Coffee diterpenes are the main constituents of the coffee oil unsaponifiable fraction. The three most important diterpenes are cafestol, kahweol, and 16‐O‐methylcafestol (16‐OMC), and they are produced, except for cafestol, only by plants of the Coffea genus. Recently, in addition to these three major diterpenes, another 16‐O‐methylated diterpene (16‐O‐methylkahweol: 16‐OMK) has been identified and quantified, for the first time, in Robusta coffee. For many years, 16‐OMC has been considered present exclusively in Robusta, and so it has been reputed an excellent authenticity marker for the presence of Robusta in coffee products. For its quantification, nuclear magnetic resonance (NMR) has proved very useful when compared with other methods. Quite recently, the detection of very low levels of the two 16‐O‐methylated diterpenes (16‐OMD) 16‐OMC and 16‐OMK in roasted Arabica was reported. This finding makes the use of NMR methods in 16‐OMD quantification in Arabica coffee particularly challenging in view of both the trace amounts of 16‐OMD and the impossibility to discriminate between 16‐OMC and 16‐OMK. The ultra‐high performance liquid chromatography mass spectrometry (UHPLC‐MS) method, already used to detect 16‐OMC and 16‐OMK in Arabica roasted coffee, is then more suitable for quantitative analyses. Up to now however, no quantification of coffee 16‐OMD via ultra‐high performance liquid chromatography tandem mass spectrometry (UHPLC‐MS/MS) has been carried out; this largely stimulated the present study. For the first time, a simple procedure for the quantitative detection of 16‐OMD in Arabica coffee has been developed, and as far as 16‐OMC is concerned, fully validated in terms of specificity, linearity, concentration range, limit of detection (LOD), limit of quantification (LOQ), and repeatability following the criteria specified in the EU Commission Decision 2002/675/EC. This method proved to be very specific and sensitive. In order to avoid the chemical complexity generated by the roasting process, the method was optimized and validated on several green Arabica samples from different geographical origins.

中文翻译：

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绿色阿拉比卡咖啡中的 16-O-甲基化二萜：超高效液相色谱-串联质谱方法优化和验证。

咖啡二萜是咖啡油不皂化物的主要成分。三种最重要的二萜是咖啡醇、咖啡豆醇和16- O-甲基咖啡醇(16-OMC)，除咖啡醇外，它们仅由咖啡属植物产生。最近，除了这三种主要的二萜外，另一种 16- O-甲基化二萜（16- O‐methylkahweol: 16‐OMK) 已在罗布斯塔咖啡中首次被鉴定和量化。多年来，16-OMC 一直被认为只存在于罗布斯塔，因此它被认为是咖啡产品中罗布斯塔存在的极好真实性标志。与其他方法相比，核磁共振 (NMR) 已证明其量化非常有用。最近，检测到非常低水平的两种 16- O报道了焙烤阿拉比卡咖啡中的甲基化二萜 (16-OMD) 16-OMC 和 16-OMK。考虑到痕量 16-OMD 和无法区分 16-OMC 和 16-OMK，这一发现使得在阿拉比卡咖啡中使用 NMR 方法进行 16-OMD 定量特别具有挑战性。超高效液相色谱质谱 (UHPLC-MS) 方法已经用于检测阿拉比卡烘焙咖啡中的 16-OMC 和 16-OMK，因此更适合定量分析。然而，到目前为止，还没有通过超高效液相色谱串联质谱 (UHPLC-MS/MS) 对咖啡 16-OMD 进行定量。这在很大程度上刺激了本研究。首次开发了一种用于定量检测阿拉比卡咖啡中 16-OMD 的简单程序，就 16-OMC 而言，根据欧盟委员会决定 2002/675 中规定的标准，在特异性、线性、浓度范围、检测限 (LOD)、定量限 (LOQ) 和重复性方面得到充分验证/欧共体。该方法被证明是非常特异和灵敏的。为了避免烘焙过程产生的化学复杂性，该方法在来自不同地理来源的几个绿色阿拉比卡咖啡样品上进行了优化和验证。