Ultrasensitive detection of phenolphthalein in slimming products by gold-based immunochromatographic paper

An anti-phenolphthalein monoclonal antibody (mAb) was prepared based on the N,N′-Carbonyldiimidazole (CDI) method through phenolphthalein conjugated with proteins. Indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and colloidal gold-based immunochromatographic assay (ICA) methods were used to determine phenolphthalein in slimming products. A standard curve was established, and the IC50 and limit of detection of ic-ELISA were 0.95 and 0.10 ng/mL with a linear detection range of 0.27–3.37 ng/mL. The developed ICA was used to detect phenolphthalein in tablets, capsules, and slimming tea samples with visual limit of detection values of 10 μg/kg, and cut-off values of 200 μg/kg. The results indicated that these two methods could be used to quickly detect phenolphthalein in slimming products. Colloidal gold-based ICA methods were developed to determine phenolphthalein in slimming products. The developed ICA strip was used to detect phenolphthalein in tablets, capsules, and slimming tea samples with visual limit of detection values of 10 μg/kg, and cut-off values of 200 μg/kg. [Display omitted] •A sensitive anti-phenolphthalein monoclonal antibody (mAb) was fabricated.•ic-ELISA and the ICA strip methods were developed to determine phenolphthalein.•The visual limit of detection and cut-off values of the ICA were 10 and 200 μg/kg.