Tsumura Y, Nakamura Y, Tonogai Y, Shibata T
National Institute of Health Sciences, Osaka Branch, Japan.
J AOAC Int. 1996 Nov-Dec;79(6):1471-6.
A convenient method is described for the determination of tricyclazole in brown rice, and the interference of free fatty acids with flame thermionic detection (FTD) is reported for the first time. Brown rice is extracted with acetone, the extract is filtered, and the filtrate is evaporated. To the residue is added 10% (w/v) NaCl solution, and the mixture is extracted with ethyl acetate. The extract is charged on a Sep-Pak Plus silica cartridge. Free fatty acids are removed from the rice by washing with diethyl ether, and tricyclazole is eluted with acetone-n-hexane (1 + 1). Tricyclazole is determined on a DB-1 capillary column by gas chromatography with FTD (GC-FTD). Linoleic acid and oleic acid, which have essentially the same retention time as tricyclazole, cannot be detected by FTD. Thus, without the Sep-Pak Plus silica cleanup, the peak height of tricyclazole in the chromatogram decreased, the extent depending on the concentration of linoleic acid. n-Hexane-acetonitrile partitioning was not used for cleanup because it could not remove 50% of the free fatty acids. Recoveries (mean +/- standard deviation, n = 5) of tricyclazole from rice fortified at 2 and 0.1 ppm were 90.5 +/- 9.4% and 81.3 +/- 10.6%, respectively. The limit of quantitation was 0.05 ppm.
本文描述了一种测定糙米中三环唑的简便方法，并首次报道了游离脂肪酸对火焰热离子检测（FTD）的干扰。用丙酮提取糙米，提取物过滤后滤液蒸发。向残渣中加入10%（w/v）氯化钠溶液，并用乙酸乙酯萃取混合物。提取物加载到Sep-Pak Plus硅胶柱上。用乙醚洗涤可去除糙米中的游离脂肪酸，并用丙酮-正己烷（1 + 1）洗脱三环唑。三环唑通过气相色谱-火焰热离子检测（GC-FTD）在DB-1毛细管柱上进行测定。与三环唑保留时间基本相同的亚油酸和油酸不能通过FTD检测到。因此，不进行Sep-Pak Plus硅胶净化时，色谱图中三环唑的峰高会降低，降低程度取决于亚油酸的浓度。未使用正己烷-乙腈分配进行净化，因为它不能去除50%的游离脂肪酸。在2 ppm和0.1 ppm加标水平下，三环唑在糙米中的回收率（平均值±标准差，n = 5）分别为90.5±9.4%和81.3±10.6%。定量限为0.05 ppm。
