Analysis of pesticide residues by leaf spray mass spectrometry

Leaf spray, a rapid and simple ambient ionization method for mass spectrometry is shown to allow identification of a number of typical pesticides (acetamiprid, diphenylamine, imazalil, linuron, thiabendazole) directly in the peel and pulp of a variety of different fruits and vegetables (apple, pear, lemon, orange, carrot, cucumber, eggplant, potato). These identifications were confirmed by tandem mass spectrometry. Attempts were made to quantify the amount of pesticide using MS/MS data from calibration curves created with external standards. Calibration samples were made using samples created by adding pesticide standards to organic fruit or vegetable. Typical experiments take approximately 100 seconds to perform; limits of detection are within the levels specified for residue analysis by the EU. Linear dynamic ranges of three orders of magnitude and precisions of better than 15% are obtained.