Programmed-temperature injector for large-volume sample introduction in capillary gas chromatography and for liquid chromatography-gas chromatography interfacing

Water samples were analyzed using off-line and online extn. with gas chromatog. (GC) anal. In the off-line method, pollutants were extd. into hexane or methylene chloride. Using the programmed-temp. injector, ?250 mL of the ext. could be introduced into the GC system. In this way, reproducible quant. analyses of polycyclic arom. hydrocarbons (PAHs) and herbicides were achieved at sub-ppb concns. using flame ionization detection. In the online mode, pollutants were preconcd. on a short liq. chromatog. column packed with a PLRP-S solid phase extn. material. After the trapping step, the components were desorbed by EtOAc and transferred directly into the programmed-temp. vaporizer system. Using this method, detection limits of .ltorsim.1 ppb of herbicides in water were obtained