The two main sources for human exposure to arsenic (As), a known carcinogen, are drinking water and food including rice and seafood. Four arsenic species, namely As (III), DMA, MMA and As (V), have been analyzed mainly in rice or rice products using HPLC-ICP-MS or IC-ICP-MS and the sum of the concentrations of As (III) and As (V) is reported as inorganic arsenic (iAs). Currently there is no established regulatory level for iAs in rice or rice products. The 4 arsenic species were well separated in the standard method using an ammonium phosphate buffer, however some rice samples have unknown arsenic species coeluting with As (III) peak affecting the calculated amounts of As (III) which is the most toxic arsenic species found in food. Using novel experimental conditions, we were able to separate As (III) and the unknown As species without using any oxidation steps. The separation of the unknown peak results in a decrease in the reported amounts of iAs and suggests overestimation of iAs amounts in cases where the coeluting peak exists.

Separation of unknown arsenic species in rice

248th National Meeting (2014)

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