【摘要】 利用循环伏安法制备了聚缬氨酸修饰电极,在缬氨酸浓度为0.01 mol/L的磷酸盐缓冲溶液(pH=9.0)中,起止电位范围为1.0~2.4 V,以40 mV/s扫描速率循环扫描9周进行聚合。聚缬氨酸膜对去甲肾上腺素(NE)的电化学氧化具有明显的催化作用。研究了NE在聚缬氨酸修饰电极上的电化学行为,建立了测定NE的电化学分析新方法。pH值在2.2~8.0范围内,研究了磷酸盐缓冲溶液pH值对NE电化学行为的影响。结果表明,氧化还原峰电位随pH值升高发生负移;在pH=4.0磷酸盐缓冲溶液中,NE在修饰电极上呈现1对灵敏的氧化还原峰,利用循环伏安法测定NE还原峰电流可排除抗坏血酸(AA)干扰。NE在聚缬氨酸修饰电极上的还原峰电流与其浓度在4.6×10-7~1.1×10-5mol/L和1.1×10-5~1.2×10-4mol/L范围内呈良好线性关系;相关系数分别为0.995 7和0.991 8;检出限(S/N=3)为8.0×10-8mol/L;其回归方程为ipc(A)=6.80×10-7+1.05c,ipc(A)=1.23×10-5+0.16c。修饰电极具有良好的灵敏度、选择性和稳定性,可用于去甲肾上腺素针剂样品分析。更多还原

【Abstract】 A glassy carbon eletrode(GCE) was modified with electropolymerized films of valine by cyclic voltammetry(CV) in phosphate buffer solution(PBS) of pH=9.0 containning 0.01 mol/L valine and conditioned by cyclic sweeping from 1.0~2.4 V at 40 mV/s for 9 scans.The modified electrode showed an excellent electrocatalytical effect on the oxidation of norepinephrine(NE).The voltammetric behavior and electrochemical analysis method of NE were studied on the modified electrode.The effect of PBS pH value on the response of NE was studied in a pH value range of 2.2~8.0.The results show that the redox peak potential of NE shifts negatively with increasing of pH value and a pair of well-defined redox waves are observed in PBS of pH=4.0.The modified electrode was used to determine NE in an excess of ascorbic acid(AA) by reduction peak current of CV.The reduction peak currents increased linearly in two concentration ranges of NE,one is 4.6×10-7~1.1×10-5 mol/L,the other is 1.1×10-5~1.2×10-4 mol/L,correlation coefficients of which are 0.995 7 and 0.991 8 respectively,the detection limit(S/N=3) is 8.0×10-8 mol/L.The linear regression equations are ipc(A)=6.80×10-7+1.05c and ipc(A)=1.23×10-5+0.16c.The valine modified electrode showed good sensitivity,selectivity,stability.It was applied to the NE injection sample analysis.更多还原