6th Episode of the Video Series of www.photometry-compendium.com
Besides the methods that use a chemical reaction to create a concentration dependant colour change, which can then be measured, there are many substances that can be measured without a colour reaction provided they absorb light within the wave length range of the photometer.
Photometric measuring of RNA, DNA and protein concentrations are examples of such methods. To date, used exclusively in water treatment plants for the online measuring of processes, a measurement was taken that recorded several parameters simultaneously while directly determining the cumulative parameters of the “Chemical Oxygen Demand (COD)” in addition.
This technology is now available for lab photometers and, under certain conditions, makes it possible to measure COD, nitrate and nitrite content quickly, directly, without any reagents or an extraction process, therefore making it environmentally friendly.