advantages n limitations of quantitative ir spectroscopy

advantages n limitations of ir spectroscopy

1. Advantages & Limitations Quantitative IR spectroscopy Mr. Sakharkar Mohammad Anzar MSc-I SEM-II Analytical Chemistry Ramniranjan Jhunjhunwala College 1 By Mohd Anzar Sakharkar

2. IR Spectroscopy Infrared spectroscopy is certainly one of the most important analytical techniques available to today’s scientists. One of the great advantages of infrared spectroscopy is that virtually any sample in virtually any state may be studied. Liquids, solutions, pastes, powders, films, fibers, gases and surfaces can all be examined with a judicious choice of sampling technique. Mr. Sakharkar Mohammad Anzar MSc-I SEM-II Analytical Chemistry Ramniranjan Jhunjhunwala College 2 By Mohd Anzar Sakharkar

3. Applications of Infrared Spectrometry Infrared spectrometry is applied to the qualitative and quantitative determination of molecular species of all types. The most widely used region is the mid-infrared that extends from about 670 to 4000 cm -1 (2.5 to 14.9  m). The near-infrared region from 14000 to 4,000 cm -1 (0.75 to 2.5  m) also finds considerable use for the routine quantitative determination. The far-infrared region has been for the determination of the structures of inorganic and metal-organic species. Mr. Sakharkar Mohammad Anzar MSc-I SEM-II Analytical Chemistry Ramniranjan Jhunjhunwala College 3 By Mohd Anzar Sakharkar

4. Advantages of Quantitative IR Analysis Application of IR spectroscopy as a analytical tool varies widely from one laboratory to other. Quantitative IR analysis is based on Beer’s law. Apparent deviation arise from either chemical or instrumental defects. The base line technique involve selection of an absorption band of the substance under analysis. The value of incident radiation energy P is obtained by drawing a straight line to spectral absorption curve at the position of sample absorption. Mr. Sakharkar Mohammad Anzar MSc-I SEM-II Analytical Chemistry Ramniranjan Jhunjhunwala College 4 By Mohd Anzar Sakharkar

5. The transmittance speed is measured at point maximum absorption. The value of log P is then plotted against concentration. Many possible error are eliminated by base line technique. The same cell is used for all determinations. Mr. Sakharkar Mohammad Anzar MSc-I SEM-II Analytical Chemistry Ramniranjan Jhunjhunwala College 5 By Mohd Anzar Sakharkar

6. Mr. Sakharkar Mohammad Anzar MSc-I SEM-II Analytical Chemistry Ramniranjan Jhunjhunwala College 6 By Mohd Anzar Sakharkar

7. LIMITATION With IR spectroscopy it is not possible to know molecular weight of substance. It is frequently non-adherence to Beer’s law of complexity spectra. The narrowness of spectra and effect of stray radiations make the measurements of absorbance upon slit width and wavelength setting. Mr. Sakharkar Mohammad Anzar MSc-I SEM-II Analytical Chemistry Ramniranjan Jhunjhunwala College 7 By Mohd Anzar Sakharkar

8. Generally, IR spectroscopy does not provide information of the relative positions of different functional groups on a molecule. From single IR spectrum of an unknown substance, it is not possible to know whether it is pure compound or a mixture of compound. For e.g : mix of paraffin and alcohol will give the same IR spectra as high molecular weight of alcohol. Mr. Sakharkar Mohammad Anzar MSc-I SEM-II Analytical Chemistry Ramniranjan Jhunjhunwala College 8 By Mohd Anzar Sakharkar

9. BIBILIOGRAPHY R.D Braun, Instrumental Analysis Mr. Sakharkar Mohammad Anzar MSc-I SEM-II Analytical Chemistry Ramniranjan Jhunjhunwala College 9 By Mohd Anzar Sakharkar