title: Comparative study of low- versus high-resolution liquid chromatography-mass spectrometric strategies for measuring perfluorinated contaminants in fish.
abstract: Perfluorinated compounds (PFCs) are usually monitored by high-performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) on triple quadrupole instruments. Although not yet widely implemented in the field, high-resolution mass spectrometry (HRMS) today appears as a valuable alternative for these halogenated chemicals due to their significant mass defect. Indeed, this second approach offers a way to cope with particular matrix effects caused by co-eluting and isobaric interferences affecting the measurement of some PFCs in fish. The present study compares three different LC-MS-related instruments and various signal acquisition modes, from low-resolution full-scan and selected ion-monitoring (SIM) mode on a triple quadrupole (QqQ) instrument to high-resolution full-scan or product ion-scan mode on orbital trap (LTQ-Orbitrap) or quadrupole-time-of-flight (Q-TOF) devices. Performances are compared for seven model compounds belonging to seven PFCs subclasses: perfluoralkylsulfonate, perfluoroalkylcarboxylate, perfluoroalkylsulfinate, perfluoroalkyl-sulfonamide, fluorotelomer saturated acid, fluorotelomer unsaturated acid and perfluoroalkylphosphonic acid. Low-resolution MS/MS was found to be unsurprisingly reliable for extended multi-residue monitoring. However, the high stability of PFCs leads to a relatively poor and non-specific fragmentation pathway in MS/MS. In addition, biliary acid-interfering compounds (e.g. taurochenodeoxycholic acid), which where encountered in the present case in fish samples but that may be present in other biological samples, were found particularly disturbing in low-resolution MS/MS. Indeed, these interferences presented the same retention time and diagnostic signals as PFOS, leading to a possible overestimation of the PFOS quantification in LC-MS/MS. On the other hand, high-resolution MS and MS/MS (LTQ-Orbitrap and Q-TOF) provided better results in terms of signal specificity and sensitivity. For instance, the estimated limits of detection (LOD) reached for PFOS on QqQ, Q-TOF and LTQ-Orbitrap instruments were 3.8, 0.7 and 0.5 pg injected, respectively.
authors.affiliation: ONIRIS, USC 2013 LABERCA, Atlanpole - La Chantrerie, BP 50707, Nantes F-44307, France.
authors.forename: H
authors.initials: H
authors.lastname: Kadar
authors.forename: B
authors.initials: B
authors.lastname: Veyrand
authors.forename: J-P
authors.initials: JP
authors.lastname: Antignac
authors.forename: S
authors.initials: S
authors.lastname: Durand
authors.forename: F
authors.initials: F
authors.lastname: Monteau
authors.forename: B
authors.initials: B
authors.lastname: Le Bizec
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D005399:Fishes; D005506:Food Contamination; D006845:Hydrocarbons, Fluorinated / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods*; D015394:Molecular Structure
chemical_list: D006845:Hydrocarbons, Fluorinated