Capillary Gas Chromatographic Determination Of Cypermethrin In Formulations:
Collaborative Study
Abstract A method is described for the determination of cypermethrin, 3-(2,2- dichloroethenyl)-2,2-dimethyl-cyclopropanecarboxylate cyano-(3- phenoxyphenyl)methyl ester, in technical and formulated material by capillary gas chromatography (CGC). Samples of technical or formulated material are dissolved in CH2Cl2 containing dicyclohexyl phthalate as internal standard. The solution is injected into a gas chromatograph fitted with a flame ionization detector and capillary column of 25 m x 0.32 mm fused silica with a thick film OV-1 phase at 240°C. Injection is made into a heated injection port fitted with an antidiscrimination device in a split mode. Peak areas obtained at retention times of the internal standard and active ingredient are measured with an integrator. The quantity of cypermethrin is determined by comparing the internal standard and active ingredient peak areas with those obtained from a calibration solution containing known amounts of internal standard and pure active ingredient. Five samples were chosen for collaborative study: technical cypermethrin, 70% liquid concentrate, 3 lb/US gal. emulsifiable, 3 ib/US gal. oil concentrate, and 40% wettable powder. Twelve collaborators carried out replicate determinations on each sample on separate days. Coefficients of variation between laboratories (CVX) were 2.13 for the technical, 2.94 for the emulsifiable concentrate, 3.51 for the liquid concentrate, 2.66 for the wettable powder, and 2.29 for the oil concentrate. The method was adopted official first action.