Evaluation of the Mark-VI Spray Chamber for Flame Atomic Absorption Spectrometry Application Note
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1. Author Michael Knowles Evaluation of the Mark VI Spray Chamber for Flame Atomic Absorption Spectrometry Application Note Atomic Absorption Introduction The atomization system nebulizer spray chamber and burner plays an integral part in the analytical performance of a flame AA spectrometer The spray chamber in particular plays a crucial role In promoting intimate mixing of the nebulized aerosol with the fuel Proper spray chamber design ensures the minimization of carbon build up burner blockage and volatilization interferences The spray chamber must also provide excellent drainage to reduce sample clear out times and signal spikes caused by irregular drainage In this paper the performance of the Agilent Mark VI spray chamber Is evaluated Performance aspects such as characteristic concentration drainage carbon build up burner blockage and the effect of interferences are investigated Description of Design In the Mark VI spray chamber Figure 1 aerosol production begins with a high effi ciency pneumatic nebulizer employing an inert platinum iridium capillary and a tan talum venturi The adjustable glass bead breaks up the aerosol droplets and pro vides the operator with control over the aerosol concentration The acetylene Is injected tangentially into the aerosol promoting intimate mixing As the mixture spi rals toward the burner It encounters a twin head mixing paddle which twice reverses the direction of rotat2. closer to the nebulizer venturi to give approximately 25 of the original absorbance The glass bead of the Mark VI spray chamber was adjusted closer to the venturi to give a matching absorbance and therefore an approximately equal aerosol concentration The results from this experiment are shown in Figure 6 The conventional spray chamber showed significant flame disrup tion at approximately 13 minutes by which stage the quality of the flame and the analytical signal had begun to deterio rate From Figure 6 it can be seen that a 50 reduction in analytical signal occurred within approximately 17 minutes THETA TTT TTT TTT TT TT TTT TT er TT 10 20 ASPIRATION TIME minutos CONVENTIONAL SYSTEM CJ MARK VI The measurement of silicon in a continuously aspirated solution of 5 sodium chloride The new Mark VI spray chamber showed only a gradual decrease in analytical signal during the 27 minute experiment The maximum signal deviation from the original absorbance over the time of the trial was 12 No significant flame dis ruption was observed during the operation of the Mark VI system Determination of Aluminium in Soft Drink The determination of metals In soft drink is complicated by the high sugar content of the samples Deposition of the sample aerosol within the burner jaws followed by evapora tion of water results in the build up of crystalline sugar Thermal degradation takes place leaving a carbon residue which may
3. tent the high vac nebulizer may be operated in the HIGH VAC position The high vac narrow bore plastic sample uptake cap illary is fitted to the nebulizer The nebulizer thimble is then adjusted anti clockwise to withdraw the platinum iridium neb ulizer capillary deep into the throat of the venturi This results in maximum suction through the venturi which minimizes the effects of hydrostatic head on sample uptake rate These effects occur because of the increasing distance between the sample liquid level and the nebulizer As the sample is con sumed the liquid level drops and the nebulizer is required to pump sample from an increasing distance The use of the high vac nebulizer in the high vac setting greatly reduces this effect 3 The aerosol concentration can also be regulated by adjusting the position of the glass bead The position of the glass bead is controlled by an adjusting screw which the operator can adjust while aspirating solutions into the flame If the glass bead is brought closer to the nebulizer venturi a greater pro portion of large droplets will be removed from the aerosol resulting in an aerosol consisting of fine droplets A fine droplet aerosol will pass through the burner jaws with mini mal deposition resulting in longer operation without burner blockage for samples with a high dissolved solids content By adjusting the glass bead away from the nebulizer venturi more aerosol with a greater proportion of large dropl
