Chemiluminescence is the production of light from a chemical reaction. It occurs when two chemicals react to form an excited intermediate that releases energy in the form of photons as it decays to the ground state. Examples include fireflies, where the oxidation of luciferin produces light, and luminol, which was the first chemiluminescent molecule discovered. Applications include detecting gases, metal ions, and blood at crime scenes using luminol.

1. CHEMILUMINESCENCE
Presented by TANVI VYAS
M. Sc. (CHEMISTRY)

2. • LUMINESCENCE – It is general term for the
emission of light from a cool object. Most of
these fall into on of three categories :
• Phosphorescence
• Fluorescence
• Chemiluminescence
• bioluminescence

3. CHEMILUMINESCENCE
• The Chemiluminescence is the production of the
light from a chemical reaction.
• 2 chemicals reacts to form an excited high
energy intermediate which breaks down
releasing some of its energy as photons of light
to reach its ground state.
• The Packet of energy (a photon) is released in
the form of electromagnetic radiation.

4. • If the wavelength is within the range of visible
light then the electron transition will be
perceived as light of the particular colour.
• It involves the oxidation of an organic
compound.
• Light is emitted from the excited product formed
in the oxidation reaction.
• In this there is no need of an external source of
photon to excite a molecule.
• Luminol is chemiluminescent Molecule was
discovered by the german scientist H. O
ALBERECHT in 1928.

6. BIOLUMINESCENCE
• When Chemiluminescence is occurs in any
biological process it is called bioluminescence.
• Examples – when fireflies glow, the luciferin is
oxidized to produce an excited complex, which
falls back down to the ground state releasing a
photon of light.
• And the another examples are the sea pency,
certain jelly fishes, bacteria, protozoa.

7. JELLY FISH
FIREFLIES

8. Application of Chemiluminescence
• Application include the determination of gases
like oxides of nitrogen, ozone, sulphur
compounds.
• Determination of inorganic species, such as
hydrogen peroxide and some metal ions.
• Immuno assay techniques.
• DNA probe assay.
• Polymerase chain reaction.

9. • Chemiluminescence reaction generally involves
those that are very highly energetic, often
involving strong oxidants.
• Ozone reacts with many substance producing
light.
• Many metals hydrides are also show
Chemiluminescence as ASH3

11. • Chemiluminescence reaction that doesn’t
involve ozone is production of monoatomic
sulphur in a hydrogen flame.
• Other example is Ru(bipy)3+ oxidizes to its
reduced form Ru(bipy)2+, which in return to
the ground state emit orange light.

13. Chemiluminescence in forensics
• Luminol to detect blood an crime scenes.
• Mixture of luminol in a dilute solution of
hydrogen peroxide sprayed on to the areas
where the blood is present.
• The iron present in Haem unit of a haemoglobin
act as a metal catalyst in the reaction.
• If the blood is present, the blue colour glow
observed.