Highly sensitive immunochromatographic assay for simultaneous determination of azaperone and azaperol in pork

In this study, a sensitive immunochromatographic assay (ICA) was developed for simultaneously detecting azaperone (AZN) and its metabolite azaperol (AZL) based on the high-affinity monoclonal antibody (mAb). Herein, the hapten AZL-SA was synthesized by succinic anhydride method, and then the conjugates AZL-SA-OVA and AZL-SA-KLH were prepared by EDC/NHS method. Subsequently, mAb was produced for targets monitoring through two detection modes. In direct ICA (using gold nanoparticles labeled specific antibodies), the visual LOD of AZN was 80 ng/g. For indirect ICA (using gold nanoparticles labeled anti-species antibodies), the visual and instrumental LODs of AZN were 8 and 0.14 ng/g, and AZL were 8 and 0.12 ng/g, respectively. The results indicated that the visual detection limit (LOD) of indirect format was tenfold lower than that of direct format. The established analytical method obtains the results within 15 min and provides a sensitive and simple tool for on-site detection of AZN and AZL.