Radio-high-performance liquid chromatography for ecotoxicity assessment of insect growth regulators

The described radiochromatographic method permits fast and high-sensitivity monitoring of soil biodegradation products of an insect growth regulator for its environmental risk assessment. We analyzed and compared two diastereoisomers of ethyl N-(2-{4-[(2-hydroxycyclohexyl)methyl]phenoxy}ethyl)carbamate, namely its cis-(1S,2S) isomer JN-W330 and a trans-(1R,2S) isomer JN-W331. Microbial conversion of the cis-isomer to the trans-isomer was proved by mass spectrometry analyzer. Among the chromatographic columns tested, the best separation was found with a 125 mm×4 mm i.d. column packed with Supersphere 100 RP-C18, 5 μm and an acetonitrile–water gradient. The detection limit for the both isomers was in the range of 120–250 Bq (0.3–0.8 ng) at a concentration of 2 ng/ml with radiometric detection. The calibration curves for standard solutions were linear in the range of 150 Bq–150 kBq (r=0.996). The method enabled us to compare the analyzed juvenoids with biologically active oostatic peptides in terms of their environmental safety.