PENCIL GRAPHITE ELECTRODES FOR IMPROVED ELECTROCHEMICAL DETECTION OF OLEUROPEIN BY THE COMBINATION OF NATURAL DEEP EUTECTIC SOLVENTS AND GRAPHENE OXIDE

FEDERICO J. V. GOMEZ; MAGDALENA ESPINO; ADRIAN SPISSO; MARIA FERNANDA SILVA; MARÍA A. FERNANDEZ

Mendoza

Simposio; 24thLatin-American Symposium on Biotechnology, Biomedical, Biopharmaceutical, and Industrial Applications of Capillary Electrophoresis and Microchip Technology; 2018

Grupo de Química Analítica Verde (GQAV-IBAM)

A novel methodology is presented for the enhanced electrochemical detection of oleuropein incomplex plant matrices by Graphene Oxide Pencil Graphite Electrode (GOPGE) incombination with a buffer modified with a Natural Deep Eutectic Solvent, containing 10%(v/v) of lactic acid, glucose and H2O (LGH). The electrochemical behavior of oleuropein in themodified-working buffer was examined using differential pulse voltammetry. The combinationof both modifications, NADES modified buffer and nanomaterial modified electrode,LGH-GOPGE, resulted on a signal enhancement of 5.3 times higher than the bare electrodewith unmodified buffer. A calibration curve of oleuropein was performed between 0.10 to 37µM and good linearity was obtained with a correlation coefficient of 0.989. Detection andquantification limits of the method were obtained as 30 and 102 nM, respectively. In addition,precision studies indicated that the voltammetric method was sufficiently repeatable, %RSD0.01 and 3.16 (n = 5) for potential and intensity, respectively. Finally, the proposedelectrochemical sensor was successfully applied to the determination of oleuropein in an oliveleaf extract prepared by ultrasound-assisted extraction. The results obtained with the proposedelectrochemical sensor were compared with capillary zone electrophoresis (CZE) analysis withsatisfactory results.