Premium
Separation and aquatic toxicity of enantiomers of the pyrethroid insecticide lambda‐cyhalothrin
Author(s) -
Xu Chao,
Wang Jiajia,
Liu Weiping,
Sheng G. Daniel,
Tu Yunjie,
Ma Yun
Publication year - 2008
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/07-134.1
Subject(s) - enantiomer , chemistry , chromatography , chiral column chromatography , carbamate , tris , acute toxicity , high performance liquid chromatography , toxicity , stereochemistry , organic chemistry , biochemistry
Abstract Chiral pollutants are receiving growing environmental concern due to differential biological activities of their enantio‐mers. In the present study, enantiomeric separation of the pyrethroid insecticide lambda‐cyhalothrin (LCT) was investigated by high‐performance liquid chromatography (HPLC) using the columns of Chiralpak AD (amylase tris[3,5‐dimethyl‐phenylcarbamate]), Chiralpak AS (amylase tris[(S)‐1‐phenyl carbamate]), Chiralcel OD (cellulose tris[3,5‐dimethylphenyl carbamate]), and Chiralcel OJ (cellulose tris[4‐methyl benzoate]) with different chiral stationary phases. The differential toxicities of the enantiomers in aquatic systems were evaluated using the acute zebrafish ( Danio rerio ) toxicity test and the zebrafish embryo test. The enantiomers of LCT were separated completely on all the columns tested and detected by circular dichroism at 236 nm. Better separations were achieved at lower temperatures (e.g., 20°C) and lower levels of polar modifiers (≤5%) in mobile phase. Ethanol was found to be a good modifier of the mobile phase for all the columns, although isopropanol acted better for the Chiralcel OD column. The (—)‐enantiomer was >162 times more toxic than its antipode to zebrafish in the acute test. The embryo test indicated that the exposure to LCT enantioselectively induced crooked body, yolk sac edema, and pericardial edema and that the (—)‐enantiomer was 7.2 times stronger than the (+)‐enantiomer in 96‐h mortality. The malformations were induced by the racemate and its (—)‐enantiomer at lower concentrations tested (e.g., 50 μg L −1 ), whereas the (+)‐enantiomer induced malformations at relatively higher concentrations (≥100 μg L −1 ). These results suggest that the toxicological effects of chiral pesticides must be evaluated using their individual enantiomers.