Departamento de Química Analítica y Alimentaria, Área de Química Analítica, Facultad de Química, Universidad de Vigo, Campus As Lagoas-Marcosende s/n, 36310 Vigo, Spain.
Anal Chim Acta. 2012 Jul 6;733:28-33. doi: 10.1016/j.aca.2012.04.039. Epub 2012 May 10.
A green assay based on the development of an enzymatic reaction in drop format under headspace single-drop microextraction conditions is described for the first time. An aqueous drop containing the enzyme alcohol dehydrogenase and the cofactor β-Nicotinamide adenine dinucleotide has been used as fluorescence probe for determining ethanol in alcohol-free cosmetics by microvolume fluorospectrometry. Experimental parameters affecting the microextraction performance were carefully optimized. Under the conditions employed, the contribution of other alcohols was found to be negligible. After 10 min of microextraction, a detection limit of 0.04 μg g(-1) ethanol, a repeatability, expressed as relative standard deviation, of 5.3% for a 0.05 mM ethanol standard and a preconcentration factor of 391, were reached. Accuracy of the proposed methodology was evaluated by comparison of calibration slopes corresponding to external calibration with aqueous standards and standard addition calibration. The method was successfully applied to different alcohol-free cosmetics (external calibration was carried out in all cases). Additional advantages such as simplicity and high sample throughput can be highlighted. The greenness profile of proposed methodology was established using NEMI criteria (US National Environmental Methods Index).
本文首次描述了一种基于顶空单滴微萃取条件下酶促反应发展的绿色分析方法。含有酶醇脱氢酶和辅酶β-烟酰胺腺嘌呤二核苷酸的水滴被用作荧光探针，通过微量荧光光谱法测定无醇化妆品中的乙醇。仔细优化了影响微萃取性能的实验参数。在所采用的条件下，发现其他醇的贡献可以忽略不计。经过 10 分钟的微萃取，检测限达到 0.04 μg g(-1)乙醇，0.05 mM 乙醇标准品的相对标准偏差为 5.3%，浓缩因子为 391。通过比较外部校准和水溶液标准品的校准斜率以及标准加入校准，评估了所提出方法的准确性。该方法已成功应用于不同的无醇化妆品（在所有情况下均进行外部校准）。可以突出显示简单和高样品通量等额外优势。使用 NEMI 标准（美国国家环境方法指数）建立了所提出方法的绿色指标。
