Capillary gas chromatography coupled with negative ionization microplasma mass spectrometry for halogen-selective detection

Gas chromatography was coupled with plasma mass spectrometry with a micropl asma ion source for negative ion detection. The ion source, which was kept inside the high vacuum chamber of the mass spectrometer, was a rigid fused silica capillary tube containing a capacitively coupled radiofrequency heli um plasma. This made the setup quite simple: eliminating the sampler-skimme r pressure-reducing interface traditionally used in plasma mass spectrometr y. The present study describes the utilization of halogen-selective negativ e ion detection. A high selectivity of fluorine to hydrocarbon compounds (3 x 10(3)), and a highly sensitive detection for F, Cl, Br, and I (0.13-12 p g s(-1)), were obtained. The mechanisms of negative ion formation and break down were discussed in conjunction with the results that were achieved.