Two-dimensional thin-layer chromatographic method for the analysis of ochratoxin a in green coffee
Two-dimensional thin-layer chromatographic method for the analysis of ochratoxin a in green coffee
复制标题
DOI：
10.4315/0362-028x-68.9.1920
复制
发表时间：
2005-09-01
影响因子：
2
通讯作者：
Comellas, L
中科院分区：
文献类型：
--
作者：
Ventura, M;Anaya, I;Comellas, L
开发了一种低成本的薄层色谱方法，用于推定测量绿色咖啡豆中5 μ g/kg的赭曲霉毒素A（OTA）。分析方法包括通过用甲醇和碳酸氢钠水溶液的混合物摇动大豆来提取OTA，然后通过液-液分配将其纯化到甲苯中。OTA通过正相二维薄层色谱法分离，并通过在365 nm处的UV灯下目视估计荧光强度来检测。色谱溶剂为甲苯-甲醇-甲酸（8：2：0.03）用于第一次展开，石油醚-乙酸乙酯-甲酸（8：10：1）用于第二维展开。该方法用未污染的绿色咖啡豆样品进行了测试，该样品加入了四种不同浓度（5、10、20和30 μ g/kg）的OTA标准品。该方法快速、简单，在咖啡生产国非常容易实施。它具有高度选择性，在样品提取步骤中不使用氯化溶剂。这种廉价的方法已被应用于不同类型的绿色咖啡样品从不同的国家（津巴布韦，巴西，印度，乌干达，哥伦比亚和印度尼西亚）和不同的制造商，并没有OTA低于检测限5微克/千克被检测到在任何样品分析。
A low-cost thin-layer chromatographic method has been developed for the presumptive measurement of ochratoxin A (OTA) at 5 mu g/kg in green coffee beans. The analytical method consisted of extracting OTA by shaking the beans with a mixture of methanol and aqueous sodium bicarbonate solution, which was then purified by liquid-liquid partition into toluene. OTA was separated by normal-phase two-dimensional thin-layer chromatography and detected by visual estimation of fluorescence intensity under a UV lamp at 365 nm. The chromatography solvents were toluene-methanol-formic acid (8:2:0.03) for the first development and petroleum ether-ethyl acetate-formic acid (8:10:1) for the second dimension development. This method was tested with uncontaminated green coffee bean samples spiked with an OTA standard at four different concentrations (5, 10, 20, and 30 mu g/kg). The method is rapid, simple, and very easy to implement in coffee-producing countries. It is highly selective and does not involve the use of chlorinated solvents in the sample extraction step. This inexpensive method has been applied to different types of green coffee samples from various countries (Zimbabwe, Brazil, India, Uganda, Colombia, and Indonesia) and different manufacturers, and no OTA below the detection limit of 5 wg/kg was detected in any samples analyzed.