Quantitative analysis
A quantitative analysis is a chemical and / or physical process that aims to answer the question of how much of a substance is present in a given sample. In qualitative analysis . on the other hand, it is examined which substances are present in the sample.
All methods can be divided into the “classic” and the physical analysis methods.
Classic methods
The classical methods are about chemical conversions, after which a mass, amount of substance and volume is determined. The masses of the individual elements can then be determined using stoichiometric conversion factors. Because of the measurement types, there are therefore the following sub-categories:
- Gravimetry or weight analysis
- Volumetry ( titrimetry ) or dimensional analysis
Physical methods
The physical methods are about the measurement of concentration-dependent physical properties from which a concentration or mass can be calculated.
- Electroanalytical methods:
- Conductometry (measurement of the conductivity of an electrolyte solution)
- Spectroscopic methods use the interaction of electromagnetic radiation with the molecules of the sample.
- Photometry
- Colorimetry (measurement of absorbed light )
- Atomic spectroscopy
- X-ray fluorescence analysis
- nuclear physics methods
Physico-chemical methods
Methods in which both chemical reactions and physical processes play a role include:
- Chromatography with the subgroups:
-
Mass spectrometry with the areas of application
- Qualitative analysis of mainly organic substances in environmental samples
- Structure elucidation of organic substances
- Highly sensitive detection method in chromatography.
- Proteomics and there with the methods
- Electrochemical analysis methods:
- Electrogravimetry (measurement of weight, electrolytic deposition)
- Potentiometry (measurement of the change in potential)
- Amperometry (measurement of the electrolysis current at constant potential)
- Coulometry (measurement of the required electrical charge )
- Voltammetry (measurement of current at known potential)
- Polarography (voltammetry on a dripping mercury electrode)
- 2D-PAGE (two-dimensional gel electrophoresis)
Web links
literature
- Daniel C. Harris: Textbook of Quantitative Analysis . Ed .: Gerhard Werner, Tobias Werner. 8th edition. Springer Spectrum, Berlin, Heidelberg 2014, ISBN 978-3-642-37787-7 .