壳聚糖无纺布在酶抑制法农药残留快速检测上的应用研究

    Research on the application of chitosan nonwoven fabric in rapid detection of pesticide residues by enzyme inhibition method

    • 摘要: 有机磷与氨基甲酸酯类农药残留超标严重威胁食品安全,开发高效快速的筛查技术至关重要。本研究以酶抑制法为核心,利用乙酰胆碱酯酶(AChE)的催化特性,以碘化乙酰硫代胆碱(ATCI)为底物、双二硝基苯甲酸(DTNB)为显色剂,制备一步式农药残留快速检测试纸条。试纸条构造如下:以PVC板为支撑载体,依次集成样品垫、酶垫、阻滞垫、底物垫、显色垫和吸附垫等六大组件。其中酶垫、底物垫、显色垫的最佳固定材料均为壳聚糖无纺布。经优化确定酶垫最优固定条件为pH = 8.0、4 ℃恒温固定8 h。敏感性测试表明,该试纸条对农药的敏感性显著优于游离酶及市售卡,敌百虫、辛硫磷、马拉硫磷、甲萘威、呋喃丹的检出限(LOD)分别达0.2、0.25、0.35、1.6、0.4 mg/L。常温条件下该试纸条15 min即可完成检测,兼具快速检测与可降解特性,4 ℃避光环境中可稳定保存60 d,适配基层现场检测场景,应用价值显著。

       

      Abstract: Organophosphorus and carbamate pesticide residues pose severe threats to food safety, making it essential to develop efficient and rapid screening technologies. This study was based on the enzyme inhibition method, using the catalytic activity of acetylcholinesterase (AChE), with acetylthiocholine iodide (ATCI) as the substrate and 5,5’-dithiobis-(2-nitrobenzoic acid) (DTNB) as the chromogenic agent, to prepare a one-step rapid test strip for pesticide residue detection. The test strip was constructed as follows: using a PVC plate as the supporting substrate, it integrated six key components sequentially, including the sample pad, enzyme pad, blocking pad, substrate pad, chromogenic pad, and adsorption pad. Chitosan nonwoven fabric was identified as the optimal immobilization material for the enzyme pad, substrate pad, and chromogenic pad. Optimization results indicated that the best immobilization conditions for the enzyme pad were pH = 8.0 and immobilization at 4 ℃ for 8 hours. Sensitivity tests demonstrated that the test strip exhibited significantly higher sensitivity to pesticides compared to free enzymes and commercially available kits, with half-maximal inhibitory concentrations (IC50) for trichlorfon, phoxim, malathion, carbaryl and carbofuran reaching 0.2, 0.25, 0.35, 1.6 and 0.4 mg/L, respectively. The test strip enables detection within 15 minutes at room temperature, featuring both rapid detection and biodegradable properties. It remained stable for up to 60 days when stored at 4 ℃ away from light, making it well-suited for on-site testing at the primary level and demonstrating significant application value.

       

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