The bi-band bismuth microelectrode: Design, properties and application

[Display omitted] •First report on a new sensor: the bi-band bismuth microelectrode (b-BBimE).•User-friendly and environmentally friendly mercury-free working electrode.•Good surface renewability for stripping voltammetry.•Simple and fast (5 s) activation of the b-BBimE surface before each measurement.•Voltammetric quantitative analysis of Eu3+, riboflavin and folic acid. The easily-operated and environmentally friendly, reusable voltammetric sensor combining the advantages of both micro- and macroelectrodes – the bi-band bismuth microelectrode (b-BBimE) is presented for the first time. The original arrangement of the microelectrodes on the lateral surface of the sensor body facilitates its preparation, use and, most importantly, ensures the spherical stream of depolarizer transport to the electrodes. The active surface of the sensor consists of two symmetrical and oppositely located bismuth micro-bands, each 25 µm thick and 5 mm long. The use of bismuth as an electrode material enables a wide range of b-BBimE's applications. Excellent reproducibility of results, stability of operation, a wide range of useful potentials and linearity of sensor response were achieved by short-term (5 s) activation at the potential of hydrogen evolution reaction. The advantages of the sensor were documented with voltammetric determination of Eu3+ ions, riboflavin (vitamin B2), and folic acid (vitamin B9) under previously optimized conditions. The calculated RSD values for three concentrations of Eu3+ from the linearity range of the method did not exceed 5% (n = 3) for short-term reproducibility and 6% for long-term reproducibility (13 days, n = 10).