微分脉冲吸附溶出伏安法测定苯胺的研究

Determination of Aniline by Differential Adsorptive Stripping Voltammetry

苯胺经重氮化、偶合反应定量生成的偶氮化合物具有很强的电活性。作者用微分脉冲吸附溶出伏安法测定偶氮化合物来定量分析苯胺的含量。以ＮＨ３·Ｈ２Ｏ－ＮＨ４Ｃｌ（ｐＨ＝１０）缓冲液为底液，富集电位为－０１５Ｖ，富集时间１２０ｓ，电位扫描速度４ｍＶ／ｓ，在－０６７０Ｖ处产生一个灵敏度高、峰形好的溶出峰。苯胺浓度在１０－９～１０－７ｍｏｌ／Ｌ时与峰电流成线性关系。用印染厂土壤、废水和广州垃圾填埋场的渗出液作标准回收试验，平均回收率分别为９８２％、９７０％、９７５％，测定的相对标准偏差为４３％、４０％、３３％。

The azo dyes formed by aniline diazotization and coupling are adsorbed more strongly on a hanging mercury drop electrode than aniline itself.Hence,differential pulse adsorptive stripping voltammetry can be used for the quantitative determination of aniline by detecting the azo dyes derived from aniline.Under optimum conditions (pH=10 with buffer electrolyte NH3·H2O-NH4Cl,accumulation potential=-015 V,accumulation time=120 s,scan rate=4 mV·s-1),a sensitive,symmetric dissolution peak occurs at -0670 V.The peak current of the differential response has a linear relationship with the aniline concentration in the range of 10-9～10-6mol·L-1.Contaminated soil and waste water from dyeing and printing industry as well as the leachate from Guangzhou land filling site were used in a standard recovery test.The recoveries for these three types of samples are 982%,970%and 975%,respectively,while their relative standard deviations are 43%,40% and 33%,respectively.