1) Atomic absorption spectroscopy (AAS) was introduced in 1955 by Alan Walsh as a technique to determine the concentration of metals in liquid samples.
2) AAS works by vaporizing the metallic species from a liquid sample into a flame, where some metal atoms absorb light at specific resonant wavelengths that are characteristic of each metal.
3) The amount of light absorbed at the resonant wavelength is directly proportional to the number of ground state metal atoms in the flame and can be used to determine the concentration of the metal in the original sample.
1. PRESENTATION ON:
PRINCIPLE OF ATOMIC ABSORPTION
SPECTROSCOPY(AAS)
INTEGRAL UNIVERSITY,LUCKNOW
Session: 2016-2017
Presented by: Under the guidence of:
Mohd Muztaba
M.Pharm Mr. Paramdeep Bagga
Pharmacology
2. Alan walsh in mid 1950s
One element can be estimated at time
Qualitative determination of trace metal in liquid
Detection of element 1 PPM
No sample preparation
No role of temperature
3. The technique was introduced in 1955 by Alan Walsh in
Australia ( 1916 – 1998 ).
4. When a solutin containing metallic species is introduced into
flame,the vapour of the metal atom will be obtained some of
the metal atom will be raised to a energy level to sufficient
high to emitt the characterstic rediation of a metal
A phenomena that utilized in the familiar technique a emission
flame photometry
But a large percentage of metal atom will remain in the non
emitting ground state these ground state atom of a particular
element are receptive of light radiation of there on specific
resonsnce wavelength
5. When a light of this wavelength is to pass through a flame
having atom of the metallic species path of that light will be
observed and the absorption will directly propotional to the
density of atom in the flame
Once this value of absorption is known the concentration of
metallic element can be known because the absorption is
directly propotional to the density of atom in the flame
Mathemetically the total amount of light absorb may be given
by expression
6. V is the total amount of light absorb
e change on electron on mass
c speed out light
N total number of atom
f Oscillator strength
πe are constant
7. Sr.no Name of the substance Element
assay
Measured at nm
1 Ascorbic acid Fe 248.3nm
2 Cispalstin Ag 328nm
3 Glucagon Zn 213.9nm
4 Oxy prenol hydrochloride Pb 217nm
5 Parazosin hydrochloride Ni 232nm
6 Zinc
Oxide
Cd
Pd
228.7nm
217nm
8. Assay of total zinc in insulin suspension
Assay of palledeum in carbenicillin sodium
Assay of lead in petrol
Assay of pharmaceutical substance by AAS
