Abstract: The caffeine detector uses a paper chromatographic technique to measure the concentration of caffeine in a beverage. The device includes a well or other receptacle for containing a predetermined test volume of the beverage. A paper strip is suspended so that one end of the strip dips into the well. The strip is divided into two zones, the first zone being coated with at least one molecular imprint polymer (MIP) which absorbs substances which may interfere with quantification of caffeine. The second zone is coated with an MIP which selectively absorbs caffeine and chromogenic reagents which provide calorimetric visualization of the migration of caffeine through the second zone. The second zone bears indicia calibrating the paper strip so that the concentration of caffeine in the beverage may be determined by the height or distance which the caffeine migrates up the paper strip.