid solution through the system for 2 to 5 minutes then immerse the three uptake capillary tubes in a container of distilled water at least 200 mL and leave the pump running for 10 to 20 minutes to flush the system 3 Remove the capillary tubes from the distilled water Leave the pump running until the distilled water has been pumped through the system 4 Switch the VGA 77 off but leave the inert gas supply on at the regulator Open the pressure bar and swing the pump tube beds clear of the pump rollers Remove the pump tubes from the pum
37. eration Before starting the analytical program you must measure the analytical signal caused by the presence of analyte in e The acid and reductant solutions being pumped through the system e The analytical blank solution To do this 1 Place all three uptake tubes in a single container of distilled water Wait for about 40 seconds to allow the system to stabilize Perform an instrument zero 2 Leave the sample uptake tube in distilled water and place the acid and reductant uptake tubes in their respective reagent solutions Wait for about 40 seconds and measure the signal Any signal registered is attributable to analyte in the solutions being pumped through the system 3 Place the sample uptake tube in the analytical blank solution Wait for about 40 seconds and measure the signal This measurement is the total signal attributable to analyte in all solutions used acid reductant analytical blank 4 The measurements obtained in the previous two steps allow you to decide whether the blank signal is acceptable or not before using the blank solution to calibrate the instrument at analytical Zero You can now calibrate the system and measure your samples Samples can be presented to the system manually by dipping the sample capillary tube into a flask test tube or vial You can use the VGA 77 with non Agilent instruments and autosamplers The general procedure for using automatic samplers is given in the next section Agil
38. gure 4 Drain outlets To connect drain tubing to the drain outlet of an AA reagent module 1 Cuta suitable length of the plastic drain tubing supplied with your reagent module 2 Connect one end of the tubing to the large outlet underneath the module tray The tubing should be connected between the inner and outer rings on the outlet 3 Place the free end in your waste vessel Ensure that the tubing is free of kinks or sharp bends so that the waste liquid will drain freely into the waste vessel The end of the tube must be above the surface of the liquid If the end of the drain tube is submerged possible back pressure may lead to unreliable results 26 Agilent Vapor Generation Accessory VGA 77 User s Guide Getting Started ICP To connect drain tubing to the drain outlet of an ICP reagent module 1 Fita purple black pump tube to the instrument peristaltic pump as described in your instrument operation manual 2 Connect the inlet of the purple black pump tube to the drain outlet of the gas liquid separator in the ICP reagent module Refer to Page 41 for a diagram of the ICP plasma gas liquid separator 3 Attach a suitable length of the Nalgene tubing supplied to the outlet of the purple black pump tube from the ICP instrument 4 Place the free end of the Nalgene tubing into the waste container Ensure that the tubing is free of kinks or sharp bends so that the waste liquid will drain freely into the waste vessel Use
39. he product indicates that the product has been certified evaluated to CSA C US 61010 1 and UL 61010 1 10 Agilent Vapor Generation Accessory VGA 77 User s Guide Safety Practices and Hazards Color Coding The various indicator lights appearing on the instrument and any associated accessories have been color coded to represent the status of the instrument or accessory e A green light indicates the instrument is in normal standby condition e An orange light indicates that a potential hazard is present e A blue light indicates that operator intervention is required e A red light warns of danger or an emergency Electromagnetic Compatibility EN55011 CISPR11 Group 1 ISM equipment group 1 contains all ISM equipment in which there is intentionally generated and or used conductively coupled radio frequency energy which is necessary for the internal functioning of the equipment itself Class A equipment is equipment suitable for use in all establishments other than domestic and those directly connected to a low voltage power supply network which supplies buildings used for domestic purposes This device complies with the requirements of CISPR11 Group 1 Class A as radiation professional equipment Therefore there may be potential difficulties in ensuring electromagnetic compatibility in other environments due to conducted as well as radiated disturbances Operation is subject to the following two conditions 1 This
40. here is no KI contamination you can clean the tubing by flushing it well with distilled water Agilent Vapor Generation Accessory VGA 77 User s Guide 75 Maintenance and Spare Parts 76 If there is KI contamination you need to remove traces of KI as follows 1 Disconnect and remove the tubing 2 Soak the tubes in sodium hydroxide solution 0 5 w v Wash thoroughly with dilute hydrochloric acid and then wash thoroughly with distilled water 3 Allow the tubes to air dry in a dust free location 4 Reconnect the tubing An alternative method of removing traces of iodine from the tubing and gas liquid separator is to pump a freshly prepared 1 w v sodium thiosulfate solution through the system for 5 10 minutes You must then remove the thiosulfate by pumping distilled water through the system for 5 10 minutes Replacement Procedures Pump Tubes To remove the pump tubes use the reverse procedure of that given on Page 27 Reaction Coil To replace the reaction coil 1 Remove the gas liquid separator as described previously 2 Remove the thumbscrew holding the reagent manifold cover in place Remove the cover by pulling the top of the cover away from the manifold block and pushing the cover down 3 Remove the black fluoro elastomer sleeve from the end of the reaction coil Pull the end of the reaction coil through the hole in the manifold block then pull the reaction coil out of the channel 4 Slide the T conne
