Direct Determination of Trace Arsenic in Flour by Suspension-sampling Hydride-generation Atomic Absorption Spectrometry

SUN Han-wen,LIU Xiao-li (Key Laboratory of Analytical Science and Technology of Hebei Province, College of Chemistry and Environmental Science, Hebei University, Baoding 071002, China)

suspension sampling;hydride generation;atomic absorption spectrometry;flour;arsenic

A novel suspension-sampling hydride-generation atomic absorption spectrometry was proposed for direct determination of trace arsenic in flour. The experimental conditions of suspension and hydride generation affecting the intensity of arsenic signal were investigated and optimized. The satisfactory result was obtained by using 0.3% agar as a stabilizing agent, 1% citric acid as a sensitizing agent, and n-octanol as an defoaming agent. The interferences of coexisting ions were also examined. Furthermore, the reliability of the procedure was to be proved by analyzing three varieties of Chinese certified reference flours, and the results showed no significant difference (p=0.05) between the certified and determined values. The method was applied to the determination of arsenic in 5 flour samples (e.g. wheat, rice)with the detection limit of 0.239 μg/L, recovery of 95.5% to 108%, and relative standard deviation (n=3) of 0.86% to 3.02%. The proposed method in this study has the advantages of simple operation, high speed and high sensitivity.