Nov. 20, 2015

Photometry Compendium Episode 6

Optical Reagent-Free Measurement

  • Optical Reagent-Free Measurement

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.

To date, used exclusively in water treatment plants, a technique is available which is able to detect several parameters simultaneously while directly determining cumulative parameters like 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.


Supplemental Material:

Online Measurement Brought into the Lab

SAC is Not Equal to SAC

Data to the Lab and Back

Spectral UV-VIS and UV Online Sensors

Optical Reagent-Free Measurement of COD, Nitrate, Nitrite with photoLab 7600

Reagent-Free Measuring Methods


Do you have any questions regarding photometry? Please contact WTW!




Xylem Analytics Germany Sales GmbH & Co., WTW
Dr.-Karl-Slevogt-Str. 1
82362 Weilheim
Phone: +49 881 183 0
Telefax: +49 881 183 420

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