Determination of B, Si, P and S in steels by inductively coupled plasma quadrupole mass spectrometry with dynamic reaction cell

An inductively coupled plasma quadrupole mass spectrometer equipped with a dynamic reaction cell™ (DRC) was successfully used for the accurate determination of B, Si, P and S in steel samples, using the reaction of Si+, P+ and S+ ions with O2 in the cell. The method obviated the effect of polyatomic isobaric interferences at m/z 28, 31 and 32 by detecting 28Si+, 31P+ and 32S+ as the oxide ion 28Si16OH, 31P16O and 32S16O at m/z 45, 47 and 48, respectively, which is less interfered. The effects of the operating conditions of DRC system were optimized to get the best signal to noise ratio for 28Si16OH, 31P16O and 32S16O. As there is no spectroscopic interference, boron was determined under the standard mode. Validation of the method was carried out by the determination of B, Si, P and S in steel standard reference materials (NIST SRM 361, 362 and 364). Since the sensitivities of Si, P and S in digested sample solutions and standard solutions were found to be quite different, standard addition method was used for the determination of B, Si, P and S in this study. Good agreement was obtained between the certified values and the experimental results. The precision between sample replicates was better than 6.3% for all the determinations.