Cc lec luminescence Flashcards
Is the production of light from a chemical
reaction
The excitation of the substance does not
involve electromagnetic radiation and no
monochromators are needed, instead the
excitation energy comes from a chemical or electrochemical reaction
Light signal is measured against a completely dark background
Chemiluminescence
a physical phenomenon that
results from the interaction of light with particles in solution
Light scattering
Filters out fluorescence from stray light
radiation
It should be positioned at a right angle from the cuvette to eliminate potential
interference from the excitation light
Emission/ secondary monochromator
Sample holder
Cuvette
Mercury vapor lamp or xenon arc lamp
Light source
Measures the amount of light scattered in a particulate suspension at 90° angle
Useful method to determine the concentration of solution that contains particles too large for absorption spectrometry
Nephelometry
Measures the amount of light blocked in a particulate suspension
if there is increase of concentration in
sample meaning there is decrease in light
transmission
Turbidimetry
Wavelength of light > particle size
Light symetrically scattered around the particle
Rayleigh
Wavelength of light = particle size
More forward light scatter
Antigen-antibody reaction
Rayleigh debye
Wavelength or light < particle size
Light scatters backward but appears forwardmdue to destruction out of phase background scatter
Mie
Mercury vapor lamp or Xenon arc lamp
Light source
Selects the wavelength that is best
absorbed by the solution to be measured
Excitation/primary monochromator
quick disappearance of fluorescence
Quenching
The emission of light by a substance
Occurs when an electron returns to the
electronic ground state
Luminescence
When a beam of light is incident on certain substances, they emit visible light or radiations
It starts immediately after absorption of light and stops as soon as the incident light is cut off
Fluorescence
Measures the fluorescence or the energy emission that occurs when
a certain compound absorb electromagnetic radiation, become excited and then return to an energy state that is usually higher than their original level
Fluorometry
Delayed fluorescence
When light radiation is incident on certain substance, they emit light continuosly even after the incident light is cut off
Phosphorescence
