Very large volume sample introduction in capillary gas chromatography using a programmed temperature injector for pesticide analysis

This article describes a method to determine standard pesticides in a model solution based on very large volume injection in capillary gas chromatography using a temperature-programmable injector (PTV). The influences of sample volume, speed of sample introduction, flow rate during sampling, and both initial and final PTV temperatures on the performance of the procedure are considered. Experimental values for sample volume and introduction speed were selected to make it possible subsequently to perform an eventual liquid chromatatographic preseparation for on-line GC analysis. The technique was applied to the analysis of 10 pesticides and allowed the direct introduction into the PTV of sample volumes as high as 10 mt. Relative standard deviation values for the absolute peak areas obtained from the direct introduction of standard mixtures containing the pesticides at 1 ppm and 10 ppb were in general 15%. (C) 1999 John Wiley & Sons, Inc.