婴儿奶粉中维生素B_1和B_2的高效液相荧光测定法

Determination of Vitamin B_1 and B_2 in Infant Milk Powder by HPLC Fluorescencedetector

目的检测婴儿配方奶粉中低含量的维生素B1和维生素B2。方法婴儿配方奶粉中加入0．5％乙酸溶液沉淀蛋白、过滤进样，采用反相高效液相法，选用含35％甲醇＋65％0．05mol／L醋酸钠溶液（pH=4．5）作为流动相，流量1ml／min，经Zorbax SB-Aq 100％水相反相色谱柱分离，柱温为室温，维生素B1的激发波长（λex）为375nm，发射波长（λem）为435nm，以0．25g／L碱性铁氰化钾溶液为柱后衍生剂，流量为0．3ml／min，反应温度为室温；维生素B2直接进行荧光测定（λex=462nm，λem=522nm）。结果方法的线性范围为10—1000ug/L，相关系数均为0．9999，维生素B1最低定量检出限为5．1ug／L，方法检出限为1．5ug/L，维生素B2最低定量检测限为4．7ug／L，方法检测限为1．4ug／L，平均回收率为86．5％-98．1％，相对标准偏差小于5％。结论该方法简便快捷、灵敏，满足日常快速分析要求。

Objective To develop a method for the determination of low content vitamin B1 and B2 in infant formula milk powder. Methods 0.5% acetic acid was used as the protein precipitator in infant formula, RP-HPLC, 35% methanol and 65% 0.05 mol/L NaAc solution （pH=4.5） was used as the mobile phase, flow rate was 1 ml/min, Zorbax SB-Aq 100% water soluble separate column was used, the temperature was at room temperature, vitamin B1 was determined by fluorescencedeteetor （λex=375 nm, λem=435 nm）, 0.25 g/L hexacyanoferrate （ Ⅲ ） as the post column derivation; vitamin BE was determined by fluorescencedetector （λex=462 nm,λem=522 nm）, vitamin Bl and B2 were analyzed by external calibration method. Results The linear range for vitamin B1 and vitamin B2 were 10-1 000 ug/L, the linear coefficients were 0.999 9, and the detection limits for quantification were 5.1 and 4.7ug/L, the detection limits for method were 1.5 and 1.4 ug/L, the recoveries were between 86.5%-98.1%, the relative standard deviations were less than 5%. Conclusion This method is simple, rapid, sensitive and is applicable to the fast determination of low content vitamin B1 and B2 in infant formula milk powder.