We report a new method for determination of ethanol based on anti-aggregation of silver nanoparticles (AgNPs) in the presence of melamine. In the system, ethanol and melamine act as protecting and aggregating agents, respectively. Melamine can induce citrate-stabilized AgNPs to aggregate, leading to a color change from yellow to green. However, if the AgNPs are pre-incubated in ethanol, ethanol readily surrounds the particles by forming hydrogen bonds with the citrate stabilizer. An external nanoshell of ethanol hinders particle aggregation caused by melamine. Minor aggregation of AgNPs was observed, the solution color maintained its yellow-orange color. Higher ethanol concentrations result in a lower degree of particle aggregation. The colorimetric response of AgNPs was monitored using a UV–vis spectrophotometer at 390 nm. The current method could determine ethanol concentrations over a wide dynamic range of 5–80% (v/v), with a detection limit of 3.1% (v/v) (3SD of blank/slope). This method was applied for direct quantification of ethanol in alcoholic drinks without sample pretreatment and the results are well correlated with those of gas chromatography. Our method is convenient and cost effective, making it auspicious for ethanol monitoring in alcoholic drink manufacture and control.

我们报告了一种在三聚氰胺存在下基于银纳米粒子 (AgNPs) 的抗聚集来测定乙醇的新方法。在该系统中，乙醇和三聚氰胺分别充当保护剂和聚集剂。三聚氰胺可以诱导柠檬酸盐稳定的 AgNPs 聚集，导致颜色从黄色变为绿色。然而，如果 AgNPs 在乙醇中预孵育，乙醇很容易通过与柠檬酸盐稳定剂形成氢键来包围颗粒。乙醇的外部纳米壳阻碍了由三聚氰胺引起的颗粒聚集。观察到 AgNPs 的少量聚集，溶液颜色保持其黄橙色。较高的乙醇浓度导致较低程度的颗粒聚集。使用紫外-可见分光光度计在 390 nm 处监测 AgNPs 的比色响应。目前的方法可以在 5-80% (v/v) 的宽动态范围内测定乙醇浓度，检测限为 3.1% (v/v)（空白/斜率的 3SD）。该方法应用于酒精饮料中乙醇的直接定量，无需样品预处理，结果与气相色谱法的结果具有很好的相关性。我们的方法方便且具有成本效益，使其有利于酒精饮料制造和控制中的乙醇监测。