在线二维高效液相色谱法测定发酵食品中的苯乳酸

Detection of phenyllactic acid in fermented food using two-dimensional high-performance liquid chromatography

苯乳酸是一种能够存在于食品中的新型抑菌物质,为了避免传统高效液相色谱法(HPLC)检测苯乳酸时出现灵敏度低和色谱峰相连的问题,建立了一种二维高效液相色谱法(2D-HPLC)检测发酵食品中苯乳酸的方法,测定了酸奶、甜米酒、东北酸菜、酱黄瓜和广式腊肠5种常见发酵食品中苯乳酸的含量。利用超高效液相色谱-串联四级杆质谱(ultra high performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)验证了样品中存在苯乳酸。2D-HPLC方法:第一维色谱柱为C18色谱柱,流动相为0.1%甲酸和甲醇;第二维色谱柱为C8色谱柱,流动相为0.05%三氟乙酸和乙腈,流速1.0 mL/min,柱温30℃,检测波长210 nm。结果表明:该方法在0.4~10.0 mg/L内呈现良好的线性关系,r=0.999 9,检出限0.16 mg/L,定量限0.52 mg/L,方法的日内和日间重复性相对标准偏差(relative standard deviation,RSD)分别为0.60%和0.94%,5种发酵食品的加标回收率91.79%~107.37%,RSD<7.5%;UPLC-MS/MS验证样品中含有苯乳酸。利用2D-HPLC法测定食品中的苯乳酸前处理简单、结果准确、抗干扰能力强,适用于大批量样品检测,为2D-HPLC法检测发酵食品中组分提供理论依据。

A two-dimensional high-performance liquid chromatography(2 D-HPLC) was established for the determination of phenyllactic acid(PLA) in fermented food. The 2 D-HPLC system was: C8 column(100×4.6 mm, 2.7 μm), 0.05% TFA-acetonitrile(87∶13, v/v) as mobile phase with the flow rate of 1.0 mL/min, 30 ℃ of the column temperature, and UV detector detecting at 210 nm. The contents of PLA in five kinds of common fermented food, yogurt, fermented glutinous rice wine, Chinese sauerkraut, pickled cucumber and Cantonese sausage was determined. The accuracy was verified by the recovery rate, and the presence of PLA in the samples was verified by ultra-high-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS). The results showed that in the above detection conditions, the retention time of PLA was 11 min, the linear relationship were in the range of 0.4-10.0 mg/L, r=0.999 9, LOD 0.16 mg/L, LQD 0.52 mg/L, the relative standard deviations(RSD) of days and intraday were 0.60% and 0.94%, respectively, and the recovery rateswere 91. 79%-107. 37%,with RSD less than 7. 5%. The amounts of PLA in samples( pickled cucumber,Chinese sauerkraut,yogurt and fermented glutinous rice wine) were 8. 01,5. 05 1. 57,9. 08 mg/L,respectively. It has been found that the determination of PLA in food by 2 D-HPLC possesses the advantages of high resolution,simple pretreatment,accurate results and high detection efficiency.