汞膜电极上N-乙酰-L-半胱氨酸的电化学行为

Electrochemical Behavior of N-Acetyl-L-cysteine at Mercury Film Electrode

研究了汞膜电极上N 乙酰 L 半胱氨酸 (C5H8O3 SH ,NAC)的电化学行为和测定方法。在 0 .1mol LHAc NaAc缓冲溶液 (pH =4 .5 )介质中 ,方波伏安扫描于～ -0 .2 5V(vs.Ag AgCl)处出现一灵敏的阴极还原峰 ,用循环伏安法、线性扫描极谱法和脉冲极谱法等手段研究了体系的电化学行为及其反应机理。实验表明 :该峰具有明显吸附性 ,吸附分子为Hg2 (C5H8O3 S) 2 ,电子转移系数α为 0 .82 ,电子转移数为 1。NAC的浓度在1 2×1 0 - 8～ 5 .0× 1 0 - 6 mol L范围与其方波伏安峰高有良好的线性关系。方法的检出限为 5 .0× 1 0 - 9mol L ,用于富露施颗粒剂中NAC含量的测定 。

In the medium of 0.1 mol/L HAc-NaAc buffer solution (pH = 4.5), a sensitive square wave voltammetric peak of N-acetyl-L-cysteine (NAC) at mercury film electrode at about -0.25 V(vs . Ag/AgCl) was observed. The electrochemical behavior and. reaction mechanism of this system have been studied by linear sweep, cyclic voltammetry and pulse polarography. The experiment results indicated that the number of electron involved in the electro-reduction was 1, and the electrode transfer coefficient was 0.82. There was a good linear relationship between the peak current and the concentration of NAC in the range of 1.2 x 10(-8) similar to 5.0 x 10(-6) mol/L. The detection limit of the method was 5. 0 x 10(-9) mol/L. The concentration of NAC in Fluimucil has been determined with satisfactory results by this method.