电化学还原氧化石墨烯/纳米金-壳聚糖复合膜修饰玻碳电极对尿酸的灵敏测定

A Glassy Carbon Electrode Modified with Electrochemically Reduced Graphene Oxide /Gold Nanoparticles-Chitosan Composite Film for Sensitive Determination of Uric Acid

将氧化石墨烯（GO）在玻碳电极（GCE）表面进行直接电化学还原，再组装上纳米金-壳聚糖（AuNP-CS）聚阳离子，形成了电化学还原氧化石墨烯/纳米金-壳聚糖（ERGO/AuNP-CS）复合膜修饰的玻碳电极。采用扫描电子显微镜（SEM）表征了不同修饰膜表面的形貌，探讨了其对尿酸（UA）分子的差分脉冲伏安（DPV）行为，发现ERGO/AuNP-CS复合膜对UA分子表现出显著的电催化氧化活性。在0.10mol/L磷酸盐缓冲溶液（pH=6.5）中，扫速为100mV/s时，此复合膜修饰电极的DPV响应与UA的浓度在0.05-110μmol/L范围内呈性关系，检测限为12.4nmol/L（S/N=3）。此修饰电极具有良好的选择性、重现性和稳定性，可应用于人体血清和尿液样品中UA的测定，回收率达到93.8%-104.1%。结果与分光光度法和尿酸酶试剂盒法相符。

An electrochemically reduced graphene oxide/gold nanoparticle-chitosan（ERGO/AuNP-CS） composite film modified glassy carbon electrode （ GCE） was constructed by directly electrochemical reduction of GO, and then assembly of AuNP-CS polycation on the surface. The surface morphologies of different modified electrodes including bare GCE, GCE/GO, GCE/ERGO and GCE/ERGO/AuNP-CS were characterized by scanning electron microscopy （ SEM ） . The differential pulse voltammetric behaviors of the electrodes were investigated, and the results indicated that the composite of ERGO/AuNP-CS exhibited excellent electrocatalytic oxidation activity to uric acid （ UA） molecule. In 0. 10 mol/L of phosphate buffer solution （pH=6. 5） with a scanning rate of 100 mV/s, the proposed composite film modified electrode showed a linear electrochemical response to UA in the range of 0 . 05-110 μmol/L with a detection limit of 12. 4 nmol/L （ S/N = 3 ）. The electrode displayed good selectivity, reproducibility and stability in the determination of UA in human serum and urine samples with a recovery of 93 . 8%-104 . 1%. The detection results were agreed with those of conventional spectrophotometry and uricase Kit methods.