Abstract:Sulfur (S) content is a key index of pure copper. A dynamic reaction cell inductively coupled plasma mass spectrometry (ICP MS/MS) was developed for the determination of trace sulfur in pure copper samples. Due to serious mass spectrum interference, it is difficult to determine the content of S element in the sample by the common Q-ICP-MS. In this study, four different detection modes of NexION 5000G ICP-MS were compared, and the detection of S element in oxygen reaction mass-shift mode can significantly reduce the mass spectrum interference and improve the signal-to-noise ratio. Three isotopes of sulfur (32S, 33S and 34S) were determined by ICP MS/MS, and the correlation coefficients (R2) of the established standard curves were all better than 0.999. However, due to the low abundance and signal-to-noise ratio of 33S compared with 32S and 34S, 32S and 34S isotopes were chosen for quantitative analysis. Finally, the detection limits of the method obtained by ICP-MS/MS for 32S and 34S were 1.2 μg/g and 1.1 μg/g, respectively, which can meet the requirements of S content analysis of 3-5N pure copper. The S content values of two pure copper standard samples were consistent with the recommended value within the error range, which indicated the reliability of the method.