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建立了一种冷冻液液萃取-高效液相色谱法测定可乐中4-甲基咪唑的方法。样品在碱性条件下,以乙腈作为萃取溶剂,经涡旋后,在-23℃下冷冻净化;取上清液氮气吹干,用蒸馏水定容,然后利用高效液相色谱仪在UV 210nm处检测。结果表明,该方法4-甲基咪唑的检出限和定量限分别为0.033μg/mL和0.100μg/mL;在浓度0.25μg/mL~100μg/mL范围内,线性相关系数为0.9999;样品在1.5μg/mL、3.0μg/mL、6.0μg/mL 3个水平上,加标回收率平均值均大于85%,相对标准偏差均不超过5%(n=7),具有良好的准确度和重复性。与常规液液萃取相比,该前处理方法操作简单,有机试剂用量少,适合一次处理多个样品,具有一定的推广价值。
A method for the determination of 4-methylimidazole in Cola was established by liquid chromatography-liquid chromatography-high performance liquid chromatography. Under basic conditions, acetonitrile was used as the extraction solvent. After vortexing, the sample was frozen and purified at -23 ° C. The supernatant was air-dried under nitrogen and distilled with distilled water. The sample was then analyzed by high performance liquid chromatography at UV 210 nm Detection. The results showed that the detection limit and the limit of quantification of 4-methylimidazole were 0.033μg / mL and 0.100μg / mL, respectively. The linear correlation coefficient was 0.9999 in the range of 0.25μg / mL ~ 100μg / mL. 1.5 μg / mL, 3.0 μg / mL and 6.0 μg / mL, the average recoveries were all over 85% with relative standard deviations less than 5% (n = 7), with good accuracy and Repeatability. Compared with the conventional liquid-liquid extraction, the pretreatment method has the advantages of simple operation, less amount of organic reagents and suitable for processing a plurality of samples at a time, and has certain promotion value.