Thin Layer Chromatography (TLC): Principle, Procedure & Applications

薄层色谱法is a kind of chromatography used to separate and isolate mixtures that are non-volatile in nature. Just like other chromatography processes, this one consists of a mobile phase and a stationary phase.

后者是一层薄薄的吸收剂material, such as aluminium oxide, silica gel, or cellulose. This layer is applied to plastic, glass, or aluminium foil sheets called an inert substrate. The mobile phase in the TLC procedure是溶剂或其混合物。

如果您想了解更多信息the thin layer chromatography procedure, you have landed at the right place. Here we will be discussing its principle, process, and applications in different industries.

We will begin with the TLC principle.

Thin Layer Chromatography Principle

TLC程序的分离原理基于给定的化合物对移动和固定相的相对亲和力。该过程通过在固定阶段的表面上移动移动相来开始。在该运动期间，与较低亲和化合物相比，较高亲和化合物的速度较低。这导致它们的分离。

Once the procedure gets completed, different spots can be found on the stationary surface at distinct levels, reflecting various elements of the mixture. Basically, the compounds that are more attracted towards the stationary phase secure their position at lower levels while others move towards the higher levels of the surface. So their spots can be seen accordingly.

在TLC原理之后，现在让我们继续前进。

Thin Layer Chromatography Procedure

From the information mentioned above, it must be clear to you how TLC works. However, you still need to learn about its complete procedure to see its entire functioning. A few components involved in the TLC procedure are as follows.

TLC板：这些用于施加薄层固定阶段。它们本质上是惰性或稳定的。静止阶段的层甚至保持在整个板上，以便更好地分析。通常，通过进行实验的人员优选即用板。

流动阶段：这包括溶剂（或溶剂混合物）。溶剂需要化学惰性，最高纯度和无颗粒状。只有那么TLC斑点只能发展。

TLC室：This is where the thin layer chromatography procedure takes place. It keeps the dust particles away from the process and does not let the solvent evaporate. In order to develop the spots appropriately, a uniform environment is maintained inside this chamber.

过滤纸：This gets placed inside the chamber after being moistened with the mobile phase solution. It ensures that the mobile phase rises uniformly throughout the TLC plate’s length.

收集所有这些组件后，进程开始。以下是其中遵循的步骤：

• 该过程通过用铅笔在TLC板的底部制作薄标记。它有助于应用样本斑点。这些斑点保持在相等的距离。
• The sample is then applied to these spots made on the line.
• Then the TLC chamber is filled with the mobile phase up to a few centimetres of its bottom.
• 在浇注流动相之后，润湿的滤纸与腔室壁的内部置于。这有助于通过保持相同的湿度来避免边缘效果。
• 最后，将制备的固定相板放入室内。此时，样品斑点保持在移动阶段侧。
• 然后将板放入其中后腔室关闭。
• Once enough time has elapsed for the process, the plate is taken out and allowed to dry.
• At last, the sample spots get analyzed through a suitable method for the sample, such as UV light, KMnO4 stain, and iodine staining.

This way, the TLC procedure gets completed. After analyzing the compound, it gets described in its relative mobility’s terms, i.e., its Rf value is calculated. This value changes for each compound, even under the same circumstances.

Usually, relative Rf comes into use here because keeping all the TLC factors constant may not be possible. These aspects include adsorbent, temperature, adsorbent thickness, spotted material’s amount, and solvent system. The formula used for Rf value calculation is:

Rf = (distance covered by the sample) / (distance covered by the solvent)

薄层色谱应用

只是理解TLC的原理和程序是不够的。您还需要了解薄层色谱法用于了解它在现实世界中的工作方式和位置。一些标准TLC应用包括：

• 作为分离过程，TLC证明对分离多种组分的药物制剂非常有效。
• 该过程可用于检查给定的产品的纯度。
• 像局部麻醉剂，镇痛药，镇静剂，催眠药，抗惊厥药镇静剂和类固醇一样的药物TLC procedurefor their qualitative testing.
• The cosmetic industry also uses TLC for checking the presence of preservatives in the products.
• 可以使用TLC纯化给定化合物，然后与标准样品进行比较。
• TLC还发现它在生化分析中使用。这里，它可用于生化代谢物与尿液，血浆，血清和体液的分离。
• 就像化妆品行业一样，食品工业也利用TLC检测防腐剂，人造色谱和甜味剂。
• 在TLC中还可以跟踪反应的进度，以查看它是否完整。

这些是您可以在不同的地方找到的一些典型的薄层色谱应用。但是，该过程不限于这些，您也可以在许多其他行业中看到它的使用。

Thin Layer ChromatographyBenefits and Drawbacks

Finally, let’s explore some of the benefits and drawbacks of using the thin layer chromatography procedure.

TLC的优势

这些包括：

• 没有任何问题，可以进一步可视化TLC的分离点。
• 与其他方法相比，这种色谱法具有成本效益。
• 它可用于许多化合物，它不花很多时间，因为它更快。
• 该过程比其他方法更直接。
• TLC makes it simple to analyze any given compound’s purity standards.
• 几种化合物可以容易地通过TLC孤立。

TLC的缺点

该过程的缺点是：

• TLC程序不能用于较低的检测限实验，因为它具有高检测限。
• The plates used in TLC do not possess a more extended stationary phase.
• 结果再现在TLC中具有挑战性。
• TLC is limited to qualitative analysis, and it can not be used for quantitative analysis.
• 与其他色谱方法相比，分离长度也受到限制。
• The process here does not take place in a closed system. Therefore, aspects like temperature and humidity can affect the results, making them inaccurate.

我们希望所有这些信息都帮助您了解薄层色谱概念的一切。