CONICET | Buscador de Institutos y Recursos Humanos

Tetracyclines are an important group of antibiotics commonly used in human and veterinary medicine, aquaculture and animal husbandry. Owing to their extensive uses, these compounds are one of the pharmaceutical products most widely distributed as environmental pollutant. The presence of low levels of antibiotics and their metabolites in the environment could provide adverse effects like bacterial resistance, disruption of critical cycles to aquatic ecology, crop and animal production. Therefore, it is important to develop an analysis tool for the determination of tetracycline antibiotics in water samples. The purpose of this work was the electrochemical determination of chlortetracycline (CTC) in synthetic water samples. Electrochemical experiments were performed using a BAS 100B/W electrochemical analyzer. Cyclic and square-wave voltammograms were obtained using a three electrodes system: glassy carbon working electrode modified with multi-walled carbon nanotubes (MWCNT), an Ag|AgCl|3M NaCl reference electrode and a Pt wire counter electrode. For the electrode modification 1 milligram of MWCNT was dispersed with the aid of ultrasonic stirring for 45min in methanol/water (50:50, v/v) in an aqueous 0.1% Nafion solution. Then, 5µL of this dispersion was dropped on the working electrode and the solvent was evaporated under an infrared heat lamp. CTC synthetic water samples were prepared by diluting CTC stock solution of 119 mg L-1 in purified deionized water. The CTC quantification was carried out by Square Wave Voltammetry (SWV) in 10 mL of 0.01 M phosphate buffer. The CTC calibration plot was performed using SWV in a concentration range of 2 to 119 mg L-1. The calibration equation was ΔI (μA) = 0.1026 + 0.0074 CCTC with a regression coefficient of 0.997. Based on the results, the proposed approach was successfully used to analyze the CTC content in water samples.