Evaluation of Arsenate Content of Rice and Rice Bran Purchased from Local Markets in the People's Republic of China

In previous studies, inorganic arsenic and total arsenic concentrations in rice bran have been much higher than those in polished rice obtained from the same whole paddy rice. However, the arsenic species distribution between rice and bran is still unknown, especially for arsenite (AsIII) and arsenate (AsV). To characterize the arsenic species in rice and bran and explain the elevated concentrations of inorganic arsenic and total arsenic, four arsenic species, AsIII, AsV, dimethylarsinic acid, and monomethylarsonic acid, were evaluated. Rice and bran samples (n = 108) purchased from local markets in the People's Republic of China were analyzed using high-performance liquid chromatography with hydride generation and atomic fluorescence spectrometry and then microwave extraction. As expected, most of the arsenic was found in bran, with bran/rice ratios of 6.8 for total arsenic species and 6.4 for inorganic arsenic. Among four arsenic species, the maximum bran/rice ratio was 104.7 (335/3.2 μg kg−1) for AsV f...