Optimization of Fiber Coating Structure Enables Direct Immersion Solid Phase Microextraction and High-Throughput Determination of Complex Samples

This study presents a new approach for improving the structure, and hence the robustness, of the SPME fiber coating applied for gas chromatography (GC) analysis. It involves application of an external layer of poly­(dimethyl siloxane) (PDMS) over the commercial PDMS/divinyl benzene (DVB) extraction phase. The fiber provided extraction capabilities similar to that exhibited by the original PDMS/DVB fiber toward triazole pesticides from water samples. Furthermore, the fiber could be utilized for over 100 extractions in direct contact with a complex food matrix such as whole grape pulp, with no sample pretreatment required. The amount of extracted pesticides from whole grape pulp had RSD values below 20% throughout 130 extraction/desorption/conditioning cycles, which is a dramatic improvement when compared to commercial PDMS/DVB fiber coating applied in food analysis facilitating high-throughput automation