Abstract: Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) is often applied to determine sulfur in minerals, proteins, fossil fuels and other materials. The study of sensitivity, limit of detection and background noise during determination of sulfur, using both Quadrupole Inductively Coupled Plasma-Mass Spectrometry (Q-ICP-MS) and Sector Field Inductively Coupled Plasma-Mass Spectrometry (SF-ICP-MS), are presented in this paper. One focus of the paper is to study the effect on sulfur species during determination of sulfur in two different matrices (water and 2% HNO₃) by SF-ICP-MS. The results indicate that the signals for S^2-, S₂O₃^2-, SO₃^2-, SO₄^2-, respectively, in 2% HNO₃ are consistently more stable than in water matrix. Therefore, the matrix of 2% HNO₃ is more suitable for sulfur determination by ICP-MS. In addition, sulfur sensitivities for S^2- were higher than those for SO₄^2- and S₂O₃^2- by ICP-MS. The sulfur sensitivities of S^2- and SO₃^2- were 6 and 4 times higher respectively than those of S₂O₃^2- and SO₄^2-. The reason for higher sulfur sensitivities for both S^2- and SO₃^2- is that the formation of aerosols (H₂S and SO₂) in 2% HNO₃ improves atomization efficiency.