Abstract

Ruttiya Poonyaka and Saksit Chanthai

DOI : http://dx.doi.org/10.13005/ojc/330315

This study described selenium speciation analysis under catalytic activation and/or reduction using silver nanoparticles (AgNPs) in conjunction with common flow injection (FI) -hydride generation atomic absorption spectrometry (HGAAS). Generally, Se(IV) could be directly determined by HGAAS consisting of 0.25% (w/v) NaBH₄ in 0.1% (w/v) NaOH as a reductant and 2 M HCl as carrier solution, while Se(VI) could not be detected. In this regard, AgNPs in which was generated in the presence of 0.25% (w/v) NaBH₄ was accordingly subjected in the same reducing background. Thus, the effects of the AgNPs on various factors affecting the Se analysis were investigated. From the results, it was demonstrated that the AgNPs gave insight into the catalytic activation for Se(IV) analysis, and also acted as pre-reducing agent for Se(VI) compared with 10% (w/v) thiourea/conc. HCl. So, the dispersed AgNPs in the HG system could serve for better sensitivity and selectivity for Se analysis. Furthermore, the conversion of Se(VI) to Se(IV) and its recovery study were validated using both of the pre-reducing agents. Both LOD and LOQ of the method were 0.5 and 1.0 µg L^-1, respectively. The method precision (%RSD) was ranged of 5.69 and 3.23 for an intra-day and an inter-day analysis, respectively. Therefore, the method using AgNPs was successfully applied to determine trace amounts of Se species in drinking water samples and found in the ranges of 0.03-0.10, 0.12-1.0 and 0.22-0.97 µg mL^-1 for Se(IV), Se(VI), and total Se, respectively.

Selenium; silver nanoparticles; hydride generation; atomic absorption spectrometry; catalytic activation; reducing agent; drinking water

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