Whenever it is time to analyze pesticides in complex matrices I always hope that we can use the QuEChERS sample preparation approach and not something more laborious! The Quick-Easy-Cheap-Effective-Rugged-Safe method was developed for multiresidue pesticides in fruits and vegetables, however we have been using this approach outside of the typical fruit and vegetable matrices with success. When compared to more traditional sample prep techniques (liquid-liquid and solid phase extraction) QuEChERS significantly decreases the time spent and solvent used.
Tobacco can be a very complex sample, but with a few modifications to the EN QuEChERS method we were able to get good spike recoveries (92%) for a wide range of pesticides. Some of the modifications that we made were to use a 2 g sample and add 10 mL of water to hydrate the sample, then after the addition of 10 mL of acetonitrile we vortexed the sample for 30 min, instead of the typical 1 min shake. We also used the power of GCxGC-TOFMS to separate some of the matrix interferences away from our analytes of interest (Figure below). In a 1D GC-MS analysis we would have needed to perform cartridge SPE instead of the dispersive SPE to further remove matrix interferences.
If you want all of the details check out the full application note that was recently published! Evaluation of Dispersive and Cartridge Solid Phase Extraction (SPE) Cleanups for Multiresidue Pesticides in QuEChERS Extracts of Finished Tobacco Using GCxGC-TOFMS