An highly sensitive, stable and label-free electrochemical immunosensor for the detection of 1 -pyrenebutyric acid (PBA) was developed based on graphene (GS) and chitosan (CS) composites modified glassy carbon electrode ( GS - CS/GCE ) . The proposed GS - CS/GCE was activated by the l-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride ( EDC ) and N-hydroxysuccinimide (NHS) (4:1) solution in order to covalently immobilize PAHs antibody (anti-PAHs). The morphology of the GS - CS composites film was characterized by transmission electron microscopy (TEM). In phosphate buffer solution (pH 7. 0) containing 0. 1 mol/L KC1 and 10 mmol/L K3Fe( CN)6 solution (0. 1 mol/L KC1 + 10 mmol/L K3Fe(CN)6 +0. 1 mol/L PBS(pH 7. 0)), the electrochemical behaviors of the modified electrode and the electrochemical properties of the immunosensor were studied by cyclic voltammetry ( CV) and differential pulse voltammetry ( DPV). Due to the synergistic effect of grapheme and chitosan, the peak current of GS - CS/GCE in the supporting electrolyte was largely increased, which was attributed to improve sensitivity of the immunosensor. Under the optimized conditions, the immobilization amount of antibody was significantly improved on the modified e-lectrode, resulting in amplifying the molecular recognition ability of the modified electrodes. Because of the poor conductivity of the antybody - antigen immunocomplex, the current response of the proposed immunosensor decreased linearly with increase of PBA concentration. The linear range of the immunosensor for PBA detection was 0. 1 -80 μg/L with a detection limit of 0. 03 μg/L. With excellent selectivity and reproducibility, the proposed immunosensor was applied in the determination of PBA in the real sample with spiked recoveries of 90% -105% .%采用石墨烯(GS)和壳聚糖(CS)复合膜修饰玻碳电极(GS-CS/GCE),利用1-乙基-(3-二.甲基氨基丙基)碳二亚胺盐酸盐(EDC)和N-羟基丁二酰亚胺(NHS)(4∶1)活化GS-CS/GCE,共价固定多环芳烃抗体(anti-PAHs),构建灵敏度高、稳定性好的非标记电流型免疫传感器,用于1-芘丁酸(PBA)的检测.运用扫描电子显微镜对GS-CS复合膜的形貌进行表征.在pH 7.0含10 mmol/L K3Fe(CN)6和0.1 mmol/L KCl的磷酸盐溶液中,通过循环伏安法和示差脉冲伏安法研究修饰电极表面的电化学性质,并考察了免疫传感器的电化学性能.研究表明,由于石墨烯和壳聚糖的协同作用,GS-CS修饰的玻碳电极在Fe(CN)64-/3-溶液中的峰电流明显增大,有利于提高免疫传感器的灵敏度.在优化实验条件下,电极表面的anti-PAHs抗体固定量显著提高,增强了电极的分子识别性能.由于anti-PAHs抗体-.抗原结合物的导电性较差,免疫传感器的峰电流随着待测溶液中PBA浓度的增大而减小,PBA浓度在0.1～ 80 μg/L范围内呈良好的线性关系,检出限为0.03μg/L.该免疫传感器重现性好、特异性强,用于实际样品的测定,回收率为90％～105％.
展开▼
