Determination of 19-nortestosterone residues in aquaculture tissues by enzyme-linked immunosorbent assay and comparison with liquid chromatography and tandem mass spectrometry

19-Nortestosterone (17β-NT) was oximated by carboxymethoxylamine and then coupled with bovine serum albumin (BSA) in a mixed-anhydride reaction in order to produce an antibody. The conjugate rate of 17β-NT and BSA was estimated to be 24 by ultraviolet spectrophotometry. Polyclonal antibody of 17β-NT was acquired from the animal immunized with the conjugate. Through an indirect enzyme-linked immunosorbent assay (ELISA), which demonstrated that the synthesis of immunogen was successful, the titre of antiserum was found to be 6.4?×?10⁵. Based on the purified antibody, a competitive indirect ELISA was developed. ELISA revealed that the limit of detection (LOD) was 0.07?ng?g^?1, the recovery (in edible tissues) was 71–89%, and the working range was 0.05–31.25?ng?g^?1. The preliminary evaluation of assay performance through specificity, sensitivity, precision, and accuracy revealed that this ELISA method could be used in the practical detection of 17β-NT in tissue samples. Moreover, this method was compared with high-performance liquid chromatography tandem mass spectrometry, for which the transition for quantification of 17β-NT was 275.4/109.1.