分子印迹电化学发光传感器的制备及其对卡那霉素的测定应用

Preparation of Molecularly Imprinted Electrochemiluminescence Sensor and Its Application for Determination of Kanamycin

制备了硫化镉量子点-壳聚糖(CdS-CS)复合物修饰的玻碳电极(GCE),记作CdS-CS/GCE。以卡那霉素为模板分子,3-氨基苯硼酸(APBA)为功能单体,采用循环伏安法在CdS-CS/GCE表面电聚合得到了分子印迹聚合物(MIP)膜,所制备的传感器记作MIP/CdS-CS/GCE。卡那霉素可与传感器表面的MIP特异性结合,占据印迹孔穴,阻断共反应剂K2S2O8扩散到电极表面的通路,使电化学发光强度减弱。以传感器在空白溶液中的电化学发光强度(I_(0))与传感器在卡那霉素标准溶液中的电化学发光强度(I)的差值ΔI(ΔI=I_(0)-I)作为响应信号,在优化的试验条件下,响应信号ΔI与卡那霉素浓度的对数值在1.0×10^(-11)~1.0×10-7mol·L^(-1)内呈线性关系,相关系数为0.9990,检出限(3S/N)为5×10^(-12)mol·L^(-1)。按标准加入法对实际样品进行回收试验,回收率为99.9%~103%,测定值的相对标准偏差(n=5)为2.5%~4.3%。

A glass carbon electrode(GCE)modified with a composite of CdS quantum dots and chitosan(CdS-CS)was prepared,and the modified electrode was denoted as CdS-CS/GCE.Kanamycin was used as the template molecule and 3-aminophenylboronic acid(APBA)was used as the functional monomer.Molecularly imprinted polymer(MIP)membrane was prepared with electropolymerization on the surface of the modified electrode by cyclic voltammetry(CV).The constructed sensor was denoted as MIP/CdS-CS/GCE.Kanamycin could specifically bind to the MIP on the sensor surface and occupy the imprinting hole.Therefore,kanamycin could block the diffusion of K2S2O8 as a co-reactant to the electrode surface and reduce the electrochemiluminescence intensity.The differenceΔI(ΔI=I_(0)-I)between the electrochemiluminescence intensity(I_(0))of the sensor in blank solution and the electrochemiluminescence intensity(I)of the sensor in kanamycin standard solution was used as response signal.Under the optimized experimental conditions,linear relationship between the response signalΔI and the logarithm values of kanamycin concentration was found in the range of 1.0×10^(-11)-1.0×10-7mol·L^(-1),and the correlation coefficient was 0.9990.The detection limit(3S/N)was 5×10^(-12)mol·L^(-1).Test for recovery was made by standard addition method on the actual sample,giving results in the range of 99.9%-103%,with RSDs(n=5)of the determined values in the range of 2.5%-4.3%.