Determination of mercury in urine and seawater by flow injection vapor generation isotope dilution inductively coupled plasma mass spectrometry

A simple and inexpensive laboratory-built vapor generator was used with ind uctively coupled plasma mass spectrometry (ICP-MS) for the determination of mercury in urine and seawater samples. The applications of vapor generatio n ICP-MS alleviated the non-spectroscopic interferences and the sensitivity problem of mercury determination encountered when the conventional pneumat ic nebulizer was used for sample introduction. The concentration of mercury was determined by isotope dilution method. The isotope ratio of mercury wa s calculated from the peak areas of each injection peak. The repeatability of the peak areas and isotope ratio determinations of seven consecutive inj ections of 1 ng mL(-1) Hg solution were 2.3% and 2.2%, respectively. This m ethod has a detection limit of 0.07 ng mL(-1) for mercury. This method was applied to determine mercury in a CASS-3 nearshore seawater reference sampl e, NASS-4 open ocean seawater reference sample, NIST SRM 2670 freeze-dried urine reference sample and several urine and seawater samples collected fro m National Sun Yat-Sen University. The results for the reference samples ag reed satisfactorily with the reference values. Results for other samples an alyzed by the isotope dilution method and the method of standard additions agreed satisfactorily. Precision was better than 10% for most of the determ inations.