A state-of-the-art approach for facile and reliable determination of benzocaine in pharmaceuticals and biological samples based on the use of miniaturized boron-doped diamond electrochemical sensor

For the first time, the miniaturized thick-film boron-doped diamond electrode was applied as progressive electrochemical sensor for simple, facile and reliable quantification of local anesthetic agent, benzocaine (BZC). Cyclic voltammetric measurements revealed that the electrode reaction of this analyte was manifested by one irreversible and diffusion-driven oxidation peak at +1.0 V in Britton-Robinson buffer at pH 4.0. Pulse voltammetric techniques with the suitably chosen values of operating parameters were used for the construction of calibration curves for BZC determination with the essential analytical characteristics as follows: the linear concentration range of 0.1-400 μM and 0.4-200 μM, the limit of detection of 80 nM and 100 nM for differential pulse voltammetry (DPV) and square-wave voltammetry (SWV), respectively. The excellent repeatability with the relative standard deviation below 5% was reached for both pulse voltammetric techniques. The developed protocols were applied to analysis of the commercial pharmaceuticals with the recoveries ranging from 97.4 to 104.5% and from 97.0 to 102.7% for DPV and SWV procedures as well as model human urine samples with recoveries from 96.0 to 104.0% and from 98.5 to 100.8%. This platform based on biocompatible, portable and easy-to-operate electrochemical sensor could encourage the viability of the proposed state-of-the-art approach for field applications, such as quality control of pharmaceuticals and monitoring of BZC in biological samples.