Development of an Enzyme-Linked Immunosorbent Assay for the Detection of 2-Amino-3-Methylimidazo [4, 5-f] Quinoline (IQ) in Processed Foods

Abstract

2-amino-3-methylimidazo [4, 5-f] quinoline (IQ), is a type of heterocyclic aromatic amines (HAAs) formed during the thermal treatment of food processing, which possesses potential carcinogenicity and mutagenicity for humans. In this work, a simple, selective and sensitive direct competitive enzyme-linked immunosorbent assay (dcELISA) for detecting IQ has been developed for the first time. 1H-pyrrolo [2, 3-f] quinoline (PQ), a structural analogue of IQ, was connected with two-carbon arm to obtain the hapten PQ acid (PQA), and then a specific polyclonal antibody was produced with PQA-bovine serum albumin (BSA) as immunogen. The half-maximum inhibition concentration (IC50) and limit of detection (LOD; calculated as IC15 value) of the assay were 50 ± 3 and 3 ± 0.3 μg L−1, respectively. The assay showed no cross-reactivity with other HAAs analogues except 2-amino-3,4-dimethylimidazo [4,5-f] quinoline (MeIQ) (12 %), which indicated that the assay had high specificity for the IQ. The proposed method was further applied successfully to determine IQ in fried beef, fried pork, and dried fish floss samples with satisfactory recoveries (84.96–116.23 %) and precision (CV%, 4.96–17.26 %). The LOD for IQ in processed foods was 15 μg kg−1. In addition, the results of the established method were in good agreement with the high-performance liquid chromatography (HPLC) (R 2 = 0.9917). All above shows the proposed immunoassay allows for a cost-effective, specific, accurate, and reliable quantitative detection of IQ in real processed food samples.