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A simple, highly-sensitive and accurate method is presented for the determination of both inorganic mercury and total mercury in marine biological samples. 0.1 g of sample was completely solubilized in 1 g of tetramethylammonium hydroxide (TMAH) at room temperature. The TMAH-digested samples were spiked with 199 Hg enriched isotope and diluted to about 14 mL with deionized water. The spiked sample solutions were then analyzed for inorganic mercury determinations by isotope dilution inductively coupled plasma mass spectrometry with cold vapor generation. The solutions were further 5 times diluted with deionized water for total mercury determinations. SnCl 2 reducing agent was used for the inorganic mercury determinations, and NaBH 4 for the total mercury determinations. No reagents other than the reducing agents with acid solutions were used for the mercury determinations. The proposed method was validated by the analysis of three certified reference materials, DORM-2 (dogfish muscle), NIST SRM1566b (oyster) and KRISS tuna CRM. The detection limit of the method was found to be 0.018 ng g À1 .

Nickel was determined in natural water samples by inductively coupled plasma mass spectrometry (ICP-MS ) with sample introduction by on-line carbonyl vapor generation. The isotope dilution method was used for quantification with 60Ni and 62Ni as the major and minor isotopes. With sample introduction by the common pneumatic nebulization, the two isotopes may suffer from spectral interferences arising from molecular ions such as CaO, ArMg and Na 2 O. In order to obtain accurate results free from spectral interferences, nickel in the water samples was reduced with sodium borohydride to its elemental form, and the mixed solution of sample and sodium borohydride subsequently met a stream of 10% CO gas to form the volatile nickel carbonyl. The generated carbonyl vapor was directed by a stream of argon carrier gas into the ICP after separation in a liquid-gas separator made of a polytetrafluoroethylene membrane tube. Optimum conditions for carbonyl generation were investigated. The analyte transport efficiency of the carbonyl generation method was estimated to be >50%. Good agreement was achieved with the certified values in the analysis of two water reference materials, SLRS-3 riverine water and CASS-3 sea-water. The uncertainty of the analytical results was estimated to be 4.56% for CASS-3 and 1.64% for SLRS-3 with the coverage factor k=2.Inductively coupled plasma mass spectrometry (ICP-MS ) has applied method of sample introduction by vapor generation.Elements that form volatile covalent hydrides such as As, Bi, attracted widespread interest because of its analytical figures Ge, Pb, Sb, Se, Sn and Te were determined with hydride of merit such as the excellent power of detection and the generation.11,12 Osmium tetraoxide vapor generation was used ability to measure isotope ratios. The most common sample to separate 187Os from 187Re without prior chemical separaintroduction method for ICP-MS is the pneumatic nebulization tion.13 Recently B14, Cd15 and Cu16 were also successfully of solutions. The pneumatic nebulization technique is simple determined following the generation of some volatile species to use and relatively inexpensive, but it is also a very inefficient in the ICP. method, only about 2-3% of the sample being introduced into Nickel, in its elemental form, is known to react with carbon the plasma.1 Despite such salient features, ICP-MS suffers monoxide to form volatile nickel carbonyl vapor at room from both spectral and the non-spectral interferences in most temperature.17 Lee18 determined nickel in sea-water by the applications.2,3 The non-spectral interference problem or the carbonyl generation. He trapped the carbonyl vapor in liquid matrix effect can be solved by using isotope dilution,4,5 stannitrogen-cooled glass-wool and subsequently stripped it to dard addition6 and internal standard7 methods. However, the detect nickel by atomic absorption spectrometry. In this work, spectral interference can be eliminated only by somehow a continuous-flow nickel carbonyl vapor generation device was separating the...

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