41. icals Contact with concentrated acids can cause severe chemical burns Always wear protective clothing and gloves while cleaning the separator To clean the gas liquid separator 1 2 3 Disconnect the tubing from the vapor outlet of the separator Disconnect the tubing from the sample inlet of the separator Carefully remove the rubber mounting strap holding the separator in place Disconnect the drain tubing from the drain in the bottom of the module You may now lift the separator out of the module Disconnect the tubing from the inert gas inlet of the separator If the separator has been exposed to solutions containing potassium iodide soak the separator in sodium hydroxide solution 0 5 w v for at least 30 minutes Wash thoroughly with dilute hydrochloric acid and then wash thoroughly with distilled water Allow to air dry in a dust free location If the separator has not been exposed to potassium iodide solutions it may be treated in the same way as the absorption cell To avoid KI contamination it is recommended that you dedicate a separate module to the analysis of those elements requiring pre reduction with KI i e As or Sb 7A Refit the separator into its mounting bracket secure it with the retaining strap and reconnect all tubing If the system is not to be used for some time the separator should be filled with distilled water Agilent Vapor Generation Accessory VGA 77 User s Guide Maintenance and S
42. ion Accessory VGA 77 User s Guide 21 Getting Started The indicator light is the single blue light on the top panel of the accessory If the indicator light turns on switch the VGA 77 off immediately rectify the gas supply problem then switch the VGA 77 back on If the indicator light again turns on you should call your Agilent field service engineer Power Supply Requirements The voltage selector mains receptacle power switch and fuses are located on the right hand side of the accessory Before connecting the mains power for the first time check that the correct power supply is available the voltage selector switches on the accessory are set correctly and that the correct fuses are installed and both fuses are of the same rating Shock and Fire Hazard Application of the wrong supply voltage connection of the accessory to an incorrectly wired supply outlet or lack of proper electrical grounding can create a fire or shock hazard that can cause death serious injury or serious damage to equipment 22 For power supply and fuse specifications refer to the Specifications section in Section 2 of this manual Refer to the Fuses section in the Maintenance chapter of this manual for details of how to inspect and replace fuses Selecting the Voltage Refer to the table immediately above the selector switches or consult the following table and set the switches as required For example if the accessory is connect
43. ixture You should refer to your spectrometer operation manual for details Explosion Hazard With the VGA 77 cell installed the burner will be lower than usual and a standard mixture or a fuel lean mixture may not ignite readily To avoid an explosive accumulation of fuel and oxidant in the sample compartment ALWAYS ensure that the gas mixture is fuel rich before operating the Ignite button 3 Ifa Mark VI burner is fitted tilt the absorption cell clear of the burner On older instruments this will also ensure that the igniter arm does not strike the cell If you leave the absorption cell in a fuel rich flame carbon particles may be deposited on the outside wall of the cell Under these conditions the cell can be permanently damaged by local overheating 48 4 Ignite the flame and adjust the fuel flow to give a lean flame If necessary lower the cell back to its normal position Conditioning the System The objective of this procedure is to condition the complete system and obtain a stable signal before calibrating the instrument and analyzing your samples This procedure should be carried out e When the system is first installed e After the system has been completely flushed and cleaned Agilent Vapor Generation Accessory VGA 77 User s Guide Operation e When a new absorption cell or flow through mercury cell is fitted e Whenever new pump tubes are fitted e When the reaction coil is renewed To con
44. lytical solutions should be stabilized by the addition of nitric acid 5 v v and hydrochloric acid 5 v v Prepare fresh standards daily If you are using the AA module Acceptable results can be obtained with the standard absorption cell however the flow through mercury cell is recommended since this will generally provide better analytical sensitivity and precision AA mercury determination is a cold vapor technique Mercury is best determined with a cold cell as the analytical sensitivity is reduced when the cell is heated Under no circumstances should the flow through cell be heated Heating the flow through cell may damage it If you are experiencing problems with carryover of water vapor into the cell or condensation in the cell heating of the flow cell can eliminate this One approach to heating the cell is to use the ETC 60 Electrothermal Temperature Controller programmed at 300 C Alternately another switch in heat source like a lamp can reduce the occurrence of this problem For locations where the discharge of mercury vapor in nanogram quantities is not permitted the standard absorption cell is not suitable and you should use the flow through mercury cell together with a suitable trap Refer to Page 42 Mercury be determined using stannous chloride as the reductant Reductant container SnCl 25 w v in HCl 20 v v Acid container H O Agilent Vapor Generation Accessory VGA 77 User s Guide 65 A
