INOSITOLPHOSPHATES IN COFFEE AND RELATED BEVERAGES .1. IDENTIFICATIONAND METHOD OF QUANTITATION

A HPLC method has been developed for the determination of several inos itol phosphates (hexakis-, tetrakis-, tris-and four pentakisphosphates ) in coffee and related beverages. The inositol phosphates are extract ed with hot water or cold hydrochloric acid and isolated by anion exch ange, followed by purification on RP-18. For HPLC, an anion exchange c olumn, a water/sodium nitrate/magnesium nitrate gradient, post-column reaction with ferric perchlorate and detection at 310 nm was used. Sta ndards for the tris- to pentakisphosphates were isolated from hydrolys ates of phytic acid and characterized by H-1-NMR and FAB-MS. In roaste d coffee and roasted malt, the recovery rates range from 89 to 101%, t he coefficients of variation from 3 to 8%, the detection limits from 3 4 to 55 mg/kg (roasted product) and the determination limits from 62 t o 116 mg/kg.