Abstract Carcinogenic 4-methylimidazole (4-MEI) formed by Maillard reaction is commonly found in various food, which are colored with caramel or prepared in cooking and roasting processes. The sample preparation and detection of 4-MEI are extremely difficult due to its low molecular weight and high water solubility. In this study, a simple sample preparation based on the dispersive micro solid-phase extraction (dispersive micro SPE) procedure was developed for the analysis of 4-MEI in food. Dispersive micro SPE method is convenient, time-saving and low-cost, and its cleanup effect is comparable to that of the traditional SPE method. Moreover, liquid chromatography-high resolution mass spectrometry (LC-HRMS) was also used for the accurate qualitative and quantitative detection of 4-MEI. Among various acquisition modes of HRMS, a new parallel reaction monitoring (PRM) mode was found to contribute to a significant reduction in background noise of 4-MEI, resulting in its detection performance increased by 50- or 100-fold. Finally, this method was validated in eight kinds of food, including the complex matrices (soy sauce, vinegar, coffee and tea), and applied in real food samples. The results showed that the presence of 4-MEI in cooking and roasting food (e.g. coffee and tea) is of concern.

中文翻译：

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液相色谱-高分辨质谱联用分散微固相萃取并行反应监测提高食品中致癌物4-甲基咪唑的检测性能

摘要 美拉德反应形成的致癌物质4-甲基咪唑(4-MEI)广泛存在于各种食品中，如用焦糖着色或在烹饪和烘烤过程中制备的。由于 4-MEI 分子量低、水溶性高，因此其样品制备和检测极为困难。在本研究中，开发了一种基于分散微固相萃取（分散微固相萃取）程序的简单样品制备方法，用于分析食品中的 4-MEI。分散微细SPE方法方便、省时、成本低，净化效果与传统SPE方法不相上下。此外，液相色谱-高分辨质谱 (LC-HRMS) 也被用于 4-MEI 的准确定性和定量检测。在 HRMS 的各种采集方式中，发现一种新的平行反应监测 (PRM) 模式有助于显着降低 4-MEI 的背景噪声，使其检测性能提高 50 或 100 倍。最后，该方法在包括复杂基质（酱油、醋、咖啡和茶）在内的八种食品中得到验证，并应用于实际食品样品。结果表明，4-MEI 在烹饪和烘焙食品（例如咖啡和茶）中的存在值得关注。