Negative ion mass spectrometry of organotin compounds—an aid to environmental monitoring?

Abstract Positive‐ion mass spectra of organotin compounds include a large number of different ions and therefore the absolute detection level is reduced. Negative‐ion mass spectra are usually less complex and detection levels may therefore be improved. The negative‐ion mass spectra of selected organotin compounds of the type R 4 Sn, R 3 SnCI, R 2 SnCI 2 and RSnCl 3 were investigated using conventional electron impact ionization conditions. Simplified mass spectra, suitable for compound speciation, were obtained for R 3 SnCI 2 and R 2 SnCI 2 materials but the same fragmentation product SnCI   3 −was obtained from all the RSnCI 3 samples. R 4 Sn compounds produced no negative‐ion data in these studies. No significant gains in detection levels were noted but some interesting re‐arrangement reactions leading to the formation of compounds consisting of substituents from the original tin atom were identified. These reactions may be of synthetic importance.