固相萃取-高效液相色谱-柱后衍生荧光法测定奶粉中维生素B11含量

建立了固相萃取-高效液相色谱-柱后衍生荧光法用于测定奶粉中维生素B11含量。奶粉酶解样液经固相萃取小柱纯化后,在ZORBAX SB-C18色谱柱上,以pH=3.5、浓度为0.05mol/L磷酸二氢钾-乙腈体系为流动相,流速为1.0mL/min,进样量20μL,以0.5%过硫酸钾溶液为衍生试剂,反应器温度为60℃,流速0.5mL/min,经荧光检测器(Ex=365nm,Em=440nm,增幅值100,衰减值16)检测定量。结果表明:在0.02～1.76μg/mL范围内该方法线性良好,R2=0.9999,检测限为4ng/mL,定量限为12ng/mL,灵敏度足以满足奶粉检测的需要,方法回收率在92.5%～95.7%之间,变异系数为1.32%。

Determination of vitamin B11 contents in powdered milk by SPE-HPLC-Postcolumn fluorescence detection

The solid phade extraction-high performance liquid chromatography-post column derivatization fluorescence detection was applied to determinate the Vitamin B 11 contents in powdered milk.After the solid phade extraction purification,the moving phade of the sample on the ZORBAX SB-C 18 chromatographic column was a monopotassium phosphate-acetonitrile system whose pH was 3.5,concentration was 0.05mol/L with a moving speed of 1.0mL/min and a sample size of 20μL.The derivatization reagent taken was the potassium persulfate solution with a solubility of 0.5% and the temperature of reactor was 60℃ with a speed of 0.5mL/min,then the sample was detected and fixed by fluorescence detector(E x =365nm,E m =440nm,added values=100,attenuation values=16).The result showed that the detection method worked well linearly within the range of 0.02～1.76μg/mL and R 2 =0.9999 with a detectability of 4ng/mL and a quantitation limitation of 12ng/mL.The sensitivity could meet the demand of powdered milk detection well.The method’s coefficient of recovery was between 92.5%～95.7% and coefficient of variation was 1.32%.