To differentiate between the raw type and ripe type of tung oil, it is important to distinguish between the types of tung oil before its application. In the present work, an efficient headspace gas chromatography-mass spectrometry (HS-GC–MS) method was developed for identifying eight samples T1–T8, including the raw tung oil and ripe tung oil. The HS-GC–MS experiments results showed that octanoic acid existed only in ripe tung oil of T2, T4, T6, T8, not in raw tung oil of T1, T3, T5, T7. Combined with structural characterization by tandem mass spectrometry, octanoic acid was screened as an effective marker for distinguishing between raw tung oil and ripe tung oil. Then, the HS-GC–MS method was applied into the putty samples of X1 (raw tung oil with lime) and X2 (ripe tung oil with lime) and successfully identified the samples X1 mixed with raw tung oil and X2 mixed with ripe tung oil. The further validations results suggested that the detection limit of our HS-GC–MS method could reach 1.05 mg/L for octanoic acid, whereas the detection limit of derivative gas chromatography-mass spectrometry (DR-GC–MS) method was 2.74 mg/L for methyl octanoate. The investigation results can also provide the useful information and technical support for the selection of restoration materials and technology in ancient buildings.

中文翻译：

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使用顶空 GC-MS 有效鉴定生桐油和熟桐油

为了区分桐油的生油类型和熟油类型，重要的是在应用前区分桐油的类型。在目前的工作中，开发了一种高效的顶空气相色谱-质谱 (HS-GC-MS) 方法来鉴定 8 个样品 T1-T8，包括生桐油和成熟桐油。HS-GC-MS实验结果表明，辛酸只存在于T2、T4、T6、T8的成熟桐油中，T1、T3、T5、T7的生桐油中不存在。结合串联质谱的结构表征，筛选出辛酸作为区分生桐油和熟桐油的有效标记物。然后，将 HS-GC-MS 方法应用于 X1（生桐油加石灰）和 X2（熟桐油加石灰）的腻子样品，成功鉴定了 X1 与生桐油混合的样品和 X2 与熟桐油混合的样品。进一步的验证结果表明，我们的 HS-GC-MS 方法对辛酸的检测限可以达到 1.05 mg/L，而衍生气相色谱-质谱 (DR-GC-MS) 方法的检测限为 2.74 mg/L。 L 为辛酸甲酯。调查结果还可以为古建筑修复材料和修复技术的选择提供有用的信息和技术支持。而衍生气相色谱-质谱 (DR-GC-MS) 方法的检测限为 2.74 mg/L 辛酸甲酯。调查结果还可以为古建筑修复材料和修复技术的选择提供有用的信息和技术支持。而衍生气相色谱-质谱 (DR-GC-MS) 方法的检测限为 2.74 mg/L 辛酸甲酯。调查结果还可以为古建筑修复材料和修复技术的选择提供有用的信息和技术支持。