45. marked Inert gas A to reaction coil The nipple has a contoured profile Push the tubing onto the nipple until it covers all of the contoured section Agilent Vapor Generation Accessory VGA 77 User s Guide Getting Started Figure 3 Inert gas tubing from pump unit correctly connected to nipples on reagent manifold 5 Fit the end of the tube from the pump unit marked Inert gas B to the nipple near the bottom of the reagent manifold marked Inert gas B to separator The nipple has a contoured profile Push the tubing onto the nipple until it covers all of the contoured section NOTE To remove a module and replace it with another see instructions on Page 54 Installing the Drain Tubing WARNING Corrosive Liquid Waste solutions from the VGA 77 may contain concentrated acids which can cause severe burns Your waste vessel must be of durable acid resistant material Do not use a glass container Locate the vessel where it cannot be knocked over Empty it frequently Dispose of waste solutions in accordance with relevant safety practices Agilent Vapor Generation Accessory VGA 77 User s Guide 25 Getting Started AA There are two drain outlets located on the underneath side of the reagent module The outlet closest to the front face of the module is for tray overflow the other is to drain liquid from the gas liquid separator Drain tubing should be connected to both of these drain outlets Fi
46. nalytical Notes To prepare the SnClz solution add SnClz crystals to concentrated HCI and warm the mixture on a hot plate to complete dissolution before adding the water A piece of granulated tin added to the mixture will reduce any Sn to Sn and produce a clear solution Mercury suffers from memory effects as it adheres to plastic Keep concentrations low to minimize these memory effects An alternative method for mercury determination with AA uses the NaBH reduction procedure In this method it is preferable to use a lower concentration of sodium borohydride than would normally be used for the hydride forming elements The concentration of acid pumped through the VGA 77 system is generally not critical For ICP analysis ensure the spray chamber drain is clamped to avoid loss of the mercury analyte Reductant container NaBH 0 3 w v NaOH 0 5 w v Acid container 5 M HCl A lower analytical signal may be obtained with this method than with the stannous chloride method Selenium If arsenic and selenium are both to be determined see Page 69 Additional Notes at the end of this section The selenium in the sample must be in the inorganic form otherwise digestion will be necessary If digestion is necessary use acid digestion or ashing with an appropriate ashing aid Simple dry ashing is not recommended because selenium is highly volatile and recovery will be poor Agilent Vapor Generation Accessory VGA 77 User
47. nect the inert gas connections from the pump unit to the module refer to Page 24 Steps 4 and 5 Undo the locking screw on the bottom left of the VGA 77 frame Ensure the drain tube is completely empty and remove it from the module Lift the module up to release the pins at the back of the module from the VGA 77 frame then remove the module Immerse the removed module in distilled water and back flush the lines to clear them of acid remnants Dry the module in air before using again Install the required module following the procedures described in Section 3 Agilent Vapor Generation Accessory VGA 77 User s Guide Analytical Notes l e Y d ee o0 Q 9 5 Analytical Notes Q eo Background 56 s Factors Affecting the Formation of Hydrides 57 Acid Concentration 57 Oxidation State 57 Interferences 58 Contamination 59 Memory Effects 59 Background Absorption AA only 59 Laboratory Procedures 60 General 60 Standards 61 Reductant Sodium Borohydride 61 Pump Tubing 61 Sources AA only 62 Basic Methods 62 Antimony 62 Arsenic 63 Bismuth 64 Mercury 64 Selenium 66 Tellurium 67 Tin 68 Additional Notes 69 References 69 Additional References 69 Agilent Vapor Generation Accessory VGA 77 User s Guide 55 Analytical Notes Background The VGA 77 employs continuous flow technology where samples and liquid reagents are pumped together and mixed The gaseous reactions products are swept
48. ned only by Agilent field service engineers Use of the wrong supply voltage connection of the accessory to an incorrectly wired supply outlet or lack of proper electrical grounding can create a fire or shock hazard that can cause death serious injury or serious damage to equipment e Always use a 3 wire outlet with a ground connection that is adequately rated for the load The installation must comply with local state and national safety regulations e Before connecting the VGA 77 make sure the voltage selector is correctly set for the mains supply to which you are connecting the accessory A blown fuse should be replaced with one of the same size and rating stated in the text near the fuse holder Chemical Hazards Vapor generation methods of analysis involve the generation of toxic hydrides and use materials which are toxic highly corrosive or otherwise hazardous Careless improper or unskilled use of such materials can cause serious personal injury 8 Agilent Vapor Generation Accessory VGA 77 User s Guide Safety Practices and Hazards Always ensure that laboratory safety practices governing the use handling and disposal of such materials are strictly observed These safety practices should include the wearing of appropriate safety clothing In the VGA 77 system highly concentrated acids are pumped under pressure If a leak occurs acid could be sprayed from the system causing serious personal injury Always wear
