title: Ultra-high pressure liquid chromatography-mass spectrometry for plant metabolomics: a systematic comparison of high-resolution quadrupole-time-of-flight and single stage Orbitrap mass spectrometers.
abstract: The response of Arabidopsis to stress caused by mechanical wounding was chosen as a model to compare the performances of high resolution quadrupole-time-of-flight (Q-TOF) and single stage Orbitrap (Exactive Plus) mass spectrometers in untargeted metabolomics. Both instruments were coupled to ultra-high pressure liquid chromatography (UHPLC) systems set under identical conditions. The experiment was divided in two steps: the first analyses involved sixteen unwounded plants, half of which were spiked with pure standards that are not present in Arabidopsis. The second analyses compared the metabolomes of mechanically wounded plants to unwounded plants. Data from both systems were extracted using the same feature detection software and submitted to unsupervised and supervised multivariate analysis methods. Both mass spectrometers were compared in terms of number and identity of detected features, capacity to discriminate between samples, repeatability and sensitivity. Although analytical variability was lower for the UHPLC-Q-TOF, generally the results for the two detectors were quite similar, both of them proving to be highly efficient at detecting even subtle differences between plant groups. Overall, sensitivity was found to be comparable, although the Exactive Plus Orbitrap provided slightly lower detection limits for specific compounds. Finally, to evaluate the potential of the two mass spectrometers for the identification of unknown markers, mass and spectral accuracies were calculated on selected identified compounds. While both instruments showed excellent mass accuracy (<2.5ppm for all measured compounds), better spectral accuracy was recorded on the Q-TOF. Taken together, our results demonstrate that comparable performances can be obtained at acquisition frequencies compatible with UHPLC on Q-TOF and Exactive Plus MS, which may thus be equivalently used for plant metabolomics.
authors.affiliation: Chemical Analytical Service of the Swiss Plant Science Web, University of Neuchâtel, Rue Emile-Argand 11, 2009 Neuchâtel, Switzerland. gaetan.glauser@unine.ch
authors.forename: Gaetan
authors.initials: G
authors.lastname: Glauser
authors.forename: Nathalie
authors.initials: N
authors.lastname: Veyrat
authors.forename: Bertrand
authors.initials: B
authors.lastname: Rochat
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Wolfender
authors.forename: Ted C J
authors.initials: TC
authors.lastname: Turlings
mesh_terms: D017360:Arabidopsis / Q000737:chemistry / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation*; D013058:Mass Spectrometry / Q000295:instrumentation*; D055432:Metabolomics / Q000295:instrumentation*; D015999:Multivariate Analysis