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.