Quantitative analysis (chemistry)

A quantitative analysis is a chemical and / or physical process which is concerned with answering the question of how much of a substance is present in a given sample.

All methods can be divided into the "classical" and the physical methods of analysis.

Classical methods

In the classical methods it comes to chemical reactions by which a mass, molar and volume determination is made. About stoichiometric conversion factors can then determine the masses of the individual elements. Due to the measurement types, therefore it has the following subcategories:

  • Gravimetry or gravimetric analysis elemental analysis
  • Complexometry
  • Acid -base titration
  • Redox titration
  • Precipitation reaction

Physical Methods

In the physical methods, concerns the measurement of the concentration-dependent physical properties, from which the 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 the absorbed light )
  • Atomic Spectroscopy
  • X-ray fluorescence analysis
  • Nuclear methods Neutron Activation Analysis

Physico-chemical methods

Among the methods in which both chemical reactions and physical processes play a role include:

  • Chromatography with the sub-groups: liquid chromatography
  • Gas chromatography
  • Qualitative analysis mainly of organic substances in environmental samples
  • Structure elucidation of organic substances
  • Highly sensitive detection method in chromatography.
  • Proteomics and there with the methods iTRAQ
  • Electrogravimetry ( measurement of the weight, the electro-deposition )
  • Potentiometry ( measuring the potential change )
  • Amperometry ( measurement of electrolytic current at constant potential )
  • Coulometry (measurement of the required electrical charge )
  • Voltammetry ( measurement of current in the known potential )
  • Polarography ( voltammetry at a dropping mercury electrode)
  • 2D -PAGE (two-dimensional gel electrophoresis)