Jasnowska J, Ligaj M, Stupnicka B, Filipiak M
Chair of Biochemistry and Microbiology, Poznan University of Economics, 60-967, Poznan, Poland.
Bioelectrochemistry. 2004 Aug;64(1):85-90. doi: 10.1016/j.bioelechem.2004.03.004.
o-Dianisidine (3,3'-dimethoxybenzidine) is applied in the production of some dyes and also used in analytical tests. However, this compound is anticipated to be a human carcinogen. An analytical strategy utilizing square wave voltammetry for the determination of o-dianisidine is presented. An electrochemical system was consisted of three electrodes: carbon paste working electrode, platinum wire counter electrode and silver-silver chloride (Ag/AgCl) reference electrode. However, square wave voltammograms of direct measurements of o-dianisidine were found to be hardly reproducible, exhibiting few peaks due to some labile short-lived intermediates with the only exception of a quite stable peak at +0.7 V vs. Ag/AgCl. Quantitative determination of o-dianisidine gave satisfactory results only when the carbon paste working electrode was replaced by deoxyribonucleic acids (DNA) electrode obtained by immobilization of double-stranded (ds) DNA on carbon electrode. Square wave voltammogram of DNA showed two peaks attributed to adenine and guanine and the latter was used as analytical signal. After interaction with o-dianisidine, guanine oxidation peak was reduced to the extent related to the concentration of the analyte. Initial reduction of guanine peak took place already at the concentration of o-dianisidine equal to 0.4 microM; high concentrations (above 100 microM) of the analyte quenched completely a guanine response. The presented electrochemical system enables a specific detection of o-dianisidine by the presence of an oxidation peak at +0.7 V and its quantitative determination by measuring a reduction of guanine peak by means of a DNA sensor.
邻联茴香胺（3,3'-二甲氧基联苯胺）用于某些染料的生产，也用于分析测试。然而，该化合物被认为是一种人类致癌物。本文提出了一种利用方波伏安法测定邻联茴香胺的分析策略。电化学系统由三个电极组成：碳糊工作电极、铂丝对电极和银-氯化银（Ag/AgCl）参比电极。然而，直接测量邻联茴香胺的方波伏安图很难重现，由于一些不稳定的短寿命中间体，只显示出很少的峰，唯一的例外是在相对于Ag/AgCl为+0.7 V处有一个相当稳定的峰。只有当碳糊工作电极被通过将双链（ds）DNA固定在碳电极上得到的脱氧核糖核酸（DNA）电极取代时，邻联茴香胺的定量测定才能得到满意的结果。DNA的方波伏安图显示出两个归因于腺嘌呤和鸟嘌呤的峰，后者用作分析信号。与邻联茴香胺相互作用后，鸟嘌呤氧化峰降低的程度与分析物浓度有关。在邻联茴香胺浓度等于0.4 microM时，鸟嘌呤峰就开始出现初始降低；分析物的高浓度（高于100 microM）会使鸟嘌呤响应完全淬灭。所提出的电化学系统能够通过在+0.7 V处出现氧化峰来特异性检测邻联茴香胺，并通过DNA传感器测量鸟嘌呤峰的降低来对其进行定量测定。
