Capillary gas chromatography coupled with microplasma mass spectrometry for organotin speciation

Gas chromatography was coupled with microplasma mass spectrometry for selec tive detection of organotin compounds. The microplasma ion source was a cap acitively coupled radiofrequency helium plasma, which was located inside th e high vacuum area of the mass spectrometer. Only 1-3 mi min(-1) of helium carrier gas from the gas chromatograph was necessary for sustaining the pla sma while 0.15-1.5 ml min(-1) of hydrogen was added as reagent gas. Hydroge n was applied for prevention of carbon deposition and served to minimize th e interactions between tin and the fused-silica inner surface of the microp lasma ion source. Both carbon and tin were detected as positively charged a tomic ions, which were expelled from the microplasma ion source and directl y focused by electrostatic lenses towards the quadrupole mass analyzer. Tin exhibited high selectivity to carbon (>10(4)) and a detection limit of 3.5 pg s(-1). (C) 1999 Elsevier Science B.V. All rights reserved.