Immunochemical techniques for anabolic androgenic steroid: matrix effects study for food supplements

Anabolic androgenic steroid contaminations in food supplements are common, and their consumption may lead to positive doping results. One of such anabolic steroid is mesterolone selected as an analyte for the present study. Some contaminated supplements cannot be detected by traditional methods due to the matrix effect. Two variants of indirect competitive immunochemical method—an enzyme-linked immunosorbent assay and an immunochromatographic method were developed using rabbit polyclonal antibodies and corresponding mesterolone conjugated at position C-17 to bovine serum albumin. Under optimal experimental conditions, the ELISA achieved the limit of the detection value of 0.010 ± 0.003 ng mL−1 and for LFIA visual detection limit was determined as concentration 50 ng mL−1. Both methods showed the mesterolone specificity of anti-mesterolone antibodies. The developed ELISA and LFIA were then applied to artificially contaminated food supplements. Before immunoassays, the samples were treated using a simple extraction protocol that did not include preliminary clean-up steps. For ELISA, a negative effect on the sensitivity of the method was observed for complex matrix samples. All type of analysed sample matrixes have minimal effect on LFIA sensitivity and, therefore, it could be successfully applied for the simple screening quality of food supplements.