[目的]对即将实施的《GB5009.211—2022 食品安全国家标准食品中叶酸的测定》中两种微生物法测定乳粉中叶酸进行比对研究。[方法]验证试管法和微孔板法测定叶酸的准确度和重复性,根据数据的差异与试验操作过程对两种方法进行比较分析。[结果]由准确性试验可知,两种方法所测结果均与标准物质真值相符,相对标准偏差（RSD）分别为2.7%和2.9%,无明显差异。由重复性试验结果可知试管法RSD值为1.3%~3.1%,微孔板RSD值为1.6%~2.9%。[结论]新国标的两种微生物法的准确性和重复性都较好,均能对乳粉中叶酸进行有效测定;微孔板法效率更高,成本更低,适用于大批量样品的检测需求。
[Objective]This study compared two microbial methods for the determination of folic acid in milk powder in the upcoming GB5009.211-2022 National Food Safety Standard for the Determination of Folic Acid in Food. [Method]The accuracy and repeatability of the test tube method and the microplate method for the determination of folic acid were verified,and the two methods were compared and analyzed according to the difference of the data and the experimental operation process.[Result]It can be seen from the accurate experiment that the measured results of the two methods are consistent with the true value of the reference material,and the relative standard deviation（RSD）is 2.7% and 2.9%,respectively,with no significant difference. From the consequences of repeatability experiments,it can be known that the RSD value of the test tube method is 1.3% to 3.1%, and the RSD value of the microplate is 1.6% to 2.9%.[Conclusion]The accuracy and repeatability of the two microbiological methods of the new national standard are good,and both can effectively determine folic acid in milk powder. The microplate method has higher efficiency and lower cost,and is appropriate for the detection needs of large batches of samples.
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