4. volatilization interferences In the evaluation of interference effects the flame stoichiometry and the height of the light path above the burner are important In this work such variables were adjusted initially to give maximum sensi tivity The glass bead was then adjusted closer to the nebulizer venturi to reduce the sensitivity to the desired level The performance of the Mark VI spray chamber was evalu ated for the interference effect of aluminium on magnesium absorbance A solution of 0 5 mg L magnesium containing 50 mg L aluminium was prepared The magnesium absorbance of this solution was compared to a 0 5 mg L magnesium solution not containing the aluminium interferent at various settings of the glass bead The Mark Vi spray chamber was compared to a conventional spray chamber system The results of this experiment are shown in Figure 8 The bar graph shows the suppression of the magnesium signal due to the interferent vertical axis versus the reduction in magne sium absorbance horizontal axis due to the adjustment of the glass bead closer to the venturi As the glass bead is wound in closer to the nebulizer it acts to break up the aerosol into smaller droplets therefore reducing the effect of volatilization interferences 100 60 REDUCTION IN Mg Abs BY BEAD ADJUST J MARKVI The effect of aluminium interferent on magnesium absorbance RSS CONVENTIONAL SYSTEM Figure 8 The Mark VI spray chamber sh
5. aluminium in a continuously aspirated solu tion simulating a steel sample dissolved by sodium pyrosulfate fusion The results from this experiment are shown in Figure 5 It is clear from these results that the Mark VI spray chamber showed less than a 10 variation in aluminum signal over the period of the experiment The conventional chamber how ever showed a 50 deterioration in analytical signal over the same period approximately 12 minutes Figure 6 During the experiment with the conventional spraychamber disruption of the flame by burner blockage was observed during the first three minutes of testing and the burner was covered by carbon build up after 11 minutes The burner used with the Mark VI spray chamber showed no significant signs of blockage during the experiment although the flame was more ragged after the experiment than before Determination of Silicon in 5 Sodium Chloride A 5 wgt vol sodium chloride solution containing approxi mately 90 ppm silicon was prepared to represent a high salt sample Typical sea water concentrations of sodium chloride are approximately 2 7 wgt vol The element silicon was chosen as it requires a fuel rich nitrous oxide acetylene flame for maximum sensitivity The combination of a high salt matrix with a rich flame will promote burner blockage The spray chambers studied were optimized to give maximum sensitivity for silicon The glass bead of the conventional spray chamber was set
6. block the burner particularly when the nitrous oxide acetylene burner is used In this experiment the determination of aluminium in a cola flavored soft drink was investigated The soft drink sample was degassed in an ultrasonic cleaning bath and then spiked to give an aluminium concentration of approximately 50 mg L The instrument was set up to perform 40 replicates of 20 seconds each with continuous sample aspiration The spray chambers studied were set to give maximum sensitivity and therefore highest aerosol concentration Under these conditions the burner would be expected to block more rapidly than If the systems were set up for high solids operation by adjusting the nebulizer and glass bead The results from this experiment are detailed In Figure 7 The conventional spray chamber showed a decline in absorbance of approximately 20 during the first 100 seconds of aspira tion and a decline of 50 after approximately 230 seconds The Mark VI spray chamber gave a much more stable absorbance for the first 230 seconds and a decline in absorbance of 50 after approximately 340 seconds The major cause of signal deterioration in both cases was the build up of carbon sugar deposits within the burner jaws It is evident from Figure 7 that the Mark VI spray chamber offers a substantially longer operation time It should be noted that each of the experiments for burner blockage employed continuous aspiration of the sample In practical operat
