检测乳制品中山梨酸、苯甲酸含量最常见方法是 《GB 5009.28—2016 食品安全国家标准 食品中苯甲酸、山梨酸和糖精钠的测定》中的第一法高效液相色谱法。在使用高效液相色谱分析时,流动相的pH值对试验结果,尤其是对出峰时间和稳定性影响极大。在一定范围内,pH值越小,出峰时间越迟,越稳定,峰偏移幅度越小;pH值越大,出峰时间越快,越不稳定,峰偏移幅度越大。目标峰偏移对结果定性和定量判定具有严重影响,所以获得稳定出峰时间和良好峰型对试验结果至关重要。本文以流动相中pH值为变量,探究当其pH值为7.0、6.5、6.0、5.8、5.5、5.0时对出峰时间和稳定性影响规律,找出当前实验室环境最适宜流动相pH值,提高检测质量。

The most common method for detecting the content of sorbic acid and benzoic acid in dairy products is the first method of high performance chromatography in GB 5009.28—2016 National Food Safety Standard for the Determination of Benzoic Acid, Sorbic Acid and Sodium Sacchar in Foods. When using high performance liquid chromatography for analysis, the pH value of the mobile phase has a great influence on the test results, especially on the retention and stability. Within a certain range, the smaller the pH value, the later the retention time, the more stable, and the smaller the peak offset, the larger pH value, the faster the retention time, the more unstable, and the larger the peak offset. The offset of the target peak has a significant impact on the qualitative quantitative determination of the results, so it is essential to obtain stable retention time and good peak shape for the experimental test results. This paper took the pH value in the phase as a variable, explored the influence law of the retention time and stability when its pH value was 7.0, 6.5, 6., 5.8, 5.5, 5.0, and found out the most suitable pH value of the mobile phase in the current laboratory environment to the detection quality.