화학공학소재연구정보센터
Electrochimica Acta, Vol.128, 41-47, 2014
Voltammetric investigation of complex growth media at a bare glassy carbon electrode: A case study of oxytetracycline
Reports regarding the voltammetric properties of microbiological growth media are scarce in the literature and limited focus has been placed towards the application of electroanalysis for analyte monitoring in these complex media. This work aims to investigate the viability of voltammetry as a quantification method for analytes in microbiological growth media, using oxytetracycline (OTC) as a model analyte. Analysis of both commercially available and laboratory prepared growth media indicated the presence of interfering media components which produced anodic peaks at potentials ranging from similar to+0.85V to similar to+1.30V (vs. Ag/AgCl) under acidic conditions and similar to+0.62V to similar to+1.35V (vs. Ag/AgCl) under neutral pH. These peaks were identified as originating from proteinaceous components of growth media and correlated to the presence of peptone, malt extract and yeast extract. Electrochemical impedance spectroscopy demonstrated significant increases in the charge transfer resistance for Fe(CN)(6)(3-/4-) redox probes at glassy carbon electrodes in the presence of peptone-comprised media (130.3 Omega) compared to media-free buffer (50.4 Omega). Adsorption of the aforementioned media components to the electrode surface thus contributes to analytical interference through faradaic and non-faradaic processes. By adapting the growth media for analyte detection purposes, this study proves the feasibility of detecting OTC, as well as the use of dilution of the media to further decrease the interferent effects of growth media. A 50-fold dilution of the media provided a 96.7% recovery of the OTC peak current at 20 mu M concentration. The empirical detection limit of OTC in 50-fold diluted media was determined to be 0.5 mu M, which makes it applicable to current industrial OTC fermentation processes. (C) 2013 Elsevier Ltd. All rights reserved.