1. 7 Classifications
31
By exclusion, Instrumental Analysis thus involves obtaining information in
the second step of the analytical process by using instruments other than a
burette (volume), a balance (weight) or human senses. Its purpose can be qualitative, quantitative or structural. According to the type of matter-energy interaction involved, instrumental analytical techniques can be classified as follows:
• Optical (e. g. atomic spectroscopy and molecular spectroscopy, both of which
can measure absorption and emission of light);
• Electroanalytical (e. g. conductimetry, potentiometry, polarography, coulometry);
• Magnetic (e. g. mass spectrometry, nuclear magnetic resonance spectroscopy); and
• Radiochemical (e.g. isotope dilution).
Even a brief description of each group is well beyond the scope of this section.
Their discussion is thus deferred to Chaps. 5 and 6.
Strictly speaking, separation methods are not techniques proper but warrant
some comment in respect of this classification by virtue of their extensive use in
current analytical processes and their impact on analytical properties. Separations involve mass transfer between two phases, which can take place in widely
variable forms during the preliminary operations of the analytical process.
Separations can be classified according to various criteria. The most simple
divides them into the following categories according to the state of aggregation
of the phases involved:
• Gas-liquid (gas diffusion, distillation, chromatography).
• Liquid-liquid (dialysis, extraction, chromatography).
• Solid-liquid (precipitation, ion exchange, chromatography).
• Solid-supercritical fluid (extraction, chromatography).
I-i
1 -0
I-b
O-i 0-0
O-b
B-i
B-o BFig. 1.22. Types of analysis according to nature of samples and analytes
31
By exclusion, Instrumental Analysis thus involves obtaining information in
the second step of the analytical process by using instruments other than a
burette (volume), a balance (weight) or human senses. Its purpose can be qualitative, quantitative or structural. According to the type of matter-energy interaction involved, instrumental analytical techniques can be classified as follows:
• Optical (e. g. atomic spectroscopy and molecular spectroscopy, both of which
can measure absorption and emission of light);
• Electroanalytical (e. g. conductimetry, potentiometry, polarography, coulometry);
• Magnetic (e. g. mass spectrometry, nuclear magnetic resonance spectroscopy); and
• Radiochemical (e.g. isotope dilution).
Even a brief description of each group is well beyond the scope of this section.
Their discussion is thus deferred to Chaps. 5 and 6.
Strictly speaking, separation methods are not techniques proper but warrant
some comment in respect of this classification by virtue of their extensive use in
current analytical processes and their impact on analytical properties. Separations involve mass transfer between two phases, which can take place in widely
variable forms during the preliminary operations of the analytical process.
Separations can be classified according to various criteria. The most simple
divides them into the following categories according to the state of aggregation
of the phases involved:
• Gas-liquid (gas diffusion, distillation, chromatography).
• Liquid-liquid (dialysis, extraction, chromatography).
• Solid-liquid (precipitation, ion exchange, chromatography).
• Solid-supercritical fluid (extraction, chromatography).
I-i
1 -0
I-b
O-i 0-0
O-b
B-i
B-o BFig. 1.22. Types of analysis according to nature of samples and analytes