This document provides an overview of the instrumentation used in atomic absorption spectroscopy. It discusses the main components, including radiation sources like hollow cathode lamps and electroless discharge lamps, a chopper to create a pulsating light beam, atomizers to convert liquid samples to a gaseous form, monochromators to select wavelengths of light, detectors to convert light to electrical signals, and readout devices to display the results. The key components work together to excite metal atoms in a sample, measure the absorption of light, and determine the concentration of metals present.

1. INSTRUMENTAL METHOD OF
ANALYSIS
Presented by,
Keerthana shanmugam
Bpharm 7th sem

2. Instrumentation of atomic absorption
spectroscopy

3. Radiation source
1 .Hollow cathode lamp
 Consist of evacuated glass tube with a tungsten anode and
cylindrical cathode .
 It is made up of alloy enclosed by glass to avoid the diffusion
of atom produced .
 Glass tube filled inert gas.potential – 100 to 200 volts across
the electrodes cause the ionization of inert gas The charged
gas then migrates at high velocity towards cathode and
collides metal atom .
 Metal atom excited higher energy level transmit lower energy
level emit radiation .
 Spectral line produced are narrower than absorption of the
source
Example:
copper cathode emits a copper spectrum.

4. 2. Electrodless discharge lamps
■ It is used to determine the volatile element.
■ Each lamb is consist of sealed quartz tube filled with
inert gas .the test metal is placed .
■ Lamp is placed in microwave radiation field the
sample element vapourise higher energy level to lower
level ,the metal element is emitted.
■ The emitted intensity of radiation 10 times more tha
obtained using cathode lamps.

5. Chopper
■ Rotating wheel called chopper placed between radiation source and flame.
■ Function:
■ To breaks the steady beam of light from the source into pulsating light which in
turns induces a pulsating current in the detector.
■ Steady current produced by flame ,but pulsating current is amplified and recorded.

6. 3. Atomizers
■ It is used for converting liquid sample into gaseous
form
■ Flame atomiser like
■ Total consumption burner / pneumatic Nebulizer
■ Premix burner
(A) pneumatic Nebulizer :
■ Hydrogen + oxygen = flame
■ Liquid sample reach base of the flame it converts
fine droplets and then gets evaporated.The residue
left further reduced into atom which are then
excited .

7. (b) Premix burner
■ Also called laminar air flow burner.liquid sample aspirated with air thoroughly mixed
with fuel and oxidant.
■ Mixture the reaches opening of burner and enters into flame. 5% sample forms of fine
droplets reaches the flame .large droplets 95% of sample drains out from the side of
spray chamber (burner).
■ Small portion of sample easily decomposed in the flame helps in effective atomization
of sample

8. Monochromators
■ Commonly used monochromators are
■ Prism monochromators
■ Grating monochromators.
■ It is used to select the specific wavelength of light

9. Detector
■ Devices which convert light energy into
electrical signals ,that are displayed on the
readout devices .
■ After passing through sample cell,part of
radiation absorbed by sample and remaining
transmitted .
■ Transmitted radiation fall on the detector
which determines the intensity of radiation
absorbed by sample
■ Photo multiplier tube

10. Readout devices
Read out devices includes
 Meters,
 Chart recorders.
 Digital readout devices

11. Thank you