Porous boronate affinity monolith for on-line extraction coupled to high-performance liquid chromatography for sensitive analysis of heterocyclic aromatic amines in food samples

A novel on-line solid-phase microextraction-high-performance liquid chromatography (SPME-HPLC) system was developed for the determination of heterocyclic aromatic amines (HAAs) in food samples. A poly(vinylphenylboronic acid-co-ethylene glycol dimethacrylate) polymer monolith was prepared for on-line efficient extraction and large-volume injection was used to increase the sensitivity of detection. The polymermonolith, based on a ternary porogen, was prepared by in situ polymerization of vinylphenylboronic acid (VPBA) and ethylene glycol dimethacrylate (EGDMA) in a fused-silica capillary column. It showed good permeability, high extraction capacity, and high selectivity. The column-to-column reproducibility was satisfactory, and the enrichment factors for HAAs were 3746-7414. Conditions influencing the on-line extraction efficiency, including pH of sample solutions, flow rate of extraction and desorption, and desorption volume, were investigated. The proposed method had low limit of detection (0.10-0.15 ng/L) and good linearity. Trace HAAs in roast beef and Iamb samples were determined, and the amounts of 2-amino-3-methylimidazo[4,5-f]quinoline, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline, and 2-amino-3,4,7,8-tetramethyl-3H-imidazo[4,5-f]quinoxaline in these samples were 0.235-2.08 ng/g. The recoveries for the five HAAs ranged from74.3% to 119%, and the relative standard deviation (RSDs) were less than 8.2%. The results showed that the proposed on-line method was highly sensitive for monitoring HAAs in different food samples. (C) 2015 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.