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 chlorine determinations (APHA 4500-Cl G (2017) and DIN EN ISO 7393-2) at four different chlorine concentrations between 0.1 ppm and 4.5 ppm which are simulated by liquid absorbance standards.
The calibration of the reference instrument is periodically verified by an external ISO 17025 accredited lab.