多壁碳纳米管修饰丝印电极的制备及在尿酸测定中的应用

Preparation of multi-walled carbon nanotube modified screen printed electrode and its application in uric acid determination

利用丝网印刷技术制作一次性使用的丝印碳糊电极,采用吸附法将羧基化的多壁碳纳米管修饰在电极表面,建立测定尿酸的简单快捷的电化学分析方法。将该法用于全血尿酸的测定,在pH 7.4的磷酸盐缓冲溶液中,测定尿酸的伏安行为,多壁碳修饰电极比裸电极具有更好的选择性和更高的灵敏度。差示脉冲伏安法测得尿酸浓度在2～100μmol/L范围内,峰电流值与浓度呈线性,相关系数为0.997 9,检测限为1.0μmol/L。在全血样本中,加入0～0.4 mmol/L的尿酸溶液,线性相关系数为0.9975。该方法简单、快速,电极制作成本低,所需仪器简单,样品不需预处理,用于全血尿酸的测定结果满意,可作为一次性测试条使用,为尿酸检测走入小型化、家庭化提供了实验基础。

The one-off screen printed carbon paste electrode was prepared using screen printing technology. Carboxylic multi-walled carbon nanotubes were absorbed on the working surface of screen printed electrode, which proved to be a simple and rapid electrochemical analysis method of uric acid determination. The assay was applied to the determination of uric acid in whole blood. The electrocatalytic response of uric acid on the modified screen printed electrode was evaluated by cyclic voltammetry in a 0.1 mol/L phosphate buffer （pH 7.4） and the modified electrode exhibited better selectivity and higher sensitivity than the bare screen printed electrode. The linear calibration curve was obtained in the range of 2-100 μmol/L, with a correlation coefficient of 0.9979, and a detection limit of 1.0 μmol/L in differential pulse voltammetry. Linearity was obtained with correlation coefficient of 0.9975 for adding 0-0.4 mmol/L uric acid in the blood sample. The method is simple and rapid with a low manufacturing cost of the electrode and a simple apparatus. The samples can be assayed directly without pretreatment. The assays were applied to the determination of uric acid in whole blood with satisfactory results. The electrode can be used as one-off test strip. The method offered an experimental basis for family testing of uric acid and miniaturization of uric acid sensors.