49. ng installation refer to the following diagram to help you identify the different parts of your VGA and pump module 18 Agilent Vapor Generation Accessory VGA 77 User s Guide Getting Started Capillary tubes sample acid Slots provided for module reductant locating studs Gas liquid Vapor Q 9 separator outlet Pump o Rear tube bed Front i ume tube bed KU S gt Pressure bar At Do N Tu Drip w Hose 5 tray connected to Retaining gas supply Locking bracket for Screw pump tubes Cell rests Figure 1 VGA 77 with AA module installed Installation Checklist Use the following checklist to help you complete each step of the installation e Check that the correct gas supply is available and then connect your VGA 77 to the supply See Page 20 e Check that the correct power supply is available the correct fuses are installed and that the voltage selector is correctly set See Page 22 e Check the environmental requirements See Page 15 e Install the pump unit See Page 24 e Install the reagent module See Page 24 Agilent Vapor Generation Accessory VGA 77 User s Guide 19 Getting Started e Install the drain tubing See Page 25 e Install the VGA pump tubing See Page 27 e Install the burner clamps AA only See Page 29 e Install the cell AA only See Page 36 e Connect the gas liquid separator outlet to the inlet of the absorption cell AA or the sample introduction
50. only the purple black tubing for draining the ICP VGA 77 system Other smaller diameter pump tubing for example the black black tubing may not give a large enough drain flow rate The instrument peristaltic pump rate must be sufficient to remove all waste liquid from the gas liquid separator typically 40 45 rpm Installing the VGA 77 Pump Tubing To install the VGA 77 pump tubing 1 Open the pressure bar to release the front and rear tube beds Swing both tube beds clear of the pump rollers 2 Fitblack black tubing into the two innermost tubing slots and purple black tubing to the outer most tubing 3 Connect the inlet end of the innermost tube to the black rubber connector at the top of the reagent manifold marked Red gt Connect the other end to the black rubber connector near the middle of the reagent manifold marked Reductant lt Agilent Vapor Generation Accessory VGA 77 User s Guide 27 Getting Started Connect the inlet end of the middle tube to the black rubber connector at the top of the reagent manifold marked Acid gt Connect the other end to the black rubber connector near the middle of the reagent manifold marked Acid lt Connect the inlet end of the outer tube to the nipple at the top of the reagent manifold marked Sample gt Connect the other end to the nipple near the middle of the reagent manifold marked Sample lt The nipples have a contoured profile Ensure the
51. or additional reagent modules are listed on Page 79 About this Manual This manual includes instructions for installing using and maintaining the VGA 77 You should use this manual in conjunction with your spectrometer operation manual and any other component or accessory manuals for example a printer or sampler As you use this manual there are some procedures that will apply to specific applications only For example the section referring to Installing the Cell does not apply if you are using your VGA 77 with an Agilent ICP OES system The instructions will inform you when this occurs This manual contains basic information about using the VGA 77 with ICP OES and AA instruments For detailed information refer to the ICP Expert Il or SpectrAA Help Specifications 14 Environmental Your accessory is designed for indoor use only It is suitable for the following categories e Installation Category II e Pollution Degree 2 e Equipment Class I Agilent Vapor Generation Accessory VGA 77 User s Guide Introduction Humidity RH Condition Altitude Temp C non condensing Non operating transport 0 2133 m 5 45 20 80 0 7000 ft Operating within performance specifications 0 853 m 10 35 8 80 0 2800 ft 853 2133m 10 25 2800 7000 ft Power Information is correct at time of printing information on the back of the accessory is the most up to date Voltage 100 120 220 or 240 volts AC 10
52. oth to be determined from the same sample determine selenium first and avoid KI in samples or standards You can then determine arsenic after the KI reduction step and any other appropriate treatment such as the addition of urea if excess nitric acid is present Arsenic in the sample must be in the inorganic form otherwise digestion will be necessary If digestion is necessary use acid digestion ensuring no residual oxidizing acid is present see Oxidation States on Page 57 or ashing with an appropriate ashing aid Simple dry ashing is not recommended Prepare samples in at least 1 M hydrochloric acid Ensure that any analyte present as As is reduced to As by the action of potassium iodide at a concentration of 1 w v Reduction will take about 50 minutes at room temperature The reduction can also be carried out at 70 C in about four minutes however you must cool the samples and standards to room temperature prior to analysis Since the pumping rate may vary with solution temperature the VGA 77 pump will not operate correctly with hot solutions If the reduction step is omitted and the analyte is retained as As the analytical sensitivity is about 20 30 of that obtained for As If the original solution contains As reduction by potassium iodide is not required Reductant container NaBH 0 6 w v see also above NaOH 0 5 w v Acid container 5 to 10 M HCl Agilent Vapor Generation Accessory VGA 77 Use
