The Q-Certification verifies the calibration / photometric accuracy of the Chematest under test by comparison with a reference instrument. The comparison is performed for DPD-based ozone determination (DIN 38408-3) at four different ozone concentrations between 0.08 ppm and 3.0 ppm which are simulated by liquid absorbance standards.
The calibration of the reference Chematest is periodically verified with NIST-traceable potassium permanganate standards according to APHA 4500-Cl G (2017) and DIN EN ISO 7393-2.