Determination of antimony (III), antimony (V), selenium (IV) and selenium (VI) in natural waters by hydride generation atomic absorption spectrophotometry combined with a cold trap

Shigeru Tanaka, Masaru Nakamura, Hideo Yokoi, Masanori Yumura, Yoshikazu Hashimoto

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Antimony and selenium in water samples are reduced to stibine and hydrogen selenide, respectivery, by an addition of Na[BH4]. The stibine and hydrogen selenide generated are once collected by a liquid-nitrogen cold-trap, and then led, by heating the trap, into a quartz furnace for atomic absorption spectrometry. Sb(III) is selectively reduced by Na[BH4] at pH 6, but Sb(V) not. The latter is reducible under highly acidic condition including KI as a prereducting reagent. According to the fact, Sb(III) is determined through the reduction in 1.6 M potassium citrate buffer of pH 6, and total antimony Sb(III+V) is determined in 12 M HCl/2 M KI solution of pH 1, Sb(V) is then determined by the difference. Similarly, Se(IV) is determined by the reduction with Na[BH4] under highly acidic condition, and total selenium Se(IV+VI) determined through successive reductions in KBr/HCl solution and in Na[BH4] solution, and Se(VI) determined from the difference. Detection limits of this method are: 16 ppt for the total antimony: 1 ppt for Sb(III); 2 ppt for Se(IV); and 2 ppt for the total selenium. The relative standard deviation is within a few percent for both antimony and selenium determinations. The reproducibility could be improved by removing water by using an auxiliary dry-ice/2-propanol trap. The use of EDTA as a masking reagent is effective for selenium determination. Sb(V) ranging 70–460 ppt, Se(IV) 3–30 ppt and Se(VI) 3–60 ppt were actually observed in natural waters, but Sb(III) was not.

Original languageEnglish
Pages (from-to)116-121
Number of pages6
JournalBunseki Kagaku
Volume35
Issue number2
DOIs
Publication statusPublished - 1986

Keywords

  • generation of stibine and hydrogen selenide by sodium borohydride
  • hydride generation atomic absorption spectrophotometry with a cold trap
  • overcoming interference with EDTA masking reagent
  • selective determination of antimony and selenium in natural water
  • water trap by dry-ice/2-propanol

ASJC Scopus subject areas

  • Analytical Chemistry

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