53. p rollers and release them from the retaining bracket Ensure that they are kept completely clear of the rollers while you carry out the next step 5 Switch the VGA 77 on This will allow inert gas to flow through the entire system and thus minimize the possibility of residual solutions settling in the lowest section of the tubing Allow the inert gas to flow for about five minutes Switch off the VGA 77 and the ICP pump if necessary 7 Turn off the inert gas supply at the regulator Inert gas will flow through the separator even with the VGA 77 switched off Agilent Vapor Generation Accessory VGA 77 User s Guide 53 Operation 54 8 Clean all components as described on Page 71 9 Clean your instrument according to its operation manual Hot surface For AA systems Be careful when touching the absorption cell or the burner as they may be very hot Contact with these components can cause severe burns Always ensure that these components are allowed to cool before attempting to remove them from the sample compartment Changing Modules The modular design of the VGA 77 allows easy changing of modules To change modules 1 2 Shut down the system as described in the previous section Disconnect the sample inlet to gas liquid separator tubing from the sample inlet using the reverse of the connection procedure on Page 39 If you are removing an ICP module remove the drain tubing from the instrument pump Discon
54. pare Parts Tubing Pump Tubes When the system is not being used the pressure bar should be released the pump tubes removed from around the rollers and released from the retaining bracket This will minimize distortion of the tubes and help to prolong their working life To reduce mechanical wear of the pump tubes the outside of the tubes and the surface of the pump rollers should be sprayed daily with a silicone lubricant If the procedure specified in Shutting Down on Page 53 is followed the system tubing will generally remain clean however the efficiency of all pump tubes will eventually be degraded to the point at which they must be replaced You should regularly monitor the performance of each pump tube using flow rate measurements see Page 44 Discard the pump tubes as soon as the results of this monitoring become unacceptable The tubes connecting the black black pump tubes to the pump module may occasionally need to be replaced To do this cut four 2 cm lengths of the thinner black fluoro elastomer tubing supplied Place these over each end of two of the black black pump tubes Fluoro elastomer Tubing The fluoro elastomer tubing connecting the gas liquid separator to the absorption cell is particularly susceptible to contamination with potassium iodide To avoid this it is recommended that you dedicate a separate module to the analysis of those elements requiring pre reduction with KI i e As or Sb If t
55. pply 3 Place the three capillary tubes in a container of distilled water and switch the VGA 77 on The green Power indicator light is illuminated when the power is on Agilent Vapor Generation Accessory VGA 77 User s Guide Operation The peristaltic pump will run continuously once the power is switched on 4 Slacken both pressure adjusting screws Swing both tube beds against the pump tubing and close the pressure bar 5 Slowly tighten the front sample pressure adjusting screw until water is obviously being pumped through the tube Tighten the pressure adjusting screw a further half turn At this setting the pumping rate will be close to optimum Any further tightening of the screw will tend to reduce the pumping rate CAUTION Do not over tighten the pressure adjusting screws Excessive tightening will shorten the life of the pump tubes and could cause permanent damage to the pump At this stage inert gas may be seen bubbling out of both the other tubes This is a normal consequence of pressurizing the system and this situation is automatically corrected when you adjust the pumping pressure in these tubes To see if the liquid is being pumped smoothly you can deliberately create air bubbles by dipping the capillary in and out of the container 6 Repeat Step 5 with the rear pressure adjusting screw 7 Measure the uptake rate through the sample pump tubes The uptake rate should be within the range 6 8 mL min
56. quirements 20 Power Supply Requirements 22 Installing the Pump Unit 24 Installing a Reagent Module 24 Installing the Drain Tubing 25 Installing the VGA 77 Pump Tubing 27 Installing the Burner Clamp 29 Installation of Zeeman Adapter for 2407 2807 AA 33 Installing the Cell 36 Connecting the Gas liquid Separator Outlet 39 Connecting a Mercury Trap 42 Connection to the Autosampler 42 Unpacking Carefully open the shipping case and the enclosed packages Inspect all parts for damage in transit Any damage should be reported immediately You should have received the following e VGA 77 pump unit with mounting bracket if ordered for the 700 Series ICP OES instruments e Cover for the pump unit e Drip tray for the pump unit Agilent Vapor Generation Accessory VGA 77 User s Guide 17 Getting Started e Reagent module with two reagent bottles Two quartz cells with a length of black fluoro elastomer tubing AA only e Power cable e Tubing and connectors kit and spare 6 mm ID hose used to connect a mercury trap e Clear tubing 10 mm ID e Hose clamp and fuses e Cell holder for Mark 7 burner AA only Spare parts and their part numbers are given on Page 79 Installation Before proceeding with the installation you should read the Safety practices and hazards section at the start of this manual You should also be completely familiar with the safety procedures required for operation of your spectrometer Duri
