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  1. 1. Under the guidance of Dr. R.V.Durgasai Professor & HOD Dept.of Pharm.Analysis Presented by N.Surendra pharmaceutical analysis 8008039989
  3. 3. Components of uv spectrophotometer • • • • • Source of light Monochromators Sample cells Detector Recorder
  4. 4. Entrance slit Light source Exit slit monochromator sample detector amplifier Fig.- Block diagrammatic representation of UV-Spectrophotometer Read out
  5. 5. LIGHT SOURCES: Commonly used light sources in UV region are Hydrogen discharge lamp:  consist of two electrode containing hydrogen under low pressure.  gives continuous spectrum in region 185-350 nm.
  6. 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. 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. 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 domestically Carbon arc lamp: For a source of very high intensity carbon arc lamp can be used. It also provides an entire range of visible spectrum
  9. 9. Filters – MONOCHROMATORS a)Glass filters Made from pieces of colored glass which transmit limited wavelength range of spectrum.  Color produced by incorporation of oxides of vanadium, chromium, iron, nickel, copper. b)Gelatin filters Consist of mixture of dyes placed in gelatin & sandwiched between glass plates.  Band width 25nm.
  10. 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. 11. GratingLarge number of equispaced lines ruled on a glass blank coated with aluminum film. Normal surface vector Blaze angle Normal to groove face
  12. 12. SAMPLE CELL •The materials that contain sample ideally should be transparent. •The geometries of all components in the system should be such as to maximize 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 is 1cm.
  13. 13. DETECTORS  Three common types of detectors are used 1. Barrier layer cells 2. Photocell detector 3. Photomultiplier 1. Photo voltaic cells or barrier layer cells : Maximum sensitivity-550nm.  It consist of flat Cu or Fe electrode on which semiconductor such as selenium is deposited.  on the selenium a thin layer of silver or gold is sputtered over the surface.
  14. 14.  A barrier exist between the selenium & iron which prevents the electron flowing through iron.  Therefore electrons are accumulated on the silver surface.  These electrons are produced voltage. - terminal Silver surface selenium + terminal Fig.-Barrier layer cell
  15. 15. 2. Photocell detector: It consist of high sensitive cathode in the form of a half cylinder of metal which is evacuated 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. light Fig.- photocell detector + -
  16. 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. 17. RECORDER:  Signal from detector received by the recording system  The recording done by recorder pan.
  18. 18. fig.-Schematic representation of single beam UV-spectrophotometer
  19. 19. Single beam spectrophotometer:-
  20. 20. Double beam spectrophotometer:- Fig.-schematic representation of double beam UV- spectrophotometer
  22. 22. Instrumentation of infrared spectroscopy
  23. 23. Commercial IR instruments Perkin elmer IR spectrometer
  24. 24. FT-IR
  25. 25. The main parts of IR spectrometer are as follows:  IR radiation sources  Monochromators  Sampling cells  Detectors
  26. 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. 27. NERNST GLOWER: • hollow rod • Diameter: 2mm • It provides maximum radiation at about 7100 cm-1. •ADV: more intense than globar source
  28. 28. GLOBAR SOURCE:  Rod of sintered silicon carbide  length :50mm ,diameter : 4mm  It is heated to 1300 -17000 C  Maximum radiation at 5200cm-1 ADV:  Self-starting High intense beyond 15µ m
  29. 29. MERCURY ARC: A special high pressure mercury lamps are used. Maximum radiation at <200cm-1
  30. 30. MONOCHROMATORS: They select desired frequencies from source. There are two types: I. Prism Monochromator: It is again of 2 types: a. Single pass Monochromator b. Double pass Monochromator II. Grating Monochromator
  32. 32. Prism Monochromator types a. Single pass Monochromator b. Double pass Monochromator
  33. 33. 2. Grating Monochromator
  34. 34. SAMPLE CELLS: • The material containing sample must be transparent to IR radiation • Cells should be very narrower-----0.01 to 1mm Ex: Salts like sodium chloride potassium bromide are widely used
  35. 35. DETECTORS : 1. 2. 3. 4. 5. 6. 7. Bolometer Thermocouple Thermisters Golay cell Photo conductivity cell Semiconductor detectors & Pyroelectric detectors
  36. 36. 1. BOLOMETERS:
  37. 37. 2. GOLAY CELL:
  38. 38. 3. THERMOCOUPLE: Hot junction Infra red ,cold junction
  39. 39. 4.THERMISTORS
  41. 41. Single beam spectrophotometer
  42. 42. Double beam spectrophotometer
  45. 45. NMR Spectrophotometer
  46. 46. Instrumentation  Sample holder  Permanent magnet  Magnetic coils  Sweep generator  Radiofrequency generator  Radiofrequency receiver
  47. 47. Diagrametic representation of the process
  48. 48. 1.Sample holder: • Glass tubes are employed which are sturdy,practical and cheap • 8.5cm long ,0.3 cm in diameter
  49. 49. 2.Permanent magnet: • These magnets are generally used in spectrometers operating upto 100mhz • Magnetic field must be constant over long periods of time
  50. 50. 3.Magnetic coils: • It is not easy to vary the magnetic field of a large ,stable magnet.The problem can be overcomed by placing a pair of Helmholtz coils in the pole faces of pole magnet.
