Macherey-Nagel test strips for ascorbic acid, in one presentation.
91314
A semi-quantitative test strip for ascorbic acid, vitamin C. Dip it, wait the stated time, and compare the pad against the colour scale on the tube.
Ascorbic acid is added to food and drink both as a nutrient and as an antioxidant that stops browning. It degrades with heat, light and time, so the amount declared on a label and the amount present after storage are different questions.
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.
Ascorbic acid is also used to neutralise chlorine before dechlorination testing; that is a second, quite different use for the same strip.
Supplied in one presentation.