Development of enzyme-linked immunosorbent assay for rapid determination of sildenafil in adulterated functional foods

Abstract

Abstract To determine the sildenafil in adulterated functional foods, a rapid direct competitive enzyme-linked immunosorbent assay (ELISA) procedure employing a polyclonal antibody generated from sildenafil-KLH was established. The antibody showed high sensitivity and specificity in phosphate buffer, with an IC50 of 6±0.1 ng/mL and the limit of detection was 0.6±0.02 ng/mL. The matrix effect of the functional food samples was easily eliminated by using methanol and distilled water for extraction and dilution with PBS, without any clean-up procedure such as solid phase extraction or liquid–liquid extraction, much more simple and rapid than the other reports. For the validation of the established SIL–ELISA, the functional food sample spiked at three different concentrations, analysed by HPLC. The results showed good correlation between the data of ELISA and HPLC (r 2=0.9832). It approved that HPLC methods show the same results with ELISA, and the developed immunoassay method is considered reliable for detection of sildenafil.