  51. 51. 4.Sweep generator: • Generally the field sweep method is regarded as better because it is easy to vary H0 than the RF radiation so as to bring about resonance in nuclei.
  52. 52. 5.Radiofrequency generator: • RF oscillator is used to generate radiofrequency. • To achieve maximum interaction of the RF radiation with the sample the coil of oscillator is wound around the sample container. 6.RF receiver: • The line shapes associated with absorption and dispersion can be determined
  53. 53. NMR spectrophotometer
  54. 54. Instrumentation of Mass spectroscopy
  55. 55. Mass spectrophotometer
  56. 56. Mass spectrophotometer consists of  The inlet system  The ion source {ionisation chamber}  The electrostatic accelerating system  The magnetic field  The ion separator  The ion collector{detector and readout system}  The vacuum system
  57. 57. How does a mass spectrometer work? Create ions Separate ions Detect ions
  58. 58. Flow chart representation of the process
  59. 59. Types of ionization  Chemical ionization  Electron spray ionization  Electron impact ionization  Fast atom bombardment ionization  Field desorption technique  Field ionization process  Matrix assisted laser desorption ionization
  60. 60. CHEMICAL IONIZATION  Chemical Ionization (CI) is a soft ionization technique that produces ions with little excess energy.  Gaseous samples are ionized by collision with ions produced by electron bombardment of an excess of reagent gas.  The most common reagent gases are methane, isobutane and ammonia.
  61. 61. ELECTROSPRAY IONIZATION  Most important technique for analyzing biomolecules such as proteins,polypeptides.  Little fragmentation of large and thermally fragile biomolecules occur.  Very sensitive technique, requires less than a picomole of material  Strongly affected by salts & detergents
  62. 62. Electrospray (Detail)
  63. 63. Electron Impact Ionization  Sample introduced into instrument by heating it until it evaporates  Gas phase sample is bombarded with electrons coming from rhenium or tungsten filament (energy = 70 eV)  Molecule is “shattered” into fragments  Fragments sent to mass analyzer
  64. 64. FAST ATOM BOMBARDMENT  Sample in glycerol solution  Bombarded by high energy Ar or Xe atoms  Atoms and ions sputtered from surface  Both M+ and M- produced  Applicable to small or large unstable molecules
  65. 65. Field desorption ionisation It refers to an ion source in which a high potential electric field is applied to an emitter with a sharp surface. This results in a very high electric field which can result in ionization of gaseous molecules of the analyte.
  66. 66. MATRIX ASSISTED LASER DESORPTION/ IONIZATION  Matrix Assisted Laser Desorption/Ionization (MALDI) is used to analyze extremely large molecules.  This technique directly ionizes and vaporizes the analyte from the condensed phase.
  67. 67. Different Mass Analyzers  Magnetic Sector Analyzer (MSA)  High resolution, exact mass.  Quadrupole Analyzer (Q)  Low resolution, fast, cheap  Time-of-Flight Analyzer (TOF)  No upper m/z limit, high throughput  Ion Trap Mass Analyzer (QSTAR)  Good resolution, all-in-one mass analyzer  Ion Cyclotron Resonance (FT-ICR)  Highest resolution, exact mass, costly
  68. 68. MAGNETIC SECTOR ANALYZER Sector instruments have higher resolution and greater mass range than quadrupole instruments.
  70. 70. Ion Trap Mass Analyzer  Ion traps are ion trapping devices that make use of a three-dimensional quadrupole field to trap and mass-analyze ions  Offer good mass resolving power
  73. 73. MASS DETECTOR The detector records the charge induced when an ion passes by or hits a surface 1. Electron Multipliers (EM): Most common detector Can Detect positive and negative ions
  74. 74. 2.Faraday cup • Least expensive detector • Captured ions transfer charge to cup • used to calibrate other MS detectors
  75. 75. 3.Microchannel plate Not used as frequently, yet Allows ‘3-D’ analysis of data Photographic detection
  76. 76. VACCUM SYSTEM  10-7mm Hg pressure has to be maintained in the vaccum system from ion source to detector. DATA SYSTEM •The final component of a mass spectrometer is the data system. •This part of the instrument has undergone revolutionary changes in the past twenty years. •It has evolved from photographic plates and strip chart recorders to data systems that control the instrument, acquire hundreds of spectra in a minute .
  77. 77.  Instrumental Methods Of Chemical Analysis- Gurdeep R. chatwal; Sham K. Anand;  Elementary organic spectroscopy- Y. R.Sharma;  Instrumental methods of chemical analysis- B.K.Sharma;  Instrumental methods of analysis - willard, merritt, dean, settle  www.wickepedia.com