Content Handbook P
Outline of methodThe sample is dissolved in a prepared solution of a mixture of iso-octane, n-butyl chloride, toluene, and acetonitrile in a ratio by volume of 800:200:20:1, respectively. The mobile phase is a solution of 1,2-dichloroethane and hexanes in a ratio also by volume of 110:1000. The analysis is conducted via normal phase chiral chromatography using a 5 μm particle size 25 cm by 4.6 mm i.d. stainless steel column packed with Chiral D-PGC (phenyl glycine column) available from a variety of suppliers. UV detection at 280 nm is used to determine the peak areas
of S-enantiomer and R-enantiomer of zeta-cypermethrin diastereoisomer (peak D in CIPAC Method No. 332) and are measured by a data handling system. These areas are then used to further calculate the area percent ratio between the two Trans-2 (Peak D) enantiomers in zeta cypermethrin technical. Subsequently, the area percent ratio is used to calculate the weight percent of the R or S enantiomers in zeta-cypermethrin technical i.e., the result of the CIPAC Method No. 332 is multiplied by the area ratio to give the desired weight percent of R and S enantiomers in zeta-cypermethrin.