Upcoming SlideShare
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Standard text messaging rates apply

Uv – Visible Spectrophotometer.HARIS

10,291

Published on

Published in: Education, Technology
1 Comment
5 Likes
Statistics
Notes
• Full Name
Comment goes here.

Are you sure you want to Yes No
• thanxfor outstanding presentation

Are you sure you want to  Yes  No
Views
Total Views
10,291
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
581
1
Likes
5
Embeds 0
No embeds

No notes for slide

Transcript

• 1. UV - VISIBLE SPECTROPHOTOMETER HARIS P
• 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
BEER - LAMBERT'S LAW
• 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
• 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