Organic Instrumentation

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 Mobile phase = liquid Process = - draw pencil line 1cm 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 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 = liquid Stationary phase = solid (silica or aluminium oxide) Process = Same as paper Uses = forensic science

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

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 Stationary phase = non-volatile liquid

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 = solvent (non-volatile) Stationary phase = tiny particles of silica

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 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 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. 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