Automated high performance liquid chromatography and liquid scintillation counting determination of pesticide mixture octanol/water partition rates.
Two novel methods are reported for measuring octanol/water partition rates of pesticides. A liquid scintillation counting (LSC) method was developed for automated monitoring of 14C-labeled pesticides partitioning in biphasic water/octanol cocktail systems with limited success. A high performance liquid chromatography (HPLC) method was developed for automated partition rate monitoring of several constituents in a pesticide mixture, simultaneously. The mean log Kow +/- SD determined from triplicate experimental runs were for: 2,4-D-DMA (2,4-dichlorophenoxyacetic acid dimethylamine), 0.65 +/- .17; Deet (N,N-diethyl-m-toluamide), 2.02 +/- .01; Guthion (O,O-dimethyl-S-(4-oxo-1,2,3-benzotriazin-3(4H)-ylmethyl) phosphorodithioate), 2.43 +/- .03; Methyl-Parathion (O,O-dimethyl-O-(p-nitrophenyl) phosphorothioate), 2.68 +/- .05; and Fenitrothion (O,O-dimethyl O-(4-nitro-m-tolyl) phosphorothioate), 3.16 +/- .03. A strong positive linear correlation (r = .9979) was obtained between log Kow and log k' (log Kow = 2.35 (log k') + 0.63). The advantages that this automated procedure has in comparison with the standard manual shake-flask procedure are discussed.
Moody
R P
RP
Bureau of Chemical Hazards Health and Welfare, Canada, Ottawa, Ontario.
Carroll
J M
JM
Kresta
A M
AM
D001322:Autoanalysis; D002851:Chromatography, High Pressure Liquid; D004058:Diffusion; D005278:Fenitrothion / Q000032:analysis; D000442:Octanols; D010575:Pesticides / Q000032:analysis*; D012588:Scintillation Counting; D014867:Water
D000442:Octanols; D010575:Pesticides; D014867:Water; D005278:Fenitrothion