The Vitamin C test strip uses 2,6-dichlorphenolindophenol as the indicator for ascorbic acid levels. It changes from blue to colorless as the amount of ascorbic acid (Vitamin C) increases. Unfortunately, this indicator also reacts with other acids which adds shades of red to the strip color.
Buffer salts are added to the formulation to offset this but it doesn't work as well when the other acid is present in large amounts as found in some fruit. The result in this case is that the blue color shifts towards lavender.
The color scheme of this chart shows the effect of citric acid which is the most likely source of interference when testing fruit juices. The mechanism for the color change is based on the effect of pH on the indicator.
This list of Acids in Fruits and Vegetables will show what can affect the response of the test strips to other acids besides citric. If you are interested in testing the acidity of different fruits, try these pH 0-7 acid test strips.
The number of strips (100) per pack is approximate.
The guaranteed shelf life is 3 years if the pack is kept sealed & stored in a cool dark place. 5 years is typical but test against a calibrated tablet to be sure.
Works with any form of ascorbic acid; eg. calcium ascorbate or sodium ascorbate.
Reviews (2)
2021-05-18
very satisfied
— carole
2017-09-06
I purchased this product to monitor urine levels of ascorbic acid after beginning Liposomal Vitamin C. These test strips are an indispensable tool to verify that, yes indeed, Liposomal Vitamin C greatly increases blood levels of Vitamin C.
Anyone in doubt on the subject of Liposomal Vitamin C can easily and inexpensively confirm for themselves how effective this method of administration actually is. I heartily recommend these test strips to anyone considering Liposomal Vitamin C as an addition to their daily diet. Liposomal Vitamin C works and these test strips confirm it.
