title: Quantitation of 5-Methyltetrahydrofolate in Cerebrospinal Fluid Using Liquid Chromatography-Electrospray Tandem Mass Spectrometry.
abstract: We describe a simple stable isotope dilution method for accurate and precise measurement of cerebrospinal fluid (CSF) 5-methyltetrahydrofolate (5-MTHF) as a clinical diagnostic test. 5-MTHF is the main biologically active form of folic acid and is involved in regulation of homocysteine and DNA synthesis. Measurement of 5-MTHF in CSF provides diagnostic information regarding diseases affecting folate metabolism within the central nervous system, in particular inborn errors of folate metabolism. Determination of 5-MTHF in CSF (50 μL) was performed utilizing high performance liquid chromatography coupled with electrospray positive ionization tandem mass spectrometry (HPLC-ESI-MS/MS). 5-MTHF in CSF is determined by a 1:2 dilution with internal standard (5-MTHF-(13)C5) and injected directly onto the HPLC-ESI-MS/MS system. Each assay is quantified using a five-point standard curve (25-400 nM) and has an analytical measurement range of 3-1000 nM.
authors.affiliation: Center of Metabolomics, Institute of Metabolic Disease, Baylor Research Institute, 3812 Elm Street, Dallas, TX, 75226, USA. erlanda@baylorhealth.edu.
authors.forename: Erland
authors.initials: E
authors.lastname: Arning
authors.affiliation: Center of Metabolomics, Institute of Metabolic Disease, Baylor Research Institute, 3812 Elm Street, Dallas, TX, 75226, USA.
authors.forename: Teodoro
authors.initials: T
authors.lastname: Bottiglieri
mesh_terms: D053000:Analytic Sample Preparation Methods; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013223:Statistics as Topic; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013763:Tetrahydrofolates / Q000134:cerebrospinal fluid*
chemical_list: D013763:Tetrahydrofolates; C005984:5-methyltetrahydrofolate
keywords: 5-Methyltetrahydrofolate; Cerebral folate deficiency; Mass spectrometry; Methylation