Determination of selenium in nickel-based alloys by flow injection hydride generation reaction cell inductively coupled plasma mass spectrometry

An inductively coupled plasma dynamic reaction cell mass spectrometry (ICP-DRC-MS) method was developed for the determination of selenium in nickel-based alloys using flow injection hydride generation as the sample introduction system. Different masking agents were tested to reduce non-spectroscopic suppression effects caused by the presence of high concentrations of transition metals in the solution. A mixture of thiourea and citric acid reduced the interferences arising from transition metals. The effect of the operating conditions of the DRC system was studied to get the best signal-to-noise ratio. Using methane as the reactive cell gas in the DRC reduced the argon dimer interferences at selenium masses m/z 78 and 80. Validation of the method was carried out by determining selenium in standard reference materials of nickel-based alloys (NIST SRM 897-899). Good agreement was obtained between the certified values and the experimental results. The detection limit for Se was in the range 0.003-0.007 ng ml(-1), which corresponded to 3-7 ng g(-1) in the original alloy samples. The precision between sample replicates was better than 5% for all the determinations.