10
DESCRIPTION
Instrument Block Diagram
The internal reference system (reference detector) of the
HI83303
photometer compensates for any
drifts due to power fluctuations or ambient temperature changes, providing a stable source of light
for your blank (zero) measurement and sample measurement.
LED light sources offer superior performance compared to tungsten lamps. LEDs have a much higher
luminous efficiency, providing more light while using less power. They also produce little heat,
which could otherwise affect electronic stability. LEDs are available in a wide array of wavelengths,
whereas tungsten lamps have poor blue/violet light output.
Improved optical filters ensure greater wavelength accuracy and allow a brighter, stronger signal to
be received. The end result is higher measurement stability and less wavelength error.
A focusing lens collects all of the light that exits the cuvette, eliminating errors from cuvette
imperfections and scratches, eliminating the need to index the cuvette.
4.5. OPTICAL SYSTEM
I
o
= intensity of incident light beam
I
= intensity of light beam after absorption
e
l
= molar extinction coefficient at wavelength
l
c
= molar concentration of the substance
d
= optical path through the substance
Therefore, the concentration "c" can be calculated from the absorbance of the substance as the
other factors are constant.
Photometric chemical analysis is based on specific chemical reactions between a sample and
reagent to produce a light‑absorbing compound.