Electrochemical behavior of simetryn herbicide at water|1,2-dichloroethane interface

Herein, the electrochemical behavior of the simetryn herbicide at the water|1,2-dichloroethane interface was investigated by cyclic voltammetry and electrochemical impedance spectroscopy. Parameters such as transfer Gibbs energy, ionic partition coefficient, and the apparent rate constants across the interface were evaluated. According to the results, the ionic form of this herbicide is highly hydrophobic because Δw o G0 SIMH w→o + is 3.57 kJ mol−1 and logPSIMH 0 + is −0.622. In addition, the ionic partition diagram for this compound shows dual behavior as a function of pH: when pH pKa, simetryn serves as a mobile proton carrier across the interface. The present study offers some important insights that help in understanding the partitioning and kinetic processes of environmentally important molecules across biological membranes.Fil: Velázquez-Manzanares, Miguel. Universidad Autonoma de Coahuila; MéxicoFil: García Martínez, Humberto. Universidad Autonoma de Coahuila; MéxicoFil: Yudi, Lidia Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Amador-Hernández, Judith. Universidad Autonoma de Coahuila; MéxicoFil: de la Garza Rodríguez, Iliana M.. Universidad Autonoma de Coahuila; MéxicoFil: Colunga Urbina, Edith M.. Universidad Autonoma de Coahuila; Méxic

SEMI-CONTINUOUS DETERMINATION OF NO2 IN PASSIVE DIFFUSERS BY FLOW INJECTION/UV-VIS SPECTROPHOTOMETRY

In this work the development of a semi-automated method by flow injection for spectrophotometric indirect determination of NO2, is described. The gas of environmental importance is captured through passive diffusers built in the laboratory, where it undergoes a reaction with triethanolamine to form nitrite ions in relation 1:1, which are determined after the derivatization with sulfanilamide and N-(1-naphthyl) ethylenediamine. It’s concluded that the proposal method is quick and easy, as well as sensitive and selective to determine the chemical specie of interest. The estimated NO2 concentration in the air of Saltillo in Coahuila was 2.6 ± 0.3 mg m-3, which was above the maximum recommended by NOM-023-SSA1-1993 norm