It was concluded that 18.7mg of caffeine were found in a single Louisiana Tea sample. The purified caffeine sample was found to have a melting point of 505K compared to the textbook caffeine melting point of 509K.

Sublimination is when a substance in the solid phase passes directly into the vapor phase without going into the liquid phase. This happens because the vapor pressure of a substance generally goes up as temperature increases and the boiling point of a liquid happens when its vapor pressure is equal to the applied pressure. If this vapor can then be re-solidified it will separate compounds with low vapor pressures and high vapor pressures. This re-solidification is usually collected in crystal form on the outside of a glass tube with some sort of very cold liquid inside to attract and solidify the compound with a higher vapor pressure in a vacuumed atmosphere. This method is generally quick however it is not as selective as other methods of purification.

The following is a sample calculation for pure caffeine from crude sample:

13.65% recovery = 0.0187 (g) / 0.137 (g) * 100

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