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.