57. r standard cell holder and cell inside sample compartment Cell Holder and Adapter Removal The standard cell holder must be removed to allow installation of the ETC 60 Workhead Mk 2 Agilent Vapor Generation Accessory VGA 77 User s Guide 35 Getting Started To remove the standard cell holder and adapter from the sample compartment 1 Lift the cell holder up to unhook the cell holder from the adapter mounting 2 Lift the adapter out of the sample compartment carefully avoiding the crossbar Installing the Cell This section applies to AA modules only While acceptable results for mercury can be obtained with the standard absorption cell Agilent s flow through mercury cell is recommended since this will generally provide better analytical sensitivity and precision Also for locations where the discharge of mercury vapor in nanogram quantities is not permitted the standard absorption cell is not suitable In these locations you should use the flow through mercury cell together with a suitable trap see Page 42 Sharp Objects Absorption cells are fragile Handle with care 36 Agilent Vapor Generation Accessory VGA 77 User s Guide Getting Started Installing a Standard Absorption Cell on a Mark 7 Burner To install a standard absorption cell on a Mark 7 burner 1 Lift the left hand spring and pass the left hand side of the cell through the cut out in the mounting bracket 2 Gently release the left hand sp
58. r s Guide 63 Analytical Notes Bismuth The presence of potassium iodide will severely suppress the analytical response Always ensure that the VGA 77 system is completely free of potassium iodide before performing bismuth determinations To avoid contamination it is recommended that you dedicate a separate module to the analysis of those elements requiring pre reduction with KI As and Sb Prepare samples in 1 M hydrochloric acid Reductant container NaBH 0 6 w v NaOH 0 5 w v Acid container 5 M HCI Higher acid concentrations will depress the analytical signal Mercury Traces of potassium iodide will interfere severely with the production of mercury vapor and the analytical response may be completely suppressed Always ensure that the VGA 77 system is completely free of potassium iodide before performing mercury determinations To avoid contamination it is recommended that you dedicate a separate module to the analysis of those elements requiring pre reduction with KI As and Sb 64 The mercury in the sample must be in the inorganic form otherwise digestion or use of releasing agents e g CdCl will be necessary If digestion is necessary use acid digestion or ashing with an appropriate ashing aid Simple dry ashing is not recommended as the mercury will be lost Agilent Vapor Generation Accessory VGA 77 User s Guide CAUTION Analytical Notes Dilute mercury solutions tend to be unstable all ana
59. r tubing supplied 3 Fit the large black fluoro elastomer tubing over the vapor outlet of the plasma gas liquid separator 4 Measure the minimum length of the supplied polyethylene tubing required to connect the free end of the black fluoro elastomer tubing to the sample inlet of the ICP nebulizer Neatly cut the required length and make the connection to nebulizer Z PVC tubing polyethylene tubing purple black pump tube fitted to peristaltic pump on instrument black acid flexible tubing connection from reaction coil Nalgene tubing to waste vessel argon inlet Figure 18 Plasma gas liquid separator for ICP module Agilent Vapor Generation Accessory VGA 77 User s Guide 41 Getting Started For mercury analysis using SnCl the drain peristaltic pump tubing from the spectrometer should be pinched to prevent loss of gaseous mercury through the pumped drain Connecting a Mercury Trap Use a sharp scalpel to cut two suitable lengths of the supplied 6 mm diameter clear PVC tubing and connect them to the two cell ports Connect the free ends to a I piece and then to a suitable mercury trap in accordance with local regulations governing the discharge of mercury vapor Fitting is easier if the ends of the tubing are first softened in hot water CAUTION Bubble type collectors must not be used because the VGA 77 is not designed to accommodate the excessive back pressure generated by such collec
60. re fitted e When the reaction coil is renewed e Before each analysis To set up the ICP 1 Ensure that the plasma is on and the peristaltic pump is operating 2 Allow the pump to operate for three or four minutes to stabilize the flow rates 3 Perform a time scan on the Time Display page See the online Help for more information View the signal as you alternate between the blank and top calibration standard Use the cursor to determine the suitable delay time required Due to the high sensitivity of the VGA 77 ICP OES system the upper concentration of standards used for calibration is limited by memory effects etc For hydride forming elements use a top standard of about 100 ppb 4 Continue the previous step until a consistent response is obtained When the response is consistent the system is ready for use Remember to optimize the operating conditions for your program Pay particular attention to sample delay stabilization and rinse times If a consistent response cannot be obtained within a reasonable time contamination is the likely cause Even slight contamination of the system can suppress production of hydride or mercury vapor If this happens stop the conditioning procedure and clean the system thoroughly before continuing Refer to Page 71 for VGA cleaning instructions and refer to your instrument manual for details on cleaning your ICP 50 Agilent Vapor Generation Accessory VGA 77 User s Guide Operation Op
