Janusz Pawliszyn, Abir Khaled, Alexander Kasperkiewicz
The current sample preparation techniques used in multiclass multiresidue analysis of pesticides in fruits and vegetables as well as veterinary drugs in animal tissue involve time-consuming procedures that are not always effective at minimizing matrix interferences. These methods often involve the use of large amounts of organic solvents which lead to hazardous waste. Moreover, they lack automation and high-throughput capabilities. Screening of contaminants present in food and origin of food is an important task. New developments in high throughput determinations facilitated by SPME in thin film format  have been demonstrated not only with GC/MS and LC/MS, but direct couplings to MS. These are critical advances which will impact effectiveness of public protection. In this presentation we will describe two alternative approaches for multiclass multiresidue analysis based on solid phase microextraction. The first approach is based on conventional liquid chromatography- tandem mass spectrometry methods (LC–MS/MS) . The second approach is based on the emerging direct analysis MS techniques . In both approaches, the main goal is aimed at minimizing matrix effects and organic solvent use, while maximizing sample throughput. The fully automated sample preparation workflow allows for total extraction time of less than 1 min per sample when 96 extractions are simultaneously conducted, while the direct to MS workflow allows for total analysis time of less than 1 min per sample with screening in both negative and positive ionization modes in the Coated Blade Spray (CBS) method. Strategies of determination of hydrophobic pesticides will be discussed as well . All methods were able to achieve excellent accuracy and precision results .
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