title: Stereoisomeric separation and toxicity of a new organophosphorus insecticide chloramidophos.
abstract: Chloramidophos (CP), O,S-dimethyl-[(2,2,2)-trichloro-1-hydroxyethyl]phosphoramidothioate, is a new organophosphorus pesticide (OP) with two chiral centers each on the phosphorus and carbon atoms. Although CP has been widely used in some provinces of China, it has received very limited attention toward its environmental behaviors, in particular, with regard to stereospecificity. In this study, the stereoisomeric separation and toxicity of CP were investigated. All of the four stereoisomers of CP were successfully separated by high-performance liquid chromatography on a Chiralpak AD column. The stereoisomers (pk 1 to pk 4) were distinguishable on their mass and circular dichroism spectra. The inhibition on acetylcholinesterases (AChE, in vitro) and the acute aquatic toxicity to Daphnia magna (in vivo) tested with optically pure stereoisomers of CP showed its stereoselectivity. The inhibitory potency toward AChE decreased in the order of pk 4 > pk 3 > pk 2 > pk 1. In comparison, the acute toxicity to D. magna was in the order of pk 3 > pk 2 > pk 1 > pk 4. The stereoselectivity was found to be isomer-dependent, with 1.1-18.1-fold differences (in vitro) and 1.2-13-fold differences (in vivo) among the stereoisomers. These results suggest that the overall toxicity of chiral OPs should be assessed using their individual enantiomers.
authors.affiliation: Research Center of Green Chirality, College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Zhou
authors.forename: Kunde
authors.initials: K
authors.lastname: Lin
authors.forename: Huayun
authors.initials: H
authors.lastname: Yang
authors.forename: Ling
authors.initials: L
authors.lastname: Li
authors.forename: Weiping
authors.initials: W
authors.lastname: Liu
authors.forename: Jian
authors.initials: J
authors.lastname: Li
mesh_terms: D000110:Acetylcholinesterase / Q000097:blood; D000465:Algorithms; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D003621:Daphnia; D004593:Electrophorus; D004912:Erythrocytes / Q000187:drug effects / Q000201:enzymology; D066298:In Vitro Techniques; D007202:Indicators and Reagents; D007306:Insecticides / Q000302:isolation & purification* / Q000633:toxicity*; D009943:Organophosphorus Compounds / Q000302:isolation & purification* / Q000633:toxicity*; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism
chemical_list: D007202:Indicators and Reagents; D007306:Insecticides; D009943:Organophosphorus Compounds; C519624:chloramidophos; D000110:Acetylcholinesterase