Classical analytical methods involve separating sample components through precipitation, extraction, or distillation and then qualitatively analyzing the separated components using color, odor, solubility, or other physical properties. Quantitative analysis in classical methods involves gravimetric or volumetric techniques. Instrumental methods exploit other phenomena like conductivity, light absorption, and mass spectrometry for separation and quantification and have largely replaced classical techniques due to greater efficiency and precision. Instrumental methods are based on physical and chemical properties like conductivity, light absorption, and mass that have been used analytically for over a century.

1.  Analytical methods are often classified as being either
 Classical
 Instrumental
Note
Classical methods preceded instrumental methods by a century or
more.
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chapter 1
Analytical separation techniques and classical method of analysis

2. con
• Classical methods
 Most analyses were carried out by separating the components
of interest in a sample by
Precipitaion, extraction or distillation
 For qualitative analyses the separated components were then
treated with reagents that yielded products which could be recognized
by their;
 Colors, odors,
 Boiling or melting points
 Solubilities in a series of solvents
 Optical activities and refractive index
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3. con
 For quantitative analyses, the amount of the analyte was
determined by;
• Gravimetric
Mass of the analyte or some cpd produced from the analyte was
determined.
• Volumetric
• Volume of a standard reagent required to react completely with the
analyte was measured.
Note
 These methods are still used in many laboratories.
 However the extent of their application is decreasing with the
passage of time & with the advent of instrumental methods.
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4. con
Instrumental methods
 Early in the 20 Century, scientists begun to exploit phenomena other than
those used in the classical methods for solving analytical problems.
 Measurements as conductivity, electrode potential, light absorption or
emission, mass to charge ratio and fluorescence begun to be used for
quantitative analysis.
 Highly efficient chromatographic & electrophoretic techniques begun to
replace the classical methods of separation prior to qualitative Or
quantitative.
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5. con
 These new methods for separating and determining chemical
species are known as instrumental methods of analysis.
Note
 Many of the phenomena underlying instrumental methods
have been known for a century or more.
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6. Types of Instrumental Methods
• Table 1. Chemical and physical properties used in instrumental
analysis
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