Aflatoxins are a class of highly toxic chemical contaminants occurring in food. Consumption of aflatoxincontaminated food can lead to harmful effects on human health. A rapid and reliable analysis of aflatoxins in food is crucial. In this study, we generated a broad-specific monoclonal antibody (MAb) 3 C10 against aflatoxin B 1 (AFB 1 ). The MAb 3 C10 binds specifically to AFB 1 and AFM 1 and has a IC 50 of 0.13 μg L −1 for AFB 1 and 0.16 μg L −1 for AFM 1 . Furthermore, the MAb showed high cross-reactivity to AFB 2 , AFG 1 , and AFG 2 . To enable simultaneous AFB 1 and AFM 1 detection in different food matrices, an indirect competitive enzyme-linked immunosorbent assay (icELISA) based on MAb 3 C10 has been developed and optimized. In addition, the extraction methods of different food matrices (peanut, corn, soybean, wheat flour, rice, soy sauce, vinegar, wine, raw milk, pure milk, skimmed milk, and yogurt) were established. The average recovery ranged from 73 to 121 %, with relative standard deviation values less than 15 %. The limit of detection was 0.52+0.36 μg kg −1 (mean+3SD) for AFB 1 in eight agricultural products and 0.031+0.015 μg kg −1 (mean+3SD) for AFM 1 in four dairy products. The sensitivity of icELISA was below the limit set by the European Commission for aflatoxin detection in different food matrices and similar to LC-MS/MS method. We demonstrate a rapid, simple, and reliable method for simultaneous screening of AFB 1 and AFM 1 in different food matrices.

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In this study, a high sensitivity chemiluminescence enzyme immunoassay (CLEIA) based on novel enhancers was developed. Under optimal conditions, we developed an enhanced chemiluminescence reaction (ECR) catalyzed by horseradish peroxidase (HRP-C) in the presence of 3-(10'-phenothiazinyl) propane-1-sulfonate (SPTZ) and 4-morpholinopyridine (MORP) as enhancers. The limit of detection of the newly prepared chemiluminescent cocktail for HRP was 0.33 pg/well, which is lower than that of commercial Super Signal substrate. The results showed that this novel chemiluminescent cocktail can significantly increase the light output of HRP-catalyzed ECR, which can be translated into a corresponding improvement in sensitivity. Similar improvements were observed in CLEIA for the determination of chloramphenicol in milk. In addition, the ECR of N-azoles as secondary enhancer was also presented.

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A competitive indirect chemiluminescent enzyme-linked immunosorbent assay (CL-ELISA) for florfenicol (FF) and its major metabolite florfenicol amine (FFA) residues in chicken muscle has been developed and validated according to Commission Decision 2002/657/EC criteria. The IC 50 value of the method was 0.153 mg kg À1 for FFA with a cross-reactivity of 74.3% for FF under optimum conditions, in which FFA-F-BSA (FFA-formaldehyde-BSA) and FF-G-OVA (FF-glutaric anhydride-OVA) were used as an immunogen and a coating antigen, respectively. FFA and FF were easily extracted from chicken muscle with a 40 : 1 ethyl acetate-ammonia mixture, obtaining recoveries of 70.3-100% (FFA) and 71.8-102.0% (FF). Accuracy, precision, selectivity, robustness, limit of detection (LOD), limit of quantification (LOQ) and detection capability (CCb) of the assay have been assessed during the validation process. LOD values in chicken muscle were 0.353 mg kg À1 for FFA and 0.526 mg kg À1 for FF (10-fold dilution) and 0.453 mg kg À1 for FFA and 0.657 mg kg À1 for FF (100-fold dilution). Furthermore, the CL-ELISA method gave CCb values of 1.0 mg kg À1 for FFA and FF. Finally, real chicken muscle samples were analyzed with the CL-ELISA method, traditional ELISA and a previously reported gas chromatography-negative chemical ionization mass spectrometry (GC-MS), and results confirmed the utility of this new CL-ELISA for trace determination of FF and FFA, simultaneously.