7. ets will be passed through the burner resulting in greater sensitivity Since a greater number of large droplets is passing through the burner slot the analytical signal will be more noisy and clogging of the burner may result when samples with a high content of dissolved solids are aspirated Adjustment of the glass bead to the maximum sensitivity position is therefore only recommended for samples with a low content of dis solved solids It should be noted that on any spraychamber samples containing thermally unstable oxidizing agents such as perchloric acid may cause the nitrous oxide acetylene flame to flash back with a loud noise The chance of such an event is greatly increased if the system is operated at high sensitivity If a flash back occurs using a SpectrAA instrument the pressure relief bung at the rear of the spraychamber will be ejected automatically triggering an interlock which safely shuts down the flame Moving the glass bead even further away from the venturi than the maximum sensitivity position results in a decrease in aerosol production and therefore a decrease in sensitivity However the proportion of large droplets remains higher than when the bead is close to the venturi and burner clogging will be worse than if the bead is close to the nebulizer venturi Several experiments were performed to evaluate the perfor mance of the Mark VI spray chamber for samples with high dissolved solids content Determination of Al
8. ffected only minimally by the presence of the interferent 0 3 0 2 Mo Abs 7 0 1 g Pa f 10 25 Mo CONCENTRATION ppm PZA MK6 0 MKE ALT O ALT Figure 9 The effect of sodium sulfate inteferent on molybdenum absorbance 7 0 no interferent present with interferent present ALT alternative conventional spray chamber MK6 Agilent Mark VI spray chamber Characteristic Concentration and Detection Limits In designing a spray chamber for flame AAS a balance must be achieved between performance for difficult samples and sensitivity It has been shown that the production of a large proportion of small aerosol droplets provides the best perfor mance in the presence of interferents and for difficult sam ples In achieving this performance poorer sensitivity may be observed as large aerosol droplets are removed from the aerosol For most elements the dominant source of noise at normal working levels is analyte flicker noise arising from fluctua tions in the aerosol produced by the spray chamber The pro duction of a uniform small droplet aerosol reduces analyte flicker noise and produces a more stable signal Lower detection limits can generally be achieved if the sensi tivity for an element can be increased The Mark VI spray chamber can be operated with the mixing paddle in place for best performance for high dissolved solids samples and for general use and with the mixing paddle out fo
9. g a conventional spray chamber The floor of the Mark VI spray chamber slopes steeply to a recessed wide bore drainage tube Drainage of aerosol droplets deflected from the glass impact bead is aided by a ceramic face plate fitted to the nebulizer bung This drainage plate is very easily wetted and droplets in contact with this surface drain rapidly to waste and are not re nebulized Significantly the drainage tube is placed at the point of maxi mum drainage demand beneath the adjustable glass bead The shape of the glass bead arm has been optimized so that solution draining from the bead drips almost directly into the drainage hole In a study of aerosol deposition patterns in a spray chamber O Grady et al 2 showed that the majority of aerosol is deposited within the first third of the spray cham ber with or without the glass bead in place For spray cham ber designs with the drainage tube placed under the burner at the rear of the spray chamber the majority of the drained fluid must traverse the length of the spray chamber before it can be drained Figure 3 shows the drainage performance of the Mark VI spray chamber for a 1000 ppm copper solution using the air acetylene flame After aspirating the copper solution for ten seconds distilled water was immediately aspirated Figure 3 a shows that the drainage Is rapid and complete the signal returning to the baseline and showing no sign of spik ing afterwards Figure 3 b shows
