Forensic Analysis - Chrom4

These flashcards cover key concepts and vocabulary related to the lecture on chromatography, focusing on liquid chromatography, its components, and the effects of pH and polarity.

Chromatography

A laboratory technique for the separation of a mixture.

Liquid Chromatography

A technique used to separate substances in a liquid phase through a stationary phase.

Thin Layer Chromatography (TLC)

A simple and quick method used to separate non-volatile mixtures.

Retardation Factor (Rf)

A ratio that indicates how far a compound travels in comparison to the solvent front.

Polarity Index

A numerical expression of a solvent's polarity, indicating its ability to dissolve substances depending on their polarity.

Normal Phase TLC

Chromatography where the stationary phase is polar and the mobile phase is non-polar.

Reverse Phase TLC

Chromatography where the stationary phase is non-polar and the mobile phase is polar.

Mobile Phase (MP)

The solvent that carries the analytes through the stationary phase in chromatography.

Stationary Phase (SP)

The phase that stays fixed in place while the mobile phase moves through it.

Gradient Elution

A technique that progressively changes the composition of the mobile phase during the chromatography process.

Ionisable Components

Compounds that can gain or lose protons depending on pH, thus affecting their chromatographic behavior.

Buffer

A solution that resists changes in pH when an acid or alkali is added, often used in chromatography.

High Performance Liquid Chromatography (HPLC)

An advanced type of liquid chromatography that allows for faster separations and better resolution.

Acidic Buffer Solutions

Buffers made from a weak acid and its salt, used to maintain a specific pH range.

Alkaline Buffer Solutions

Buffers made from a weak base and its salt, used to maintain a specific pH range.

pKa

The measure of the strength of an acid in solution; a lower pKa indicates a stronger acid.

Acid Modifiers

Compounds added to the mobile phase to enhance the separation of analytes, particularly those that are ionizable.

Sample Plug

The portion of the sample injected into the chromatography system.

Selectivity (α)

A measure of how well different components in a mixture can be separated.

Solvent Strength

The ability of a solvent to dissolve a substance, correlated with the solvent's polarity.