Investigations into sulfur speciation by electrospray mass spectrometry
Abstract
Sulfur is an element that manifests itself in a wide variety of chemical forms in the environment and it is generally not sufficient just to determine the elemental level of sulfur in environmental samples. In this study it is shown that electrospray mass spectrometry (ESMS) has the potential to provide a powerful direct probe for sulfur species in solution samples. The basic electrospray mass spectra to be expected for species such as SO42–, S2O82– and S2O32– are presented, and the important role of controlling and varying collision induced dissociation (CID) conditions in order to validate the species identity is illustrated. It is also shown that ESMS can be used to monitor sulfur species such as S4O62– and S2O62–, which are products in certain redox reactions and also thiosulfate complexes, such as Ag(S2O3)23–. Finally, quantitative results are presented for the determination of sulfate in waste water.