title: Rapid analysis of GABA and glutamate in microdialysis samples using high performance liquid chromatography and tandem mass spectrometry.
abstract: A liquid chromatography/tandem mass spectrometry (LC-MS/MS) method has been established for the rapid and reliable determination of gamma-aminobutyric acid (GABA) and glutamate in brain microdialysates. The microdialysis samples were analysed using a HILIC (hydrophilic interaction liquid chromatography) column, which is able to retain the polar amino acid neurotransmitters. The mobile phase consisted of a binary gradient elution profile comprising 0.1% formic acid in water and acetonitrile. GABA, glutamate as well as the respective internal standards [D(6)]-GABA and [D(5)]-glutamate were detected by a triple quadrupole mass spectrometer in the positive electrospray ionisation mode within a running time of 3 min. The linearity ranged from 1 nM to 10 microM for GABA and 10 nM to 10 microM for glutamate. The limit of quantitation was found to be 1 nM for GABA and 10nM for glutamate (injection volume 10 microl). The present LC-MS/MS method was compared to the classical method for analysis of GABA and glutamate using high performance liquid chromatography (HPLC) and fluorescence detection (FD). Eventually, the feasibility of the LC-MS/MS method was demonstrated using in vivo microdialysis in rats by monitoring changes of the extracellular concentrations of GABA and glutamate in the globus pallidus following stimulation with potassium.
authors.affiliation: Department of CNS Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Strasse 65, 88397 Biberach, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Buck
authors.forename: Patrizia
authors.initials: P
authors.lastname: Voehringer
authors.forename: Boris
authors.initials: B
authors.lastname: Ferger
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D018698:Glutamic Acid / Q000032:analysis*; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D017551:Microdialysis / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D005680:gamma-Aminobutyric Acid / Q000032:analysis*
chemical_list: D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid