Polarographic Determination of O,O-Diethyl O-p-Nitrophenyl Thiophosphate (Parathion)

Abstract

Parathion may be determined quantitatively by means of the polarograph.The electrolysis is carried out in an acetone-water solution with 0.05 N potassium chloride as electrolyte, and 0.01% gelatin as suppressor at 25°= *= 0.5°C. An accuracy of ±1% ¡s obtained.Several commercial products were analyzed.

Nucleophilic displacements at sulfur. III. The exchange of oxygen-18 between sodium thiosulfate-18O and water

“…It is clear that the pentacovalent species shown in eq 9a must be actual intermediates rather than transition states, in contrast with the situation applicable to displacement in studying the oxygen-18 exchange was to aid in the elucidation of the mechanisms of all three of these processes. 6 Reaction 14 was reported previously;24 it is superficially extremely similar to eq 13. These two reactions, however, differ in activation energy by over 40 kcal¡ mole.…”

“…Journal of the American Chemical Society / 89:14 / July 1.41 0 See Table I for concentrations. 6 The pH value for runs 10 through 15 was assumed to be 7.0. This is obviously not strictly correct.…”

“…The first involves a rate-determining proton transfer (eq 5 and 6). H+ + S2(V-HO-SO2-S- (5) HO-S02-S-HO-+ S202 (6) This can be eliminated as inherently improbable and also since it predicts general acid catalysis. The second possibility is analogous to the A-l hydrolysis of esters (eq 7 and 8).…”

Electrochemical Methods in Pesticides Control

“…[12] Parathion and p-nitrophenol show different reduction potentials, respectively 20.39 and 20.68 V relative to SCE, and therefore do not interfere. With respect to parathion and paraoxon, the simultaneous determination is possible due the process of adsorption of the parathion.…”

Electrolysis of organophosphorus compounds. Study of mechanisms of reduction of various diethyl aroylphosphonates at a dropping mercury electrode

“…A series of papers has been released concerning the polarographic behavior of various metal ions and complex ions in the presence of certain organophosphorus compounds (6)(7)(8)(9). A few electrochemical studies which describe the development of polarographic methods for analyses of such compounds as Malathion [S-(l ,2-dicarbethoxyethyl) , -dimethyl dithiophosphate] and Parathion ( , -diethyl 0-/>nitrophenyl thiophosphate) have also been reported (10)(11)(12)(13). Santhanam and coworkers (14) examined the behavior of tris-(/>nitrophenyl) phosphate at the DME and determined the mechanism for the electroreduction of this compound.…”