Retention dependences support highly confident identification of lipid species in human plasma by reversed-phase UHPLC/MS

Anal Bioanal Chem. 2021 Jul 9. doi: 10.1007/s00216-021-03492-4. Online ahead of print.ABSTRACTReversed-phase ultrahigh-performance liquid chromatography-mass spectrometry (RP-UHPLC/MS) method was developed with the aim to unambiguously identify a large number of lipid species from multiple lipid classes in human plasma. The optimized RP-UHPLC/MS method employed the C18 column with sub-2-μm particles with the total run time of 25 min. The chromatographic resolution was investigated with 42 standards from 18 lipid classes. The UHPLC system was coupled to high-resolution quadrupole-time-of-flight (QTOF) mass analyzer using electrospray ionization (ESI) measuring full-scan and tandem mass spectra (MS/MS) in positive- and negative-ion modes with high mass accuracy. Our identification approach was based on m/z values measured with mass accuracy within 5 ppm tolerance in the full-scan mode, characteristic fragment ions in MS/MS, and regularity in chromatographic retention dependences for individual lipid species, which provides the highest level of confidence for reported identifications of lipid species including regioisomeric and other isobaric forms. The graphs of dependences of retention times on the carbon number or on the number of double bond(s) in fatty acyl chains were constructed to support the identification of lipid species in homologous lipid series. Our list of identified lipid species is also compared with previous publications investigating human blood samples by va...

Source: Analytical and Bioanalytical Chemistry - July 10, 2021 Category: Chemistry Authors: Zuzana Va ňková Ond řej Peterka Michaela Chocholou šková Denise Wolrab Robert Jir ásko Michal Hol čapek Source Type: research