Characterization of cerebrospinal fluid by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry

Comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC × GC–TOFMS) was applied in the quantification and identification of organic compounds in patient-matched human cerebrospinal fluid (CSF) and serum samples. Concentrations of 21 amino and hydroxyl acids varied from 0.04 to 77 ng/μl in CSF and from 0.1 to 84 ng/μl in serum. In total, 91 metabolites out of over 1200 detected were identified based on mass spectra and retention indices. The other metabolites were identified at the functional group level. The main metabolites detected in CSF were sugar and amino acid derivatives. The CSF and serum had clearly distinct metabolic profiles, with larger biological variation in the serum than in CSF. The GC × GC–TOFMS allowed detection and identification of several metabolites that have not been previously detected in CSF.