Large-Scale Interlaboratory DI-FT-ICR MS Comparability Study Employing Various Systems

Ultrahigh resolution mass spectrometry (UHR-MS) coupled
with direct
infusion (DI) electrospray ionization offers a fast solution for accurate
untargeted profiling. Fourier transform ion cyclotron resonance (FT-ICR)
mass spectrometers have been shown to produce a wealth of insights
into complex chemical systems because they enable unambiguous molecular
formula assignment even if the vast majority of signals is of unknown
identity. Interlaboratory comparisons are required to apply this type
of instrumentation in quality control (for food industry or pharmaceuticals),
large-scale environmental studies, or clinical diagnostics. Extended
comparisons employing different FT-ICR MS instruments with qualitative
direct infusion analysis are scarce since the majority of detected
compounds cannot be quantified. The extent to which observations can
be reproduced by different laboratories remains unknown. We set up
a preliminary study which encompassed a set of 17 laboratories around
the globe, diverse in instrumental characteristics and applications,
to analyze the same sets of extracts from commercially available standard
human blood plasma and Standard Reference Material (SRM) for blood
plasma (SRM1950), which were delivered at different dilutions or spiked
with different concentrations of pesticides. The aim of this study
was to assess the extent to which the outputs of differently tuned
FT-ICR mass spectrometers, with different technical specifications,
are comparable for setting the frames of a future DI-FT-ICR MS ring
trial. We concluded that a cluster of five laboratories, with diverse
instrumental characteristics, showed comparable and representative
performance across all experiments, setting a reference to be used
in a future ring trial on blood plasma.