基于铁氰化钾选择性氧化方波伏安法测定制剂中半胱氨酸和胱氨酸

目的：建立方波伏安法测定制剂中半胱氨酸和胱氨酸含量。方法：六氰合铁酸根（［Fe（CN）₆］^3-）作为一种高选择性弱氧化剂，能氧化半胱氨酸而不能氧化胱氨酸和亚硫酸根离子，胱氨酸与亚硫酸氢钠定量反应生成还原性更强的半胱氨酸；半胱氨酸分子中的巯基（-SH）可将［Fe（CN）₆］^3-还原为［Fe（CN）6］4-，通过方波伏安法测定反应液中剩余［Fe（CN）₆］^3-的浓度，从而间接测得半胱氨酸总量和胱氨酸分解量。结果：溶液中剩余［Fe（CN）₆］^3-在活化玻碳电极上仍有良好的电化学响应，还原峰电流差与半胱氨酸浓度在0~1.8 mmol·L^-1范围内呈良好的线性关系，检测下限为0.9 μmol·L^-1（S/N=3）。结论：本方法对制剂中的半胱氨酸和胱氨酸进行测定，简便快速、灵敏度高。

Objective:To measure the contents of cysteine and cystine in the potions by square wave voltammetry. Methods:As a highly selective weak oxidant,[Fe(CN)₆]^3- could oxidize cysteine,and could not oxidize cystine and the ions of sulfurous. Cysteine and NaHSO₃ could quantitatively react to produce reductive cysteine;[Fe(CN)₆]^3- could be reduced to[Fe(CN)6]4- by(-SH)in cysteine molecule.[Fe(CN)₆]^3- of the remaining concentration in the reaction liquid was measured by square wave voltammetry. Thus the total contents of cysteine and the amounts of decomposition of cystine could be obtained indirectly. Results:The remaining[Fe(CN)₆]^3- in reaction liquid still had a good electrochemical response on the activated glassy carbon electrode. The differences between reductive peak currents have a good linear relationship in the cysteine concentrations of range of 0-1.8 mmol·L^-1.The detection limit was 0.9 μmol·L^-1(S/N=3). Conclusion:This method can be applied to detect cysteine and cystine in the potions. It is simple,rapid and highly sensitive.

[1] 陈时洪,刘勋.溴-亚铁滴定法测定胱氨酸[J].西南师范大学学报(自然科学版),2002,27(4):614 CHEN SH, LIU X. Cystine measured by ferrous bromine titration[J]. J Southwest China Normal Univ(Nat Sci),2002,27(4):614
[2] 王万岭.比色法测定胱氨酸片的含量[J].中国生化药物杂志,2000,21(6):293 WANG WL. The contents of cystine measured by colorimetric method[J]. Chin J Biochem Pharm,2000,21(6):293
[3] 中华人民共和国药典2015年版.二部[S]. 2015:1175 ChP 2015. Vol Ⅱ[S]. 2015:1175
[4] 陈耀祖.有机分析[M].北京:高等教育出版社,1983:266 CHEN YZ. Organic Analysis[M]. Beijing:Higher Education Press,1983:266
[5] HSIAO Y,SU W,CHENG J,et al. Electrochemical determination of cysteine based on conducting polymers/gold nanopar-ticles hybrid nanocomposites[J]. Electrochim Acta, 2011, 56(20):6887
[6] ZHENG Y,LIU H,MA G,et al. Determination of S-propar-gyl-cysteine in rat plasma by mixed-mode reversed-phase and cation-exchange HPLC-MS/MS method and its application to pharmacokinetic studies[J]. J Pharm Biomed Anal, 2011, 54(5):1187
[7] 张卫办,翟丽.旋光度法测定L-半胱氨酸含量[J].华北煤炭医学院学报, 2001,3(4):435 ZHANG WB,ZHAI L. Determination of L-cysteine content by polarimetry[J]. J North China Coal Med Coll,2001,3(4):435
[8] 赵成,崔吉茂,陈松.单扫描极谱法测定胱氨酸与半胱氨酸的研究[J].职业卫生与疾病, 2004,19(3):206 ZHAO C, CUI JM,CHEN S. Determination of cysteine by single scan polarography[J]. J Occup Health Dis,2004,19(3):206
[9] 曹秋娥,李菲.药物中半胱氨酸的流动注射荧光测定方法研究[J].云南大学学报, 2003,25(3):266 CAO QE,LI F. Study on the flow injection fluorometry of cysteine in drugs[J]. J Yunnan Univ,2003,25(3):266
[10] 刘海坤,周端赐,李拓,等.用自动滴定微库仑计分别测定混合物中半胱氨酸及胱氨酸的含量[J].分析化学,1983,12(9):836 LIU HK,ZHOU DC,LI T,et al. The contents of the mixture in cysteine and cystine respectively measured by the automatic titration microcoulomb[J]. Anal Chem,1983,12(9):836
[11] 杜宝中,姚秉华,薛力,等.电位滴定法测定半胱氨酸和胱氨酸的研究及应用[J].分析科学学报,2004,20(6):622 DU BZ,YAO BH,XUE L,et al. The research and application of cysteine and cystine measured by the potentiometric titration method[J]. J Anal Sci,2004,20(6):622
[12] 王鸿漳.脱毛废水中硫离子、半胱氨酸和胱氨酸的测定[J]. 陕西科技大学学报,1983,2(2):39 WANG HZ. Sulfur ions,cysteine and cystine measured in the hair removal wasted water[J]. J Shaanxi Univ Sci Technol,1983,2(2):39