How to Test Fruit Drinks for Vitamin C Content

Many fruit drinks now advertise that they are fortified with vitamin C. You can do a simple test to see if this is true and to compare which drinks contain the most vitamin C.

Things You'll Need

• Iodine (see resources below)
• Clear plastic cup
• Water
• Spray starch
• Effervescent vitamin C tablets
• Samples of fruit drinks to test
• Eyedropper

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Instructions

• 1

  Pour water into the clear plastic cup until it is two-thirds full.

• 2

  Put three drops of iodine into the cup of water.

• 3

  Squirt a little spray starch into the water. It should turn a deep bluish-purple color.

• 4

  Put an effervescent vitamin C tablet into the cup and observe what happens. The solution should turn clear. The vitamin C reduces the colored iodine molecules (made of two iodine atoms) to colorless ions (a single iodine atom).

• 5

  Empty the cup and rinse it out.

• 6

  Repeat the same steps as above: fill with water, add three drops of iodine, then squirt in some spray starch.

• 7

  Add your first test fruit drink one drop at a time, counting how many drops you need to add to turn the solution clear. If it does not eventually turn the solution clear, then the drink does not contain vitamin C.

• 8

  Repeat this experiment for each test drink. You can compare which drinks contain the most vitamin C by comparing the number of drops it took to turn the solution clear. The drinks with the most vitamin C will be those that took the least number of drops to turn the solution clear.