Reinhardt Julian, Steinhaus Martin
Technical University of Munich, TUM School of Natural Sciences, Department of Chemistry, Lichtenbergstraße 4, 85748 Garching, Germany; Leibniz Institute for Food Systems Biology at the Technical University of Munich (Leibniz-LSB@TUM), Lise-Meitner-Straße 34, 85354 Freising, Germany.
Technical University of Munich, TUM School of Natural Sciences, Department of Chemistry, Lichtenbergstraße 4, 85748 Garching, Germany; Leibniz Institute for Food Systems Biology at the Technical University of Munich (Leibniz-LSB@TUM), Lise-Meitner-Straße 34, 85354 Freising, Germany.
J Chromatogr A. 2025 Jan 25;1741:465624. doi: 10.1016/j.chroma.2024.465624. Epub 2024 Dec 21.
Odor-active compounds are major quality parameters in food and other consumer products. In the analysis of odorants, gas chromatography (GC) plays a dominant role and is particularly indispensable for odorant screening by GC-olfactometry (GC-O). Whereas artifact formation during workup before GC analysis has been widely discussed, artifact formation during GC injection has not been adequately addressed so far. Using a set of 14 test compounds, we evaluated ten different GC injection approaches. Artifact-producing reactions were particularly 1,2-eliminations. Linalyl acetate additionally showed [1,3]-sigmatropic shifts. On-column injection was confirmed as the gold standard, with virtually zero artifact formation observed not only with classic cold on-column injection in the oven, but also with on-column injection in a programmable temperature vaporizing (PTV) injector. Substantial artifact formation was observed when a high fixed injector temperature was combined with splitless injection. This applied to the injection of liquid samples but even more so to headspace solid-phase microextraction (HS-SPME) approaches. In conclusion, we recommend using on-column injection whenever aiming at a representative odorant spectrum, such as in GC-O. In targeted analysis, critical approaches such as SPME should be carefully tested for artifact formation. For the evaluation of the artifact formation potential of different injection approaches, cedryl acetate emerged as an excellent test compound.
气味活性化合物是食品和其他消费品中的主要质量参数。在气味物质分析中，气相色谱法（GC）起着主导作用，对于通过气相色谱 - 嗅觉测定法（GC - O）进行气味物质筛选尤为不可或缺。虽然在GC分析前的样品处理过程中假象的形成已被广泛讨论，但到目前为止，GC进样过程中假象的形成尚未得到充分解决。我们使用一组14种测试化合物，评估了十种不同的GC进样方法。产生假象的反应主要是1,2 - 消除反应。乙酸芳樟酯还表现出[1,3] - 西格玛重排。柱上进样被确认为金标准，不仅在柱温箱中进行经典的冷柱上进样时几乎观察不到假象形成，而且在可编程温度汽化（PTV）进样器中进行柱上进样时也是如此。当高固定进样器温度与不分流进样结合时，会观察到大量假象形成。这适用于液体样品的进样，但对于顶空固相微萃取（HS - SPME）方法更是如此。总之，我们建议在旨在获得代表性气味物质谱时，如在GC - O中，使用柱上进样。在靶向分析中，对于SPME等关键方法，应仔细测试假象的形成。对于评估不同进样方法产生假象的可能性，乙酸雪松酯是一种出色的测试化合物。
