Optimization of Chiral Separation in Cypermethrin using Response Surface Methodology

Cypermethrin (CPM) is a chiral insecticide compound, consists of eight stereoisomers with similar mass, structure and functional group. Hence, due to great structural similarities which lead to difficulties to resolve and lack of isomer standards, analysis of CPM stereoisomers is still poorly developed. In this study, a Cyclosil-B type chiral column was used to separate the CPM stereoiosmers via gas chromatography-electron capture detector (GC-ECD). A multivariate technique called response surface methodology (RSM) was utilized to optimize the separation conditions for CPM stereoiosmers. Four optimization steps were designed which involved two operating parameters i.e column temperature and holding time in order to establish the temperature programming approach. The results indicate that using the designed optimal conditions (step 1, 101 oC initial temperature with 3.0 min holding time; step 2, the temperature was increased to 106 oC with 2.50 min holding time; Step 3 was 115 oC for the next temperature with 0.5 min holding time; and final temperature of 123 oC with 2.0 holding time for step 4), all the eight peaks of CPM stereoiosmers were successfully separated with high resolution and short analysis time