Macherey-Nagel test strips for dissolved tin, in one presentation.
91309
A semi-quantitative test strip for dissolved tin. Dip it, wait the stated time, and compare the pad against the colour scale on the tube.
Tin plating baths lose concentration as they work and the coating thins with them. In canned food the question runs the other way: how much tin has migrated from the can into the product.
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.
Tin readily forms colloids that a strip cannot see; a filtered sample and a digested one can give very different numbers.
Supplied in one presentation.