色谱 ›› 2020, Vol. 38 ›› Issue (12): 1388-1395.DOI: 10.3724/SP.J.1123.2020.03020

• 研究论文 • 上一篇    下一篇

超高效合相色谱-串联质谱法测定食用植物油和油条中15种3-氯-1,2-丙二醇脂肪酸酯

杨光勇1,*(), 郭苍亭2, 薛光1, 郭金喜1   

  1. 1.新疆维吾尔自治区产品质量监督检验研究院, 新疆 乌鲁木齐 830011
    2.乌鲁木齐市疾病预防控制中心, 新疆 乌鲁木齐 830026
  • 收稿日期:2020-03-19 出版日期:2020-12-08 发布日期:2020-12-01
  • 通讯作者: 杨光勇
  • 基金资助:
    新疆生产建设兵团食品安全风险监测计划项目(兵市监发[2019]25号);Food Safety Risk Monitoring Program Project of Xinjiang Production and Construction Corps (Market Supervision and Administration Bureau of Corps, [2019] Reference No. 25)

Determination of 15 3-chloro-1,2-propanediol fatty acid esters in vegetable oils and fritters by ultra performance convergence chromatography-tandem mass spectrometry

YANG Guangyong1,*(), GUO Cangting2, XUE Guang1, GUO Jinxi1   

  1. 1. Xinjiang Uygur Autonomous Region Product Quality Supervision and Inspection Institute, Urumqi 830011, China
    2. Urumqi Center for Disease Control and Prevention, Urumqi 830026, China
  • Received:2020-03-19 Online:2020-12-08 Published:2020-12-01
  • Contact: YANG Guangyong

摘要:

建立了超高效合相色谱-三重四极杆质谱(UPC2-MS/MS)测定食用植物油和油条中15种3-氯-1,2-丙二醇脂肪酸酯(3-MCPDE)含量的方法。3-MCPDE的结构与甘油酯极为相似,因此很难将其从植物油中分离出来。为降低基质干扰,实验以不同极性的溶剂依次洗脱载有样品的氨基填料层析柱,用UPC2和ACQUITY QDa质谱检测器分析每单元洗脱液以绘制洗脱曲线。分段收集的洗脱液经混合、浓缩和过滤后,以Viridis HSS C18 SB色谱柱(150 mm×2.1 mm, 1.8 μm)为分析柱,超临界CO2和40%乙腈甲醇溶液(含0.1%甲酸)为流动相梯度洗脱,以97%异丙醇水溶液(含0.2%氨水)为补偿液,用配备电喷雾电离源的三重四极杆质谱在正离子、多级反应监测模式下测定,外标法定量。结果表明:15种3-MCPDE在各自范围内线性关系良好(相关系数(r2)≥0.9973),检出限为0.01~0.68 μg/L(S/N=3),定量限为0.04~1.74 μg/L(S/N=10);在3个加标水平下的平均回收率为81.6%~98.5%(n=9),相对标准偏差为1.8%~6.4%。利用该法对实际样品进行检测,并对考察范围以外的疑似3-MCPDE化合物进行了分析。该法基质兼容性强,操作简便,灵敏度高,专属性好,绿色环保,较传统方法极具优势,用于测定植物油和油条中3-MCPDE单体的种类和含量,结果满意;但该法也存在定性能力较弱、定量过度依赖单体标准品、单酯较二酯离子化效率低等问题,可作为后期研究关注的方向。

关键词: 超高效合相色谱-串联质谱, 3-氯-1,2-丙二醇脂肪酸酯, 食用植物油, 油条

Abstract:

The presence of 3-chloro-1,2-propanediol fatty acid esters (3-MCPDE) in food and processed materials has recently become a topic of concern because of the toxicity of their metabolites. 3-MCPDE structurally similar to glyceride, which makes it difficult to separate or extract them from oils and fritters. A method based on ultra performance convergence chromatography-tandem mass spectrometry (UPC2-MS/MS) was established for the determination of 15 3-MCPDE in vegetable oils and fritters. Amino-packed columns were used to purify the samples. The analytical conditions were optimized, and the matrix effect was investigated. The sample was treated by column chromatography to remove glyceride and free fatty acids, which induce strong matrix effects. The amino-packed column was eluted with hexane and hexane-ethyl acetate (6∶4, v/v). Every 1 mL of the eluent was analyzed using a UPC2 and ACQUITY QDa detector. Elution curves were drawn based on the testing data and used to determine the collection volume. The collection volumes for 3-chloro-1,2-propanediol diesters and monoesters according to the elution curves were 7-14 mL and 3-9 mL. The collected eluent was mixed and dried under nitrogen flow at a temperature of 60 ℃. A hexane-isopropanol (98∶2, v/v, 1 mL) mixture was used to dissolve the residue. The resulting solution was separated on a Viridis HSS C18 SB column (150 mm×2.1 mm, 1.8 μm) under gradient elution. Supercritical carbon dioxide and methanol (containing 40% acetonitrile and 0.1% formic acid) were used as the mobile phases, and the flow rate was 1 mL/min. The separated compounds were analyzed by tandem MS with an electrospray ionization (ESI) source in positive and multiple reaction monitoring modes. Water (containing 97% isopropanol and 0.2% ammonia water) was used as the auxiliary pump mobile phase, and the flow rate was 0.2 mL/min. The method showed good linear relationships in the range of 0.5-100 μg/L (r2≥0.9973). The limits of detection (LODs) and limits of quantification (LOQs) were 0.01-0.68 μg/L (S/N=3) and 0.04-1.74 μg/L (S/N=10), respectively. The average recoveries (n=9) at the three spiked levels were in the range of 81.6%-98.5%. The relative standard deviations were in the range of 1.8%-6.4%. The matrix effects in the case of the oils and fritters were weak. The developed method was used to detect 44 oil samples and eight fritter samples. Meanwhile, some suspect 3-MCPDE compounds outside the scope of the investigation were analyzed based on their primary and secondary mass spectra. The detection rates of 3-MCPDE in oils and fritters were 84.1% and 87.5%, and their amounts were in the range of 0.024-4.481 mg/kg and 0.018-1.144 mg/kg, respectively. The detection rates of 3-MCPDE in rapeseed oil were higher compared to those for other kinds of oil. The method is specific, fast, simple, accurate, reliable, and environmentally friendly, in addition to being more sensitive than other methods and showing better matrix compatibility for oils. This method has been successfully used to determine the types and amounts of 3-MCPDE in vegetable oils and fritters. The research findings provided accurate data to assess the exposure risk of 3-MCPDE. The results of our experiment also provided valuable information for elucidating the formation mechanism of 3-MCPDE. The proposed method can be used to analyze waste edible oil based on large amounts of analysis data. However, this method has some limitations. The resolution ratio of the mass spectrometer used in this method is too low for the qualitative analysis of unknown compounds. The qualitative results for the suspect 3-MCPDE compounds are not particularly accurate, and a large variety of monomer standards are required for the quantitative determination of 3-MCPDE. The 3-MCPDE standards are expensive, and there is limited choice of these standards; moreover, they are difficult to synthesize. The poor ionization yield of 3-chloro-1,2-propanediol monoesters under the ESI conditions resulted in high LODs. Hence, it is necessary to develop a method for increasing the ionization of monoesters, for example, via derivatization.

Key words: ultra performance convergence chromatography-tandem mass spectrometry (UPC2-MS/MS), 3-chloro-1,2-propanediol fatty acid esters (3-MCPDE), vegetable oil, fritters

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