Your SlideShare is downloading. ×
  • Like
Uv – Visible Spectrophotometer.HARIS
Upcoming SlideShare
Loading in...5

Thanks for flagging this SlideShare!

Oops! An error has occurred.


Now you can save presentations on your phone or tablet

Available for both IPhone and Android

Text the download link to your phone

Standard text messaging rates apply

Uv – Visible Spectrophotometer.HARIS



Published in Education , Technology
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
  • thanxfor outstanding presentation
    Are you sure you want to
    Your message goes here
No Downloads


Total Views
On SlideShare
From Embeds
Number of Embeds



Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

    No notes for slide


  • 2. Spectrophotometer
    • • Measures the light that passes through a liquid sample
    • • Spectrophotometer gives readings in Percent Transmittance (%T) and in Absorbance (A)
  • 3. The Electromagnetic Spectrum  = c /  E = h 
  • 4. Absorbance and Complementary Colors
  • 5. I o I Cell with Pathlength, b, containing solution light source detector blank where I o = I concentration 2 concentration 1 b with sample I < I o The process of light being absorbed by a solution As concentration increased, less light was transmitted (more light absorbed).
  • 6.
    • The law states that the amount of light absorbed by a solution (colored) is proportional to the concentration of the absorbing substance and to the thickness of the absorbing material (path length). Absorbance is also called optical density
    • A = abc
    • where a – molar absorptivity, b – pathlength, and c – molar concentration
  • 7. Some terminology
    • I – intensity where I o is initial intensity
    • T – transmission or %T = 100 x T
    • (absorption: Abs = 1 – T or %Abs = 100 - %T)
    • T = I/ I o
    • A – absorbance
    • A = - log T = -log I/ I o
  • 8.
    • The blank contains all substances expect the analyte.
    • Is used to set the absorbance to zero:
    • A blank = 0
    • This removes any absorption of light due to these substances and the cell.
    • All measured absorbance is due to analyte.
    The Blank
  • 9. Conventional Spectrophotometer 1. A stable and cheap energy source. 2. A monochromator to break the polychromatic radiation into component and wavelength/bands of wave length. 3. Transparent vessels (cuvettes) to hold the sample. 4. A photo sensitive detector and associated amplifier and recorder
  • 10. Conventional Spectrophotometer Optical system of a split-beam spectrophotometer
  • 11. LIGHT SOURCES   UV Spectrophotometer 1. Hydrogen Gas Lamp 2. Mercury Lamp Visible Spectrophotometer 1. Tungsten Lamp IR Spectrophotometer 1. Carborundum (SIC)
  • 12. Light Source
    • Deuterium Arc Lamp
    • UV Region
    • Wavelength Range :
    • 190~420nm
    • Tungsten Lamp
    • Wavelength Range : Part of the UV and the whole of the Visible
    • range ( 약 350 ~ 2,500nm)
    • Xenon Lamp
    • Wavelength Range : 190~800nm
  • 13. Monochromator
    • Accepts polychromatic input light from a lamp and outputs monochromatic light
    • Components : Entrance slit, Dispersion device, Exit slit.
    • The resolving element are of two kinds namely,
    • prisms and diffraction gratings. Simple glass prisms are used for visible range. For UV region silica, fused silica or quartz prism is used. Fluorite is used in vaccum UV range.
    • Gratings are often used in the monochromators of spectrophotometers operating in UV, visible and infra red regions. Their resolving power is far superior to that of prisms & they yield a linear resolution of spectrum.
  • 14. Dispersion Devices
    • Non-linear dispersion
    • Temperature sensitive
    • Linear Dispersion
    • Different orders
  • 15. CELLS UV Spectrophotometer Quartz (crystalline silica)   Visible Spectrophotometer Glass   IR Spectrophotometer NaCl
  • 16. Cell Types I Open-topped rectangular standard cell (a) and apertured cell (b) for limited sample volume
  • 17. Cell Types II Micro cell (a) for very small volumes and flow-through cell (b) for automated applications
  • 18. Detection Devices
    • Most detectors depend on the photoelectric effect, where incident light photons) liberates electrons from a metal or other material surface.
    • Important requirements for a detector
    • (1)high sensitivity to allow the detection of low levels of radiant energy,
    • (2)short response time,
    • (3)long term stability, and
    • (4)an electronic signal which is easily amplified for typical read out apparatus, Ultraviolet and visible radiation detectors are photocells, phototubes and photo multiplier tubes.
  • 19. Photomultiplier Tube Detector Anode
    • High sensitivity at
    • low light levels
    • Cathode material
    • determines spectral sensitivity
    • Good signal/noise
    • Shock sensitive
  • 20. Amplification and Readout
    • Radiation detectors generate electronic signals which are proportional to the transmitter light.
    • These signals need to be translated to a form that is easy to interpret.
    • This is accomplished by using amplifiers, ammeters, potentiometers, and potentiometric recorders.
  • 21.
    • 1. Qualitative Analysis
    • 2. Quantitative Analysis
    • 3. Molecular weight determination
    • 4. Study of cis-trans Isomerism
    • 5. Other Physiochemical studies
    • 6. Control of Purification
    • 7. Difference Spectroscopy
    • 8. Turbidimetry
    Applications of UV - Visible Spectroscopy
  • 22.
    • Thank You