Analysis of pyrethrins using capillary supercritical fluid chromatography and capillary gas chromatography with fourier transform infrared detection

The six insecticidally active components in a commercial preparation of pyrethrin extract are separated by capillary gas chromatography (GC) and by capillary supercritical fluid chromatography (SFC). Thermal degradation of pyrethrin I and II are observed under the GC conditions required to separate the pyrethrin components. The use of shorter columns and thinner stationary phase coatings reduce the amount of degradation but cannot eliminate degradation of pyrethrin II. The SFC chromatograms, obtained under thermally mild conditions, show that all components including pyrethrin II elute without degradation. Infrared spectra of cinerin I & II, jasmolin I & II, and pyrethrin I & II are obtained using a flow through SFC/IR detection cell. Spectra clearly reveal the structural differences needed to distinguish and identify the components in the extract.