Vitamin C Test Strips

These vitamin C (ascorbic acid) test strips are great for biology labs or home use. Click on this link for more information on which is the chemical used to measure Vitamin C either in aqueous solution or in blood.

These strips are calibrated such that 0.01% equals 10mg/100ml and 0.1% equals 100mg/100ml. Most fruits are in the range of 40-70mg per 100g of fruit so if you only get 20ml of squeezed juice, you might have to dilute the juice bit to get a reading. A good way to test your solutions is to crush vitamin C tablets & add water. Since vitamin C tablets can have up to 1000mg/tablet you will have to dilute them by as much as 1/100 to get a reading.

Fruit juices that claim 100% or more of RDA will very likely show >0.1% concentration (the strip maximum) so you might need to dilute them to get an accurate reading. For example, 9 parts water & 1 part of juice is equal to 1 in 10 dilution so would then multiply the strip reading by "10" to get the real value. Try to compare similar juices since tomato & apple may look a little different even if the vitamin C level is the same. Different types of lighting can also affect the appearance. The best results are given with natural lighting, i.e. indirect or diffuse sunlight.

The chemical in the test strip is blue when unreacted & changes to lighter shades of blue & finally white once saturated. This is what you will see if pure vitamin as found in tablets & in some fruits. However, many fruits have been cross bred & many juices have preservatives. So, you may see shades of purple to pink instead of blue to white. In the case of lime, pink (instead of white) indicates ~16 times the strength of deep purple (instead of deep blue).

full strength......pink
half strength.....dark pink
1/4 strength.....light purple
1/8 strength.....purple
1/16 strength...deep purple

Try the following with the same volume of a given type of juice (sealed containers should have no room at the top for air):

Put an unsealed container in the refrigerator
Put 2 sealed containers in the refrigerator; 1 is a control
Put an open container on your countertop (loose cover is ok)
Put a sealed container on the countertop

After 5 days (or more) take one of the juices stored in a refrigerated, sealed container & boil gently for 15-30 minutes. Now compare the Vit. C levels in all 5 containers; the 2nd sealed, refrigerated container is the control. Is there be a difference? Why?

Note (1): The number of strips per pack or vial is approximate.
Note (2): Works with any form of acorbic acid; eg. calcium ascorbate or sodium ascorbate

P/N	Description	Unit
33814-VitC	Vitamin C test strips, 50/vial	1-9	17.95
		10-99	17.80
		100+	17.70

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