B. Feier^*, A. Blidar^*, L. Vlase, C. Cristea. The complex fingerprint of vancomycin using electrochemical methods and mass spectrometry. Electrochemistry Communications 104 (2019) 106474; https://doi.org/10.1016/j.elecom.2019.05.023

^*equal contribution

ABSTRACT

Vancomycin (VAN) is a glycopeptide antibiotic, active against Gram-positive bacteria resistant to other antibiotics. VAN therefore needs to be monitored for maximum efficacy and minimum toxicity. Electrochemical sensors can be used for this purpose, using the direct electrochemical signal of VAN. Due to its molecular complexity and the need for analysis from complex matrices, the electrochemical detection of VAN requires the development of a complex electrochemical fingerprint (CEF), which covers a large variety of possible combinations of samples and interferents at concentrations of interest.

The objective of this study was to develop a CEF for VAN, involving a battery of tests and the elucidation of the mechanism of anodic oxidation of VAN, using high-performance liquid chromatography coupled with mass-spectrometric analysis of the products obtained after small-scale electrolysis.

A CEF for VAN was obtained, describing the electrochemical behavior of VAN at different commercially available screen-printed electrodes, with several electrolytes, considering successive analyses, after simple pretreatments, and examining both anodic and cathodic peaks. The concept was successfully applied to analysis of VAN in real samples and in the presence of some common interferents. Furthermore, a two-step combined electrochemical–chemical mechanism was proposed for the electrooxidation of VAN.