title: Determination of some thiophosphorus insecticides based on coulometric titration with the anodically generated chlorine: a further insight in the reaction mechanism in aqueous medium.
abstract: A new method of analytical determination of some thiolo (PS) and thiono (PS) group containing phosphorus insecticides using a coulometric titration with the anodically generated chlorine and biamperometric end-point detection was described. The method worked well for compounds containing one (methamidophos) or two PS bonds (iso-malathion) or one PS bond (fenitrothion) but failed for compounds containing both PS and PS bonds (malathion, dimethoate) or additional sterically hindered CSC bond (fenthion). Based on the found number z of electrons transferred per mol of oxidized compounds, mechanistic pathways for chlorination of PS and PS containing thiophosphorus insecticides with molecular chlorine in aqueous, acidic medium were proposed.
authors.affiliation: Department of Instrumental Analysis, University of Łódź, Pomorska 163, 90-236 Łódź, Poland.
authors.forename: Witold
authors.initials: W
authors.lastname: Ciesielski
authors.forename: Monika
authors.initials: M
authors.lastname: Skowron
authors.forename: Piotr
authors.initials: P
authors.lastname: Bałczewski
authors.forename: Aldona
authors.initials: A
authors.lastname: Szadowiak