61. ring 3 Liftthe right hand spring gently push the cell fully home and gently release the right hand spring The cell should be positioned as shown in Figure 15 4 Position the central inlet stem in the cell holder slot 5 Fit one end of the purple black pump tubing to the drain outlet of the plasma gas liquid separator see Figure 15 To the other end attach the drain tubing that leads to the waste vessel Ensure that the tubing is free of kinks or sharp bends so that the waste liquid will drain freely into the waste vessel Figure 15 Mark 7 burner with standard absorption cell in cell holder positioned on top Use only the purple black pump tubing with the VGA 77 and the ICP spectrometer Other pump tubing e g blue blue does not give a large enough drain flow rate 6 Adjust the speed of the peristaltic pump on the ICP spectrometer to ensure that liquid is being pumped out of the gas liquid separator faster than it is being pumped in by the VGA 77 Agilent Vapor Generation Accessory VGA 77 User s Guide 37 Getting Started Installing a Flow through Mercury Cell on a Mark 7 Burner To install a flow through mercury cell for mercury analysis in a Mark burner 1 Openthe spring clips and place the cell into position 2 Close the spring clips 3 Place the cell in its holder on top of the burner Installing a Standard Absorption Cell on Older Burners To install a standard absorption cell on older burners e g Ma
62. rk VI Mark VI A Mark V 1 Liftthe left hand spring clip and pass the central inlet stem through the hole in the mounting bracket while lowering the left side of the cell into position 2 Close the left hand spring clip 3 Openthe right hand spring clip gently push the cell fully home and close the right hand spring clip 4 Mount the cell in its holder on the burner Note that the slots on the cell holder must engage the mounting pegs on the burner clamp Installing a Flow through Mercury Cell on Older Burners To install a flow through mercury cell for mercury analysis on older burners e g Mark VI Mark VI A Mark V 1 Open the spring clips and place the cell into position 2 Close the spring clips 3 Mount the cell in its holder on the burner The slots on the cell holder must engage the mounting pegs on the burner clamp 38 Agilent Vapor Generation Accessory VGA 77 User s Guide Getting Started Connecting the Gas liquid Separator Outlet The VGA 77 is supplied with a length of black fluoro elastomer tubing AA only This tubing is used to connect the vapor outlet of the gas liquid separator to the inlet stem of the quartz absorption cell Itis good analytical practice to keep this tubing as short as possible Your VGA 77 should be located immediately in front of the instrument sample compartment AA Module If you are using the AA reagent module connect the outlet of the gas liquid separator
63. s tin determination by hydride generation The L cysteine reduces metal interferences and improves precision and sensitivity Some improvement in calibration linearity has also been noted The concentration of acid pumped into the VGA 77 is also critical in tin determinations and the analytical signal will be severely depressed at concentrations higher than 0 5 M See Page 57 Acid Concentration When determining tin using the AA technique it is essential to determine tin at the 286 3 nm wavelength and 0 2 nm slit since this will provide the best combination of analytical sensitivity and dynamic range The 235 5 nm line commonly used for flame and furnace AA gives very poor sensitivity and the 224 6 nm line shows very little increase in analytical response above approximately 0 3 absorbance Reductant container NaBH 0 6 w v NaOH 0 5 w v Acid container 0 5 M HCl Sample 1 Tartaric acid controlled pH 2 0 to 3 0 Alternative method Reductant container NaBH 0 5 w v NaOH 0 1 w v Acid container D I H O Sample 1 w v Tartaric acid 1 w v L cysteine Agilent Vapor Generation Accessory VGA 77 User s Guide Analytical Notes Additional Notes e If arsenic and selenium are both to be determined from the same sample determine selenium first and avoid KI in samples or standards You can then determine arsenic after the KI reduction step and any other appropriate treatment such as the addition of urea if ex
64. sion Spectrometer ICP OES involves the use of compressed gases and hazardous materials including corrosive fluids Unskilled improper or careless use of equipment can create explosion hazards fire hazards or other hazards which can cause death serious injury to personnel or severe damage to equipment and property Appropriate safety practices have been included in this operation manual and your spectrometer operation manual to help users operate the equipment safely Read all safety practices thoroughly before attempting to operate your system If the equipment is used in a manner not specified by the manufacturer the protection provided by the equipment may be impaired Do not position the equipment so that it is difficult to operate the disconnecting device Safety Practices and Hazards Hazard Warnings In addition to the hazard warnings contained in your spectrometer operation manual specific hazard warnings have been included in this operation manual These warnings state the hazard describe how to avoid it and specify the possible consequences of not following the instructions Read all warnings carefully and observe them at all times Electrical Hazards The VGA 77 contains electrical circuits devices and components operating at dangerous voltages Contact with these circuits devices and components can cause death serious injury or painful electric shock Covers that are retained by screws on the VGA 77 may be ope
