Determination of thallium in sea-water by flow injection hydride generation isotope dilution inductively coupled plasma mass spectrometry

A simple and inexpensive laboratory-built vapor generator was used with inductively coupled plasma mass spectrometry (ICP-MS) for the determination of Tl in sea-water samples. The application of vapor generation (VG) ICP-MS alleviated the non-spectroscopic interferences encountered when the conventional pneumatic nebulizer was used for sample introduction. The concentration of Tl was determined by the isotope dilution method. The isotope ratio of Tl was calculated from the peak area of each injection peak. The repeatability of the peak area and isotope ratio determinations of seven consecutive injections of 1 ng ml(-1) Tl solution was 2.8% and 2.4%, respectively. This method has a detection limit of 0.01 ng ml(-1) for Tl in sea-water. This method was applied to determining Tl in CASS-3 nearshore sea-water reference sample, NASS-4 open ocean sea-water reference sample and sea-water samples collected from the Kaohsiung area. The result for the reference sample CASS-3 agreed satisfactorily with the reference value. Results for other samples analyzed by different quantitation methods agreed satisfactorily. Precision was better than 10% for most of the determinations.