高效液相色谱法测定特殊医学配方食品中的色氨酸

Determination of tryptophan in food for special medical purpose by high performance liquid chromatography

中文关键词:  色氨酸  高效液相色谱法  特殊医学配方食品

英文关键词:tryptophan  high performance liquid chromatography  food for special medical purpose

中文摘要:

      目的 建立高效液相色谱法测定特殊医学配方食品中色氨酸的分析方法。方法 样品加入4 mol/L的氢氧化锂溶液, 在110 ℃恒温干燥箱中碱解16 h, 用pH为4.5的乙酸钠缓冲溶液中和后, 经Inertsil@ ODS-SP (4.6 mm×150 mm, 5 μm)分离, 以甲醇-0.1%乙酸溶液(95:5, V:V)为流动相等度洗脱, 流速1.0 mL/min, 柱温30 ℃, 进样量10 μL, 二极管阵列检测器277 nm波长采集数据, 外标法定量。结果 色氨酸在1~ 100 mg/L浓度范围内线性良好, 相关系数r为0.9999, 3个浓度水平的加标回收率在91.7%~94.5%之间, 相对标准偏差(n=6)为2.2%~3.7%, 精密度的相对标准偏差(n=6)为2.1%, 方法检出限为20 μg/g, 定量限为65 μg/g。 结论 该方法操作简便, 灵敏度高, 具有良好的准确度和精密度, 适用于特殊医学配方食品中色氨酸的测定。

英文摘要:

      Objective To establish an analytical method for determination of tryptophan in food for special medical purpose by high performance liquid chromatography. Methods The samples were added with 4 mol/L lithium hydroxide solution, hydrolyzed in a drying oven at a constant temperature of 110 ℃ for 16 h, neutralized with sodium acetate buffer solution with pH of 4.5, separated by Inertsil@ ODS-SP (4.6 mm×150 mm, 5 μm), eluted with methanol-0.1% acetic acid solution (95:5, V:V) at flow rate of 1.0 mL/min, column temperature of 30 ℃, and injection volume of 10 μL. Data at the wavelength of 277 nm by diode array detector were collected, and quantified by external standard method. Results Tryptophan had good linearity in the range of 1-100 mg/L, and the correlation coefficient was 0.9999. The recoveries of 3 different spiked concentrations were between 91.7%-94.5%, with relative standard deviations at 2.2%-3.7%. The relative standard deviation of precision was 2.1% (n=6). The limits of detection and the limits of quantification of this method were 20 μg/g and 65 μg/g, respectively. Conclusion This method has simple pretreatment, high sensitivity, good accuracy and precision. It is suitable for the determination of tryptophan in food for special medical purpose.