This application note describes a method for analyzing pesticides at the trace level using large-volume injection (LVI) with the Agilent programmable temperature vaporizing (PTV) inlet. With LVI, the detection limit of gas chromatography systems can be improved by one to two orders of magnitude over standard methods that require 1- or 2-microliter injections. An Agilent 6890 Series gas chromatograph (GC), configured with a PTV inlet, an Agilent 6890 Series automatic liquid sampler (ALS), and an Agilent 5973 mass selective detector (MSD), was used for the analysis of pesticides in standards and several food extracts. By making 100-microliter injections, several pesticides could be identified by scanning gas chromatography/mass spectrometry (GC/MS) at the 100 ppt (100 ng/L) level. The PTV inlet tolerated dirty food extracts very well; more than 1,500 microliters of such samples were injected into a single PTV liner. This application note includes recommendations for performing LVI using the PTV/6890/5973 GC/MSD system.
This document details a method for improving gas chromatography/mass spectrometry (GC/MS) detection limits for pesticide analysis by utilizing large-volume injection (LVI). The technique employs an Agilent 6890 Series gas chromatograph with a programmable temperature vaporizing (PTV) inlet and an Agilent 5973 mass selective detector (MSD). By injecting 100-uL samples, the method achieves detection limits as low as 100 parts per trillion (ppt) for various pesticides in food extracts.
The typical injection volume limit for this system is 250 uL.
Ten sequential injections of 10 uL each were made to achieve the total volume.