尿酸在聚L-苯丙氨酸修饰电极上的伏安测定

Cyclic Voltammetry Determination of Uric Acid at a L-Phenylalanine Modified Electrode

采用循环伏安法制备了聚L-苯丙氨酸薄膜修饰玻碳电极,研究了尿酸在该修饰电极上的电化学行为,循环伏安法测定了尿酸。研究发现,在pH=5.6的磷酸盐缓冲溶液中,尿酸在聚L-苯丙氨酸修饰电极上于0.43V处产生1灵敏的氧化峰;循环伏安法测定其氧化峰电流与尿酸的浓度在2.0×10-6～3.0×10-4mol/L呈良好的线性关系,检出限为1×10-6mol/L。对1.0×10-5mol/L尿酸平行测定5次,相对标准偏差为3.0%。该聚合物修饰电极制作简单,重现性好,可用于尿液中尿酸的测定,结果令人满意。

L-Phenylalanine modified electrode was prapared and used to detect uric acid （UA） in urine via cyclic vohammetry. In phosphate buffer solution （pH = 5.6 ）, UA displayed a sensitive oxidation peak at 0. 43 V on L-phenylalanine modified electrode. The peak current was well proportional to the concentration of UA in a range of 2.0 × 10^-6- 3.0 × 10^ -4 mol/L with a detection limit of 1 × 10^-6 mol/L. The relative standard deviation was estimated to be 3.0% from the parallel determinations of 1.0 × 10 ^-5 mol/L uric acid in quintuplicate. The modified electrode is easy to prepare with good reproducibility and has been applied to the determination of UA in urine with satisfactory results.