Application of liquid chromatography with electrospray tandem mass spectrometry to the determination of a new generation of pesticides in processed fruits and vegetables.
This paper describes a method for the sensitive and selective determination of 24 new pesticide residues (azoxystrobin, trifloxystrobin, kresoxim-methyl, fenazaquin, indoxacarb, fenothiocarb, furathiocarb, benfuracarb, imidachloprid, dimethomorph, fenpyroximate, hexythiazox, tebufenpyrad, tebufenozide, difeconazole, fenbuconazole, flusilazole, paclobutrazol, tebuconazole, tetraconazole, bromuconazole, etofenprox, fenhexamid, pyridaben) in apple puree, concentrated lemon juice and tomato puree. A miniaturized extraction-partition procedure requiring small amounts of non-chlorinated solvents was used. The extracts are analyzed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS-MS) without any further clean-up step. The pesticides are separated on a reversed-phase polar column using a gradient elution. Fifty-five simultaneous MS-MS transitions of precursor ions were monitored (two or three for each pesticide). Studies at fortification levels of 0.001-0.020 and 0.010-0.200 mg/kg gave mean recoveries ranging from 76 to 106% for all compounds, except for imidacloprid, with (R.S.D.s) < or = 15%. The excellent sensitivity and selectivity of LC-MS-MS method allowed quantitation and identification at low levels also in difficult matrices with a run time of 20 min. With the developed method almost 100 samples of commercial fruit products (nectars, juices, purees) were analyzed. None of samples contained residues higher than 0.010 mg/kg.
Sannino
Anna
A
Stazione Sperimentale per l'Industria delle Conserve Alimentari, Viale F Tanara 31/A, 43100 Parma, Italy. lra.ssica@libero.it
Bolzoni
Luciana
L
Bandini
Mirella
M
D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005638:Fruit / Q000737:chemistry*; D010575:Pesticides / Q000032:analysis*; D012015:Reference Standards; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014675:Vegetables / Q000737:chemistry*
D010575:Pesticides