Disadvantages Of Qualitative Analysis

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B) Classification of Analytical Methods Analytical methods are often being classified as either classical or instrumental methods: a) Classical Methods: For qualitative analysis the separated compounds were then treated with reagents that could be recognized by either color, by their boiling or melting points, their solubility in a series of solvents, their optical activities or their refractive indices. For quantitative analysis, the amount of analyte was determined by gravimetric or titrimetric measurements. Advantages of Classical Methods: 1. Procedure is simple and accurate. 2. The equipment needed is cheap. 3. Methods are based on absolute measurements. 4. Specialized training is not required. Limitations of Classical Methods: 1. Chemical…show more content…
b) Size of sample available and the proportion of the constituent to be determined. c) The purpose for which analytical data is required. Analytical chemistry is a sub discipline of chemistry that has the broad mission of understanding the chemical composition of all matter and developing the tools to elucidate such compositions. Analytical chemistry is concerned with chemical characterization of matter, both qualitative and quantitative. Qualitative • Qualitative inorganic analysis seeks to establish the presence of given element or inorganic compound in a sample. • Qualitative organic analysis seeks to establish the presence of a given functional group or organic compound in a sample. Quantitative • Quantitative analysis seeks to establish the amount of a given element or compound in a sample. A) Aims of Analytical Chemistry: 1. Analysis of natural substances, environment (as sample) and industrial materials. 2. Improvement and scientific substantiation of the existing analytical…show more content…
Ultraviolet and visible spectrophotometry – Excitation of valence electrons. 2. Infra-red spectroscopy - Excitation of molecular vibrations. 3. Raman spectroscopy - Excitation of molecular vibrations by light scattering. 4. Atomic absorption spectroscopy - Absorption of atomic resonance line. 5. Atomic emission spectroscopy - Light emission from excited electronic states of atoms. 6. X-ray diffraction- Diffraction of X-ray from crystal surface. 7. X-ray fluorescence- Re-emission of X-ray from excited atoms. 8. Fluorometry and Phosphorimetry- Emission of light energy by electrons. 9. NMR spectroscopy - Reorientation of magnetic nuclei in a magnetic field. 10. Photoemission spectroscopy - Energy measurement of electrons emitted from solids, gases or liquids by the photoelectric effect, in order to determine the binding energies of electrons in a substance. 11. Mass spectroscopy- Ionisation of molecule and conversion of molecule into fragment ions. 12. Electron spin resonance spectroscopy-Reorientation of magnetic electrons in a magnetic

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