基于变色酸比色原理的白酒中甲醇的快速筛查方法研究

Rapid detection of methanol in liquor based on chromotropic acid colorimetric principle

中文关键词:  变色酸比色  甲醇  白酒  快速检测

英文关键词:chromotropic acid colorimetry  methanol  liquor  rapid detection

中文摘要:

      目的 建立基于变色酸比色原理快速筛查白酒中甲醇含量的方法。方法 对样品进行稀释, 同时将酒精度调整至5% vol后, 取1.0 mL, 加入高锰酸钾-磷酸溶液(30 g/L) 0.5 mL, 反应15 min。加入0.3 mL偏重亚硫酸钠溶液(100 g/L), 使试液完全褪色。加入5 mL变色酸显色剂(1 g/L), 密塞, (70±2) ℃水浴显色20 min。将样品溶液与甲醇对照溶液目视比较判读。对酒精度影响、干扰因素以及方法适用性等关键指标进行深入研究, 确定方法的检出限, 并对性能指标进行评价。结果 反应体系中5% vol酒精度对显色干扰较小; 柠檬黄、日落黄、赤藓红等10种合成着色剂、苯甲酸钠、山梨酸钾、糖精钠、甜蜜素对显色不产生干扰, 白砂糖、三氯蔗糖会对显色产生干扰; 方法适用于蒸馏酒, 不适用于发酵酒和配制酒; 方法检出限为0.2 g/L(按100%酒精度折算); 假阴性率、假阳性率、特异性、灵敏度以及与参比方法一致性各性能指标满足要求。结论 该方法灵敏、准确、快速, 适用于白酒中甲醇含量的现场快速检测。

英文摘要:

      Objective To establish a rapid method for determination of methanol in liquor based on chromotropic acid colorimetric principle. Methods After diluting the sample and adjusting the alcohol content to 5% vol, 1.0 mL sample was added to 0.5 mL of potassium permanganate-phosphoric acid solution (30 g/L) for 15 min. Zero point three milliliter sodium sulfite solution (100 g/L) was added to make the test solution fade completely. Five milliliter chromogenic acid reagent (1 g/L) was added, and the chromomeric reagent was packed at (70±2) ℃ for 20 min. The sample solution and methanol control solution were visually compared and interpreted. The key indexes such as the influence of alcohol content, interference factors and applicability of the method were deeply studied to determine the detection limit of the method and evaluate the performance indexes. Results The 5% alcohol in solution had little effect on color reaction. Ten synthetic colorants, including lemon yellow, sunset yellow and erythrina, sodium benzoate, potassium sorbate, saccharin and cyclamate, did not interfere with the color development, while white granulated sugar and sucralose did. This method was suitable for distilled liquor, and not fermented liquor and prepared liquor. The detection limit of the method was 0.2 g/L (converted from 100% alcohol content). False negative rate, false positive rate, specificity, sensitivity and consistency with reference methods had met the requirements. Conclusion This method is sensitive, accurate and fast, which is suitable for the field rapid detection of methanol content in liquor.