Determination Of Pyrethrins In Pyrethrum Oil Extracts By UHPLC-UV-CAD

Pyrethrins are terpenoid esters derived from the flowers of Chrysanthemum cinerariifolium. The pyrethrin family includes six similar compounds containing a cyclopropane core, named pyrethrin 1 and 2, cinerin 1 and 2 and jasmolin 1 and 2. Pyrethrins both repel and kill insects by delaying the closure of voltage-gated sodium ion channels in the nerve cells. The insecticidal and insect repellent properties of these compounds have been known for millennia and Chrysanthemum species have long been cultivated for this purpose. Interest in using pyrethrin insecticides is growing because of their low toxicity to humans (allowing home use) and favorable, fast biodegradability. On the negative side, pyrethrum oil can trigger allergic reactions in susceptible people. It is also toxic to bees with fatal doses as low as 0.02 micrograms, thus requiring very cautious application. With their increasing use in agricultural and consumer products, there is a need for improved analytical techniques both to assure product quality and to monitor the fate of pyrethrins in the environment. Current reversed phase HPLC methods using UV detection fail to fully resolve the closely eluting components without excessively long run times. In this work, we show that a new UHPLC system comprising a binary parallel pump capable of operating at pressures up to 1500 bar, a high sensitivity diode-array detector with new light-pipe technology and an integrated charged aerosol detector, enables the resolution and detection of more compounds in pyrethrum oil in less time than previously possible.