制备了聚L-半胱氨酸修饰电极,研究了去甲肾上腺素在聚合物薄膜上的电化学行为,试验结果表明:在磷酸盐缓冲溶液中,聚L-半胱氨酸薄膜对去甲肾上腺素的电化学氧化具有明显的催化作用,对应用此修饰电极的循环伏安法测定去甲肾上腺素的条件进行试验并优化.结果发现:在pH 7.0的磷酸盐缓冲介质中测定时可排除肾上腺素与抗坏血酸干扰.还原峰电流的测定值与去甲肾上腺素浓度在5.0×10-7~1.2×10-4mol·L-1范围内呈线性关系,其检出限为2.0×10-8mol·L-1,已用于针剂样品分析,测得回收率在97.6%~102.1%之间.

The glassy carbon electrode was modified through electropolymerization with a film of L-cysteine in a phosphate buffer medium of pH 5.0 by cyclic voltammetry,and the electrochemical behavior of norepinephrine(NEP) at this modified electrode was studied.It was found that the electrochemical oxidation of NEP at the modified electrode was significantly catalyzed essentially due to the presence of L-cysteine.Conditions for determination of NEP by cyclic voltammetry with the modified electrode were studied and optimized.In the phosphate buffer of pH 7.0,interferences due to epinephrine and ascorbic acid were eliminated and NEP was determined by measuring the reductive peak current(Ipc).Linear relationship between Ipc and concentration of NEP was obtained in the range from 5.0×10-7 to 1.2×10-4mol·L-1and the detection limit(S/N=3) was found to be 2.0×10-8mol·L-1.The proposed method has been applied to the analysis of NEP injection samples,giving values of recovery in the range from 97.6% to 102.1%.