The reduction of Cu(II)/neocuproine complexes by some polyphenols: Total polyphenols determination in wine samples

Lee G.; Rossi M.V.; Coichev N.; Moya H.D.

The reduction of Cu(II)/neocuproine complexes by some polyphenols: Total polyphenols determination in wine samples

Tipo

Artigo

Data de publicação

2011

Periódico

Food Chemistry

Citações (Scopus)

21

Autores

Lee G.
Rossi M.V.
Coichev N.
Moya H.D.

Resumo

A new method is presented for spectrophotometric determination of total polyphenols content in wine. The procedure is a modified CUPRAC method based on the reduction of Cu(II), in hydroethanolic medium (pH 7.0) in the presence of neocuproine (2,9-dimethyl-1,10-phenanthroline), by polyphenols, yielding a Cu(I) complexes with maximum absorption peak at 450 nm. The absorbance values are linear (r = 0.998, n = 6) with tannic acid concentrations from 0.4 to 3.6 μmol L-1. The limit of detection obtained was 0.41 μmol L -1 and relative standard deviation 1.2% (1 μmol L-1; n = 8). Recoveries between 80% and 110% (mean value of 95%) were calculated for total polyphenols determination in 14 commercials and 2 synthetic wine samples (with and without sulphite). The proposed procedure is about 1.5 more sensitive than the official Folin-Ciocalteu method. The sensitivities of both methods were compared by the analytical responses of several polyphenols tested in each method. © 2010 Elsevier Ltd. All rights reserved.

Assuntos Scopus

Absorbance values , Absorption peaks , Cu complexes , Limit of detection , Mean values , Neocuproine , Phenanthrolines , Polyphenols , Relative standard deviations , Spectrophotometric determination , Tannic acid , Wine sample