Influence of the Matrix on the Atomic Absorption of a Transversely Heated Graphite Atomizer

Voloshin, A. V.; Gil'mutdinov, A. Kh.; Zakharov, Yu. A.

doi:10.1023/b:japs.0000016315.45853.4a

Cited by 2 publications

(7 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is seen that the proposed method has an essential advantage, as to the elimination of matrix interferences, over the HGA atomizer operating under the STPF conditions [3]. This conclusion also holds for the THGA transverse-heating atomizer [4] in the case of the chloride matrix. The advantages of the THGA as to the elimination of sulfate interferences are largely determined by its constructional arrangement and the application of a palladium-magnesium matrix modifier, which makes it possible to considerably increase the pyro- Fig.…”

supporting

confidence: 55%

“…Upon addition to the lead sample of 400 µg of NaCl or 35 µg of K 2 SO 4 the automatization from the wall is accompanied by nonselective absorption and depression of the analytical signal ( Fig. 1a and b), which are not eliminated even under the STPF conditions [3,4]. The FC stage on the probe eliminates interferences due to the removal of a considerable part of the matrix and the displacement of the nonselective absorption signal ( Fig.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Concentration of Analytes on the Probe in an Electrothermal Atomizer

2005

Self Cite

View full text Add to dashboard Cite

543.42To increase the sensitivity of the atomic-absorption analysis, we suggest concentrating the analytes on a tungsten probe through multiple fractional condensation of the sample vapor obtained in a graphite atomizer. This technique makes it possible to additionally reduce the matrix interference. To this end, a sample with a high interference level is preliminarily diluted to the level eliminated by the stage of fractional condensation and then concentrated on the probe. The influence of potassium sulfate on the Pd, Cd, and Ag absorption has been reduced by a factor of 1.5-4.5 and that of sodium chloride -by a factor of 4-300 compared to the influences in the longitudinally heated atomizer with a platform, a modifier, and a background corrector based on the Zeeman effect. In a number of cases, advantages over the transversely heated atomizer have been attained.Introduction. For atomic-absorption determination of elements whose concentration is below the detection limit of the spectrometer, the sample concentration is used. If the content of interfering components in the sample is small, then concentration is carried out directly in the electrothermal atomizer, dosing multiply and drying before the sample atomization step and absorption measurement. Otherwise, to eliminate matrix interferences, one has to take recourse to more laborious and expensive methods of extraction or flowing injection with a concentration of elements in selectively sorbing microcolumns [1]. Earlier [2], we reported on a decrease in matrix interferences in a graphite tubular atomizer by a few orders of magnitude by means of the stage of fractional condensation (FC) of elements on a tungsten probe. At this stage the matrix volatilizes to a considerable extent from the atomizer and reevaporation of elements from the probe occurs without its influence. The probe set at the FC stage over the dosing port of the atomizer traps the analytes from the outgoing flow of sample vapors and lets the matrix components pass. However, beginning with a certain matrix content in the sample, such a selective trap loses its efficiency. This can be due to the formation in the gaseous phase of molecules and condensed particles of the matrix, which, trapping the elements, prevent their deposition on the cold surface of the probe. To get out of such a situation, it is logical to dilute the sample to a level acceptable by the probe and realize several sequential stages of FC, simultaneously concentrating the element and reliably removing the matrix. In the present work, this technique has been used for lead, cadmium, and silver with a high content of chloride and sulfate matrices that are problematic to analyze directly in production-type graphite atomizers, even those using a platform, a modifier, and a Zeeman-effect background corrector, i.e., under the conditions of the universally accepted concept of the stabilized temperature platform furnace (STPF) [3].The experiments were performed on an AAS-30 atomic-absorption spectrometer with a deuterium background co...

show abstract

supporting

confidence: 55%

mentioning

confidence: 99%

Concentration of Analytes on the Probe in an Electrothermal Atomizer

2005

Self Cite

View full text Add to dashboard Cite

show abstract

“…It is known that the absorption signal of lead at OA exhibits no interferences if the amount of salt in the sample does not exceed 40 µg. The use of a matrix modifier and the pyrolysis step, i.e., meeting the conditions of the "sta bilized temperature furnace with a platform" (STPF), allows the analyst to eliminate interferences only from 150 µg NaCl [13]. If TPA is used and sample vapors are collected by the probe within the whole five sec onds of the primary atomization step, the secondary impulse of lead can be recorded without interferences in the presence of 600 µg of NaCl in the sample.…”

Section: Resultsmentioning

confidence: 99%

“…In the OA of the sample, the integral atomic absorption signal remains unchanged if the amount of the salt reaches 1.5 µg. The use of a modifier ensures the stability of the signal up to 75 µg of sulfate [13]. Figure 3a shows how the addition of 110 µg of K 2 SO 4 reduces the atomic absorption signal by several times (compare with spec trum 1 in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Such version of TPA we will name time selective (STPA), because it is based on the choice of an instant for probe opera tion. The stability of the analytical signals to interfer ences in different atomizers is traditionally checked using chloride and sulfate matrices and highly volatile elements [6,7,[13][14][15][16], because they exhibit stronger effects than medium and hardly volatile elements. Therefore, we studied the behavior of Pb, Cd, and Tl in the presence of excess NaCl and K 2 SO 4 for compar ison with the results obtained previously in one step and two step atomizers.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Electrothermal atomic absorption spectrometry with two-step probe atomization and primary absorption signal feedback

Zakharov

Kokorina

2012

J Anal Chem

Self Cite

View full text Add to dashboard Cite

A method is proposed to reduce the relative detection limits for elements in an atomic absorption spectrometer with a graphite furnace and two step probe atomization, based on using feedback between the absorption impulse of primary sample atomization and probe fixation in the position for vapor fractionation. Deposition of sample fractions on the probe, which interferes with measuring the analytical signal, is reduced. The relative limits of the direct detection of Pb, Cd, and Tl in NaCl and K 2 SO 4 are lowered by more than one order of magnitude in comparison to the atomization of such salts under the conditions of a tem perature stabilized furnace with a platform. The detection limits are 10 -7 to 10 -8 wt %. The relative standard deviation of the analytical signals does not exceed 5%, which is appropriate for the measurement of concen tration.

show abstract

Influence of the Matrix on the Atomic Absorption of a Transversely Heated Graphite Atomizer

Cited by 2 publications

References 2 publications

Concentration of Analytes on the Probe in an Electrothermal Atomizer

Concentration of Analytes on the Probe in an Electrothermal Atomizer

Electrothermal atomic absorption spectrometry with two-step probe atomization and primary absorption signal feedback

Contact Info

Product

Resources

About