Ascorbic Acid Test Strip

Ascorbic Acid Test Strip

The Ascorbic Acid Test Strip is used to detect Ascorbic Acid, or Vitamin C in graduations of 0, 0.01, 0.02, 0.05, & 0.1%. The Ascorbic Acid test strip is based on discoloration of blue red-ox indicator, depending on the concentration of ascorbic acid. Red-ox indicator is also sensitive to acidic compounds, and its blue color turns to purple in the presence of acids.

The Vitamin C strips are buffered to a certain extent to keep the blue color of the pad, but in the presence of strong acids, contained in some fruits or juices, the color can turn to a purple-pink instead of a blue-white. In such cases, we recommend using a special color chart (See FAQs) which shows results for Vitamin C in the presence of different concentrations of citric acid. Lemons and limes contain the highest amount of citric acid at about 5 percent. Grapefruits and oranges also have high content of citric acid at about 2.5 and 2 percent, respectively.

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Ascorbic Acid Test Strip

  1. Remove one Ascorbic Acid test strip from the vial and close cap.
  2. Dip the strip into the solution to be tested for 2 seconds.
  3. Remove the strip and compare to the color chart after 30 seconds.

ascorbic acid test strip, ascorbic acid, vitamin c, vitamin c test strip
ASC50; ASC; ASC-1V-50

Product Specs

SKU:

ASC-1V-50

Strip Quantity:

50 strips

Vial Dimensions:

1.125″ (D) x 3.375″ (H) [29mm (D) x 86mm (H)]

Strip Dimensions:

2.5" (L) x .1875" (W) [64mm (L) x 5mm (W)]

Weight:

0.07 lbs [33.4 g] (50-strip vial)

Other:

Stored in a flip-top vial with built-in desiccant liner.

Shelf-Life:

2 Years

Label:

Customizable water-resistant label

Product Documentation

SDS

Fact Sheet

Ascorbic Acid Color Changes

How does citric acid change the color of the Vitamin C test strip?

The Vitamin C test strip uses 2,6-dichlorphenolindophenol as a red-ox indicator.  This indicator changes from blue to colorless as the amount of ascorbic acid (Vitamin C) increases. Unfortunately, this indicator also detects other acids by changing from blue to red.

To help offset this effect, we include buffer salts in the formulation. This works for many applications, but it doesn’t work as well when the other acid is present in large amounts (such as in some fruit). In this situation, the starting blue color becomes more lavender.

This is why we have constructed a color scheme showing the effect of citric acid on the Vitamin C strip. Citric acid was chosen because of the likelihood that it would be present in some of the same solutions being tested for Vitamin C. The mechanism for the color change is based on the effect of pH on the indicator.

Why is my Ascorbic Acid test strip turning pink or purple?

The Ascorbic Acid test strip is based on discoloration of blue red-ox indicator, depending on  the concentration of ascorbic acid. The Ascorbic Acid test strip is calibrated from 0.01% (10 mg/100 ml) to 0.1% (100 mg/100 ml). Red-ox indicator is also sensitive to acidic compounds, and its blue color turns to purple in the presence of acids.

The Vitamin C strips are buffered to a certain extent to keep the blue color of the pad, but in the presence of strong acids, contained in some fruits or juices, the color can turn to a purple-pink instead of a blue-white.  In such cases, we recommend using a special color chart (See "Ascorbic Acid Color Changes" chart below) which shows results for Vitamin C in the presence of different concentrations of citric acid. Lemons and limes contain the highest amount of citric acid at about 5 percent. Grapefruits and oranges also have high content of citric acid at about 2.5 and 2 percent, respectively.

In the "Ascorbic Acid Color Changes" chart (click button below), the values are as follows:

Low = 0.5%; Medium = 1%; High = 5%

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