10. gas velocity increases through the con stricted slot Samples containing high concentrations of salt for example sea water or sugar for example soft drinks are typical of samples which cause blockage The problem of burner blockage due to solids deposition can be minimized by optimizing spray chamber design The action of the mixing paddle and the glass bead to promote the forma tion of an aerosol of a large number of small droplets ensures passage through the burner slot with minimal deposition Performance of the atomization system for difficult samples can be further improved by proper operation If high solids samples are to be analyzed using a high vac nebulizer the nebulizer should be operated in the HIGH SOLIDS position In this position the platinum iridium capillary of the nebulizer is advanced through the throat of the nebulizer venturi as shown in Figure 4 High solids position Figure 4 Adjustment of the hi vac nebulizer In this position there is less opportunity for aerosol to deposit In the venturi and is therefore ideal for operation with sam ples containing a high percentage of dissolved solids Adjustment to the HIGH SOLIDS position is simply achieved by rotating the nebulizer thimble fully clockwise and fitting the wider bore plastic sample uptake capillary to the nebu lizer The wider bore sample capillary is supplied with the nebulizer For solutions which do not have a high dissolved solids con
11. ion promoting further mixing and large droplet removal The design incorporates a steeply angled floor and a wide bore drainage tube to ensure liquid is rapidly drained from the spray chamber The nebulizer bung is fitted with a ceramic face plate This ensures any droplets deflected from the glass bead are not re nebulized Re nebulization of droplets would cause noise spikes In the analytical signal 1 Agg Agilent Technologies Throughout the system high grade polypropylene is used to ensure chemical resistance Flame safety Is maintained by a comprehensive series of interlocks monitoring the nebulizer bung the pressure relief bung the liquid trap the burner the flame shield and the flame itself The Mark VI spray chamber is compatible with Agilent nitrous oxide and air acetylene burners of the Mark 5A or Mark 5 types cm AY ap iif y t sin NS x A N B Y 4 Na i or VU i LY KV vs act ae fi Y Vi n m A IN EA N T 3 oS aon a N The Agilent Mark VI spray chamber 1 nebulizer 2 ceramic face plate 3 adjustable glass bead 4 drainage tube 5 duel head mixing paddle 6 enhanced slope floor Figure 1 Experimental In the following evaluations the Mark VI spray chamber was tested using a SpectrAA 40 atomic absorption spectrometer Standard recommended conditions of wavelength slit width and lamp current were used unless otherwise stated Instrument settings such as bur
12. ion rinsing between samples with distilled water Is recommended Rinsing between samples would greatly extend the period for which a spraychamber could be operated without burner blockage occurring 1 3 5 ASPIRATION TIME minutes CONVENTIONAL SYSTEM 1 VARIAN MARK VI Figure 7 The measurement of aluminium in a continuously aspirated soft drink sample Interferences There are many types of interferences that occur in flame AAS that can be minimized by effective spray chamber design Browner et al 4 have studied the relationship between aerosol droplet size and the atomization process Further work 5 investigated the effect of droplet size on interferences in flame AAS A number of interferences were investigated including the effect of phosphate interference on calcium and aluminium interference on magnesium absorbance Ham and Willis 6 found that many volatilization interfer ences could be minimized by the removal of large droplets from the aerosol This will result in a reduction in sensitivity The interference of aluminium on magnesium absorbance due to the formation of magnesium aluminate can be mini mized by reducing the average sample aerosol droplet diameter The performance of the Mark VI spray chamber in minimizing the effects of such interferences has been investigated The adjustable impact bead and the dual head mixing paddle were used in combination to reduce aerosol droplet size and there fore minimize
