Basic concept of analytical technique spectrophotometry
I express my heartful gratitude to MADAM MANIKADAS KOTOKI, HOD and s/t of DEPT. OF BIOTECHNOLOGY,DARRANG COLLEGE, TEZPUR for giving me an opportunity topresent this presentation on “SPECTROPHOTOMETRY”and helping me to collect and organize the presentationdata. I sincerely hope tat the knowledge provided by herwill be beneficial in my future life.
Quantitative measurement of the reflection or transmission properties of a material as a function of wavelength. A part of BIO-INSTRUMENTATION Involves the use of SPECTROPHOTOMETER
It is a photometer that can measure intensity as a function of the light source wavelength. It is commonly used for the measurement of transmittance or reflectance of solutions, transparent or opaque solids, or gases. Also designed to measure the diffusivity on any of the listed light ranges that usually cover around 200nm - 2500nm using different controls and calibrations.
Works upon the following principles-Beer’s LawLambert’s LawBeer-Lambert’s Law
AUGUST BEER The intensity of a ray of Monochromatic Light passingthrough an absorbing medium decreases exponentially as theconcentration of absorbing medium increases. I = I e-klc
JOHANN HEINRICH LAMBERT The intensity of light or a ray of Monochromatic Light thatpasses through an absorbing medium decreases exponentially asthe length of absorbing medium increases. I = I e-k2l
The Beer–Lambert law, also known as the Lambert–Beer law or the Beer–Lambert–Bouguer law (named after August Beer, Johann Heinrich Lambert, and Pierre Bouguer) relates the absorption of light to the properties of the material through which the light is travelling. Two laws have been combined together as Beer – Lambert’s Law, which is stated below- I=I oe -kcl
Wavelength Collimator selector (lens) (slit) Detector (Photo Cell) 0.20 Digital Monochromator Sample DisplayLight Source or Meter (Prism or Grating) solution (in Cuvette)
Five types of Spectrophotometer according to the range andtype of light used- UV-Vis absorption spectrophotometer (UV-Vis) FT-IR absorption/transmission spectrophotometer (FTIR) Atomic absorption spectrophotometer (AAS) Atomic fluorescence spectrophotometer (AFS) X-ray fluorescence spectrophotometer (XFS) Two types according to the number of beams used- Single Beam Spectrophotometer Double Beam Spectrophotometer
The use of spectrophotometers spans various scientific fields,such as- Physics Materials Science Chemistry Biochemistry Molecular Biology Also used in industries including semiconductors, laser andoptical manufacturing, printing and forensic examination, as wellin laboratories for the study of chemical substances.