Instrumentation Flashcards
Who invented chromatography
Russian botanist
Mikhail Tswett
Uses of chromatography
- Separating different substances in a mixture
* Identifying and measuring the amount of the substances present
Chromatography
A separation technique in which a mobile phase carrying a mixture moves in contact with a selectively absorbent stationary phase
Principle of chromatography separation
Separation of a mixture of components occurs as a result of selective adsorbance of the components of the mixture on a stationary phase while carried by a mobile phase
Processes of Paper chromatography
- End of paper is placed in a suitable solvent
- Solvent soaks up through the paper
- Dissolved the sample being analyzed
- Solvent - mobile phase moves up through paper - stationary phase
Result of paper chromatography
Original sample separate out into its various components at different intervals along the paper
Gas chromatography
Uses a gas as the mobile phase and non-volatile liquid with a high boiling point as the stationary phase spread on solo a inert alumina that are packed into a long coiled tube
Processes of gas chromatography
- Sample being analyzed is injected into the hot column (syringe)
- Sample is vaporized and carried through tube using Ni, He or Argon (carrier gas)
- Components of the mixture are adsorbed to different extents on the stationary phase
- Carries a detector that records a signal and plots a gas chromatogram
Principle of Gas chromatography
A gaseous mobile phase is in contact with a stationary phase and separation of the mixture occurs as a result of selective absorbance of the components of the mixture on the stationary phase
Uses of gas chromatography
- Measure the level of alcohol in the blood or urine sample
* Carry out drug tests on athletes
GC-MS
Separated components from gas spectrometry passed into mass spectrometer
Uses of GC-MS
- Compounds can be analysed separately and identified
- Forensics science laboratory
- Monitor the performance of a pharmaceutical in the body
- Analyse atmosphere and soil on other planets
High-performance liquid chromatography
Substance being analyzed is added to a liquid solvent (Mobile phase) which is passed over very fine silica particles (stationary phase)
Why is a pump used to force the liquid through the column for HPLC
Better separation occurs if the particles in the stationary phase are very small and pass through slowly
Principle of high-performance Liquid chromatography
A liquid mobile phase is In contact with a stationary phase and separation of the mixture occurs as a results of selective adsorbance of the components of the mixture on the stationary phase
Processes of HPLC
- Injection of sample
- Pumping sample along the column
- Separation in the column
- Detection of components in the mixture
- Display of results
Features of HPLC
- Separation is more efficient as a pump is used
- The column isn’t as long
- Lower temperature
Uses of HPLC
- Analyse mixture of non-volatile compounds
- Analysis of food (additives in food)
- Concentration of alcohol in blood
Infra-red Spectrometry
- Wavelengths are longer than those of visible light
- Invisible
- Given off by hot objects
- Absorbed by the vibrations of bonds in organic compounds
Principle of infra-red spectrometry
Organic compound absorb infra-red radiation of certain frequencies which are absorbed depending on the bonding within the molecule
Processes of Infra-red Spectrometry
- Passed through the sample being analyzed
- Certain fixed frequencies is adsorbed
- Adsorption spectrum is obtained
Uses of infra-red spectrometry
Identify compounds
Identify plastics and illegal drugs
Principle of ultraviolet adsorption Spectrometry
Absorbance is directly proportional to the concentration of a substance
Processes of ultraviolet spectrometry
- Substance being analyzed is placed between a source of UV light and a detector
- Measures the intensity of light reaching it
- UV absorption spectrum is obtained
