Question

A new energy drink on the market is widely marketed as “caffeine-free”. Based

on the nature of complaints filed by several consumers, it appears that the “

caffeine-free” claim might actually be fraudulent. You are given the

responsibility of examining this issue. How would you go about your task of

verifying the validity of the “caffeine-free” label? Explain your strategy clearly.

Answer 1

I will simply execute an extraction of caffeine experiment.

This is a typicall approach:

1. The drink must be at room T.
2. You will need to use dichloromethane which will help us in the extraction
3. Cool the drink since the addition of dichloromethane will increase in temperature
4. Mix and shake container
5. Vent tubes for fumes
6. Centrifuge the sample
7. Pour 10 mL to an Erlenmeyer flask.
8. Time to add a fresh 3 mL of dichloromethane
9. Now you should have 2 organic layers
10. Mix/Swirl it and look at the solid.
11. Add small amounts of sodium sulfate until some of the grains
12. Let the flask rest (5mins minimum)
13. Decant the dichloromethane solution
14. Take sample for Thin Layer Chromatography
15. Allow the dichloromethane to evaporate in the hood while you are performing the TLC experiment.
16. What remains on the watch glass after the solvent evaporates should be caffeine.
17. Weight and make the calculations needed

NOTE that if the drink is caffeine free, you should not see any materiial in step 16