65. system ICP See Page 39 e If necessary connect a mercury trap to the cell exhaust to comply with local regulations on the discharge of mercury vapor AA only See Page 42 Gas Supply Requirements A regulated supply of argon must be provided for your VGA 77 through the captive hose located in the right side panel You may also use nitrogen with the AA reagent module only Nitrogen must not be used with the ICP module as it may degrade the performance of the plasma 20 The gas supply must comply with the specifications in Section 2 The VGA is fitted with a 6 mm 1 4 in internal diameter reinforced plastic hose for connection to a standard barbed tail connector If you are in any doubt about the correct fittings to use consult your supplier Connecting the Gas Supply To connect the gas supply 1 Place the clamp over the free end of the captive hose and connect the free end of the captive hose to the metal barbed tail connector on the gas supply or to your gas supply regulator Agilent Vapor Generation Accessory VGA 77 User s Guide Getting Started 2 Tighten the clamp by adjusting the screw to secure the gas supply hose to the gas supply Adjust the pressure at the regulator to the recommended pressure CAUTION The argon supply pressure supplied to the VGA 77 must be 300 to 400 kPa 43 to 57 psi The 400 600 kPa 57 88 psi pressure required to supply argon to the ICP spectrometer is too high for direct conn
66. to the inlet of the cell To connect the outlet of the gas liquid separator to the inlet of the cell 1 Usea sharp scalpel to neatly cut an appropriate length of the black fluoro elastomer tubing supplied 2 Fit one end of the tubing over the inlet stem of the cell for Hg cell push tubing into the inlet and the other end over the vapor outlet of the gas liquid separator When the VGA 77 is not being used disconnect the tubing from the separator and store the cell in its holder at the front of the module Agilent Vapor Generation Accessory VGA 77 User s Guide 39 Getting Started Fluoro elastomer tubing black Vapor outlet Connection from reaction coil Lr f Argon inlet 0 Drain outlet To waste vessel Figure 16 Gas liquid separator for an AA module cell in cell holder at front of AA module Figure 17 Cell resting in module holder when not in use 40 Agilent Vapor Generation Accessory VGA 77 User s Guide Getting Started ICP Module If you are using the ICP reagent module connect the plasma gas liquid separator outlet to the ICP instrument It is possible to connect the vapor generator to the ICP OES systems while the plasma is on To connect the plasma gas liquid separator outlet to the ICP instrument 1 Set up the sample introduction system as described in the ICP operation manual 2 Usea sharp scalpel to neatly cut an appropriate length of the black fluoro elastome
67. tors Using bubble type collectors may lead to vapor being forced through the drain of the gas liquid separator and results in an unreliable signal Collectors of loosely packed metal foil may be suitable if they comply with local laws 42 Connection to the Autosampler The VGA 77 may be connected to an Agilent or compatible autosampler for automatic sampling Use a suitable piece of tubing to join the sample capillary on the VGA 77 to the tubing attached to the probe of the autosampler Agilent Vapor Generation Accessory VGA 77 User s Guide Operation 00 Q 9 4 Operation e o Setup 44 e si General Setup 44 Pump Adjustment 44 AA Setup 47 ICP Setup 49 Operation 51 Automatic Operation 52 Shutting Down 53 Changing Modules 54 Noxious Fumes and Corrosive Liquids Vapor generation methods of analysis involve the generation of toxic hydrides and require the use of materials which are toxic highly corrosive or otherwise hazardous Careless improper or unskilled use of such materials can cause serious personal injury Always ensure that laboratory safety practices governing the use handling and disposal of such materials are strictly observed These safety practices should include the wearing of appropriate safety clothing In the VGA 77 system highly concentrated acids are being pumped under pressure If a leak occurs acid could be sprayed from the system and cause serious personal injury Always wear
68. tube is pushed all the way home and covers all of the contoured section of the nipple Swing the rear tube bed against the rear tubes and ensure that a The bed bears evenly against the tubes b The tubes are seated squarely on the pump rollers Adjust the position of the tubes if necessary Repeat Step 6 with the front tube bed If you shorten the tails of the pump tubing you may reduce reagent and sample volume in the tubing thereby reducing sample consumption and reducing pre read delays The mixing coil is particularly required for mercury analysis Analysis times for hydride elements can be reduced by using a shorter length of the mixing coil tubing A separate module could be dedicated to this application 28 Agilent Vapor Generation Accessory VGA 77 User s Guide Getting Started Installing the Burner Clamp This section applies to AA modules only CAUTION Do not use the cell with a nitrous oxide acetylene burner The cell will be destroyed if exposed to a nitrous oxide acetylene flame Mark 7 Burner The VGA 77 is supplied with a cell holder for the Mark 7 burner The Mark does not require mounting brackets as the cell holder simply sits on top of the burner Figure 5 Mark 7 burner without holder To mount the cell holder on the Mark 7 burner 1 Position the seat cut outs of the holder over the back edge of the burner Agilent Vapor Generation Accessory VGA 77 User s Guide 29 Getting St

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