Radiofrequency Glow Discharge as an Ion Source for Gas Chromatography With Mass Spectrometric Detection

A radiofrequency (rf) powered glow discharge (GD) has been used as an ion source for GC–MS. The improved GC–GD interface has allowed separation and detection of five organotin compounds with better figures of merit than previously reported. Limits of detection for four compounds were from 0.6 to 13 picogram (as tin). Optimization of the discharge pressure and sampling distance with respect to the primary analytical species of interest, elemental tin, has been performed. Characterization of the source has been made by studying the effect of the cell pressure, applied rf power and sampling distance on analyte signal and organotin fragmentation patterns. The results obtained indicate that the mass spectra generated do not differ significantly with the varying source pressure and rf power as they exhibit the same features in terms of parent-molecular peaks and fragment ions.