This ppt is so important

1.  Analytical methods are often classified as being either
 Classical
 Instrumental
Note
Classical methods preceded instrumental methods by a century or
more.
instrumental analysis I by Dawit .A 1
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
instrumental analysis I by Dawit .A 2

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.
instrumental analysis I by Dawit .A 3

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.
instrumental analysis I by Dawit .A 4

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.
instrumental analysis I by Dawit .A 5

6. Types of Instrumental Methods
• Table 1. Chemical and physical properties used in instrumental
analysis
instrumental analysis I by Dawit .A 6