13. ner position gas flows and nebulizer setting were adjusted to give maximum sensitivity Where stated the glass bead was then adjusted closer to the nebulizer venturi to reduce sensitivity The spraychamber and burner were cleaned thoroughly prior to use The ceramic face of the nebulizer bung was cleaned by immersing the nebulizer bung in a detergent solution in an ultrasonic bath for several minutes The mixing paddle was cleaned in chromic acid in an ultrasonic cleaning bath Care must be taken in handling chromic acid Agilent hollow cathode lamps were used Standard solutions were prepared in dilute nitric acid in de ionized distilled water Agilent Mark 5A burners were used Performance Evaluations Drainage A fully optimized spray chamber should be designed so that residual solution can drain quickly to waste The system should be designed so that solution is not re nebulized as it drains causing noise spikes in the analytical signal Poor spray chamber drainage will require the use of long delay times between samples to minimize carry over of solution An example of the drainage problems associated with poor spray chamber design is shown in Figure 2 Noise spikes characteristic of poor drainage are observed for greater than 100 seconds after the solution aspiration is stopped l SIGNAL EFAPNICS 208 ooo B 20 6 8 TIKE sec 180 8 Figure 2 Signal spiking due to poor drainage of a high concentration aluminium standard usin
14. ovember 1 2010 AA080 Agg Agilent Technologies
15. owed a slightly higher magne sium absorbance than the conventional system at maximum sensitivity indicating that the smaller aerosol droplet diame ter produced reduced the effect of the aluminium interferent Greater benefit was realized when the glass impact bead was brought closer to the nebulizer After reducing the analytical signal by 80 using the glass bead the Mark VI showed only a 13 reduction in absorbance due to interference while the conventional system showed a suppression of 32 In a second experiment the enhancement effect of sodium sulfate interferent on molybdenum absorbance was investi gated 7 The enhancement effect of sodium sulfate on molybdenum absorbance using the nitrous oxide acetylene flame has been previously reported 8 For the determination of molybdenum in samples containing sodium sulfate such as soil standard additions may be necessary to overcome the enhancement effect when a conventional spray chamber is used Solutions of 10 25 and 50 ug mL molybdenum were prepared with and without sodium sulfate interferent The enhance ment effect was then investigated at the different molybde num concentrations using the Mark VI and a conventional spray chamber The results of this experiment are shown in Figure 9 It can be seen that the interference effect is severe at all molybdenum concentrations using the conventional spray chamber The molybdenum absorbance obtained using the Mark VI spray chamber ts a
16. r maximum sensitivity and detection limits If the Mark VI spraychamber is operated with a nitrous oxide acetylene flame without the mixing paddle the benefits of reduced carbon build up and a more stable signal may not be seen The performance of the Mark VI spray chamber was evalu ated for a number of elements in terms of characteristic con centration detection limit and analyte signal noise For each of these tests the Mark VI spraychamber was operated with the mixing paddle in place This gives an indication of the per formance that can be achieved using the Mark VI spraycham ber with the benefits of the mixing paddle Better characteris tic concentrations and detection limits could be expected with the mixing paddle removed The performance of the new spray chamber was compared to a conventional system Tables 2 a and b detail the results of this comparison for detection limit and characteristic concentration The detection limits given in Table 2 b are based on twice the standard deviation of 10 replicate absorbance measure ments of a very low concentration standard solution of the element Note that IUPAC recommendations state that either two or three standard deviations may be used in the calcula tion of detection limits but the number used must be stated end three Is the recommended figure Two standard devia tions was used in this work so that detection limits could be compared to values previously published In the litera
17. rations of 5 seconds each Each of 31 samples was therefore aspirated for 55 seconds each Figure 11 a shows the first fourteen minutes of operation Figure 11 b shows the second fourteen minutes of opera tion It can be seen from Figure 11 that the signal remained completely stable over 28 minutes The analytical signal did not deviate by more than 0 5 from the initial absorbance over this time a nnE cine CIGNAL GRAPHICS 1 68 v to D py apy eee aisis pt te es ee ee fas 8 8 TIME sec 588 9 Figure 11 a CIGNAL GRAPHICS ow D 8 28 be Kees egtects genunertan Borapgeene se ce Tiener ppoperteteei oe i 8 8 TIME sec 588 8 Figure 11 b Figure 11 Long term signal stability for chromium in 5 sugar solution a 0 500 seconds b 500 1000 seconds Conclusion The Agilent Mark VI spray chamber has been evaluated In terms of drainage carbon build up burner blockage and Interferences characteristic concentration and detection limits and signal stability Effective drainage is achieved by a steeply angled chamber floor a ceramic nebulizer face plate and a recessed wide bore drainage tube The production of a smaller drop size aerosol reduces burner blockage and reduces signal noise and improves long term signal stability The mixing paddle pro motes better fuel and oxidant mixing resulting in reduced carbon build up Characteristic concentrations and detection limits are competitive with alternative s
