title: Determination of selected non-authorized insecticides in peppers by liquid chromatography time-of-flight mass spectrometry and tandem mass spectrometry.
abstract: In this work, two analytical methods based on liquid chromatography coupled to electrospray time-of-flight mass spectrometry (LC/ESI-TOFMS) and tandem mass spectrometry (LC/ESI-MS/MS) are described for the identification, confirmation and quantitation of three insecticides non-authorized in the European Union (nitenpyram, isocarbophos and isofenphos-methyl) but detected in recent monitoring programmes in pepper samples. The proposed methodologies involved a sample extraction procedure using liquid-liquid partition with acetonitrile followed by a cleanup step based on dispersive solid-phase extraction. Recovery studies performed on peppers spiked at different fortification levels (10 and 50 microg kg(-1)) yielded average recoveries in the range 76-100% with relative standard deviation (RSD) (%) values below 10%. Identification, confirmation and quantitation were carried out by LC/TOFMS and LC/MS/MS using a hybrid triple quadrupole linear ion trap (QqLIT) instrument in multiple-reaction monitoring (MRM) mode. The obtained limits of quantitation (LOQs) were in the range 0.1-5 microg kg(-1), depending on each individual technique. Finally, the proposed methods were successfully applied to the analysis of suspected pepper samples.
authors.affiliation: Pesticide Residue Research Group, Department of Hydrogeology and Analytical Chemistry, University of Almería, 04120 La Cañada de San Urbano, Almería, Spain.
authors.forename: Milagros
authors.initials: M
authors.lastname: Mezcua
authors.forename: Carmen
authors.initials: C
authors.lastname: Ferrer
authors.forename: Juan F
authors.initials: JF
authors.lastname: García-Reyes
authors.forename: María Jesús
authors.initials: MJ
authors.lastname: Martínez-Bueno
authors.forename: Micaela
authors.initials: M
authors.lastname: Albarracín
authors.forename: María
authors.initials: M
authors.lastname: Claret
authors.forename: Amadeo R
authors.initials: AR
authors.lastname: Fernández-Alba
mesh_terms: D002138:Calibration; D002853:Chromatography, Liquid; D007202:Indicators and Reagents; D007306:Insecticides / Q000032:analysis*; D008294:Malathion / Q000032:analysis; D000073943:Neonicotinoids; D009946:Organothiophosphorus Compounds / Q000032:analysis; D029222:Piper nigrum / Q000737:chemistry*; D011725:Pyridines / Q000032:analysis; D013030:Spain; D053719:Tandem Mass Spectrometry
chemical_list: D007202:Indicators and Reagents; D007306:Insecticides; D000073943:Neonicotinoids; D009946:Organothiophosphorus Compounds; D011725:Pyridines; C056490:methyl isofenphos; C464843:nitenpyram; D008294:Malathion