In our previous study, we established a ferricyanide chronoamperometric total antioxidant capacity (FC-TAC) assay using a carbon screen-printed disposable microchip, and then the TAC value of vegetable extraction was estimated. In the present study, we further conducted the FC-TAC assay for green tea (Japanese tea), and the TAC value of the green tea was estimated using several extracting conditions for drinking and compared with the value obtained from an optical method using 2,2-diphenyl-1-picrylhydrazyl (DPPH). First, as a typical antioxidant contained in the green tea, the response to trolox, ascorbic acid, or catechin was investigated by the FC-TAC assay, and the results corresponded well with the results obtained using the conventional DPPH assay (r > 0.973). Next, real sample applications were examined in the FC-TAC assay using a total of 20 samples from four types of tea. The results of the present FC-TAC assay showed a relatively sensitive response to the antioxidants contained in the green tea as compared with the DPPH assay, and an acceptable correlation (r = 0.804) was obtained with a good slope of regression curve (y = 1.01x).
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