Red 2G (R2.i), a cheap industrial colorant, cannot be added to food. An anti-R2C nonoclonal antibody (mAb) was prepared by ininiunizing ptice with the conjugate of R2C hapten and protein, which based on the 1-ethy1-3(3-dimethylarninopropyl) carbodiimide (EDC) method. Indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and colloidal gold-based immunocluomatographic assay (CG-ICA) rnetlods were used to determine R2G in fruit drinks, red wine, and yoghtwts. A standard curve of the developed ic-ELISA showed that the ICso of the anti-R2G rnAb was 1.02 ng/mL, and limit of detection value (LOZ) was 0.21 ng/mL. For the CGICA developed, the visual limit of detection values (vLOD) were 2 ng/ml. and cut-off valttes of 100 ng/ml. in sarnples. The results indicated that these two methods could be used to gttickly detec[ R2G in fruit drinks, red wine, and yoghtuts.

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.