title: High pressure liquid chromatographic determination of theobromine and caffeine in cocoa and chocolate products: collaborative study.
abstract: Four duplicate samples of cocoa-containing materials, a practice sample, and standards were submitted to the collaborators for theobromine and caffeine analysis by HPLC. In the method the samples are defatted with petroleum ether, and dried. The fat-free residue is then extracted with water and an aliquot is injected into the chromatograph. Compounds are quantitated by comparison with internal or external standards, either by peak height or peak area. Results for all the analyses showed that few of the values were more than 2 standard deviations from the mean. The method has been adopted as official first action.
mesh_terms: D002099:Cacao / Q000032:analysis*; D002110:Caffeine / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D011786:Quality Control; D013805:Theobromine / Q000032:analysis*
chemical_list: D002110:Caffeine; D013805:Theobromine