面粉中维生素B1和B2高效液相色谱测定的样品前处理方法优化

目的 优化面粉中维生素B1（VB1）和维生素B2（VB2）测定的样品前处理方法 。方法 以0.1 mol/L盐酸为提取液，样品提取液经中和、酶解、定容过滤后得VB2待测液，VB2待测液经铁氰化钾衍生，正丁醇萃取后得VB1待测液，分别取0.5 mlVB2和VB1待测液用甲醇定容得进样溶液，采用 Waters symmetry C18色谱柱( 4. 6 mm×250 mm，5.0 μm) 分离，荧光检测器检测。结果 VB1和VB2的定量限分别为0.003 mg/100 g和0.006 mg/100 g。VB1在0.025～0.4 μg /ml范围内，线性关系良好( r = 0.9989) ，VB2在0.001 ～ 0.1 μg /ml 范围内，线性关系良好( r = 0.9996) ，3 个添加水平的回收率VB1在83.9% ~ 91.2%之间，VB2在78.9% ~ 87.3%之间，相对标准偏差 RSD 均＜4.9%。结论 该方法前处理简单，准确度高，适用于面粉中VB1和VB2的同时测定。

Optimization of pretreatment method for determination of thiamine and riboflavin in flour by high performance liquid chromatography

Objective To optimize the pretreatment method for the determination of thiamine and riboflavin in flour by high performance liquid chromatography(HPLC). Methods Riboflavin in sample was extracted with 0.1 mol/L hydrochloric acid, and then digested for 16 h with proteinase after neutralized with sodium acetate solution. Riboflavin solution is derivatized with potassium ferricyanide and extracted with n-butanol to obtain thiamine. Finally, the extract of riboflavin and thiamine were diluted with methanol before analysis. The separation was performed on a Waters symmetry C18 column(4. 6 mm×250 mm, 5.0 μm), detection was carried out by a fluorescence detector, and the quantification was based on external standard method. Results The limits of quantitation (LOQs) of VB1 and VB2 were 0.003 mg/100g and 0.006 mg/100g, respectively． The method showed a good linearity and achieved high correlation coefficients(r>0.998). The recoveries of the method at three levels were in the range of 78.9%-91.2% with the relative standard deviations less than 4.9%. Conclusion This method could be used for screening and quantification of VB1 and VB2 in flour for its simple preparation and high accuracy.