Fabrication of 8-aminocaprylic acid doped UIO-66 as sensitive solid-phase microextraction fiber for nitrosamines

The introduction of functional groups into metal organic frameworks has great potential for enhancement in adsorption performance of nitrosamines using solid phase microextraction (SPME). However, pre-functionalization and post-modification generally suffer from the same limitation that the additional functional groups occupy the free volume and thereby decreasing pore volume and special surface area. Herein, we use a modulator-induced defect-formation strategy to prepare the 8-aminocaprylic acid doped UIO-66 (Am-UIO-66) with high adsorption capacity of nitrosamines. Then, the as-synthesized UIO-66 and Am-UIO-66 were fabricated as SPME fibers exhibiting good adsorption capacity towards nitrosoamines. The reason was that the 8-aminocaprylic acid creates structural defects and additional pore spaces of Am-UIO-66, thus increases the specific surface area as well as pore volume. Finally, the Am-UIO-66-coated SPME fiber was successfully applied to the determination of nitrosamines migration from latex gloves and achieved good linearity (20-2000ngL^-1), satisfactory recoveries (85.2-112.8%) and rather low LODs (2.61-6.12ngL^-1), by coupling with gas chromatography-mass spectrometry (GC-MS).