What Is Qualitative Analysis Used For?

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Qualitative analysis is used in chemistry in order to determine which chemical elements, either single or grouped, are present in a given sample of material. Qualitative analysis is typically performed using a mass spectrometer or chromatography.

The complexity of the techniques used in qualitative chemical analysis can vary. If one desires to verify only the presence of a certain chemical element, spot or flame tests may be used. However, more systematic tests must be made to uncover every constituent in a complex mixture. Depending on whether the sample is inorganic or organic, different analysis procedures are used.

One instrumental method involves the use of the mass spectrometer, by which an unknown material converts into a gas and then accelerates into the center of a large magnet. A curved path within the magnet transports the material to a photographic plate. Since different elements travel at different velocities and have different masses, the shape of the path and point of impact that each element makes is used to determine the element.

Chromatography is another method for element identification, whereby a sticky material in a long column is presented for the chemical mixture to pass through. Since each element differs in its tendency to stick to the mixture, a qualitative analyst can look at the pattern to deduce the specific chemical components present.