What is thin-layer chromatography? Group of answer choices a technique that separates amino acids on the basis of pKa of α-+NH3 values a technique that separates amino acids on the basis of their solubility in water a technique that separates amino acids on the basis of pKa of α-COOH values a technique that separates amino acids on the basis of their pI values a technique that separates amino acids on the basis of their polarity

Answer: Thin-layer chromatography is a technique that separates amino acids on the basis of their polarity.

Explanation:

Thin Layer Chromatography can be defined as a method of separation or identification of a mixture of components into individual components by using a thin stationary phase and liquid as a mobile phase. The stationary phase is a porous medium like silica or alumina, through which the sample mixture percolates under the influence of a moving solvent (the mobile phase).

In the separation of amino acids using thin-layer chromatography, the amino acids are separated based on the differences in their R groups, in particular, their polarity. The polarity of the R groups varies widely, from non-polar and hydrophobic (water-insoluble) to highly polar and hydrophilic (water-soluble).

The thin-layer chromatographic technique exploit these differences in their R group to separate amino acids. The amino acid with R groups that interacts strongly with silica will be carried by the solvent to a small distance, whereas the one that has R groups that interacts less with it will be moved further. By running controls (known compounds) alongside, the components of the mixture can possibly be identified. Since amino acids are colorless compounds, ninhydrin is used for positive detection of the amino acids.