The sample (5 μL) was used for molecular mass determination using an ESI Q-TOF mass spectrometer (Micromass, Manchester, England).
The sample (5 μL) was used for molecular mass determination using JOEL MALDI-TOF.
The sample (5 μL) was used for molecular mass determination using an MALDI-TOF mass spectrometer (JMS-S3000, Japan).
Fairview Diagnostic Laboratories (Minneapolis, MN) performed the serum 25(OH D determinations using liquid chromatography/tandem mass spectrometry (LC-MS/MS) methods.
We performed the final analytic determinations using gas chromatography isotope dilution high-resolution mass spectrometry employing an MAT95XP instrument (ThermoFinnigan MAT, Bremen, Germany).
The method is based on headspace solid-phase microextraction (SPME) followed by gas chromatography coupled to tandem mass spectrometry (GC MS/MS) determination using triple quadrupole analyzer (QqQ) in electron ionization mode.
Accurate mass determinations were performed using a LC/FTMS system consisting of an Exactive Orbitrap mass spectrometer, equipped with a heated ESI II source (ThermoFisher Scientific, Inc., Bremen, Germany) and operated in ultra high resolution mode (100.000) coupled to a U-HPLC system (Accela, ThermoFisher Scientific, Inc., Bremen, Germany).
Applications of the enumeration of chemical structures include structure determination using mass-spectrum and/or NMR-spectrum [4, 5], virtual exploration of the chemical universe [6, 7], reconstruction of molecular structures from their signatures [8, 9], and classification of chemical compounds [10].
MS/MS is a worthy tool for further structural characterization because of the occurrence of characteristic fragment ions, either MS n analysis for studying the fragmentation patterns using trap-based analyzers or high mass accuracy measurements for elemental composition determination using time of flight based or Fourier transform mass analyzers.
