A simple and sensitive non-chromatographic method for quantification of four arsenic species in rice by hydride generation - atomic fluorescence spectrometry

Herein, a simple, sensitive and effective non-chromatographic analytical method was developed for speciation analysis of four target arsenic (As) species in rice samples. The hydride generation conditions and sample pretreatment techniques were optimized for the determination of arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid [MMA(V)] and dimethylarsinic acid [DMA(V)]. For optimum results, hydrochloric acid/sodium citrate buffer (1.6 mol L-1 sodium citrate; pH 4.8) was used for the carrier solution and 0.06 mol L-1 citric acid for sample acidification. The concentrations of the four As species were determined by hydride generation-atomic fluorescence spectrometry using a series of linear independent equations corresponding to four different sample pretreatment procedures. The limits of detection of the method were 0.21, 0.52, 0.65 and 0.9 mu g kg(-1) for As(III), As(V), MMA(V) and DMA(V), respectively. Extraction efficiencies (96-104%) and recoveries of As species in rice (95-100%) were always good, and interconversion among the four As species in the extract did not occur.