Method Method

Chromatography is a separation technique in which a mobile phase (water, ethanol) carrying a mixture moves in contact with a selectively absorbent (paper, alumna, silica gel) stationary phase.

• Chromatography is a separation technique in which a mobile phase (water, ethanol) carrying a mixture moves in contact with a selectively absorbent (paper, alumna, silica gel) stationary phase.

Method

• Method

• a) A small amount of the mixture to be separated is placed on a strip of chromatography paper.

• b) The end of the paper is placed in a suitable solvent.

• c) The solvent soaks up through the paper and dissolves the sample of material being analysed. Each of the components of the mixture dissolves to a certain extent. The least soluble come out of solution and appear as a spot on the paper.

• d) Thus the original sample will be split into its various component sat different intervals along the paper.

• Note: Avoid handling the paper as oils from the hands can affect the result.

Stationary Phase -Thin layer of aluminium oxide or silica gel on a glass plate or aluminium foil.

• Stationary Phase -Thin layer of aluminium oxide or silica gel on a glass plate or aluminium foil.

• Method

• A spot of the mixture been analysed is placed near the bottom of the plate. When the spot is dried the TLC plate is placed standing in a suitable solvent.

• TLC is more efficient than paper in that the particles in the stationary phase are smaller and this gives better separation of components in the mixture.

• Uses of TLC

• Pharmaceutical industry - to determine the purity of drugs.

• Forensic science-To separate the colours in dyes extracted from a crime scene.

• Analysis of drugs like cannabis

Stationary Phase-made into slurry using an appropriate solvent.

• Stationary Phase-made into slurry using an appropriate solvent.

• The mixture to be separated is dissolved in a solvent and added to the top

• of the column.

• The solvent is allowed to pass through the column and is kept moist. If the

• column is long a series of coloured bands will appear along the column.

• This series of bands is called column chromatography.

• The procedure of passing a solvent through the column is called elution.

• The general term for the solvent is the eluent.

Mobile Phase=Inearth Gas(Argon, Nitrogen,Helium))

• Mobile Phase=Inearth Gas(Argon, Nitrogen,Helium))

• Stationary Phase= a high Boiling Point liquid spread on solid

• particles(alumina)that are packed into a long coiled tube called the column. This

• coiled tube of small diameter and several meters in length is kept inside a

• temperature controlled oven.

• Method

• a) The sample is injected, vaporised, and carried through the tube using an inert gas like Helium, Nitrogen, or Argon.

• b) The various components in the mixture separate as they flow through the column.

• c) As each component leaves the column, it passes a detector which records a signal.

Uses

• Uses

• Level of alcohol in blood or Urine.

• Drug test athletes

• GC-MS. Gas Chromatography + Mass Spectrometry.

• Each individual component analysed.

• Analyse performance of drugs in body

• Detect gases from waste dumps and organic pollutants in water.

The substance to be analysed is added to a liquid solvent and passed over a solid.

• The substance to be analysed is added to a liquid solvent and passed over a solid.

• Better separation if the particles in the stationary phase are very small. A pump is used, therefore the column need not be as long as in Gas Chromatography. Another advantage is that HPLC is carried out at a lower temperature and can analyse compounds that would decompose at a higher temperature.

Used

• Used

• Analysis of foods- presence of growth promoters

• - presence of additives

• - Vitamins.

Mass Spectrometry (Francis William Aston)

• Mass Spectrometry (Francis William Aston)

• - built to measure the masses of atoms.

• - Detect the presence of Isotopes.

• A Mass Spectrometer is used to

• Identify the presence of Isotopes

• Measure the relative abundance of isotopes

• Measure relative atomic masses and relative molecular masses

• Identify unknown compounds.

How a spectrometer works.

• How a spectrometer works.

• 1. Vaporisation

• 2. Ionisation

• 3. Acceleration

• 4. Separation

• 5. Detection

• Uses of a Mass Spectroscope

• Used in conjunction with Gas Chromatography to detect banned drugs in athletes.

• Test for drugs taken by drug addicts

• Analyse the gases in the tail of a comet.

Used to detect the presence of certain functional

• Used to detect the presence of certain functional

• groups in molecules.

• Also used to detect or measure the concentration of organic compounds in solution.

• Measure the amount of drug metabolite reaching a

• certain part of then body.