Post-acquisition spectral stitching. An alternative approach for data processing in untargeted metabolomics by UHPLC-ESI(-)-HRMS.
BACKGROUND
In the case of the MS-based metabolomics, the large number of false positives remains a fundamental issue.


OBJECTIVE
The aim of this study was to develop a new strategy, which highlights the number of the reliable features i.e. the detected features that correspond to a consistent peak according to chromatographic and mass spectrometric criteria.


METHODS
For the analysis blood samples from 20 chickens, which were administrated with naringin and 9 samples from control, were analyzed by UHPLC-HRMS (Orbitrap Velos). Two methodologies have been compared for data processing. In the first one (classical approach), all data in the 100-900 m/z mass-to charge range were included for the data processing procedure whereas for the newly developed methodology, the data were shred in 100Da slices generating 8 datasets, which have been then subjected to the downstream MS data processing. Each dataset was treated separately and the m/z_tRfeatures obtained by either VIP's or t-test values were merged and used as the input for the construction of the general model.


RESULTS
The new methodology resulted to a 4-fold increase of the peaks that could be considered chromatographically and mass spectrometrically valid.


CONCLUSIONS
A new strategy was reported on the detection of chromatographically reliable features during a metabolomic approach. The shredding of the LC-MS chromatograms into multiple m/z ranges increased the number of the identified chromatographically reliable features.
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, 15771, Athens, Greece.
Eirini
E
Baira
Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou, 11635 Athens, Greece.
Eleni
E
Siapi
Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou, 11635 Athens, Greece.
Panagiotis
P
Zoumpoulakis
Department of Animal Breeding and Husbandry, Faculty of Animal Science and Aquaculture, Agricultural University of Athens, 75 Iera Odos, 11855, Athens, Greece.
Deligeorgis
D
Stelios G
Department of Pharmacognosy and Natural Products Chemistry, Faculty of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, 15771, Athens, Greece.
Alexios-Leandros
AL
Skaltsounis
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, 15771, Athens, Greece. Electronic address: vgikas@pharm.uoa.gr.
Evagelos
E
Gikas
D000821:Animal Feed / Q000032:analysis; D000818:Animals; D002645:Chickens / Q000097:blood / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D044950:Flavanones / Q000008:administration & dosage / Q000378:metabolism*; D055432:Metabolomics / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
D044950:Flavanones; C005274:naringin
MZmine; PCA; PLS-DA; Permutation test; VIPs; t-test