Simultaneous determination of theobromine, (+)-catechin, caffeine, and (-)-epicatechin in standard reference material baking chocolate 2384, cocoa, cocoa beans, and cocoa butter.
A reverse-phase liquid chromatography analysis is used to access the quantity of theobromine, (+)-catechin, caffeine, and (-)-epicatechin in Standard Reference Material 2384 Baking Chocolate, cocoa, cocoa beans, and cocoa butter using water or a portion of the mobile phase as the extract. The procedure requires minimal sample preparation. Theobromine, (+)-catechin, caffeine, and (-)-epicatechin are detected by UV absorption at 273 nm after separation using a 0.3% acetic acid-methanol gradient (volume fractions) and quantified using external standards. The limit of detection for theobromine, (+)-catechin, caffeine, and (-)-epicatechin averages 0.08, 0.06, 0.06, and 0.06 microg/mL, respectively. The method when applied to Standard Reference Material 2384 Baking Chocolate; baking chocolate reference material yields results that compare to two different, separate procedures. Theobromine ranges from 26000 mg/kg in cocoa to 140 mg/kg in cocoa butter; (+)-catechin from 1800 mg/kg in cocoa to below detection limits of < 32 mg/kg in cocoa butter; caffeine from 2400 mg/kg in cocoa to 400 mg/kg in cocoa butter, and (-)-epicatechin from 3200 mg/kg in cocoa to BDL, < 27 mg/kg, in cocoa butter. The mean recoveries from cocoa are 102.4 +/- 0.6% for theobromine, 100.0 +/- 0.6 for (+)-catechin, 96.2 +/- 2.1 for caffeine, and 106.2 +/- 1.7 for (-)-epicatechin.
Risner
Charles H
CH
R.J. Reynolds Tobacco Company, Bowman Gray Technical Center, Winston-Salem, NC 27102, USA.
D002099:Cacao / Q000737:chemistry*; D002110:Caffeine / Q000032:analysis* / Q000737:chemistry; D002392:Catechin / Q000032:analysis* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D004041:Dietary Fats / Q000032:analysis*; D015203:Reproducibility of Results; D013805:Theobromine / Q000032:analysis* / Q000737:chemistry
D004041:Dietary Fats; D002110:Caffeine; C052387:cocoa butter; D002392:Catechin; D013805:Theobromine