Gravimetric analysis
Quantitative analysis by mass with high precision and accuracy.
Gravimetric analysis is a set of methods in analytical chemistry for the quantitative determination of an analyte based on its mass. The principle involves determining an ion's mass as a unique compound, then using that measurement to find the same analyte's mass in a mixture, provided the relative quantities of other constituents are known. The four main types are precipitation, volatilization, electro-analytical, and miscellaneous physical methods.
- field
- Analytical chemistry
- known_for
- Quantitative determination of analytes by mass, used to determine atomic masses of many elements to six-figure accuracy
- methods
- Precipitation, volatilization, electro-analytical, miscellaneous physical
- key_principle
- Changing the phase of the analyte to separate it in pure form from a mixture
Lore & Background
Gravimetric analysis provides exceedingly precise analysis and was used to determine the atomic masses of many elements in the periodic table to six figure accuracy. It offers very little room for instrument error and does not require a series of standards for calculation of an unknown. Gravimetric methods often do not require expensive equipment and can be used to calibrate other instruments instead of using reference standards.
Reader's Guide
Gravimetric analysis has been largely displaced by spectroscopic methods, which are faster, highly specific, and entail less intervention. For example, silver ions can be quantified by precipitation of silver chloride, but this approach is now considered archaic. The method usually provides for the analysis of only one or a few elements, and procedures can be convoluted. Challenges include impurities in the solid caused by occlusions or surface adsorption of other ions. Some problems can be averted using homogeneous precipitation, as in the case of barium sulfate. The insolubility of precipitates can be affected by other ions in solution; for instance, the solubility of silver chloride can increase by many orders of magnitude in the presence of other anions. Despite its displacement, gravimetric analysis remains significant for its high accuracy and role in establishing atomic masses.
Did You Know?
- Gravimetric analysis was used to determine the atomic masses of many elements in the periodic table to six figure accuracy.
- The four main types of gravimetric analysis are precipitation, volatilization, electro-analytical, and miscellaneous physical methods.
- Gravimetric methods often do not require expensive equipment and can be used to calibrate other instruments instead of using reference standards.
- The solubility of silver chloride can increase by many orders of magnitude in the presence of other anions.
More in Chemical Analysis And Spectroscopy 1-18
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