Macherey-Nagel test strips for EDTA, in one presentation.
91335
A semi-quantitative test strip for EDTA, a chelating agent that holds metal ions in solution. Dip it, wait the stated time, and compare the pad against the colour scale on the tube.
EDTA is added to cleaners, cosmetics and process water to stop metals from precipitating. It is also very hard to break down in a treatment plant, so what goes down the drain largely stays in the environment — which is why discharge is watched.
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.
EDTA interferes with other metal tests by hiding the very ions they look for; measure metals before adding it, not after.
Supplied in one presentation.