Will infrared-activated substances interfere with turbidity readings when using an ISO compliant turbidimeter?
Infrared-activated substances and ISO turbidimeters
European ISO 7027 compliant turbidimeters use an LED lamp light source operated at 860 nm. Infrared-activated substances in a sample may interfere with turbidity readings as those substances may absorb some of the LED energy output when they are activated, resulting in less incident light reaching the detector. Different infrared-activated compounds are activated at different wavelengths in the infrared spectrum. Because the LED is 860 nm, not all infrared-activated substances will interfere. Hach does not have support data to prove which specific substances will and will not interfere. Validation is recommended if such substances are present in the sample.