Department of Chemistry, and Center of Excellence for Innovation in Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
Talanta. 2011 May 15;84(3):745-51. doi: 10.1016/j.talanta.2011.01.078. Epub 2011 Feb 24.
Ceric ammonium nitrate has been used for qualitative analysis of ethanol. It forms an intensely colored unstable complex with alcohol. In this work, a simple flow injection (FI) colorimetric method was developed for the determination of ethanol, based on the reaction of ethanol with ceric ion in acidic medium to produce a red colored product having maximum absorption at 415 nm. Absorbance of this complex could be precisely measured in the FI system. A standard or sample solution was injected into a deionized water donor stream and flowed to a gas diffusion unit, where the ethanol diffused through a gas permeable membrane made of plumbing PTFE tape into an acceptor stream to react with ceric ammonium nitrate in nitric acid. Color intensity of the reddish product was monitored by a laboratory made LED based colorimeter and the signal was recorded on a computer as a peak. Peak height obtained was linearly proportional to the concentration of ethanol originally presented in the injected solution in the range of 0.1-10.0% (v/v) (r(2)=0.9993), with detection limit of 0.03% (v/v). With the use of gas diffusion membrane, most of the interferences could be eliminated. The proposed method was successfully applied for determination of ethanol in some alcoholic beverages, validating by gas chromatographic method.
硝酸铈铵曾被用于乙醇的定性分析。它与酒精形成一种颜色鲜艳但不稳定的配合物。在这项工作中，基于乙醇在酸性介质中与铈离子反应生成红色产物，在最大吸收波长为 415nm 处产生强烈的颜色，开发了一种简单的流动注射（FI）比色法来测定乙醇。在 FI 系统中可以精确测量该配合物的吸光度。标准溶液或样品溶液被注入去离子水供体流中，并流向气体扩散单元，在那里乙醇通过由管道 PTFE 胶带制成的透气膜扩散到接受体流中，与硝酸中的硝酸铈铵反应。红色产物的颜色强度由实验室自制的基于 LED 的比色计监测，并将信号记录在计算机上作为峰。在 0.1-10.0%（v/v）（r(2)=0.9993）范围内，所获得的峰高与最初注入溶液中乙醇的浓度呈线性比例关系，检测限为 0.03%（v/v）。使用气体扩散膜可以消除大部分干扰。该方法成功应用于一些酒精饮料中乙醇的测定，并通过气相色谱法进行了验证。
