This work describes a simple approach for the untargeted profiling of volatile compounds for the authentication of the botanical origins of honey based on resolution-optimized HS-GC-IMS combined with optimized chemometric techniques, namely PCA, LDA, and kNN. A direct comparison of the PCA–LDA models between the HS-GC-IMS and ¹H NMR data demonstrated that HS-GC-IMS profiling could be used as a complementary tool to NMR-based profiling of honey samples. Whereas NMR profiling still requires comparatively precise sample preparation, pH adjustment in particular, HS-GC-IMS fingerprinting may be considered an alternative approach for a truly fully automatable, cost-efficient, and in particular highly sensitive method. It was demonstrated that all tested honey samples could be distinguished on the basis of their botanical origins. Loading plots revealed the volatile compounds responsible for the differences among the monofloral honeys. The HS-GC-IMS-based PCA–LDA model was composed of two linear functions of discrimination and 10 selected PCs that discriminated canola, acacia, and honeydew honeys with a predictive accuracy of 98.6%. Application of the LDA model to an external test set of 10 authentic honeys clearly proved the high predictive ability of the model by correctly classifying them into three variety groups with 100% correct classifications. The constructed model presents a simple and efficient method of analysis and may serve as a basis for the authentication of other food types.

中文翻译：

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顶空-气相色谱-离子迁移谱法（HS-GC-IMS）的挥发性化合物指纹图谱作为¹ H NMR分析的替代品，用于评估蜂蜜的真实性

这项工作描述了一种简单的方法，该方法基于分辨率优化的HS-GC-IMS与优化的化学计量技术（即PCA，LDA和k NN）相结合，对挥发性化合物进行非目标分析，以鉴定蜂蜜的植物来源。HS-GC-IMS与¹之间PCA-LDA模型的直接比较1 H NMR数据表明，HS-GC-IMS分析可以用作蜂蜜样品基于NMR的分析的补充工具。NMR分析仍然需要相对精确的样品制备，特别是pH值调节，HS-GC-IMS指纹图谱可被视为真正全自动，成本有效且特别是高度灵敏的方法的替代方法。结果表明，所有测试的蜂蜜样品都可以根据其植物来源加以区分。加载图显示了导致单花蜂蜜之间差异的挥发性化合物。基于HS-GC-IMS的PCA–LDA模型由两个线性判别函数和10个选定的PC组成，这些PC可以区分低芥酸菜籽，阿拉伯树胶和蜜露蜂蜜，预测精度为98.6％。通过将LDA模型正确地划分为三个具有100％正确分类的品种组，将LDA模型应用于10个正宗蜂蜜的外部测试集可以清楚地证明该模型具有较高的预测能力。所构建的模型提供了一种简单而有效的分析方法，并且可以用作其他食品类型认证的基础。