18. rosol concentration passing through the burner is similar It can be seen that a more stable and less noisy signal is obtained using the Mark VI spray chamber compared to the conventional system This reduction in signal noise end drift is due to the production of a more uniform small droplet aerosol Tn I a ge eg a am SIGHAL GRAPHICS 8 55 an d poe s ta i e 5 i 5 pe hen are i n5 f ae tt a bpi 7 i b TIRE isec zt 8 Figure 10 a SIGHAL ERAPHICS e l l a I oy te E nno ee ee Pia ies MS ORS Soe Se eee Ie Stet we oe E rq Ee wee oe ge mm cate Iie POS Ow aP Es Pett eee mnene ue ae as A a cae i a ae wl Fio 7 oe es 4 PR e s ra e 9 8 l t sec 28 8 Figure 10 b Figure 10 Comparison of aluminum signal noise using a conventional spray chamber and b the Agilent Mark VI spray chamber An example 10 of the signal stability of the Mark VI spray chamber is shown in Figure 11 using a fuel rich air acetylene flame for chromium A solution of 10 pg mL chromium was prepared In 5 wgt vol sugar solution The sensitivity of the system was then reduced to 30 of the maximum by adjusting the glass bead closer to the nebulizer venturi The combination of the glass bead and the mixing paddle produce a fine aerosol and a stable analytical signal Thirty one samples of the solution were aspirated with 5 sec onds delay time and ten integ
19. sol and the fuel ensures that a correct and even flame stoichiometry is achieved across the burner The occurrence of localized regions in the flame which are rich in acetylene is avoided therefore mini mizing carbon build up The Mark VI spray chamber can be operated with an acetylene rich flame for longer periods than conventional systems before carbon builds up on the burner Further with the Mark VI system substantially reduced fuel flows can be used to obtain maximum sensitivity resulting in reduced carbon build up This effect is shown in Table 1 The fuel and oxidant levels required to achieve maximum sensitiv ity for several elements using the Mark VI and a conventional spray chamber are listed The results indicate that a signifi cantly lower fuel level is required when using the Mark VI system Table 1 Spray Chamber Comparison Gas Flows Required for Maximum Sensitivity Nitrous oxide acetylene L min Mark VI Conventional Element N 0 Acet N 0 Acet V 11 0 7 5 11 0 8 5 Al 11 0 7 0 11 0 7 8 Si 11 0 7 7 11 0 8 0 Burner Blockage From High Solids Solutions A common problem in flame AAS is the physical obstruction of the burner slot by solids deposited from the sample aerosol Solvent evaporates from aerosol droplets deposited inside the burner jaws leaving solid material Such deposits act to accumulate more solids Eventually disruption of the flame results the noise level may worsen and the flame may blow out as the
20. this drainage on a smaller time scale indicating that drainage is complete within 5 seconds of aspirating the blank STGHAL ERAFHIES ne ne I A 30 i ni TINE secd ae Figure 3a Drainage of 1000 mg L copper solution using the Mark VI spray chamber 10 sec aspiration shown on 120 second time scale 1000 ppm H O j i f 1 e EAE A A TINE sec 18 A Figure 3b Drainage of 1000 mg L copper solution using the Mark VI spray chamber 10 sec aspiration shown on 30 second time Carbon Build Up Flame disruption due to carbon build up may occur when a nitrous oxide acetylene flame is used Carbon build up is caused by the thermal breakdown of acetylene molecules and is therefore aggravated by the use of acetylene rich flames The build up of carbon usually occurs above the jaws of the burner but may actually block the slot if the deposit is not removed The carbon deposits may then act as a nucleus for the precipitation of dissolved salts and solids causing further blockage The problem of carbon build up can be minimized by e Proper burner cleaning e Allowing the burner to warm up on a lean flame before analysis e Using the maximum total gas flow consistent with the required flame stoichiometry e Using the leanest possible flame Spray chamber design can also contribute to minimizing carbon build up In the Mark VI spray chamber intimate mixing between sample oxidant aero
