AAS
PRINCIPLE
INSTRUMENTATION
SAMPLE AUTOMIZATION TECHNIQUES
INTERFERENCES AND
APPLICATIONS.
ELEMENTAL ANALYSIS SUCH AS DETERMINATION
OF
SODIUM, POTASSIUM, CALCIUM,
PHOSPHOROUS,
SULFUR, CHLORINE, BROMINE AND IODINE
Introduction
AAS used as an analytical tool was first
developed by an Australian physicist
Alan walah
Atomic spectrometric methods are rapid
,convenient and have high selectivity
The method involves a process called as atomization in which the sample is converted to a gaseous phase atoms or ions
Atomic absorption spectroscopy is based on the same principle as the flame test used in qualitative analysis.
When an alkali metal salt or a calcium, strontium or barium salt is heated strongly in the Bunsen flame, a characteristic flame colour is observed:
Na -- yellow
Li-- crimson
Ca-- brick red
Sr-- crimson
Ba --green
In the flame, the ions are reduced to gaseous metal atoms.
Compound
-------- heat------- atoms
The high temperature of the flame excites a valence electron to a higher-energy orbital. The atom then emits energy in the form of (visible) light as the electron falls back into the lower energy orbital (ground state).
excited state absorbed energy
emitted energy
E = h.c/ʎ
ground state
The ground state atom absorbs light of the same characteristic wavelengths as it emits when returning from the excited state to the ground state.
The intensity of the absorbed light is proportional to the concentration of the element in the flame. quantitative analysis
Absorbance or emission of atomic vapour is measured.
Oxidation states (e.g. Fe2+, Fe3+) cannot be distinguished. Atomic Spectra
Example: Hydrogen principal quantum number n ( shell) orbital quantum number l ( s, p ... orbitals) Some transitions in the H spectrum n=1 n=5 n=4 n=3 n=2 l=012 spectral line in the visible range spectral line in the UV range
Energy is absorbed or emitted, when an electron moves from one state to another. The emission spectrum consists of groups of
INSTRUMENTATION
SAMPLE AUTOMIZATION TECHNIQUES
INTERFERENCES AND
APPLICATIONS.
ELEMENTAL ANALYSIS SUCH AS DETERMINATION
OF
SODIUM, POTASSIUM, CALCIUM,
PHOSPHOROUS,
SULFUR, CHLORINE, BROMINE AND IODINE
Introduction
AAS used as an analytical tool was first
developed by an Australian physicist
Alan walah
Atomic spectrometric methods are rapid
,convenient and have high selectivity
The method involves a process called as atomization in which the sample is converted to a gaseous phase atoms or ions
Atomic absorption spectroscopy is based on the same principle as the flame test used in qualitative analysis.
When an alkali metal salt or a calcium, strontium or barium salt is heated strongly in the Bunsen flame, a characteristic flame colour is observed:
Na -- yellow
Li-- crimson
Ca-- brick red
Sr-- crimson
Ba --green
In the flame, the ions are reduced to gaseous metal atoms.
Compound
-------- heat------- atoms
The high temperature of the flame excites a valence electron to a higher-energy orbital. The atom then emits energy in the form of (visible) light as the electron falls back into the lower energy orbital (ground state).
excited state absorbed energy
emitted energy
E = h.c/ʎ
ground state
The ground state atom absorbs light of the same characteristic wavelengths as it emits when returning from the excited state to the ground state.
The intensity of the absorbed light is proportional to the concentration of the element in the flame. quantitative analysis
Absorbance or emission of atomic vapour is measured.
Oxidation states (e.g. Fe2+, Fe3+) cannot be distinguished. Atomic Spectra
Example: Hydrogen principal quantum number n ( shell) orbital quantum number l ( s, p ... orbitals) Some transitions in the H spectrum n=1 n=5 n=4 n=3 n=2 l=012 spectral line in the visible range spectral line in the UV range
Energy is absorbed or emitted, when an electron moves from one state to another. The emission spectrum consists of groups of