Determination of inorganic oxyanions of As and Se by HPLC-ICPMS

A liquid chromatographic separation of inorganic oxyanions of As (As(V) and As(III)) and Se (Se(VI) and Se(IV)) using mixed ion-pairing reagents followed by ICPMS detection is described. The separation was accomplished in less than 4min on Capcell C18 RP column using mixed ion-pairing modifier containing 5mM of butane sulfonic acid (BSA), 2mM malonic acid, 0.30mM hexane sulfonic acid (HSA) and 0.5% methanol of pH 2.5. All four species were resolved with retention times of 2.4, 2.6, 3.0, and 3.1min for Se(VI), As(V), As(III), and Se(IV), respectively. The detection limits were less than 0.08 and 0.77mugl(-1) for arsenic and selenium species, respectively. The relative standard deviation of the proposed method for arsenic (at 2.5mugl(-1)) and selenium (at 10mugl(-1)) was less than 3.7 and 4.8%, respectively. The technique was used to determine inorganic oxyanions of As and Se in water samples (tap, well, and river) and extracts of coal fly ash and sediment. Low power microwave digestion was employed for extraction from fly ash and sediment samples.