Naslov
STUDYING ELECTRODE MECHANISM AND ANALYTICAL DETERMINATION OF ELLAGIC ACID ON A GLASSY-CARBON ELECTRODE USING SQUARE-WAVE VOLTAMMETRY

Autori
Novak, Ivana ; Komorsky-Lovrić, Šebojka

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Skup
63rd Annual Meeting of the International Society of Electrochemistry

Mjesto i datum
Prag, Češka Republika, 19.08.2012. - 24.08.2012

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
ellagic acid; square-wave voltammetry; electrochemical oxidation

Sažetak
Ellagic acid (EA, C14H6O8), a dimeric derivative of gallic acid, is a polyphenolic compound found in a variety of plants. There, it is usually present in its free form or in the form of ellagitannin glycosides. The main natural sources of EA are berries and nuts. EA has a number of health-promoting effects in humans, including antioxidant, antiviral, antimutagenic, antiinflammatory and anticarcinogenic effects. Chromatographic methods coupled with diode array detector or mass spectrometer are commonly used analytical methods to study and quantify EA. EA is electroactive and can be electrochemically oxidized due to the ortho-hydroquinone groups. The mechanism of the electrochemical oxidation of EA on a glassy-carbon electrode was investigated using square-wave voltammetry (SWV) at different pHs and frequencies. The oxidation of EA is dependent on pH in the studied range between pH 2 and 11. At pH 6.5 and frequency of 100 Hz SWV response of EA consists of a single reversible peak with a potential of 0.278 V vs. Ag/AgCl. By increasing the frequency, the second peak appears at more positive potential. These two peaks can be explained by the assumption that the electrode reactions of the 2 ortho-hydroquinone groups are not equally fast. Quantitative analysis of EA in foodstuff was performed under optimized experimental conditions of pH 6.5, pulse amplitude of 50 mV, frequency of 100 Hz, and step potential of 2 mV. Under these conditions, linear responses for EA were obtained for concentrations from 5.0 × 10−7 mol/L to 8.0× 10−6 mol/L, and calculated LOD and LOQ were 1.35 × 10−7 mol/L and 4.51 × 10−7 mol/L, respectively. The proposed method was applied to the determination of EA in strawberries, raspberries and blackberries extracts.

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Prehrambena tehnologija

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