The Kemtrak DCP007-NIR photometer measures at two wavelengths. A primary "absorbing" wavelength is used to measure the concentration of the chemical being monitored while a "non absorbing" reference wavelength is used to compensate for turbidity, air bubbles and/or fouling.
The Kemtrak DCP007-NIR photometer uses precision fiber optics to shine a precisely focused monochromatic light through the process medium and back to a photo-detector.
The attenuation of the transmitted light beam caused by NIR absorbing substances in the process medium is mathematically described by the Beer-Lambert law.
Applying the Beer-Lambert law (below), the concentration of the sample can be calculated.
A = absorbance (= - log transmittance)
Ε = molar absorptivity coefficient
l = optical path length
c = concentration of absorbing species