EVALUATION OF GAS-CHROMATOGRAPHY COUPLED WITH ION MOBILITY SPECTROMETRY FOR MONITORING VINYL-CHLORIDE AND OTHER CHLORINATED AND AROMATIC-COMPOUNDS IN AIR SAMPLES

The objective of this research was to evaluate, in the laboratory, the potential of gas chromatography/ion mobility spectrometry (GC/IMS) fo r monitoring vinyl chloride and other organic compounds in air samples in the field, It was determined that GC/IMS has the potential to dire ctly detect vinyl chloride in air at the 2 ppbv level, and when concen trated on an adsorbent trap from a 1 L sample of air, detection could be Lowered to the 0.02 ppbv level, From a comparative investigation of 18 EPA priority pollutants and 34 common vapor-phase organic compound s, many compounds mere found to provide a more sensitive response in I MS than vinyl chloride, indicating that GC/IMS would be broadly applic able to the direct detection of vapor-phase organics in air. Operating parameters including drift gas, spectrometer temperature, and sample- inlet position were evaluated and discussed with respect to sensitivit y and resolution, High temperature dramatically increased sensitivity to vinyl chloride, Vinyl chloride was shown to produce both negative a nd positive ion mobility spectra, with the negative-mode spectra resul ting from electron-capture dissociation of the vinyl chloride, The lim it of detection for vinyl chloride was found to be 7 pg/s, Limits of d etection for 18 EPA priority pollutants were determined and compared t o vinyl chloride, The responses of 34 other vapor-phase organic compou nds were also compared to that of vinyl chloride, Non-selective, posit ive-ion detection of 30 of the 34 compounds was demonstrated along wit h selective, electron-capture-type detection of 29 of them, Chloride-s pecific and bromide-specific detection illustrated the advantages of s elected-ion monitoring in IMS.