Table 3.

Antioxidants present per gram of tea samples (extracted in hot water for 20 min) separated in an HPLC with CUPRAC post-column derivatization using phenyl-hexyl core-shell column

Antioxidants	Brand 1 (n = 3)	Brand 2 (n = 3)	Brand 3 (n = 3)	Brand 4 (n = 3)	Brand 5 (n = 3)
Catechin, mg/g	12.16 ± 0.24 (RSD = 1.97%)	0.68 ± 0.06 (RSD = 8.82%)	12.94 ± 0.17 (RSD = 1.31%)	0.45 ± 0.02 (RSD = 4.44%)	0.69 ± 0.05 (RSD = 7.25%)
EGCG, mg/g	40.71 ± 2.76 (RSD = 6.77%)	1.30 ± 0.01 (RSD = 0.78%)	61.57 ± 0.44 (RSD = 0.72%)	0.62 ± 0.16 (RSD = 25.81%)	1.09 ± 0.09 (RSD = 9.17%)