Abstract: Under deep frying conditions, edible oil will release a variety of deterioration chemicals that have been implicated in many diseases. Unscrupulous traders may refine used cooking oil and adulterate it as qualified edible oil, thus posing threats to public health. This research aimed to discover the chemical markers of used cooking oil by using gas chromatography-mass spectrometry (GC-MS) based profiling. Our results suggested that six monoglycerides could be used as endogenous markers to discriminate used cooking oil from fresh edible oil. Accumulation behaviors of those markers in continuous heating process were observed. A quantitative GC-MS method was further developed for the six monoglycerides with good accuracy, precision and reproducibility. This method enabled the authentication of commercial olive oil adulterated with 1% deep fried oil. Abnormally high levels of the monoglycerides markers had also been determined in 116 gutter oil samples. Therefore, quantitation of six monoglycerides markers by GC-MS could be a promising approach for elucidating the degradation state of edible oil, authenticating commercial oil products adulterated with used cooking oil, as well as screening of gutter oil.

中文翻译：

---

基于气相色谱-质谱的分析揭示了六种甘油单酯作为食用油的标志物

摘要：在油炸条件下，食用油会释放出多种与多种疾病有关的变质化学物质。不法商贩可能将用过的食用油提炼，掺假为合格食用油，对公众健康构成威胁。本研究旨在通过使用基于气相色谱-质谱 (GC-MS) 的分析来发现使用过的食用油的化学标志物。我们的研究结果表明，六种甘油单酯可以作为内源性标志物来区分用过的食用油和新鲜食用油。观察这些标志物在连续加热过程中的积累行为。进一步开发了六种单酸甘油酯的定量 GC-MS 方法，具有良好的准确度、精密度和重现性。这种方法能够对掺有 1% 油炸油的商业橄榄油进行鉴定。在 116 个地沟油样品中也检测到异常高水平的单酸甘油酯标记物。因此，通过 GC-MS 对六种甘油单酯标记物进行定量可能是阐明食用油降解状态、鉴定掺有食用油的商业油产品以及筛选地沟油的一种很有前景的方法。