胱氨酸与7,7,8,8-四氰基对苯醌二甲叉的荷移反应研究

Study on the Charge Transfer Reaction of Cystine with 7,7,8,8-Tetracyanoquinodimethane by Spectrophotometry

采用分光光度法研究了胱氨酸与7,7,8,8-四氰基对苯醌二甲叉（TCNQ）的荷移反应。通过实验可知,在硼砂缓冲溶液中,室温下反应30min可获得稳定的1∶1的络合物,其λmax=425nm,表观摩尔吸光系数ε=4.4×103 L·mol-1·cm-1,线性范围为10~40μg·mL-1,探讨了荷移反应的机理,研究了该荷移络合物的结合常数和热力学性质。应用拟定的方法测定了胱氨酸片中胱氨酸的含量,经t-检验法检验,结果与文献方法无显著性差异,回收率为94.54%~101.2%。

The charge transfer reaction of cystine with 7,7,8,8-tetracyanoquinodimethane （TCNQ） was studied by spectrophotometry in borax buffer solution. Different variables affecting the reaction were carefully studied and optimized. The apparent molar absoptivity was determined to be 4.4 ×10^3 L.mol 1 . cm-1 at 425 nm,and Beer＇s law was obeyed in the range of 10-40 μg.mL-1. The stoichiometry of the complex was found to be 1： 1 between the donor and the acceptor. The possible reaction mechanism was explored. The thermodynamic standard reaction quantities of the complex between donor and acceptor were estimated. The developed method could be applied successfully for the determination of cystine tablet with a good precision and accuracy compared to official method as revealed by t-test. The recovery was in the range of 94.54%-101.2%.