Organic Instrumentation Chromatography Principle Components of a mixture

  • Slides: 22
Download presentation
Organic Instrumentation

Organic Instrumentation

Chromatography • Principle: Components of a mixture are separated based on their selective adsorbance

Chromatography • Principle: Components of a mixture are separated based on their selective adsorbance on a stationary phase while carried by a mobile phase • The mixture is placed on a stationary phase and then a mobile phase passes through the stationary phase moving the mixture & separating the components from each other

1) Paper chromatography • Principle = as definition • Stationary phase = paper •

1) Paper chromatography • Principle = as definition • Stationary phase = paper • Mobile phase = liquid • Process = - draw pencil line 1 cm from top & bottom of paper - place spot of mixture on bottom pencil line - cover bottom of tank with solvent

- place bottom of paper in solvent - allow solvent to rise to the

- place bottom of paper in solvent - allow solvent to rise to the top pencil line - remove paper and allow to dry - measure the Rf value for each component of the mixture Rf = distance travelled by component distance travelled by solvent

2) Thin Layer Chromatography (TLC) • Principle = As definition • Mobile phase =

2) Thin Layer Chromatography (TLC) • Principle = As definition • Mobile phase = liquid • Stationary phase = solid (silica or aluminium oxide) • Process = Same as paper • Uses = forensic science

3) Column Chromatography • Principle = As definition • Mobile phase = liquid •

3) Column Chromatography • Principle = As definition • Mobile phase = liquid • Stationary phase = solid

 • Process = - pack stationary phase into column - flush solid phase

• Process = - pack stationary phase into column - flush solid phase with appropriate solvent - place sample on top of solid phase - flush the sample through the solid phase - collect all the solutions that pass through - test each solution

4) Gas Chromatography • Principle = as definition • Mobile phase = gas •

4) Gas Chromatography • Principle = as definition • Mobile phase = gas • Stationary phase = non-volatile liquid

 • Process = - sample injected and carried through a column by the

• Process = - sample injected and carried through a column by the flow of gas - separated because the more volatile components of the gas are swept along by the gas faster than the less volatile ones • Uses = drug tests on athletes & blood alcohol tests

5) High Performance Liquid Chromatography (HPLC): • Principle = as definition • Mobile phase

5) High Performance Liquid Chromatography (HPLC): • Principle = as definition • Mobile phase = solvent (non-volatile) • Stationary phase = tiny particles of silica

 • Process = - sample is injected and carried through a column by

• Process = - sample is injected and carried through a column by the solvent - high pressure has to be applied to push the solvent through the column • Uses = growth promoters in meat & vitamins in foods

Mass spectrometry - measures relative atomic mass (AR) of an element - measures relative

Mass spectrometry - measures relative atomic mass (AR) of an element - measures relative molecular mass (MR) of a compound - identification of substances • Uses = analyse gases from waste dump, analyse organic pollutants in water

Ultraviolet (UV) Absorption Spectrometry • Principle = absorption of UV radiation by molecules excites

Ultraviolet (UV) Absorption Spectrometry • Principle = absorption of UV radiation by molecules excites their electrons and the absorption of the molecules is directly proportional to their concentration • Process = UV light is passed through the sample and a blank sample and an absorption spectrum is obtained • Uses = analysis of drug metabolites and plant pigments

Infrared (IR) Absorption Spectrometry • Principle = Molecules absorb different frequencies of infrared light.

Infrared (IR) Absorption Spectrometry • Principle = Molecules absorb different frequencies of infrared light. Each molecule absorbs a different frequency. • Process = Sample is placed between a source of infrared light and a detector. Amount of light detected is compared to the amount absorbed. A spectrum is formed. • Uses = Identify plastics and drugs