Abbaspour Abdolkarim, Noori Abolhassan
Chemistry Department, College of Sciences, Shiraz University, Shiraz, Iran.
Analyst. 2008 Dec;133(12):1664-72. doi: 10.1039/b806920d. Epub 2008 Sep 2.
An electrochemical sensor for guanine and adenine using cyclodextrin-modified poly(N-acetylaniline) (PNAANI) on a carbon paste electrode has been developed. The oxidation mechanism of guanine and adenine on the surface of the electrode was investigated by cyclic voltammetry. It was found that the electrode processes are irreversible, pH dependent, and involve several reaction products. The electron transfer process occurs in consecutive steps with the formation of a strongly adsorbed intermediate on the electrode surface. Also, a new method for estimating the apparent formation constants of guanine and adenine with the immobilized cyclodextrins, through the change of surface coverage of studied analytes has been reported. Both guanine and adenine showed linear concentrations in the range of 0.1-10 microM by using differential pulse voltammetry, with an experimental limit of detection down to 0.05 microM. Linear concentration ranges of 2-150 microM for guanine and 6-104 microM for adenine have been found when cyclic voltammetry was used for determination of both analytes.
已开发出一种用于鸟嘌呤和腺嘌呤的电化学传感器，该传感器采用在碳糊电极上修饰有环糊精的聚（N - 乙酰苯胺）（PNAANI）。通过循环伏安法研究了鸟嘌呤和腺嘌呤在电极表面的氧化机理。发现电极过程是不可逆的，依赖于pH值，并且涉及几种反应产物。电子转移过程以连续步骤发生，在电极表面形成强吸附中间体。此外，还报道了一种通过研究分析物表面覆盖率的变化来估算鸟嘌呤和腺嘌呤与固定化环糊精的表观形成常数的新方法。使用差分脉冲伏安法时，鸟嘌呤和腺嘌呤的浓度在0.1 - 10 microM范围内均呈线性，实验检测限低至0.05 microM。当使用循环伏安法测定这两种分析物时，发现鸟嘌呤的线性浓度范围为2 - 150 microM，腺嘌呤的线性浓度范围为6 - 104 microM。
