The Performance of Boron-Doped Diamond Electrode in Anionic Surfactant Media for Enhancing the Adsorptive Stripping Voltammetric Determination of Fluoroquinolones

Zühre ŞENTÜRK, Van Yüzüncü Yıl University, Faculty of Science, Van, Turkey (zuhresenturk@hotmail.com)
Fatih DÖNMEZ, Van Yüzüncü Yıl University, Faculty of Pharmacy, Van, Turkey
Zehra BAŞI, Van Yüzüncü Yıl University, Van School of Health, Van, Turkey
Fatih KARAHAN, Van Yüzüncü Yıl University, Faculty of Science, Van, Turkey
Pınar TALAY PINAR, Van Yüzüncü Yıl University, Faculty of Pharmacy, Van, Turkey
Yavuz YARDIM, Van Yüzüncü Yıl University, Faculty of Pharmacy, Van, Turkey

Fluoroquinolones (FQs) are a class of synthetic broad-spectrum antimicrobial drugs derived from nalidixic acid, which are known for their broad spectrum of antibacterial activity against both Gram-negative and Gram-positive pathogens. Because of their widely consumption, excretion and persistence, FQs are disseminated via excrements, and can be released into the several environmental compartments. Therefore, their potential activity become may be potential risk for those target and non-target organisms. Additionally, the long-term application of FQs may cause an increase of resistant bacteria species within the treated body, which is an important threat against public health in the food chain. Thus; the determination of FQs is current important for pharmaceutical, clinical and environmental studies. The electroanalytical applications of FQs involve the use of mercury-based electrodes (due to their electroreductive behavior) and modified carbonaceous electrodes (due to their electrooxidative behavior). As far as we know, there are very few studies in the literature for their electrochemical determination at conventional bare electrodes. This may be because of the high oxidation potential of these compounds that gives poor reproducibility due to the overlapping with the discharge of the background electrolytic solution. Recently, the boron-doped diamond (BDD) as a new and excellent carbon electrode material can be used to overcome this difficulty. In keeping with the above knowledge in mind, in the present study, a mercury-free and modification-free electroanalytical methodology based on BDD electrode (except for a simple anodical pretreatment between individual measurements) is described for the quantification of two important fluoroquinolones, namely enrofloxacin and norfloxacin, which have been widely used in veterinary and human medicine, respectively. The oxidation of both compounds was irreversible and presented an adsorption controlled process. The sensitivity of the stripping voltammetric measurements was significantly improved when the anionic surfactant, sodium dodecylsulfate (SDS) was present in the electrolyte solution. Using square-wave stripping mode, a linear response was obtained for enrofloxacin determination in 0.1 M HNO3 solution containing 9×10-4 M SDS at +1.27 V (vs. Ag/AgCl) (after 60 s accumulation at open-circuit condition), and for norfloxacin in acetate buffer (pH 4.7) solution containing 7×10-4 M SDS at +1.32 V (vs. Ag/AgCl) (after 30 s at +0.1 V). Linearities were found within 7.0×10-8-2.8×10-6 M and 1.6×10-7-1.3×10-5 M, with detection limits 1.6×10-8 M and 4.1×10-8 M for enoxacin and norfloxacin, respectively. The proposed method could be used for the determination of these compounds in pharmaceutical formulations and the spiked urine samples with acceptable recoveries.

Acknowledgement: The authors gratefully acknowledge financial support from the Van Yuzuncu Yil University Scientific Research Foundation (Project ID: FAP-2019-8072)

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Abstract Reference & Short Personal Biography of Presenting Author

Prof. Dr. Zühre ŞENTÜRK

She received her PhD degree in 1985 from Department of Analytical Chemistry, Faculty of Pharmacy, Ankara University (Ankara, Turkey). She worked as visiting scientist in the laboratories of Prof. G.J. Patriarche and Prof. J.M. Kauffmann (ULB, Brussels; Belgium) in 1990 and 1996, respectively. She became full professor in 1997 in Faculty of Pharmacy, Gazi University (Ankara, Turkey). She attended Faculty of Science, Van Yuzuncu Yıl University (Van, Turkey) as a professor of Analytical Chemistry in 1999. Her research interest focuses on pharmaceutical, food, environmental and biomedical applications of electrochemical sensors (potentiometric ion-selective electrodes, modified electrodes, nanometerials).

Address: Van Yuzuncu Yıl Univ., Fac. of Science, Dept. of Analytical Chemistry, 65080 Van, Turkey

E-mail: zuhresenturk@hotmail.com