Macherey-Nagel test strips for quaternary ammonium compounds, in one presentation.
91337
A semi-quantitative test strip for quaternary ammonium compounds, the sanitiser in most food-service disinfectants. Dip it, wait the stated time, and compare the pad against the colour scale on the tube.
Health inspections check quat concentration in the sanitising sink, and it is the one number a kitchen can get wrong in both directions: weak and it does not sanitise, strong and it leaves a bitter residue on dishes.
A strip gives a range, not a figure. That is enough for the great majority of decisions — dose or do not dose, discharge or hold, keep running or stop — and it gives the answer where the sample is, in about a minute, with no instrument to calibrate and nothing to carry back to a laboratory.
When a number has to be defensible — a regulatory report, a dispute, a limit you are close to — a photometer or a laboratory method is the right tool. The strip's job is to tell you whether you need one.
Hard water weakens quat, so the same dispenser setting gives a different concentration on a different water supply.
Supplied in one presentation.