折光法检测食品添加剂乳酸的含量

目的 建立一种用折光法检测食品添加剂乳酸的含量的方法。方法 配置标准乳酸浓度梯度, 使用阿贝折射仪测得标准品的折光指数, 绘制出乳酸的标准曲线, 并测量样品的折光指数, 带入标准曲线计算样品中乳酸含量, 并将折光法计算得到的乳酸含量与国标法滴定值进行比较。结果 折光法线性方程为Y=9.2545X?12.3305, 相关系数r2为0.9999。折光法与滴定法的最大偏差为0.51, 折光法检测乳酸的相对标准偏差为0.1%(n=6)。结论 相比滴定法, 折光法取样量少, 操作简单、检测快速, 为乳酸含量的快速检测提供了一种新的检测方法。

Determination of lactic acid in food additives by refractive method

Objective To establish a method for the determination of lactic acid in food additive by refractive method. Methods The standard lactic acid concentration gradient was prepared and the refractive index of the standard was measured by Abbe refractometer. Then the standard curve of lactic acid was drawn, the refractive index of the sample was measured. The lactic acid content in the sample was calculated by the standard curve and the content of lactic acid calculated by refraction method was compared with the titration value of national standard method. Results The linear equation of refraction method was Y=9.2545X-12.3305, with the correlation coefficient r2 0.9999. The maximum deviation of refractometry and titration was 0.51, and the relative standard deviation of refractometry was 0.1% (n=6). Conclusion Compared with the titration value of the national standard method, the refractive method has the advantages of small sample amount, simple operation and fast detection, which provides a new method for rapid detection of lactic acid content.