Determination of aliphatic amines in food by on-fiber derivatization solid-phase microextraction with a novel zeolitic imidazolate framework 8-coated stainless steel fiber

Some harmful aliphatic diamines, e.g., putrescine (Put) and cadaverine (Cad), play important roles in food safety evaluation. In this study, we proposed on-fiber derivatization solid-phase microextraction analysis of non-volatile aliphatic diamines in fish using zeolitic imidazolate framework 8 (ZIF-8) as a solid-phase microextraction (SPME) coating. It was employed to encapsulate isobutyl chloroformate (IBCF, 40 degrees C, 15min) for aqueous extraction of Put and Cad. After that, the derivatized aliphatic amines were thermally desorbed in the GC injection port and analyzed by GC-MS. The porous and hydrophobic ZIF-8 with high surface area can increase the IBCF loading amount and prevent it from decomposing, thus increasing the amine extraction effectiveness and sensitivity. In SIM mode and using the molecular ion for quantification, the limits of detection for Put and Cad were 27.1 and 33.2 mu gL(-1), respectively under the optimal conditions. The fiber-to-fiber reproducibility values (RSDs) for three ZIF-8 coated fibers were less than 11.4% for both Put and Cad. The extraction with the new fiber was reproducible for at least 30 cycles without a noticeable decrease of performance (RSD < 10%). The new fiber was successfully applied to the detection of putrescine and cadaverine in several fish samples and showed good recoveries (78.6-104%).