Open AccessElectrochemical monitoring of the oxidative degradation of glyphosate with UV/H2O2
Author(s) -
Sandra Castro-Narváez,
Libia Vielma-Balanta,
Jairo-Nelson Quiñonez,
Alonso Jaramillo-Aguirre
Publication year - 2020
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1541/1/012018
Subject(s) - perchloric acid , electrode , chemistry , electrochemistry , sarcosine , platinum , nuclear chemistry , inorganic chemistry , glycine , catalysis , organic chemistry , amino acid , biochemistry
A voltammetric method optimized for the sensitive and reliable study of the UV/H 2 O 2 oxidation of glyphosate (N- (phosphonomethyl) glycine) (GPS). The cell consisted of three electrodes in a compartment, silver wire coated with silver chloride as a pseudo reference electrode, platinum electrode as working electrode and stainless steel as auxiliary electrode. GPS cyclic voltammetric analysis suggests the formation of a GPS-Pt complex on the electrode surface, with an enhanced signal in perchloric acid between 1.3 to -1.3V; sensitive to protonation of the amino group, no response observed at pH values greater than 5.00. The oxidative degradation of GPS with UV/H 2 O 2 is evident at pH 3.0, it exhibits first order pseudo kinetics with a half-life of 40 ± 4min. Two degradative routes are estimated depending on the concentration of H 2 O 2 : at low concentrations (H 2 O 2 /GPS 1: 100 ratio), the formation of sarcosine and then glycine is favored; at H 2 O 2 /GPS 1:20 and 1:10 ratios predominate the formation of glycine.