Nanosemiconductor-Based Photocatalytic Vapor Generation Systems for Subsequent Selenium Determination and Speciation with Atomic Fluorescence Spectrometry and Inductively Coupled Plasma Mass Spectrome

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• 作者：Huamin Li ; Yacui Luo ; Zhaoxin Li ; Limin Yang ; Qiuquan Wang
• 刊名：Analytical Chemistry
• 出版年：2012
• 出版时间：March 20, 2012
• 年：2012
• 卷：84
• 期：6
• 页码：2974-2981
• 全文大小：341K
• 年卷期：v.84,no.6(March 20, 2012)
• ISSN：1520-6882

文摘

We reported novel Ag鈥揟iO₂- and ZrO₂-based photocatalytic vapor generation (PCVG) systems as effective sample introduction techniques for further improving the sensitivity of the atomic spectrometric determination of selenium for the first time, in which the conduction band electron served as a 鈥渞eductant鈥?to reduce selenium species including Se^VI and convert them directly into volatile H₂Se, which was easily separated from the sample matrix and underwent more effectively subsequent atomization and/or ionization. These two PCVG systems helped us to overcome the problem encountered in the most conventional KBH₄/OH^{鈥?/sup>鈥揌+ system, in that SeVI was hardly converted into volatile selenium species without the aid of prereduction procedures. The limits of detection (LODs) (3蟽) of the four most typical SeIV, SeVI, selenocystine ((SeCys)₂), and selenomethionine (SeMet) species were, respectively, down to 1.2, 1.8, 7.4, and 0.9 ng mL鈥? in UV/Ag鈥揟iO₂鈥揌COOH, and 0.7, 1.0, 4.2, and 0.5 ng mL鈥? in UV/ZrO₂鈥揌COOH with the relative standard deviations (RSDs) lower than 5.1% (n = 9 at 1 渭g mL鈥?) when using atomic fluorescence spectrometry (AFS) under flow injection mode. They reached 10, 14, 18, and 8 pg mL鈥? in UV/Ag鈥揟iO₂鈥揌COOH, and 6, 7, 10, and 5 pg mL鈥? in UV/ZrO₂鈥揌COOH with the RSDs lower than 4.4% (n = 9 at 10 ng mL鈥?) when using inductively coupled plasma mass spectrometry (ICPMS). After the two PCVG systems were validated using certified reference materials GBW(E)080395 and SELM-1, they were applied to determine the total Se in the selenium-enriched yeast sample and used as interfaces between high-performance liquid chromatography (HPLC) and AFS or ICPMS for selenium speciation in the water- and/or enzyme-extractable fractions of the selenium-enriched yeast.}