TLC: Separation Of Silica Gel

As we know, the TLC is a separation technique that has two phases: the stationary phase and mobile phase. The stationary phase is silica gel (SiO2) which is very polar compound, while the mobile phase is 0.5% acetic acid which has less polar. Also, as we know, the compound will rather to stay with stationary phase or travel with mobile phase depend on its polarity. The result show as that the polarity of the solvent is the key factor for the compound to travel with it or stay in stationary phase. The result show us that the Caffeine has more polarity than other compounds because it stays in stationary phase which has high polarity. In contrast, the Ibuprofen is less polar, because it travels with the solvent which is less polar also. Therefore,
Meanwhile, the compound that has less polarity or non-polar will stay with stationary phase. In this experiment, the Rf value is determined by the difference of polarity between stationary phase and mobile phase. Rf (Retention factor) is a ratio between the travel distance of the sample to the travel distance of the solvent. It consider the identity of the compound and can help in the determination of unknown sample by comparing the known Rf value with the Rf value of unknown sample. Depend on the result, the more polar compound like caffeine has small Rf value (average 0.12) because it didn’t travel with the solvent. The Acetaminophen are less polar than the caffeine but more polar than the Aspirin and Ibuprofen and has average Rf value (0.4). The Aspirin has more Rf value (average 0.55) than the Caffeine and the Acetaminophen because it is less polar and travel with the solvent. The ibuprofen has the bigger Rf value in this experiment (average 0.7) because it has the lower polarity than the other samples in the experiment, so it travels away with the