A rapid and highly sensitive flow injection chemiluminescence immunoassay was developed to detect ractopamine residues in pork products. Palladium nanocubes with excellent catalytic performance for a traditional luminol–PIP–H₂O₂ chemiluminescence system were used as effective carriers to connect a ractopamine antibody and horseradish peroxidase (HRP). Double amplification of a chemiluminescence signal was realized because of palladium nanocubes and HRP. Carboxyl-modified resin beads were used as suitable materials to load ractopamine-coating antigens due to their good biocompatibility and large specific surface area. Based on the principle of competitive immunity, ractopamine standard solution would compete with antigen loaded on carboxyl resin beads for limited binding sites on a ractopamine antibody. Thus, the chemiluminescence intensity of an immunosensor has a linear negative correlation with the logarithm value of ractopamine concentration. Under optimal experimental conditions, the detection range of ractopamine was 0.005–1000 ng mL⁻¹, and the limit of detection (LOD) was 1.7 pg mL⁻¹ (S/N = 3). The proposed immunoassay possessed acceptable accuracy, high specificity and reproducibility and RAC was examined in pork and pig feed with satisfactory results, which would provide a better prospect for the detection of small molecules in food and environment analysis.

中文翻译：

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基于Pd纳米立方和HRP的双催化信号扩增，使用流动注射化学发光免疫分析法超灵敏地测定莱克多巴胺。

建立了一种快速，高度灵敏的流动注射化学发光免疫分析法，以检测猪肉产品中的莱克多巴胺残留。钯纳米立方体对传统的鲁米诺–PIP–H ₂ O ₂具有出色的催化性能化学发光系统被用作连接莱克多巴胺抗体和辣根过氧化物酶（HRP）的有效载体。由于钯纳米立方体和HRP，实现了化学发光信号的双重扩增。由于其良好的生物相容性和较大的比表面积，将羧基改性的树脂珠用作负载莱克多巴胺包被抗原的合适材料。基于竞争性免疫的原理，莱克多巴胺标准溶液将与负载在羧基树脂珠上的抗原竞争莱克多巴胺抗体上有限的结合位点。因此，免疫传感器的化学发光强度与莱克多巴胺浓度的对数值呈线性负相关。在最佳实验条件下，莱克多巴胺的检测范围为0.005–1000 ng mL ^-1，检出限（LOD）为1.7 pg mL ^-1（S / N = 3）。所提出的免疫测定具有可接受的准确性，高特异性和可重复性，并且在猪肉和猪饲料中检测到RAC具有令人满意的结果，这将为食品和环境分析中的小分子检测提供更好的前景。