Cooperative interaction of Ketjen black coating and electrical discharge post-treatment towards advanced screen-printed electrodes for hydroquinone and catechol

Abstract

We report on the advanced electroanalytical properties towards hydroquinone (HQ) and catechol (CC) endowed to graphite screen-printed electrode (SPE) modified with EC-600JD Ketjen black (KB) after a short (9 s) and green (no liquids are involved) direct KB/SPE-to-graphite pin electrical discharge at ambient conditions. While KB coatings or spark discharge treatment on plain SPE alone endows low or moderate electrocatalytic properties, respectively, to otherwise inactive plain SPE, post-treatment of KB/SPE with graphite pin electrical discharge results in a remarkable increase of the response. The morphology and various physicochemical properties of the electrode surfaces were examined with scanning electron microscopy, contact angle measurements, Raman spectroscopy and different electrochemical techniques. Differential pulse voltammetric data demonstrated well-resolved oxidation peaks for HQ and CC, and good selectivity against possible interfering species. The response showed a linear relationship to the concentration of both HQ (from 0.050 to 1.0 μM) and CC (from 0.050 to 2.0 μM) while, based on the 3σ/m criterion, the detection limits were calculated 2 and 9 nM, respectively. The sparked KB/SPEs were successfully applied to real world samples spiked with sub-micromolar concentrations of the targets with satisfactory recoveries.