全自动定氮仪-液相色谱测定食品中丙酸

Determination of Propionic Acid in Food by Kjeltec Auto Analyzer-Liquid Chromatography

目的:建立操作简单、准确稳定、快速高效测定食品中丙酸的方法。方法:利用全自动定氮仪快速蒸馏的特点,对样品前处理过程中蒸馏试样初始体积、磷酸加入体积、馏出液是否补加磷酸等可能影响测定结果的因素进行逐一验证核实,优化高效液相色谱的样品前处理方法,并用于实际样品的测试。结果:面包和豆腐的方法检出限可以达到0.1 g·kg^(-1),当加标浓度为2 g·kg^(-1)时,面包的加标回收率为76.08%~83.98%,相对极差约为4.9%;豆腐的加标回收率为76.75%~83.24%,相对极差约为4.1%。结论:该方法操作简单快速、结果准确稳定,可以用于面包和豆腐等食品中丙酸的测定。

Objective:To establish a simple,accurate,stable,rapid and efficient method for the determination of propionic acid in food.Method:Using the characteristics of rapid distillation of the fully automatic nitrogen fixation instrument,we verified the factors that may affect the determination results,such as the initial volume of distilled specimen,the volume of phosphoric acid added,and whether the distillate was supplemented with phosphoric acid during the sample pretreatment process,one by one,and optimized the sample pretreatment method for high performance liquid chromatography and used it for the actual sample testing.Result:The method detection limits for bread and tofu could reach 0.1 g·kg^(-1).When the spiked concentration was 2 g·kg^(-1),the spiked recoveries of bread were 76.08%~83.98%with a relative extreme difference of about 4.9%;the spiked recoveries of tofu were 76.75%~83.24%with a relative extreme difference of about 4.1%.Conclusion:The method is simple,rapid,accurate and stable,and can be used for the determination of propionic acid in foods such as bread and tofu.