Development of a new HPLC method for the determination of inorganic and methylmercury in biological samples with ICP-MS detection

In the present work a new HPLC method for the determination of mercury species in biological samples with ICP-MS detection was developed. Separation of inorganic (Hg2+) and methylmercury (CH3Hg+) was accomplished on a Hamilton PRP-X200 polymer-based cation-exchange column with a mobile phase of 50 mmol l(-1) pyridine, 0.5% w/w L-cysteine and 5% v/w MeOH, at pH 2, within 8 min. The influence of chromatographic parameters, such as pH, salt concentration, organic modi. er, and ion-pair reagent on the retention behaviour was evaluated. Based on peak areas, the experimental detection limits for inorganic and methylmercury were 0.05 and 0.08 mu g Hg l(-1), which corresponds to an absolute detection limit of 1.0 and 1.6 pg of mercury (20 mu l injection volume). The liquid chromatographic method was successfully applied to the determination of inorganic and methylmercury in the two certified reference materials DORM-2 and DOLT-3, after a rapid and simple sample preparation procedure using hydrochloric acid.