ISSN:
1432-0738
Keywords:
Dimethylphosphorothioates
;
Trimethylphosphorothioates
;
Malathion
;
Thin layer chromatography
;
Carboxylesterase
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Five dimethylphosphorothioates were tested for their toxicity to rats, potentiation of malathion toxicity in rats, inhibition of carboxylesterase in vitro, and reaction with malathion in vitro. The compounds were: potassium salts of (CH3S)2P(O)O−(I), (CH3O)(CH3S)P(O)S−(II), (CH3O)2P(O)S−(III), (CH3O)2P(S)S−(IV), and (CH3O)(CH3S)P(O)O−(V). The dimethylphosphorothioates are not toxic to rats (up to 1 g/kg, orally), they do not potentiate malathion toxicity in rats, and do not inhibit carboxylesterase activity in vitro (up to 1 mM concentrations). However, when the S-acid diesters (II, III, IV) are incubated with malathion for several days at room temperature or for several hours at 50° C they become methylated forming the trimethylphosphorothioates OSS-trimethyl phosphorodithioate, OOS-trimethyl phosphorothioate and OOS-trimethyl phosphorodithioate respectively, which potentiate malathion toxicity. Furthermore, these same acid diesters increase the rate of isomerization of malathion into OS-dimethyl-S-(1,2-dicarbethoxyethyl) phosphorodithioate (isomalathion) particularly, diester IV. The formation of the trimethylphosphorothioates and isomalathion from the interaction of the S-acid diesters with malathion was determined by thin layer chromatography (TLC), gas chromatography and mass spectrometry and could be detected by in vitro inhibition of carboxylesterase. TLC methods can detect 1 mg of the trimethylphosphorothioates and isomalathion per gram malathion.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00347877
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