Question

Which compound is more polar: Caffeine or Aspartame? Based on structure, predict the retention order using reversed phase chromatography?

Answer 1

aspartame it is made up of aspartic acid ,phenylalanine and methanol so it contain more polar groups compared to caffeine so aspartame would elute first.

because it is reverse phase chromatography in this we use nonpolar stationary phase and polar mobile phase so like dissolves like concept manner the polar compounds dissolves in polar solution and non polar compounds are dissolves in nonpolar in non polar solution so here the caffeine is little bit non polar when compared to aspartime so caffeine is going to bind stationary phase and moves very slowley and aspartime moves faster along with the mobile phase.

so the retention time is more with caffeine in reverse phase chromatography when compared with aspartime