I'm reposting the info on the link given earlier for this post. The link has been removed from the given source.
Please refer to the following information.
Q656 â€“ chemistry
On 2/13/01 Funk51563 asked:
I am 9 years old, and a student doing my science project. How can I test sugar in soft drinks?
And Researcher answered:
The major ingredients in soft drinks are water and sugar. The remaining ingredients (flavorings and preservatives) are present in very small quantities. The following methods will work for â€œclearâ€? liquids such as flat soda pop, apple juice, grape juice, etc. Juices that contain solids (orange juice, tomato juice) will have to be filtered carefully, and may not work.
Several methods could be used.
The sugar content of the soft drink can be reasonably estimate by understanding density. Water has a density of 1.00 g/ml. The addition of the sugar is assumed to be negligible in terms of the effect on the final volume of the solution.
Required materials: A method for measuring a precise volume and an analytical balance.
Example: 10 ml of â€œflatâ€? soda pop is placed in a volumetric flask weighing 100grams. The soft drink and flask together weigh 111.1 grams (its density therefore is 1.11g/ml). The soft drink weighs 11.1 grams. If the weight of the water in 10 ml of soda pop is 10g, then the weight of the sugar in 10ml of soda pop is 1.1 grams.
A 12-oz can of soda pop has 355ml of soda pop. Solving a simple algebraic equation where x is the weight of sugar in a 355 ml (12 oz) can of soda pop:
X = 1.1 then 10X = 394.05; X=39.4 grams sugar
An alternative method using density and a preparing a calibration curve can be found at:
Take any soft drink and place in a tared (pre-weighed) container that you can heat (on the stove, microwave, or Bunsen burner, for example). Pour a known quantity of soft drink into the container and carefully boil away the water leaving behind the sugar. Be careful as the container approaches dryness. When the residue is completely dry and cool (and hopefully not burned), re-weigh the container and determine how much sugar (by difference) was in the volume of liquid.
Refractometers are simple optical instruments for measuring the amount that a pure liquid or transparent solution bends light. The amount of bending is determined by the chemical nature of the liquid, or in case of sugared waters, the amount of sugar dissolved on the water. Various refractometers are made for measuring the dissolved solids content of liquids from fruits, grasses, vegetables, etc. Vintners, for example use them to determine the quality and timing of the grape harvest. Commercial refractometers designed for measuring sugar content measure in % sucrose by weight (BrixÂ©) can be calibrated with distilled water and/ or with a sugar standard solution. Refractometers should be available from stores that sell winemaking supplies, or from scientific catalogs.
You may be able to find Brix refractometers for sale on the World Wide Web.
A science project might involve comparing the three methods of determining sugar content.