高浓度抗坏血酸存在下氮掺杂石墨烯/壳聚糖修饰电极对尿酸的选择性测定

Selective Determination of Uric Acid at Nitrogen-doped Graphene/Chitosan Composite Modified Electrode in the Presence of a Large Amount of Ascorbic Acid

采用一步水热合成法制备了氮掺杂石墨烯,采用滴涂法制备了氮掺杂石墨烯/壳聚糖修饰电极（N-GN-CS/GCE）,研究了在大量抗坏血酸存在下尿酸在此修饰电极上的伏安行为。结果表明,尿酸在此修饰电极上有一个明显的氧化峰,其峰电流约为裸电极的7倍;同时,氮掺杂石墨烯/壳聚糖复合修饰材料显著提高了尿酸对抗坏血酸的选择性,尿酸和抗坏血酸的峰电位差可达362 m V,可实现高浓度抗坏血酸存在下尿酸的选择性测定。优化了修饰材料的滴涂量、溶液pH值、扫描速度等实验参数,利用差分脉冲伏安法对尿酸进行测定,尿酸的脉冲峰电流与尿酸浓度分别在0.1~20μmol/L和20~400μmol/L浓度范围呈良好的线性关系,检出限为0.01μmol/L,相对标准偏差为3.3%（n=8）。将本方法用于实际尿样的测定,回收率为99.7%~103.4%。

Nitrogen-doped graphene was synthesized by one-step hydrothermal method. A nitrogen-doped graphene-chitosan modified electrode（ N-GN-CS / GCE） was prepared and the electrochemical behavior of uric acid in the presence of a large amount of ascorbic acid was investigated at the modified electrode. The peak current of uric acid at the modified electrode was 7 times as that at unmodified electrode. The peak separation of uric acid and ascorbic acid was 362 m V and uric acid could be accurately determined in the presence of a large amount of ascorbic acid. Some experimental parameters such as dopping volume,p H and scan rate were optimized and a standard curve was also established using differential pulse voltammetry. The linear range between the peak current and the concentration of uric acid was 0. 1 ~ 20 μmol / L and 20- 400 μmol / L,and the detection limit was estimated to be 0. 01 μmol / L. The proposed method was applied to the analysis of uric acid in human urine sample with recoveries between 99. 7% and 103. 4%.