Isocratic HPLC assay with electrochemical detection of free gamma-aminobutyric acid in cerebrospinal fluid
Naini, A.B.; Vontzalidou, E.; Côté, L.J.
Clinical Chemistry 39(2): 247-250
1993
ISSN/ISBN: 0009-9147 PMID: 8432013 Document Number: 406281
A method for measuring gamma-aminobutyric acid (GABA) in human cerebrospinal fluid (CSF) by isocratic HPLC with electrochemical detection is described. The method is based on precolumn derivatization of GABA with o-phthaldialdehyde (OPA) and tert-butylthiol (t-BT), separation of the GABA-OPA complex on a reversed-phase column, and quantitation by means of a Coulochem electrochemical detector. The method is highly sensitive and specific for GABA. In three samples of human CSF containing low, medium, and high amounts of GABA, the coefficients of variation between and within runs were 4.5% and 3.6%, respectively. The concentration of GABA in 10 neurologically intact subjects was 92.5 +/- 9.4 nmol/L of CSF.