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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.

V2O5 thin films have been deposited onto an insulating support by radiofrequency (rf) reactive sputtering from a metallic vanadium target at controlled flow rates of argon–oxygen gas mixture. Glancing-incidence x-ray diffraction (GIXD) analysis and scanning electron microscopy (SEM) were used for structural and phase characterization of the obtained materials. The as-sputtered thin films were found to consist of orthorhombic V2O5 phase. Electrical properties were determined by electrochemical impedance spectroscopy (EIS) conducted over the frequency range of 0.1 Hz to 1.4 MHz and temperatures ranging from room temperature (RT) to 773 K. Between RT and 528 K, the recorded impedance spectra were interpreted in terms of an equivalent circuit composed of a resistor and non-Debye constant-phase element (CPE) connected in parallel. In this temperature range, the material exhibited n-type extrinsic conductivity. The activation energy of electrical conductivity was 0.243 ± 0.023 eV. At 528 K, an abrupt change in resistivity was observed, interpreted as a metal–insulator transition (MIT). Above 528 K, the equivalent circuit was composed of a resistor (R) and inductor (L) connected in series, typical of materials exhibiting metallic properties.