Objective: To detect the separation and tentative identification of
components present in mixtures by using thin layer chromatography.
Materials and Methods/Procedures: A thin layer plate was obtained and a
baseline was drawn in pencil approximately 1.5 cm from the bottom of the
plate. Seven equidistant spots were marked and labeled on the baseline.
Six samples were obtained and using a new capillary tube for each sample, a
spot of each drug solution was placed on the appropriate mark on the
chromatography plate. The spots were allowed to dry, and one drop of the
five drug samples were spotted on the mark labeled â€˜mixture'. The mark
labeled â€˜unknown' was spotted with the unknown sample a couple of times.
The plate was placed in a prepared â€˜solvent chamber', and when the solvent
moved up the plate Â¾ of the way, the plate was removed and allowed to dry.
The plate was then examined under short wavelength ultraviolet light.
Results: After observing the plate, the drug present in the Unknown sample
was identified as Phenacetine. The spots observed in the "Mixture" were
compared to the spots of each individual drug and it was noted that the
unknown #6, identified as Phenacetine, was the only spot to match with the
number 7 mixture. Spot #1-caffeine, and spot #5-quinine were noted to be
Discussion: When using thin layer chromatography to observe spots of
individual drugs it was noted that most of the drugs were not level or were
Conclusion: Thin layer chromatography allowed the student to determine
what the unknown drug was by running spots of the sample with known drug
samples on the same plate, and then comparing the results. This also
prevented any uncertainties which could have been caused by variations in