Analytical Chemistry

(Chris Devlin) #1

5 —


Titrimetry and Gravimetry


Titrimetric and gravimetric analyses, which are largely derived from the application of the principles of
solution chemistry, represent some of the traditional aspects of chemical analysis. The methods remain
widely used however because of their simple means of operation which enable comparatively unskilled
operators to achieve precise results. The most significant latter development has been the use of
multidentate organic chelating agents which has resulted in a substantial widening of the scope of these
types of analysis. In this chapter, emphasis will be given to these more recent applications.


5.1—


Titrimetry


Summary


Principles


Fast solution reactions between analyte and a reagent; titration to stoichiometric point by volumetric or
coulometric methods; end-point detection by visual indicators, precipitation indicators or
electrochemical means.


Apparatus


Burettes, pipettes, volumetric flasks, analytical quality chemical balance, indicator electrodes and
coulometric generating electrodes.


Applications


Very widespread for precise routine and non-routine analysis in industrial and research laboratories.
Typical uses: determination of acidic and basic impurities in finished products, control of reaction
conditions in industrial processes, mineral and metallurgical analysis. Relative precision 0.1–1%.


Disadvantages


Storage of large volumes of solutions, instability of some reagent solutions, need for scrupulously clean
glassware.

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