Immunochemical approaches for detection of aflatoxin B1 in herbal medicines.

INTRODUCTION: Aflatoxin B1 (AFB1) is a toxic low-molecular-weight secondary metabolite of Aspergillus flavus and A. parasiticus. AFB1 was classified as a Group I carcinogen by the World Health Organisation for Research on Cancer in 1993. AFB1 is an unavoidable natural contaminant of some herbal medicine, able to cause serious health issues for humans consuming the related medicine. OBJECTIVE: Therefore, this study aimed to develop an efficient fluorescence polarisation immunoassay (FPIA) and a rapid, low-cost, and easy-to-use membrane-based flow-through immunoassay (MBA) for determination of AFB1 in herbal medicine Origanum vulgare L., Rubus idaeus L., Urtica dioica L. and Sorbus aucuparia L. RESULTS: A cut-off level of the developed MBA was 0.8 ppb. Validation of the developed test was performed with blank and spiked samples. Using three naturally contaminated or three artificially spiked samples. The FPIA showed a linear working range of 8.6 to 64 ppb, and a half maximal inhibitory concentration (IC50 ) of 24 ppb. CONCLUSION: The results were in good correlation with the enzymelinked immunosorbent assay (ELISA) results (the IC50 0.1 ppb). Both the sample preparation and analysis are simple, cost-effective and easy to perform on-site in non-laboratory environments. Liquid chromatography with tandem mass spectrometry (LC-MS/MS) was used as a confirmatory technique.

New approach to quantitative analysis of benzo[a]pyrene in food supplements by an immunochemical column test.

A quantitative immunochemical rapid test for sensitive determination of benzo[a]pyrene (BAP) as a model analyte was developed making use of a handheld reader for results evaluation. The covalent immobilization of antibodies to different Sepharose gels, i.e., CNBr-activated Sepharose 4B and CNBr-activated Sepharose 4 Fast Flow was compared with adsorption to a polyethylene support. The lowest limits of detection (LOD) were 4 ng L(-1) and 40 ng L(-1), respectively, using optimized assay conditions. The developed test was applied to food supplements (garlic, black radish and maca), including a pretreatment procedure. LOD of 9 ng kg(-1) and linear range of 13-80 ng kg(-1) were obtained. Results of BAP determination in naturally contaminated samples were confirmed by high-performance liquid chromatography coupled to fluorescence detection and a good correlation was achieved. We suggest that the developed test format can be used to quantitative detection of the low molecular weight analytes, such as mycotoxins, pesticides, other pollutants in food and environmental samples.