莱茵—埃农氏法和高效液相色谱—示差折光法检测奶粉中乳糖和蔗糖的比较研究

选用市售同种品牌不同年龄段的奶粉,采用莱茵—埃农氏法和高效液相色谱—示差折光检测法对其乳糖和蔗糖进行测定,分析乳糖和蔗糖的差异,并对两种分析方法的结果进行比较,为奶粉中乳糖和蔗糖的检测方法提供依据。结果表明,莱茵—埃农氏法和高效液相色谱—示差折光检测法相比,高效液相色谱—示差折光检测法测定乳糖和蔗糖含量的准确度更高,蔗糖和乳糖的线性范围均为2~12 mg/mL,相关系数分别为0.999 3、0.999 6,精密度实验结果表明,相对标准偏差分别为2.53%、3.81%,平均加样回收率分别为99.70%、101.06%。高效液相色谱—示差折光检测法结果准确、分析时间短、前处理简单,适用于快速测定奶粉中蔗糖和乳糖含量。

Comparative Detection of Lactose and Sucrose in Milk Powder by Lane-Eynon’s Method and High Performance Liquid Chromatography with Refractive Index Detector

Lactose and sucrose in milk powder from the same commercial brand for two different age groups were assayedby the Lane-Eynon’s method and high performance liquid chromatography with refractive index detector (HPLC-RID). The differences in lactose and sucrose contents among different samples were analyzed, and the results of the two methods were compared. It was indicated that the accuracy of the HPLC-RID method was higher than that of the Lane-Eynon’s method. The linear ranges of the HPLC method for sucrose and lactose were both 2–12 mg/mL with correlation coefficients of 0.999 3 and 0.999 6, respectively. The precision, expressed as relative standard deviations, for sucrose and lactose were 2.53% and3.81%, respectively. The average recovery rates were 99.70% and 101.06%, respectively. The HPLC method had some advantages such as high accuracy, short analysis time, simple sample pretreatment and suitability for rapid determination of sucrose and lactose contents in milk powder.