Arsenic speciation in rice samples for trace level determination by high performance liquid chromatography-inductively coupled plasma-mass spectrometry

• A method was developed to separate six arsenic species. • Detection limits of the analytes ranged between 0.14 and 0.29 µg L −1 . • Percent recovery results close to 100% validated the method’s accuracy. • Precision of the method was verified with intra-day and inter-day repeatability tests. Six arsenic species, namely arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenobetaine (AsB) and arsenocholine (AsC) were speciated using a combination of high-performance liquid chromatography and inductively coupled plasma mass spectrometry (HPLC–ICP-MS). Under optimum chromatographic conditions, six arsenic species were well separated, and the performance of the combined system (HPLC–ICP-MS) for the species was determined. The limits of detection were calculated in the range of 0.14–0.29 ng/mL, and the corresponding quantification limits ranged between 0.45 and 0.97 ng mL −1 for the species. Spike recovery experiments performed on rice samples were used to validate the method’s applicability to complex matrices. The recovery results calculated ranged between 93 and 109%, validating the method’s applicability. Triplicate measurements for all spiked samples recorded percent relative standard deviation values below 10%.