Comprehensive LC x GC for enhanced headspace analysis

A chemical analyzer will be reported based upon coupling liquid chromatogra phy (LC) with a water mobile phase via a novel interface to high-speed capi llary gas chromatography (GC). The interface preserves the temporal informa tion of the LC separation, thus a comprehensive two-dimensional LC X GC sep aration is obtained. The LC separation is in the 5-10 min range, while the GC separations are in the 1-2 second range. For a 5 min LC separation, 150 GC separations are obtained if the GC separations are every 2 s, thus a tru ly comprehensive LC X GC data density is obtained. The 100% water mobile ph ase simplifies instrumental requirements, thus enhancing separation and det ection strategies, thus broadening the scope of LC to on-line process analy sis and field monitoring applications by improving safety and minimizing wa ste. Volatile organic compounds are analyzed by LC X GC with enhanced chemi cal selectivity. Thus, this comprehensive LC X GC instrument is a useful al ternative to current methods that employ headspace analysis. Separations of compounds such as benzene, toluene, ethyl benzene, o-xylene (BTEX), as wel l as chloroform and methylene chloride are presented. Injected sample conce ntration limits of detection are in the 40-200 parts-per-billion range. (C) 2000 John Wiley & Sons, Inc.