A RP-HPLC METHOD FOR THE DETERMINATION OF TEA CATECHINS

An HPLC method with gradient elution for the quantification of catechi ns ((-)-epigallocatechin (EGC), (+)-catechin (C), (-)-epicatechin (EC) , (-)-epigallocatechingallate (EGCg) and (-)-epicatechingallate (ECg)) in tea was developed. The method was used to determine catechins in b lack tea, green tea and oolong tea. Sample preparation was simple beca use only filtration and adjustment of pH was required. The levels of c atechins in different teas varied between <5 and 287 (EGC), 17 and 94 (EC), 18 and 408 (EGCg), and 8 and 85 mg/l (ECg). (+)-Catechin was not present in any of these teas. (C) 1997 Elsevier Science Ireland Ltd.