21. ture Table 2 Spray Chamber Comparison Characteristic Concentration and Detection Limits Table 2 a Characteristic Concentration mg L Element Mark VI Conventional Cu 0 04 0 03 Pb 0 10 0 08 Al 0 73 0 74 Table 2 b Detection Limit mg L Element Mark VI Conventional Cu 0 003 0 004 Pb 0 011 0 017 Al 0 03 0 035 9 Al 0 05 0 04 Ca 0 001 0 006 V 0 085 0 045 V 0 074 0 073 It can be seen from the results in Table 2 a that the charac teristic concentration figures obtained from the Mark VI spray chamber are competitive with conventional systems even with the mixing paddle in place A degree of variability can be expected in the detection limit figures The ability to achieve the best results will rely on operator ability to fully optimize the system The detection limit results for aluminium 9 and vanadium are presented In duplicate In Table 2 b to indicate the degree of variability that can be expected from such figures Analyte Signal Noise and Stability Several experiments were conducted to evaluate the analyte signal noise observed with different spray chamber systems for a number of elements The same standard solutions were examined on different spray chambers using the same spec trometer hollow cathode lamp and burner Figure 10 shows a comparison of the signal obtained for aluminium on the Mark VI spray chamber and a conventional system Note that the absorbances are approximately the same indicating that the ae
22. uminum in Steel The determination of refractory elements in steel presents a number of problems The high temperature nitrous oxide acetylene flame Is generally preferred but the nitrous oxide acetylene burner is more susceptible to slot blockage and carbon build up A sample of steel dissolved by sodium pyro sulfate fusion was recommended as a difificult test for the Mark VI spraychamber A solution simulating such a sample was prepared to test the new spray chamber The sample consisted of 50 pg mL aluminium 25 g L iron 20 g L sodium pyrosulfate 40 mL L conc hydrochloric acid The performance of the Mark VI spray chamber was com pared to a conventional spray chamber The instrument was established to give maximum sensitivity highest aerosol con centration and then the glass bead was brought closer to the nebulizer venturi to improve the high solids capability of the system The glass bead was adjusted closer to the venturi to give approximately 20 of the maximum sensitivity for alu minum on the Mark VI spray chamber The conventional chamber was adjusted to give a matching absorbance there fore matching the aerosol concentration passing through the burner slot PEN j ie ae re Doe 8807S eA oa Peres Sane ace 0 1 oF TRN 4 ss J is l A Ret b 9 054 ie 5 u 4 L 12 ASPIRATION TIME minutes i C MARK VI CONVENTIONAL SYSTEM Figure 5 The measurement of
23. ystems even with the mixing paddle in place and volatilization interferences are substantially reduced Acknowledgements The author would like to thank Bernard Field Varian United Kingdom Michel Remacle Varian Belgium and Brian Frary Varian Australia for some of the data used in this publication References 1 T C Dymott and D S Widmer International Labmate 8 4 1983 O Grady I L Marr and M S Cresser Analyst 110 1985 129 B T Sturman J An At Spec 1 1 1986 55 R F Browner A W Boorn and D D Smith Anal Chem 54 1982 1411 D D Smith and R F Browner Anal Chem 56 1984 2702 N S Ham and J B Willis Spectrochim Acta 40B No s 10 12 1985 1607 M Remacle Varian Belgium Private Communication 1987 J C Van Loon At Abs Newsletter 11 No 3 1972 60 B Field Varian United Kingdom Private Communication 1987 B Frary Varian Techtron Australia Private Communication 1988 For More Information For more information on our products and services visit our Web site at www agilent com chem www agilent com chem Agilent shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishing performance or use of this material Information descriptions and specifications in this publication are subject to change without notice Agilent Technologies Inc 1988 Printed in the USA N
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Evaluation of the Mark VI Spray Chamber for Flame Atomic Absorption Spectrometry Application Note