Exploiting the tunable selectivity features of polymeric ionic liquid-based SPME sorbents in food analysis

In this work, the performances of polymeric ionic liquid (PIL) based solid-phase microextraction (SPME) coatings were assessed for applications concerning food safety and quality. Two different polymeric ionic liquid coatings, namely poly(1-4-vinylbenzyl-3-hexadecylimidazolium) bis[(trifluoromethyl)sulfonyl] imide (poly([VBHDIM][NTf2]), PIL 1, and N,N-didecyl-N-methyl-d-glucaminium poly(2-methyl-acrylic acid 2-[1-(3-{2-[2-(3-trifluoromethanesulfonylamino-propoxy)-ethoxy]-ethoxy}-propylamino)-vinylamino]-ethyl ester) (poly([DDMGlu][MTFSI]), PIL 2, were evaluated. The PIL-based coatings were compared to commercially available SPME coatings in terms of their performance toward extraction of pesticides and fruit metabolites. The partition coefficients (K_fs) of the tested coatings were calculated, with PIL 1 demonstrating similar or better performance compared to the commercial coatings. Design of experiment (DoE) was applied to optimize the parameters that most influenced SPME extraction, and a quantitative method for determination of 5 organophosphorus pesticides was developed by using PIL-based coatings and commercial SPME fibers. Despite the thin layer of the sorbent coating, PIL 1 achieved limits of quantitation at the low part-per-billion level. Moreover, in a comparative investigation of analyte coverage carried out via HS-SPME-GCxGC-ToF/MS with grape homogenate as model matrix, excellent performances were observed for the PIL-based coatings toward the determination of fruit metabolites, demonstrating their capability towards broad extractive coverage of analytes characterized by various physicochemical properties.