Evaluation of Matrix Effects in Metabolite Profiling Based on Capillary Liquid Chromatography Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry

The coupling of liquid chromatography to electrospray
ionization quadrupole time-of-flight mass spectrometry
can be a powerful tool for metabolomics, i.e., the comprehensive detection of low molecular weight compounds
in biological systems. There have, however, been doubts
about the feasibility and reliability of this approach,
because LC−MSespecially with electrospray ionizationcan be subject to matrix effects. We evaluated matrix
effects for our metabolomics platform in three ways:  (i)
postextraction addition of a set of reference compounds
to different complex biological matrixes to determine
absolute and relative matrix effects, (ii) postcolumn infusion of two reference compounds, and (iii) mixing of two
complex matrixes. Our data demonstrate that there are
indeed significant absolute matrix effects when comparing
highly divergent samples. However, relative matrix effects
are negligibleunless extremely divergent matrixes are
comparedand do not compromise the relative quantification that is aimed for in nontargeted metabolomics
studies. In conclusion, employing LC-coupled ESI-QTOF-MS for metabolomics studies is feasible yet rigorous
validation is necessary.