A reverse flow injection spectrophotometric enzymatic method is proposed to quantify total phenols in urine samples. The polyphenol oxidase
(PPO; EC 1.14.18.1) obtained as a crude extract from sweet potato root (Ipomoea batatas) was used as enzymatic catalyze. The detection limit,
the sample throughput and relative standard deviation were 7.7 mg l−1 of total phenols, 49 h−1 and 0.9%, respectively. The method was applied to
real samples and a recovery study was carried out in order to its validation.