薄层色谱

薄层色谱法(TLC)是一种基于亲和力的方法,用于分离混合物中的化合物。TLC 是一种用途广泛的分离方法,广泛用于定性和定量样品分析。TLC 几乎可用于分析任何物质类别,包括农药、类固醇、生物碱、脂类、核苷酸、苷类、碳水化合物和脂肪酸。
特色类别
在 TLC 中,固定相是涂在惰性板(通常是玻璃、塑料或铝)表面的薄吸附材料层,通常是硅胶或氧化铝。将样品点在 TLC 板的一端,然后垂直放入装有有机溶剂(流动相)的封闭室中。当溶剂到达平板顶部时,将平板从显影室移出并烘干。被分离的成分在板上显示为斑点,并评估每种成分的保留因子 (Rf)。
TLC 过程和原理
TLC基于经典的色谱原理,即混合物成分在固定的固定相和液体流动相之间通过两相之间的亲和力差异而分离。
TLC 保留因子 (R)f)
保留因子 (Rf) 用于测量化合物沿 TLC 板的移动。Rf 的定义是单个成分移动的距离除以溶剂移动的总距离。其值始终介于 0 和 1 之间。
Rf = | 组件移动的距离 |
溶剂移动的距离 |
一般来说,化合物与固定相吸附剂的结合力越强,其在 TLC 板上移动的速度就越慢。由于 TLC 吸附剂通常是极性的,因此非极性化合物在板上移动的速度会更快,从而导致 Rf 值升高,而极性化合物则移动缓慢,Rf 值降低。
TLC的应用
TLC广泛应用于许多行业和研究领域,包括制药、临床测试、环境毒理学、食品、水和农药分析以及化妆品。TLC 的典型应用包括
- 分析食品和环境样品中的药物残留和抗生素
- 鉴别和定量食品和化妆品中的色素、成分、防腐剂和甜味剂
- 药物制剂的质量控制和纯度测试
- HPLC前的快速、高通量筛选
- 化学反应完成情况检查
相关文章
- In this article we present several HPTLC applications and analytical standards for ginsenosides.
- Discover the history of thin-layer chromatography (TLC) and its key milestones that have shaped analytical chemistry over the past century.
- HPTLC-MS was used to analyze stevioside and rebaudioside in artificial sweeteners, stevia plants, cola and isotonic drinks with a minimum of sample preparation.
- Thin layer chromatography (TLC), an analytical technique often used to separate and identify compounds present in a given mixture, can also be used to determine the purity of a particular substance within that mixture
- TLC plates, with silica gel, gypsum as binder, International Pharmacopoeia compliant, for identification of Atenolol and Chlorthalidone in tablets.
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相关协议
- TLC separation relies on capillary forces to transport substances on a stationary phase after mobile phase transport.
- Powdered black pepper tested for pierine content follows USP guidelines using HPTLC and HPLC for dietary supplements.
- HPTLC was used to analyze caffeine in coffee. Filtration of coffee through a PTFE syringe filter was the only sample preparation. Quantitation was conducted with a TLC scanner.
- Silica gel G 254 plates are suitable for analysis of Dextromethorphan following the European pharmacopeia monograph.
- The modern thin-layer chromatography (TLC) offers advantages also in the field of cosmetics to quickly and simultaneously analyze samples with densitometric detection.
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