1. Under the guidance of Dr. R.V.Durgasai Professor & HOD Dept.of Pharm.AnalysisPresented by N.Surendra pharmaceutical analysis 8008039989

2. INSTRUMENTATION OF UV-VISIBLE SPECTROSCOPY 3. Components of uv spectrophotometer Source of light Monochromators Sample cells Detector Recorder 4. Entrance slitLight sourceExit slitmonochromatorsampledetectoramplifierFig.- Block diagrammatic representation of UV-SpectrophotometerRead out 5. LIGHT SOURCES: Commonly used light sources in UV region areHydrogen discharge lamp: consist of two electrode containing hydrogen under low pressure. gives continuous spectrum in region 185-350 nm. 6. Deuterium lamps: consist of two electrode contain in deuterium filled silica envelope. gives continuous spectrum in region 185-380nm. Radiation emitted is 3-5 times more than the hydrogen discharge lamps. 7. Xenon discharge lamp: Xenon stored under pressure in 10-30 atmosphere. It possesses two tungsten electrode separated by 8 cm. Intensity of UV radiation more than hydrogen lamp.Mercury arc: Mercury vapour filled under the pressure . Spectrum obtained is not continuous. 8. Visible sources Tungsten lamp: This lamp find its place in most of colorimeter and spectrophotometer It consists of a tungsten filament in a vacuum bulb similar to ones used domesticallyCarbon arc lamp: For a source of very high intensity carbon arc lamp canbe used. It also provides an entire range of visible spectrum 9. Filters MONOCHROMATORSa)Glass filters Made from pieces of colored glass whichtransmit limited wavelength range of spectrum. Color produced by incorporation of oxides ofvanadium, chromium, iron, nickel, copper. b)Gelatin filters Consist of mixture of dyes placed in gelatin& sandwiched between glass plates. Band width 25nm. 10. Interferometric filtersConsists of two parallel plates silvered internally and seperated by a thin film of cryolite or other dielectric material Band width 15nm.Prisms Prism bends the monochromatic light. Amount of deviation depends on wavelength. Quartz prism used in UV-region. Glass prism used in visible region spectrum.Function : They produce non linear dispersion. 11. GratingLarge number of equispaced lines ruled on a glass blank coated with aluminum film.Normal surface vectorBlaze angle Normal to groove face 12. SAMPLE CELL The materials that contain sample ideally should be transparent. The geometries of all components in the system should be such as tomaximize the signal and minimize the scattered light. Quartz or fused silica is required in the UV region Most common cell length in the UV region is1cm. 13. DETECTORS Three common types of detectors are used1.Barrier layer cells2.Photocell detector3.Photomultiplier1. Photo voltaic cells or barrier layer cells : Maximum sensitivity-550nm. It consist of flat Cu or Fe electrode on which semiconductor such as selenium isdeposited. on the selenium a thin layer of silver or gold is sputtered over the surface. 14. A barrier exist between the selenium & iron which prevents the electronflowing through iron. Therefore electrons are accumulated on the silver surface. These electrons are produced voltage. - terminalSilver surfaceselenium + terminal Fig.-Barrier layer cell 15. 2. Photocell detector: It consist of high sensitive cathode in the form of a half cylinder of metal which isevacuated and it is coated with caesium or potassium or silver oxide Which can liberate electrons when light radiation falls on it. Anode also present which fixed along the axis of the tube Photocell is more sensitive than photovoltaic cell.lightFig.- photocell detector +- 16. 3. Photomultiplier tube: It is the combination of photodiode & electron multiplier. It consist of evacuated tube contains photo-cathode. 9-16 anodes known as dynodes.Fig.-photomultiplier tube 17. RECORDER: Signal from detector received by the recording system The recording done by recorder pan. 18. fig.-Schematic representation of single beam UV-spectrophotometer 19. Single beam spectrophotometer:- 20. Double beam spectrophotometer:-Fig.-schematic representation of double beam UV- spectrophotometer 21. ELICO UV VISIBLE DOUBLE BEAM SPECTROPHOTOMETER 22. Instrumentation of infrared spectroscopy 23. Commercial IR instrumentsPerkin elmer IR spectrometer 24. FT-IR 25. The main parts of IR spectrometer are as follows: IR radiation sources Monochromators Sampling cells Detectors 26. IR RADIATION SOURCE Sources must emit radiations Which must be Intense enough for detection Steady Extend over desired wavelength.INCANDESCENT LAMP : It contains tungsten filament Longer life 27. NERNST GLOWER: hollow rod Diameter: 2mm It provides maximum radiation at about 7100 cm-1.ADV: more intense than globar source 28. GLOBAR SOURCE: Rod of sintered silicon carbide length :50mm ,diameter : 4mm It is heated to 1300 -17000 C Maximum radiation at 5200cm-1ADV: Self-starting High intense beyond 15 m 29. MERCURY ARC: A special high pressure mercury lamps are used. Maximum radiation at