Gravimetric analysis describes a set of methods in analytical chemistry for the quantitative determination of an analyte based on the mass of a solid. A simple example is the measurement of solids suspended in a water sample: A known volume of water is filtered, and the collected solids are weighed.
In most cases, the analyte must first be converted to a solid by precipitation with an appropriate reagent. The precipitate can then be collected by filtration, washed, dried to remove traces of moisture from the solution, and weighed. The amount of analyte in the original sample can then be calculated from the mass of the precipitate and its chemical composition.
In other cases, it may be easier to remove the analyte by vaporization. The analyte might be collected—perhaps in a cryogenic trap or on some absorbent material such as activated carbon -- and measured directly. Or, the sample can be weighed before and after it is dried; the difference between the two masses gives the mass of analyte lost. This is especially useful in determining the water content of complex materials such as foodstuffs.
Read more about Gravimetric Analysis: Procedure, Example, Advantages, Disadvantages
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... The term "equivalent weight" had a distinct sense in gravimetric analysis it was the mass of precipitate which corresponds to one gram of analyte (the species ... The different definitions came from the practice of quoting gravimetric results as mass fractions of the analyte, often expressed as a percentage ... For example, in the gravimetric determination of nickel, the molar mass of the precipitate bis(dimethylglyoximato)nickel is 288.915(7) g mol−1, while the molar mass of nickel is 58.6934(2) g m ...
... Gravimetric analysis usually only provides for the analysis of a single element, or a limited group of elements, at a time ... flash combustion coupled with gas chromatography with traditional combustion analysis will show that the former is both faster and allows for simultaneous ... are often convoluted and a slight mis-step in a procedure can often mean disaster for the analysis (colloid formation in precipitation gravimetry, for example) ...
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