Background Full scent profiles emitted by living tissues can be screened by using total ion chromatograms generated in full scan mode and gas chromatography-mass spectrometry technique using Headspace Sorptive Extraction. This allows the identification of specific compounds and their absolute quantification or relative abundance. Quantifications ideally should be based on calibration curves using standards for each compound. However, the unpredictable composition of Volatile Organic Compounds (VOCs) and lack of standards make this approach difficult. Researchers studying scent profiles therefore concentrate on identifying specific scent footprints i.e. relative abundance rather than absolute quantities. We compared several semi-quantitative methods: external calibration curves generated in the sampling system and by liquid addition of standards to stir bars, total integrated peak area per fresh weight (FW), normalized peak area per FW, semi-quantification based on internal standard abundance, semi-quantification based on the nearest n-alkane and percentage of emission. Furthermore, we explored the usage of nearest components and single calibrators for semi-quantifications. Results Any of the semi-quantification methods based on a standard produced similar or even identical results compared to quantification by a true-standard for a compound, except for the method based on standard addition. Each method beholds advantages and disadvantages regarding level of accuracy, experimental variability, acceptance and retrieved quantities. Conclusions Our data shows that, except for the method of standard addition to the biological sample, the rest of the semi-quantification methods studied give highly similar statistical results. Any of the methodologies presented here can therefore be considered as valid for scent profiling. Regarding relative proportions of VOCs, the generation of calibration curves for each compound analysed is not necessary.

中文翻译：

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适用于建立挥发性曲线的半定量方法的比较。

背景 使用在全扫描模式下生成的总离子色谱图和使用顶空吸附萃取的气相色谱-质谱技术可以筛选活组织发出的完整气味曲线。这允许识别特定化合物及其绝对定量或相对丰度。理想情况下，量化应基于使用每种化合物标准的校准曲线。然而，挥发性有机化合物 (VOC) 的不可预测成分和缺乏标准使这种方法变得困难。因此，研究气味特征的研究人员专注于识别特定的气味足迹，即相对丰度而不是绝对数量。我们比较了几种半定量方法：在采样系统中生成的外部校准曲线和通过向搅拌棒中加入液体标准产生的外部校准曲线、每鲜重 (FW) 的总积分峰面积、每 FW 的归一化峰面积、基于内标丰度的半定量、基于内标丰度的半定量最接近的正构烷烃和排放百分比。此外，我们探索了使用最近的组件和单个校准器进行半量化。结果 除基于标准添加的方法外，任何基于标准的半定量方法都产生了与化合物真实标准的定量相似甚至相同的结果。每种方法在准确性水平、实验变异性、接受度和检索数量方面都有优点和缺点。结论 我们的数据表明，除了向生物样品中添加标准的方法外，其余研究的半定量方法都给出了高度相似的统计结果。因此，此处介绍的任何方法都可以被视为对气味分析有效。关于 VOC 的相对比例，无需为每种分析的化合物生成校准曲线。