Colorimetric Methods
These are largely based on direct adaptation of APHA standard methods, which use reagents to obtain desired complex ion formation to quantify the concentration at a specific wavelength. They require regular calibration with standard reagents using Beer’s Law to maintain their calibrated online status.
UV Absorption
The measurement principle is based on specific absorption at a specified wavelength in the UV range. They require conventional calibration according to Beer’s Law and standard reagents. The major application includes determination of parameters like DO and Turbidity.