Enantioresolution And Study Of Acute Toxicity Of Phosphonate Herbicide

In this paper,a novel method was develoed to separate the enantiomers of phosphonate herbicide O,O-dimethyl-1-(phenoxyacetoxy)ethylphosphonate(peng3) and O,O-dimethyl-1-(4-methylphenoxyacetoxy)ethylphosphonate(mo5) using chiral high performance liquid chromatography(HPLC).Daphnia magna was used as test acute toxicity of enantiomer,and also provides the evaluation standard for environmental organisms.A method of chiral separation of Mo2and Peng3was developed by HPLC on the Chiralpak AD.The effect of chromatographic conditions such as alcohols modifier in the mobile phases,added amounts of isopropanol in the mobile phases,column temperature to recognition of the Peng3and Mo2 were studied,the thermodynamical mechanism of enantioseparation have also been preliminary discussed.A simultaneous baseline separation of the enantiomers was obtained with a mobile phase of n-hexane/isopropanol (90:10,V/V)at a flow rate of 1.0mL/min and wave length 220nm under 25℃in Chiralpak AD-H column.As the main aquatic organism,the acute aquatic toxicity of peng3 and mo2 to Daphnia magna were investigated.According to OECD method,the 48h-LC₅₀ were adopted to evaluate the acute aquatic toxicities of the compounds.the results showed that 48h-LC₅₀ values of Rac-Peng3,Peng3-pk1,Peng3-pk2 for Daphnia magna in the experimental conditions were 0.2741mg/L,0.3685mg/L,0.2623mg/L respectively.And the toxicity order was:Peng3-pk2＞Rac-Peng3＞Peng3-pk1;48h-LC₅₀ values of Rac-Mo2, Mo2-pk1,Mo2-pk2 for Daphnia magna in the experimental conditions were 0.3111mg/L, 0.2561mg/L,0.2944mg/L respectively.And the toxicity order was:Mo2-pk1＞Mo2pk2＞Rac-Mo2.