title: Voltammetric determination of polyphenolic content as rosmarinic acid equivalent in tea samples using pencil graphite electrodes.
abstract: The quasi-reversible, diffusion controlled behavior of rosmarinic acid (RA) on a disposable pencil graphite electrode (PGE) was established by cyclic voltammetry. Using the anodic oxidation peak presented by RA on the PGE a differential pulse voltammetric (DPV) method was developed for the quantitative determination of RA. The linear range was 10(-8) - 10(-5) M RA and the detection and quantification limits were 7.93 × 10(-9) M and 2.64 × 10(-8) M RA, respectively. The applicability of the developed method was tested by recovery studies and by the assessment of the total polyphenolic contents (TPCDPV) of green, white and black Turkish teas, which were found to be 40.74, 30.04 and 23.97 mg rosmarinic acid equivalent/g dry tea, respectively. These results were in good agreement with those obtained by the Folin-Ciocalteu method. The developed method is a sensitive and cheap tool for the rapid and precise evaluation of TPCDPV of tea samples.
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, University of Bucharest, 4-12 Regina Elisabeta Av. District 3, 030018 Bucharest, Romania.
authors.forename: Iulia Gabriela
authors.initials: IG
authors.lastname: David
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, University of Bucharest, 4-12 Regina Elisabeta Av. District 3, 030018 Bucharest, Romania.
authors.forename: Mihaela
authors.initials: M
authors.lastname: Buleandră
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, University of Bucharest, 4-12 Regina Elisabeta Av. District 3, 030018 Bucharest, Romania.
authors.forename: Dana Elena
authors.initials: DE
authors.lastname: Popa
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, University of Bucharest, 4-12 Regina Elisabeta Av. District 3, 030018 Bucharest, Romania.
authors.forename: Ana-Maria Cristina
authors.initials: AM
authors.lastname: Bîzgan
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, University of Bucharest, 4-12 Regina Elisabeta Av. District 3, 030018 Bucharest, Romania.
authors.forename: Zenovia
authors.initials: Z
authors.lastname: Moldovan
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, University of Bucharest, 4-12 Regina Elisabeta Av. District 3, 030018 Bucharest, Romania.
authors.forename: Irinel-Adriana
authors.initials: IA
authors.lastname: Badea
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, University of Bucharest, 4-12 Regina Elisabeta Av. District 3, 030018 Bucharest, Romania.
authors.forename: Emilia Elena
authors.initials: EE
authors.lastname: Iorgulescu
authors.affiliation: Molecular Biology Genetics and Bioengineering Program, Sabanci University, Orhanlı-Tuzla, 34956 Istanbul, Turkey.
authors.forename: Tuğçe Ayça
authors.initials: TA
authors.lastname: Tekiner
authors.affiliation: Molecular Biology Genetics and Bioengineering Program, Sabanci University, Orhanlı-Tuzla, 34956 Istanbul, Turkey.
authors.forename: Huveyda
authors.initials: H
authors.lastname: Basaga
keywords: Disposable pencil graphite electrode; Rosmarinic acid; Tea infusion; Total polyphenolic content; Voltammetry