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A novel colorimetric immunosensor based on platinum colloid nanoparticles immobilized on PowerVision as signal probes and Fe3O4@β‐cyclodextrin as capture probes for ractopamine detection in pork

Sun, Yangying, Fu, Tian, Chen, Shuxian, Wu, Zhen, Guo, Yuxing, Pan, Daodong, Gan, Ning
Journal of the science of food and agriculture 2019 v.99 no.6 pp. 2818-2825
absorbance, clenbuterol, color, colorimetry, detection limit, dopamine, enzymes, immunoassays, immunosensors, iron oxides, nanoparticles, pH, platinum, pork, ractopamine, temperature, toxins
BACKGROUND: A novel colorimetric immunosensor was developed for the simple, sensitive and selective detection of ractopamine (RAC) based on using β‐cyclodextrin‐modified Fe₃O₄ particles (Fe₃O₄@β‐CD) as capture probes and complex platinum colloid nanoparticles (PtNPs‐PV) composed of platinum colloid nanoparticles (PtNPs) and polymerase chelate PowerVision (PV) as signal probes. RESULTS: PtNPs‐PV double catalyzed the chromogenic substrate 3,3′‐diaminobenzidine (DAB), which induced changes in the color of DAB and chromogenic absorbance. Incubation temperature, pH and incubation time were systematically optimized and, under optimum conditions, the measured absorbance values showed a linear relationship with the RAC concentrations in the range 0.03–8.1 ng mL⁻¹. The detection limit was 0.01 ng mL⁻¹. The sensor exhibited high sensitivity and specificity, as demonstrated by testing structurally similar organic compounds such as salbutamol, clenbuterol and dopamine. The practicality of the developed colorimetric immunosensor was supported by the successful detection of RAC in pork samples with recovery ranging from 94.00% to 106.00%. CONCLUSION: We designed a novel sandwich‐type noncompetitive colorimetric immunoassay for the detection of trace levels of RAC in pork. The proposed method can also be used for the detection of toxins in food products via PtNPs‐PV amplification. © 2018 Society of Chemical Industry