Determination of Inorganic Arsenic in a Certified Reference Material of Total Diet Matrix

Abstract

Inorganic arsenic [iAs : As(III) and As(V)] concentrations in a certified reference material of total diet matrix (NIES CRM No.27 Typical Japanese Diet, TJD) were determinate by liquid chromatography-ICP mass spectrometry (LC-ICP-MS) with three different LC conditions and with or without a hydride generation system. The iAs were extracted from TJD by a method given in the literature (0.07 mol L−1 HCl + pepsin, 37°C for 2hr). The detection limits for the iAs were better than 6.1 ng As g−1 in TJD (corresponds to 0.92 ng As g−1 on a wet diet sample), indicating sufficient sensitivity for iAs in total diet samples. The reproducibility was 1.8-12.1% and the linearity of the calibration lines was satisfactory. The recovery of added iAs was 101-106%. When the extraction was repeated 3 times, the sum of the concentrations of arsenic species detected by the LC-1 agreed with the certified values for total arsenic in TJD. The total content of As(V) and As(III) was estimated to be 65 ± 2 and 18 ± 2 ng As g−1, respectively, by LC-1 condition. The analytical results of iAs in TJD based on the three LC-ICP-MS conditions by this particular extraction method were consistent with each other and the reference value was estimated to be 43 and 17 ng As g−1 for As(V) and As(III), respectively. The present results will be valuable in the quality control of iAs analysis of total diet samples for iAs risk assessment in Japan.