Dipartimento di Scienza e Tecnologia del Farmaco, Università degli Studi di Torino, via P. Giuria 9, I-10125 Torino, Italy.
Dipartimento di Scienza e Tecnologia del Farmaco, Università degli Studi di Torino, via P. Giuria 9, I-10125 Torino, Italy.
J Chromatogr A. 2019 Jun 7;1594:173-180. doi: 10.1016/j.chroma.2019.02.012. Epub 2019 Feb 6.
A correct botanical identification and analytical quality control of volatile key-markers responsible for aroma and biological activities is necessary to monitor volatile compounds transferred from a plant to the related herbal tea and human intake to guarantee their safe use. This is mainly true for markers limited by regulations or by a recommended maximum amount of consumption per day. GC-MS is the elective technique to analyze volatiles, provided that for aqueous samples (herbal teas) an appropriate sample preparation procedure, and/or a water-compatible GC stationary phases are applied. Solid Phase Micro Extraction (SPME) on-line coupled to GC-MS in a fully automatic approach is here applied to sample and quantify key markers in plant material (headspace) and in the corresponding herbal tea (direct immersion). In parallel, a new generation of GC columns coated with ionic liquid based stationary phases compatible with aqueous samples (Watercol) was applied to test direct injection of aqueous samples (DAI-GC-FID). The latter approach fully bypasses sample preparation thus speeding up quality control. This study deals with the quantitation of menthol, α- and β-thujone, estragole, and anethole contained in several plant species commonly used for herbal teas (i.e. peppermint, sage, wormwood, fennel, aniseed) and regulated by International Organizations. The two methods gave comparable results and are characterized by high repeatability, linearity and accuracy, although, as expected, their sensitivity was different because DAI-GC-FID implies injection of the sample as such without analyte concentration as for DI-SPME-GC-MS. For instance, LOD and LOQ of estragole were 0.03 and 0.1 mg L with DI-SPME-GC-MS and 0.1 and 0.8 mg L with DAI-GC-FID. The two methods are fully complementary and their adoption depends on the amount of marker(s) to be quantified.
为了监测从植物转移到相关草药茶和人类摄入的挥发性化合物，并确保其安全使用，有必要对负责香气和生物活性的关键挥发性标志物进行正确的植物学鉴定和分析质量控制。对于受法规或每日建议最大摄入量限制的标志物，这一点尤其重要。GC-MS 是分析挥发性物质的首选技术，但对于水样（草药茶），需要应用适当的样品制备程序和/或水相容的 GC 固定相。固相微萃取（SPME）与 GC-MS 在线联用，采用全自动方法，用于对植物材料（顶空）和相应草药茶（直接浸提）中的关键标志物进行采样和定量。同时，应用新一代涂有与水样兼容的离子液体固定相的 GC 柱（Watercol）来测试水样的直接进样（DAI-GC-FID）。后一种方法完全绕过样品制备，从而加快质量控制速度。本研究涉及几种常用于草药茶的植物物种（即薄荷、鼠尾草、苦艾、茴香、八角）中所含的薄荷醇、α-和 β-侧柏酮、茴香脑和茴香脑的定量，这些植物受到国际组织的监管。这两种方法给出了可比的结果，具有高重复性、线性和准确性，尽管如预期的那样，它们的灵敏度不同，因为 DAI-GC-FID 意味着将样品直接注入，而无需像 DI-SPME-GC-MS 那样对分析物进行浓缩。例如，DI-SPME-GC-MS 测定茴香脑的检出限和定量限分别为 0.03 和 0.1 mg/L，而 DAI-GC-FID 分别为 0.1 和 0.8 mg/L。这两种方法是完全互补的，其采用取决于要定量的标记物的数量。
