Robert Shirey

A solid phase microextraction (SPME) method was developed using a new overcoated PDMS–DVB fiber for immersion extraction of pesticide residues from spaghetti sauce. The overcoating, which consisted of polydimethylsiloxane, offered protection to the SPME fiber, making it more resistant to physical and chemical damage. Also, it increased fiber selectivity for the smaller analyte molecules over macromolecules present in sample matrix. This then allowed it to be used in immersion extraction of a very complex matrix-spaghetti sauce. Performance of the overcoated fiber was compared to a nonovercoated fiber of the same chemistry for method accuracy, precision, and durability. The SPME method developed using the overcoated fiber was then compared to extraction of the same pesticides in spaghetti sauce using a conventional QuEChERS method for extraction and cleanup. SPME was comparable to the QuEChERs method for both accuracy and precision. However, its main advantage over QuEChERS was in sensitivity and method simplicity.