硝酸铋修饰碳纤维电极循环伏安法测定水样中的半胱氨酸

半胱氨酸是生物体系中的一种重要氨基酸和临床分析中的疾病标记物。以循环伏安电化学方法在碳纤维簇电极表面上沉积铋粒子，从溶液中固相微萃取半胱氨酸，研究萃取过程的动力学和热力学。在最佳实验条件下，铋一半胱氨酸络合物的氧化峰电流与半胱氨酸浓度的对数存在两段线性关系，1．0×10^-4 -1．0×10^-7mol／L和1．0×10^-10～1．0×10^-16mol／L，最低检测限为1．0×10^-16mol／L，相对标准偏差为6．6％。共存的白氨酸、胱氨酸和蛋白质不干扰测定。用于沈阳师范大学湖水样本中的半胱氨酸检测，半胱氨酸含量为6．20μm。操作简便，快速，结果令人满意。

Determination of Cysteine in waste water by cyclic voltammetry on Bismuth modified carbon fiber cluster electrode

Cysteine is an important amino acid in life science, and one of the important disease marks in clinical assays. In this paper, carbon fiber clustered electrode was modified by Bismuth particles by cyclic voltammetric deposition, and used as a solid phase micro extractant of cysteine from aqueous solution. The kinetics and thermodynamics of the extraction process were studied by cyclic voltammetry. Under optimal experimental eonditions, the oxidation peak current of hismuth-cysteine complex is proportional to the logarithm of cysteine concentration with two lines in the range of 1.0 × 10^-4 - 1.0×10^-7 mol/L and the range of 1.0× 10^-10 -1.0×10^-16 mol/L. The lowest detection limit is 1.0×10^-16 mol/ L,and the relative standard deviation is 6.6%. The common existed leucine, dicystine and protein do not interfere with the detection. The method has been used in detecting the cysteine in the water samples of Shenyang Normal University eampus lake. The result was obtained as 6.20μm. The method is simple, fast, sensitive and selective with satisfactory results.