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Analytical and mechanistic aspects of the polarographic reduction of the herbicide pyrazon
Author(s) -
Méndez J. Hernández,
Martínez R. Carabias,
Gonzalo E. Rodríguez
Publication year - 1990
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.1140020510
Subject(s) - polarography , coulometry , chemistry , detection limit , pulse (music) , electrode , reduction (mathematics) , inorganic chemistry , analytical chemistry (journal) , electrochemistry , chromatography , voltage , physics , geometry , mathematics , quantum mechanics
This article describes a study of the polarographic reduction of the herbicide pyrazon, which yields two polarographic reduction waves: one in acidic media and the other in alkaline media. Coulometric data indicate the exchange of two electrons per molecule, while infrared spectroscopic data reveal that the reduction process involves the azomethine (>CN) rather than the carbonyl group or the NN bond. A mechanism for the electrode reaction is postulated, and a pulse polarographic method for the quantitative determination of pyrazon is proposed. The detection limit achieved by differential pulse polarography in a 1.0 M sulfuric medium is 7 × 10 −8 M (0.015 ppm).