Submitted to: Talanta
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/5/2013
Publication Date: 2/15/2014
Publication URL: http://handle.nal.usda.gov/10113/58847
Citation: Chen, G., Chen, T. 2014. SPE speciation of inorganic arsenic in rice followed by hydride-generation atomic fluorescence spectrometric quantification. Talanta. 119:202-206. Interpretive Summary: Due to high toxicity, inorganic arsenics are the focus of monitoring effort worldwide. In this work, extraction was performed by microwave-assisted digestion. Inorganic arsenics were next separated from organic forms by solid phase extraction, and finally quantified by atomic fluorescence spectrometry. This method was validated by rice flour certified reference material. At 10% of instrument budget of a conventional system, this technique was fully capable to qualify trace-level As in rice.
Technical Abstract: Due to high toxicity, inorganic arsenics (iAs) are the focus of monitoring effort worldwide. In this work, extraction was performed by microwave-assisted digestion in HCl-H2O2, during which AsIII was oxidized to AsV. AsV was separated from organoarsenic species using silica-based SAX cartridge and reduced by KI to AsIII, which was finally quantified by hydride-generation atomic fluorescence spectrometry (HG-AFS). Rice samples in the market were found to contain 50-200 ng g-1 iAs, and recoveries ranged from 90+/- 5% to 76 +/- 5% at 100 ng g-1. The method was validated using NIST 1568a rice flour. SPE speciation gained throughput and cost advantages; this HG-AFS technique, at 10% of ICPMS system budget, was sensitive and selective for ng g-1 level As detection in rice.