title: Pesticide analysis at ppt concentration levels: coupling nano-liquid chromatography with dielectric barrier discharge ionization-mass spectrometry.
abstract: We report the coupling of nano-liquid chromatography (nano-LC) with an ambient dielectric barrier discharge ionization (DBDI)-based source. Detection and quantification were carried out by high-resolution mass spectrometry (MS), using an LTQ-Orbitrap in full scan mode. Despite the fact that nano-LC systems are rarely used in food analysis, this coupling was demonstrated to deliver extremely high sensitivity in pesticide analysis, with limits of detection (LODs) as low as 10 pg/mL. In all cases, the limits of quantification (LOQs) were compliant with the current EU regulation. An excellent signal linearity over up to four orders of magnitude was also observed. Therefore, this method can easily compete with conventional GC-(EI)-MS or LC-ESI-MS/MS methods and in some cases outperform them. The method was successfully tested for food sample analysis, with apples and baby food, extracted using the QuEChERS approach. Our results demonstrate an outstanding sensitivity (at femtogram level) and reproducibility of the nano-LC-DBDI coupling, capable of improving routine pesticide analysis. To the best of our knowledge, this is the most sensitive and reproducible plasma-MS-based method for pesticide analysis reported to date.
authors.affiliation: Department of Chemistry and Applied Biosciences, ETH Zurich, HCI E 329 ETH Hönggerberg, 8093, Zurich, Switzerland.
authors.forename: Mario F
authors.initials: MF
authors.lastname: Mirabelli
authors.affiliation: Department of Chemistry and Applied Biosciences, ETH Zurich, HCI E 329 ETH Hönggerberg, 8093, Zurich, Switzerland.|Plasmion UG, 85049, Ingolstadt, Germany.
authors.forename: Jan-Christoph
authors.initials: JC
authors.lastname: Wolf
authors.affiliation: Department of Chemistry and Applied Biosciences, ETH Zurich, HCI E 329 ETH Hönggerberg, 8093, Zurich, Switzerland. zenobi@org.chem.ethz.ch.
authors.forename: Renato
authors.initials: R
authors.lastname: Zenobi
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D057230:Limit of Detection; D036103:Nanotechnology; D010575:Pesticides / Q000032:analysis*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D010575:Pesticides
keywords: Active capillary plasma ionization; Ambient ionization; DBDI; Nano-liquid chromatography; Pesticides; QuEChERS