Purification Techniques: Chromatography

Vocabulary-style flashcards covering chromatography principles, types, TLC detection methods, and polarity scales based on the provided lecture transcript.

Chromatography

A purification method used to separate mixtures of soluble compounds by distributing its components between a stationary and a mobile phase.

Stationary phase

A solid, or liquid supported on a solid, used in chromatography to interact with the components of a mixture.

Mobile phase

A gas or a liquid which flows continuously around the stationary phase and carries the components of the mixture through it.

Retention time

The difference in time it takes for components to move through the stationary phase due to differences in solubility and affinity for the phases.

Gas chromatography (GC)

A type of chromatography that separates volatile and semi-volatile compounds based on their boiling points.

Liquid chromatography (LC)

A type of chromatography that separates non-volatile compounds based on their interactions with stationary and mobile phases.

Adsorption chromatography

A mechanism of separation where the stationary phase is solid, such as silica gel or paper chromatography.

Partition chromatography

A mechanism of separation where the stationary phase is liquid/solid, such as in GLC.

Ion exchange chromatography

A separation technique based on the charge of the compounds and their interaction with resins.

Size exclusion chromatography

A separation technique that differentiates compounds based on their size and shape.

Affinity chromatography

A separation technique based on specific binding interactions between the compounds and the stationary phase.

Thin layer chromatography (TLC)

A technique separating compounds based on their interaction with adsorbent silica gel coated on a plate, driven by capillary action.

Column chromatography (CC)

A technique that separates compounds based on the polarity of solvents passed through a packed column containing stationary phase like silica gel or alumina.

High Performance Liquid Chromatography (HPLC)

A high-resolution form of liquid chromatography that separates compounds based on their polarity and interaction with the stationary phase.

Ultraviolet light ($\lambda = 254\,nm$)

A common visualization method for TLC plates used for drugs possessing aromatic or conjugated chromophores.

Iodine vapour

A reversible TLC location reagent that produces a brown colour specifically with amines.

Potassium permanganate

A TLC location reagent used for sugars, sugar-like molecules, and drugs containing aliphatic double bonds.

Ninhydrin solution

A TLC location reagent yielding pink spots with primary amines and yellow spots with tertiary amines.

Alkaline tetrazolium blue

A specific TLC location reagent used to detect corticosteroids, resulting in blue spots.

Ethanol/sulfuric acid $20\%$

A reagent that produces fluorescent spots at $\lambda = 365\,nm$ when used with corticosteroids like dexmethasone and prednisolone.

Silanol (Si-OH) groups

Polar surface groups on silica gel that cause it to act as a polar adsorbent, retaining polar drugs more than non-polar ones.

Elutropic Series

A list of solvents arranged in order of their eluting power or polarity for a given adsorbent.

n-Pentane

A solvent with a Solvent-Strength Parameter ($\epsilon^\circ$) of $0.00$ in the elutropic series for alumina.

Acetic acid

A solvent characterized by a 'Large' Solvent-Strength Parameter at the top of the elutropic series for alumina.

Polarity Ranking

A scale identifying Amide as the most polar functional group and Alkane as the least polar.