Gas-liquid Chromatographic Determination of a New Pyrethroid, Permethrin(S–3151) and Its Optical Isomers

Abstract

Gas-liquid chromatographic (GLC) methods were developed for the determination of 3 -phenoxybenzyl dl-cis, trans-3 -(2,2-dichlorovinyl)-2,2-dimethy1cyc!opropane-l-carboxyla te (S-3151, permethrin or Exmin ®), its geometrical and optical isomers and its impurities. dl-Trans and dl-cis isomers were separated from each other on a 2 % LAC-2R-446 column and determined by using dioctyl phthalate as an internal standard, and the overall content of 8-3151 was obtained by the sum of them. Optical isomers, namely, d-cis, I-cis, d-trans and I-trans forms were hydrolysed to the corresponding acids, which were derivatized to the diastereoisomer esters with d-or 1-2-octanol and separated from one another on a 10% silicone DC QF-l column. The optical isomer ratios were determined by the peak area ratios. The impurities of 8-3151 were identified by mass spectrometer combined with GLC on a 2 % PEG-20 M column and they were determined by programmed temperature GLe.