Simultaneous determination of 4-ethylphenol and 4-ethylguaicol on C60 modified dual screen-printed electrochemical sensors

4-ethylphenol and 4-ethylguaicol levels in wine are associated to organoleptic defects that cause consumer rejection accompanied by significant economic losses for producers. Thus, electrochemical sensors based on screen-printed carbon electrodes (SPCEs) modified with activated fullerene C60 (AC60) have been developed for the analysis of both phenols by direct headspace amperometric measurements. Upon optimization of the experimental variables affecting the sensors performance, the AC60/SPCE sensors presented linearity ranges from 9.9 to 65.4 μg/L and from 19.6 to 107.1 μg/L for 4-ethylphenol and 4-ethylguaicol, respectively. The achieved detection capacities were 10.3 μg/L (4-ethylphenol) and 19.6 μg/L (4-ethylguaicol), with a reproducibility of 6.3 % and 9.1 % (n = 3), respectively. In addition, dual-working AC60/SPCE devices were developed for the simultaneous analysis of both phenols using different working potentials for each electrode. The dual systems were successfully applied in the analysis of different spiked wine samples, obtaining good recoveries ranging from 94 to 108 %.

Electrochemical sensors for the determination of 4-ethylguaiacol in wine

The development of an electrochemical procedure for the determination of 4-ethylguaiacol and its application to wine analysis is described. Modified screen-printed carbon electrodes (SPCEs) with fullerene C₆₀ (C₆₀) have been shown to be efficient in this kind of analysis. The developed activated C₆₀/SPCEs (AC₆₀/SPCEs) were adequate for the determination of 4-ethylguaicol, showing a linear range from 200 to 1000 µg/L, a reproducibility of 7.6% and a capability of detection (CC_β) value of 200 µg/L, under optimized conditions. The selectivity of the AC₆₀/SPCE sensors was evaluated in the presence of possibly interfering compounds, and their practical applicability was demonstrated  in the analysis of different wine samples obtaining recoveries ranging from 96 to 106%.