Evaluation of low‐pressure gas chromatography linked to ion‐trap tandem mass spectrometry for the fast trace analysis of multiclass pesticide residues

A rapid multiresidue method for the analysis of 72 pesticides has been developed using a single injection with low‐pressure gas chromatography/tandem mass spectrometry (LP‐GC/MS/MS). The LP‐GC/MS/MS method used a short capillary column of 10 m × 0.53 mm i.d. × 0.25 µm film thickness coupled with a 0.6 m × 0.10 mm i.d. restriction at the inlet end. Optimal LP‐GC conditions were determined which achieved the fastest separation in MS/MS detection mode. Also MS/MS conditions were optimized in order to increase sensitivity and selectivity. The analytical parameters of the LP‐GC/MS/MS method were compared with those obtained by GC/MS/MS using a conventional capillary column (30 m × 0.25 mm i.d. × 0.25 µm film thickness). Better precision and sensitivity values were obtained with the LP‐GC/MS/MS approach. The limits of detection (LOD) of the compounds ranged from 0.1 to 14.1 µg L −1 for LP‐GC/MS/MS, lower than those obtained for conventional GC/MS/MS that ranged from 0.1 to 17.5 µg L −1 . The peak widths obtained with the short column in LP‐GC are similar to those obtained using conventional capillary GC columns, and the peaks can be successfully identified by MS/MS detection with the conventional scan speed of ion‐trap instruments. In addition, the analysis time was significantly reduced with LP‐GC/MS/MS (32 min) versus GC/MS/MS (72 min), allowing the number of samples analyzed per day in a routine laboratory to be doubled. Copyright © 2002 John Wiley & Sons, Ltd.