Unconventional solid-like picein wax carbon paste electrode in europium determination

In this work, a new carbon paste electrode (CPE) was presented, in which as a binder picein hard wax was applied. Picein wax combines the features of high plasticity at temperatures above 90 °C as well as hardness and chemical resistance at room temperature. Repeated polishing and usage, without losing the quality of the electrode working surface, is possible and gives the effect of a high level of signal repeatability. Picein-based electrode was applied in europium(III) determination by differential pulse voltammetry in the optimized supporting electrolyte (mixture of NaClO4 and HClO4). It was proved that addition of HClO4 is necessary; otherwise, double-peak effect is observed. In voltammetric experiments, activation of the electrode surface, by applying a potential of 1600 mV for several seconds, is recommended. It was demonstrated that for concentration 1–10 μM of Eu(III), sensitivity was 0.0301 ± 0.0004 μAμM−1 with correlation r = 0.9996 and limit of detection 0.3 μM.