Coulombimetric immunosensor for paraquat based on electrochemical nanoprobes
Coulombimetric immunosensor for paraquat based on electrochemical nanoprobes
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DOI：
10.1016/j.snb.2013.12.029
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发表时间：
2014-04
影响因子：
8.4
通讯作者：
E. Valera;Raul Garcia-Febrero;I. Pividori;F. Sánchez-Baeza;M. Marco
中科院分区：
文献类型：
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作者：
E. Valera;Raul Garcia-Febrero;I. Pividori;F. Sánchez-Baeza;M. Marco
研制了一种新的用于检测食品中百草枯农药残留的电化学免疫传感器。该免疫传感器使用电化学纳米探针，其通过用CdS纳米颗粒（CdSNP）标记PQ特异性抗体和抗原生物功能化磁性μ颗粒来制备。使用石墨复合电极（GECs）进行电化学测量。免疫化学反应后，CdSNP溶解，释放的金属离子在电极上被还原，并通过众所周知的阳极溶出技术以电流或电荷信号的形式读取。由于CdSNP对电流/库仑信号产生的放大效应，达到了非常高的可检测性。因此，PQ的IC 50电流为0.18 ± 0.31 μg L−1（在PBST中）。该免疫传感器已用于马铃薯样品中PQ残留的分析。结合适当的提取程序，PQ可以在1.4 μg kg−1的LOD电流下检测到，远低于欧盟为大多数作物中该农药规定的最大残留限量（MRL，20 μg kg−1）。同样，工作范围在3.08和67.76 μg kg−1之间。初步实验表明，本文提出的免疫传感器可以用作筛选工具，以区分合规和不合规的食品样品。
A new electrochemical immunosensor has been developed to detect paraquat (PQ) pesticide residues in food samples. The immunosensor presented uses electrochemical nanoprobes prepared by labeling the PQ specific antibodies with CdS nanoparticles (CdSNP) and antigen biofunctionalized magnetic μ-particles. Electrochemical measurements are performed using graphite composite electrodes (GECs). After the immunochemical reaction, theCdSNP are dissolved and the metal ions released are reduced at the electrode and read in the form of current or charge signal, by the well-known anodic stripping technique. Due to the amplification effect produced by theCdSNP on the amperometric/coulombimetric signal, a very high detectability is reached. Thus, PQ can be detected with an IC50currentof 0.18 ± 0.31 μg L−1(in PBST). The immunosensor has been implemented in analyzing PQ residues in potato samples. Combined with a suitable extraction procedure PQ can be detected with a LODcurrentof 1.4 μg kg−1, far below the maximum residue limit (MRL, 20 μg kg−1) established by the EU for this pesticide in most crops. Likewise, the working range was in the interval between 3.08 and 67.76 μg kg−1. Preliminary experiments demonstrate that the immunosensor presented here could be used as screening tool to distinguish between compliant and non-compliant food samples.