本文提出了一种免疫比色方法用于检测猪肉中莱克多巴胺的残留。该方法结合了抗原抗体特异性结合的高选择性特点和胶体铂颗粒（PtNPs）与多聚酶螯合物复合物（PtNPs-PV）的信号放大效应，能特异、灵敏地检测样品中痕量的莱克多巴胺（Ractopamine，RAC）残留。多聚酶螯合物（PowerVision，PV）上含有二抗和大量的辣根过氧化物酶（Horseradish Peroxidase，HRP），与抗体特异结合的同时催化底物二氨基联苯胺（3,3’-diaminobenzidine，DAB）产生显色沉淀，并且胶体铂颗粒（PtNPs）也能催化DAB产生显色沉淀与复合物，从而达到双重放大效果。通过测定DAB沉淀吸光度的变化能对应计算样品中莱克多巴胺的残留量。结果表明，在优化的测定条件下，该方法具有较高的检测灵敏度并在0.05~20 ng/mL范围内具有良好的相关性，R2=0.992，检测下限是0.025 ng/mL。所提出的方案具备灵敏度高、选择性强、准确性高且检测速度快等优点，可以适应猪肉中莱克多巴胺残留的现场检测需求。

A colorimetric immunoassay for the detection of ractopamine (RAC) residues in pork is presented in this study. This method combined the high selectivity of antigen-antibody specific binding and the signal-amplification effect from the complex of colloidal platinum nanoparticles (PtNPs) and the PowerVision (PV) agent. It could detect RAC residues at ultra-trace levels specifically and sensitively. The secondary antibodies and a large amount of horseradish peroxidase (HRP) contained in the PV agent can specifically bind with antibodies and catalyze the substrate 3,3'-diaminobenzidine (DAB) to generate colored precipitates. PtNPs can also catalyze DAB to produce colored precipitates and complexes, thereby, achieving a double amplification effect. The amount of RAC residues in the sample can be calculated by measuring the changes in the absorbance of DAB precipitation. Under the optimized assay conditions, this method exhibited a high detection sensitivity and a good correlation in the range of 0.05~20 ng/mL with R2 = 0.992 And the detection limit was 0.025 ng/mL. This approach showed many advantages,including high sensitivity, selectivity, and accuracy as well as rapid detection,which can meet the requirement of onsite surveillance of RAC residues in pork.

浙江省公益性项目（2014C32051），国家支撑计划（2012BAK08B01- 2），国家水禽产业体系（CARS-43-17）