Abstract

Malathion is a toxic organophosphorus pesticide. When ingested by humans, it affects the nervous system and endangers health. Herein, a new type of aptamer-based sensor was developed for its determination. The results demonstrate that this sensor has high sensitivity and good selectivity and was successfully used for the determination of malathion in apples. The detection mechanism is as follows. The aptamer is adsorbed on the surface of gold nanoparticles (AuNPs) to prevent the aggregation of AuNPs in a high salt solution. After adding malathion, the aptamer specifically binds to malathion and is removed from the surface of the AuNPs. The quantity of aptamer adsorbed on the surface of AuNPs had a negative relationship with the malathion concentration. The unmodified AuNPs aggregated to different degrees in NaCl solution. In the Fehling reaction, various degrees of aggregated AuNPs catalyze the reduction to different size Cu₂O and exhibit different resonance scattering intensities. An excellent linear response between the resonance scattering spectra intensity and malathion concentration was obtained. The limit of detection of the developed method was 5.24 ng/L (15.86 pM). The recovery and repeatability for the apple samples were satisfactory.

摘要

马拉硫磷是一种有毒的有机磷农药。人体摄入后会影响神经系统并危害健康。在此，开发了一种新型的基于适体的传感器用于其确定。结果表明，该传感器灵敏度高，选择性好，已成功用于苹果中马拉硫磷的测定。检测机制如下。适体被吸附在金纳米颗粒（AuNPs）的表面上，以防止AuNPs在高盐溶液中聚集。加入马拉硫磷后，适体特异性结合马拉硫磷，并从AuNPs表面去除。AuNPs表面吸附的适体数量与马拉硫磷浓度呈负相关。未修饰的AuNP在NaCl溶液中以不同程度聚集。在费林反应中₂ O并表现出不同的共振散射强度。在共振散射光谱强度和马拉硫磷浓度之间获得了极好的线性响应。所开发方法的检出限为5.24 ng / L（15.86 pM）。苹果样品的回收率和重复性令人满意。