In recent years, food safety laboratories have adopted new and simplified sample preparation methods, such as QuEChERS, to reduce analysis time and and to increase throughput.  In this study, this simplified sample preparation is applied to pesticide analysis in avocado, a fruit matrix of high lipid and chlorophyll content, and in spinach, a vegetable matrix of very high chlorophyll content.  In the QuEChERS extraction, significant amounts of fat, phospholipids, and chlorophyll are co-extracted along with the target pesticides.  The presence of these co-extracted substances can lead to chromatographic interference, contamination of GC or LC systems, and contamination of the mass spectrometer.  To avoid these complications, a cleanup step is recommended prior to the instrumental analysis.  This is typically performed using cumbersome, multi-step dispersive SPE (dSPE) with mixed sorbents.  In this study, a novel reversed-phase sorbent was used for a simple, rapid, and effective pass-through cleanup to effectively remove fats, phospholipids and chlorophyll from QuEChERS extracts of avocado and spinach. Although dSPE with graphitized carbon black (GCB) is also effective for removal of chlorophyll, recovery losses can occur for some pesticides, particularly those that have a planar geometry. In this study, pesticide analysis was performed using both UPLC-MS/MS and APGC-MS/MS. No loss of planar pesticides was observed and high recoveries of pesticides were achieved after the rapid and straightforward pass-through cleanup.<br/>

Novel sorbent for pass-through cleanup: A simple, quick, and effective alternative for removal of lipids and chlorophyll from QuEChERS extracts

254th National Meeting (2017)

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