A great number of antimicrobials belonging to fluoroquinolones and sulfonamides families are used in the livestock industries. These compounds are not completely absorbed, by reaching agricultural soils and whereas maintaining their pharmacological activity. Due to this, a theoretical and electrochemical study of two pharmaceuticals that belong to sulfonamides and fluoroquinolones family, such as sulfamerazine (SRZ) and norfloxacin (NOR), respectively, are carried out in order to understand their behavior in aqueous solutions for future adsorption studies in soil organic matter. In this work, the electro - oxidation reaction of these two pharmaceuticals is studied at pH 7.0 by using a glassy carbon as working electrode and cyclic voltammetry as technique. Additionally, kinetic studies are done with the aim of determining the control of the reaction, the rate determining step and the number of transferred electrons in the whole process. Parallel to this, computational studies are done in order to support to the electrochemical results here achieved. On the other hand, the analytical parameters for the electrochemical method are obtained, which presents a highly linear equation for both pharmaceuticals. The method has a limit of detection of 38.1 and 29.6 mu moL/L and limit of quantification of 115.4 and 89.5 mu moL/L for NOR and SRZ, respectively. For accuracy, an error of 1.96% and 4.55% was obtained with respect to the analysis of a standard of 200 mu moL/L of SRZ and NOR, respectively. (C) 2019 Elsevier Ltd. All rights reserved.