Chromatographic separation of arsenic species with pentafluorophenyl column and application to rice

Arsenic species, including arsenous acid, arsenic acid, methylarsonic acid, and dimethylarsinic acid, were determined using HPLC–ICPMS. The species were separated with a Discovery HS F5 column and a simple, volatile, and isocratic mobile phase of 0.1% (v/v) formic acid and 1% (v/v) methanol. The Discovery HS F5 column with a pentafluorophenyl (PFP) stationary phase gave sharp peaks and full separation of the arsenic species in 5 min, and other PFP columns showed lower performance. This separation method was applied to arsenic species analysis in rice. The extraction of arsenic from rice samples was performed using 0.15 M nitric acid. The methodology was validated by use of certified reference materials, NMIJ CRM 7503-a and NIST SRM 1568a, and extremely low arsenic rice samples as blank samples.