Study Set Content:
200-380nm
UV
380-780 nm
VIS
780-3000 nm
NEAR IR
3000-15000nm
MED IR
3000-8000nm
GROUP FREQUENCY
8000-15000nm
FINGERPRINTING
15000-300000nm
FAR IR
Defined as the measurement of absorption of radiant energy by various substances. It involves the measurement of absorptive capacity for radiant energy in the visible, UV and IR (infrared) regions of the spectrum.
Absorption Spectroscopy
a branch of spectrometry which embraces the measurement of the absorption by chemical species of radiant energy of definite and narrow wavelength approximating monochromatic radiation.
Spectrophotometry
is radiation of a “single wavelength”. In practice, it is obtained by using a prism of diffraction grating and consists of more than a single wavelength.
Monochromatic radiation
branch of spectrophotometry in which the absorption measurement is made in the visible region of the spectrum
Colorimetry
Colorimetric methods are often used even though a compound to be analyzed absorbs in the UV region. The reason are:
•
() absorb in the visible region and therefore this technique can be used in the presence of substances which would otherwise interfere if the UV region were employed.
Fewer compounds
Chemical reactions Utilized to prepare derivatives are usually specific for a
functional group.
The derivative formed is usually _____ thereby increasing the molar absorptivity value and the sensitivity of the method
conjugated
are terms used to designate instruments which have necessary electronics to permit measurement of radiant power but which use a filter instead of prism or diffraction grating for the purpose of increasing the sensitivity of the measurement.
Colorimeter and filter photometer
defined as a functional group which absorbs radiant energy in the uv or visible regions of the spectrum. Some examples are ethylene, ketones, acetylene, organic acids, aldehydes and azomethines.
Chromophore
Three ways on how sample interacts with Light
Light Source → object/sample
Light Source → spectrometer
Light Source → Light source/towards other direction
from the light source (of radiant energy), is absorbed by the sample.
Absorption
Some energy is being absorbed, while a few are being
transmitted.
Others, if they have 100% absorption, the radiant energy is
totally absorbed
