自动标准加入法测定乳粉、乳饮料及果汁中的钠含量

Determination of sodium content in milk powder, milk drinks and juice drinks by automatic standard addition method

目的建立自动标准加入法测定乳粉、乳饮料和果汁中钠含量的方法。方法采用自动标准加入法对全脂奶粉、脱脂奶粉、浓缩乳清粉、婴幼儿配方奶粉以及市场上各类果汁饮料及乳饮料进行钠含量的测定,研究样品中钠离子的提取方式和滴定剂浓度对检测结果的影响,并将测定结果与火焰原子发射光谱法进行对比。结果自动标准加入法用于乳粉、浓缩乳清粉、果汁饮料及乳饮料中钠含量的测定结果重复性好,相对标准偏差均小于5%;而且与火焰原子发射光谱法的测定结果之间无显著性差异,两者之间的相对偏差小于5%。结论自动标准加入法重复性好、准确度高,可用于食品与饮料中钠含量的检测。

Objective To establish a method for determination of sodium content in milk powder, milk drinks and fruit juice by automatic standard addition method. Methods The sodium content in whole milk powder, skim milk powder, whey powder concentrated, infant formula and all kinds of fruit juices and milk drinks sold in markets were determined by automatic standard addition method. The effects of the extraction methods of sodium ion and the titrant concentration on the detection results were investigated, and then the results were compared with the results of flame atomic emission spectrometry method. Results The automatic standard addition method which was used to detect the sodium content in milk powder, whey powder concentration, fruit juices and milk drinks had good repeatability with the relative standard deviations（RSDs） less than 5%. There was no significant difference between automatic standard addition method and flame atomic emission spectrometry method, and the RSDs were less than 5%. Conclusion Automatic standard addition method has good repeatability and high accuracy, which can be used for determination of sodium in food and beverage.