Sensing reaching the stars: mild condition ZnO defect development for vitamin detection

Here, we present the preparation and electrochemical evaluation of a vitamin B2-riboflavin (RF) sensor based on hierarchically structured zinc oxide (ZnO) of the wurtzite type. The highly crystalline ZnO obtained under hydrothermal conditions from a zinc peroxocomplex has the appearance of “micro-stars,” with an average size of 10 μm. Development of unusual morphology was accompanied by significant lattice defect introduction. Zinc oxide as an electroactive additive for carbon paste electrode was studied with electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and differential pulse voltammetry (DPV), which revealed excellent charge mobility and low resistivity. Electrochemical properties of the semiconductor allowed for development of riboflavin (RF) electrochemical sensor with an improved linearity range and a low limit of detection. The repeatability and stability of the sensor were at a satisfactory level for real-time measurements.

Graphical abstract

Conventional hydrothermal treatment of zinc peroxocomplex provided star-shaped zinc oxide microparticles with metal-deficient lattice. Increased defect concentration facilitated charge mobility, which helped in developing of sensor for relevant vitamin.