Determination of aromatic amines in the urine of smokers using a porous organic framework (JUC-Z2)-coated solid-phase microextraction fiber

A solid-phase microextraction (SPME) fiber coated with a two-dimensional porous organic framework (POF), JUC-Z2, was synthesized by a sol-gel process. The JUC-Z2-coated SPME fiber was combined with gas chromatography-mass spectrometry/mass spectrometry (GC-MS/MS), and a direct analysis method without any derivatization step was developed for the determination of two major harmful aromatic amines (1-naphthylamine, 1-NA; 2-naphthylamine, 2-NA) in the urine of amokers. The new method exhibited satisfactory linearity in the wide range of 0.05-100 μg L−1 with correlation coefficients (R) of 0.9999. The limits of detection are 0.010 and 0.012 ng L−1. The relative standard deviations for repeated extraction (n = 6) with one fiber are less than 7.7%. The JUC-Z2-coated fiber demonstrates obviously superior extraction efficiencies for the two aromatic amines over the commercial fibers (CW/PEG, PA, PDMS/DVB, PDMS, CAR/PDMS, DVB/CAR PDMS). The structure-activity relationship was deeply investigated by the extraction comparison experiment with another similar POF material (PAF-48) and theoretical simulations. The extraction efficiencies of JUC-Z2 for 1-NA and 2-NA are 9.6 and 16.2 times higher than those of PAF-48, and JUC-Z2 has higher binding energies with the aromatic amines than PAF-48. The results indicate that the N atom on the JUZ-Z2 framework played a crucial role for adsorbing aromatic amines. Finally, the novel fiber has been successfully used to detect 1-NA and 2-NA in the urine of smokers.