Rapid determination of total polyphenolic content in tea samples based on caffeic acid voltammetric behaviour on a disposable graphite electrode

• Published in: Food chemistry 2015-04, Vol.173, p.1059-1065
• Main Authors: David, Iulia Gabriela, Bizgan, Ana-Maria Cristina, Popa, Dana Elena, Buleandra, Mihaela, Moldovan, Zenovia, Badea, Irinel Adriana, Tekiner, Tuğçe Ayça, Basaga, Huveyda, Ciucu, Anton A.
• Format: Article
• Language: English
• Subjects: Caffeic acid; Caffeic Acids - chemistry; Electrochemical Techniques - instrumentation; Electrochemical Techniques - methods; Electrodes; Graphite; Pencil graphite electrode; Polyphenols - analysis; Tea; Tea - chemistry; Total polyphenolic content
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2014.10.139

•The voltammetric behaviour of caffeic acid at a disposable pencil graphite electrode was studied.•A simple and sensitive voltammetric method for caffeic acid determination was developed.•The method is a cheap tool for rapid total polyphenolic content analysis of teas (mg CAE/g tea).•The developed voltammetric method is as precise as the Folin–Ciocalteu method. The present paper describes the voltammetric behaviour and the quantitative determination of caffeic acid (CA) on a disposable pencil graphite electrode (PGE). The anodic peak current of CA recorded by differential pulse voltammetry (DPV) varies linearly with CA concentration in the range 1×10−7–3×10−3M. The detection and quantification limits were 8.83×10−8M and 2.94×10−7M caffeic acid, respectively. The mean recoveries of CA from Turkish green, white and black teas were 98.30%, 99.57% and 91.46%. For these three tea types the corresponding total polyphenolic contents (TPCs) evaluated by DPV on PGE were 35.81, 34.59 and 31.21mg caffeic acid equivalent/g tea, respectively. These TPC values were in good accordance with those obtained by the Folin–Ciocalteu method. The developed DPV on PGE method constitutes a simple and inexpensive tool for the rapid assessment of TPC of tea samples.