Effect of nickel and palladium as chemical modifiers and influence of urine matrix on different chemical species of selenium in electrothermal atomic absorption spectrometry

Laborda, Francisco; Viñuales, Jorge E.; Mir, J. M.; Castillo, Juan R.

doi:10.1039/ja9930800737

Cited by 19 publications

(10 citation statements)

References 22 publications

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“…At a temperature of 300 ³C it is lost completely. A similar situation was also found by other workers 9,12 who, using mass spectrometry, found that the main volatile forms are SeO 2 , SeO, Se 2 , and Se(OH) 2 . Addition of palladium modi®er, in the form of nitrate into nitric acid solution and in the form of chloride into hydrochloric acid solution, stabilizes selenium up to 1200 ³C (curves C and D).…”

Section: Seleniumsupporting

confidence: 88%

Behaviour of selenium and tellurium in the presence of various modifiers in electrothermal atomic absorption spectrometry

Pszonicki¹,

Skwara²

1999

J. Anal. At. Spectrom.

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The behaviour of selenium and tellurium dissolved in nitric, hydrochloric or perchloric acid and in their mixtures was tested during the atomization process in a graphite tube with a platform. Palladium, magnesium nitrate and their mixture were used as the modi®ers. It was found that palladium is a good modi®er for selenium only in pure nitric or hydrochloric acid solutions. In perchloric acid and in all mixed media, selenium in the presence of palladium is lost almost completely during the evaporation and drying of the sample. Magnesium nitrate used as modi®er is superior to palladium since it thermally stabilizes selenium in all the media investigated up to 1200 ³C. A different situation was found for tellurium. Both modi®ers protect it in all solutions against losses during the ®rst stages of the atomization process; however, magnesium stabilizes it only to 800 ³C whereas palladium is effective up to 1200 ³C. If a mixture of both modi®ers is used in the determination of selenium and tellurium, then its activity is identical with the activity of the component of the mixture that is the more effective when the components are applied individually as modi®er. No effects suggesting a joint action of both components were found. The mechanism of activity of the modi®ers tested is discussed.

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Section: Seleniumsupporting

confidence: 88%

Behaviour of selenium and tellurium in the presence of various modifiers in electrothermal atomic absorption spectrometry

Pszonicki¹,

Skwara²

1999

J. Anal. At. Spectrom.

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“…These problems arise because (a) selenium exists in several different chemical forms in urine, each of which has different thermal stabilization characteristics [9], (b) whatever form of selenium is introduced into the furnace, it is relatively easy to lose selenium as a volatile species during thermal pretreatment, and (c) urine contains several matrix components that interfere in the measurement, such as sulfate, phosphate and iron. Several groups of workers have reported recently on the problems arising from the different chemical forms of selenium, and the difficulty of selecting a chemical modifier that is effective in conferring thermal stability on the selenium from each of the different sources [5,7,10]. The results of these studies were not particularly encouraging.…”

Section: Introductionmentioning

confidence: 37%

“…The characteristic mass of Se is around 25-35 pg [5,7,8] leading to estimates of detection limit values of about 1 mg l −1 in the solution introduced into the furnace. This would appear to be adequate for the determination of selenium in urine, as the lowest value in the range normally encountered is around 10 mg l −1 [1].…”

Section: Introductionmentioning

confidence: 99%

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Determination of Se in urine by flow injection hydride generation electrothermal atomic absorption spectrometry with in-atomizer trapping

Tyson¹,

Sundin²,

Hanna³

et al. 1997

Spectrochimica Acta Part B: Atomic Spectroscopy

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Following digestion of the sample in a mixture of bromate and hydrobromic acid, the inorganic selenium produced was quantified by trapping hydrogen selenide, formed when a 500 ml sample volume injected into a hydrochloric acid carrier stream merged with a stream of sodium borohydride solution, on the iridium-pretreated interior of a graphite furnace atomizer. A number of parameters relating to the digestion, flow injection manifold and trapping in the atomizer were investigated, including a study of factors affecting the detection limit. It was found necessary to heat the digest under reflux at a temperature of 150ЊC for 2 h. Quantitative recoveries, from a human urine matrix, of selenite, selenate, trimethylselenium, selenocystine, selenopurine and selenomethionine spikes were obtained. The efficiency of hydride generation, transport and trapping was 75%. The major factors affecting the detection limit were the reagent purity and the volume injected. For high-purity hydrobromic acid and borohydride free of caking agent, the detection limit, based on three times the standard deviation of the blank, was 0.06 mgl − 1 for a 1000 ml injection volume corresponding to a detection limit of 3 mgl − 1 for a urine sample. The method was validated by the accurate analyses of Standard Reference Material 2670 from the National Institute of Standards and Technology, and urine samples from an interlaboratory comparison program. The procedure avoids the need for perchloric acid and produces selenium in the + 4 oxidation state and thus no reduction is needed prior to generation of the hydrogen selenide. The use of a graphite furnace atomizer avoids the need for frequent reconditioning of the atomizer surface and the need for the standard additions method, both of which are drawbacks of procedures which make use of the quartz tube atomizer. All sample handling procedures following the digestion were automated by the use of flow injection technology.

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“…In any case, matrix modifiers are necessary so that high charring temperatures can be used and to reduce the nonspecific absorption signals originating from the matrix. Nickel is widely used as a matrix modifier (9,10), although palladium has been described as the best modifier for such a purpose (11,12). An interesting review has evaluated the effectiveness of a number of analytical techniques for selenium determination in body fluids (13).…”

mentioning

confidence: 99%

Selenium Determination in Biological Fluids Using Zeeman Background Correction Electrothermal Atomic Absorption Spectrometry

Campillo

Viñas

López-Garcı́a

et al. 2000

Analytical Biochemistry

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Effect of nickel and palladium as chemical modifiers and influence of urine matrix on different chemical species of selenium in electrothermal atomic absorption spectrometry

Cited by 19 publications

References 22 publications

Behaviour of selenium and tellurium in the presence of various modifiers in electrothermal atomic absorption spectrometry

Behaviour of selenium and tellurium in the presence of various modifiers in electrothermal atomic absorption spectrometry

Determination of Se in urine by flow injection hydride generation electrothermal atomic absorption spectrometry with in-atomizer trapping

Selenium Determination in Biological Fluids Using Zeeman Background Correction Electrothermal Atomic Absorption Spectrometry

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