柱后还原-高效液相色谱法同时测定调制乳粉中维生素K1和维生素K2

Determination of vitamin K 1 and vitamin K 2 in modulation milk powder by post-column reduction-high performance liquid chromatography

建立了一种同时检测调制乳粉中维生素K 1和维生素K 2的柱后还原-高效液相色谱-荧光检测方法。样品用水溶解,经脂肪酶酶解,2.5 mol/L氢氧化钠溶液和乙醇溶液皂化,正己烷萃取,氮吹浓缩后,用甲醇复溶。通过Xbridge C 18色谱柱分离,锌粉还原柱柱后还原,荧光检测器检测,激发波长为326 nm,发射波长为432 nm,外标法定量。结果表明,维生素K 1在0.0025~2.0μg/mL、维生素K 2在0.01~2.0μg/mL范围内线性关系良好,相关系数均大于0.999,维生素K 1和维生素K 2的检出限分别为0.07μg/100 g和0.24μg/100 g,定量限分别为0.2μg/100 g和0.8μg/100 g;方法的加标回收率为80.39%~94.39%,精密度为0.85%~3.98%。该方法灵敏度高,重复性好,结果准确,适用于调制乳粉中维生素K 1和维生素K 2的分析检测。

A method for the determination of vitamin K 1 and vitamin K 2 in modulation milk powder was developed by high performance liquid chromatography(HPLC)coupled with post-column reduction.The samples were dissolved in water,lipase hydrolyzed,saponified with 2.5 mol/L sodium hydroxide solution and ethanol solution,extracted with n-hexane,and dissolved in methanol after concentration.The vitamin K were first separated on an Xbridge C 18 column and then on a zinc powder reduction column,and detected using a fluorescence detector.The excitation and emission wavelengths were 326 nm and 432 nm,respectively.An external standard method was used for quantification.The results showed that the linearities of vitamin K 1 and vitamin K 2 was in the ranges of 0.0025-2.0μg/mL and 0.01-2.0μg/mL,respectively,with correlation coefficients both greater than 0.999.The spiked recoveries were 80.39%-94.39%and the precisions were 0.85%-3.98%.The limits of detection of vitamin K 1 and vitamin K 2 were 0.07μg/100 g and 0.2μg/100 g,respectively.The limits of quantification of vitamin K 1 and vitamin K 2 were 0.2μg/100 g and 0.8μg/100 g,respectively.The method has high sensitivity and good repeatability,and gives accurate results.It is suitable for the analysis and determination of the vitamin K 1 and vitamin K 2 in formula milk powder.