Detection of heterocyclic amine (PhIP) by fluorescently labelled cucurbit[7]uril

Abstract

Heterocyclic amines (HCA) are the main mutagenic factors in cooked meat products and are considered to be hazardous chemicals in the field of food safety. In this study, inspired by the “host–guest” interaction mechanism, a new technique for detecting 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP) was developed, taking advantage of the molecular cavities of cucurbit[7]uril (CB[7]) and the powerful guest recognition properties between CB[7] and PhIP. Based on this recognition mechanism, three steps were included in the detection procedure: firstly, regenerated cellulose (RC) membrane was oxidized by NaIO₄ to generate aldehyde groups; secondly, the PhIP molecules to be detected were trapped by the aldehyde groups via amine–aldehyde conjugation chemistry; thirdly, the RC membrane with trapped PhIP was immersed into solutions of dansyl chloride-labelled CB[7] to allow the host–guest interaction to occur, so that PhIP could be quantified by fluorescence of the dansyl chloride dye. The limit of detection, linear range and recovery of this method were about 0.224 μg kg⁻¹, 10–1000 nM and 89.0–96.4%, respectively. So far, most reported techniques for HCA detection are based on HPLC coupled with mass spectroscopy, and the method reported here might be the first quick measurement technique for HCA and may find wide application in food safety detection.