Electron ionization gas chromatography-mass spectrometric determination of residues of thirteen pyrethroid insecticides in whole blood

A new rapid and sensitive electron ionization gas chromatography-mass spectrometry method in selective ion monitoring mode (SIM) was developed for the determination of l3 synthetic pyrethroid insecticide molecules and their stereo isomers in whole blood. The pyrethroid insecticides investigated are allethrin, bifenthrin, cypermethrin, cyphonothrin, cyfluthrin, lambda-cyhalothrin, deltamethrin, fenvalerate, fenpropathrin, imiprothrin, permethrin, prallethrin and transfluthrin. The residues of pyrethroids are extracted from the whole blood using hexane and acetone mixture (80 + 20%) as solvent. All the pyrethroid residues were separated by using a gas chromatography-mass spectrometry operated in electron ionization mode and quantified in selective ion monitoring mode. The method can detect the residues of different pyrethroids down to the level 0.05-2 ng/ml. Recovery experiments conducted in whole blood samples at the fortification level 1-1000 ng/ml showed 91-103% recovery. The applications of the analytical method for the determination of pyrethroid residues in real samples were tested by analyzing 45 human blood samples collected from the population exposed continuously to different pyrethroid based formulations. The results are confirmed by spiking the known quantity of pyrethroids and subsequently their positive detection.