Analysis of glutamine, glutamate, pyroglutamate, and GABA in cerebrospinal fluid using ion pairing HPLC with positive electrospray LC/MS/MS

J Neurosci Methods. 2008 Jun 30;171(2):190-6. doi: 10.1016/j.jneumeth.2008.02.019. Epub 2008 Mar 18.


A simple and sensitive method for the separation and quantitation of glutamine, glutamate, pyroglutamate, and gamma-aminobutyric acid (GABA) in cerebrospinal fluid (CSF) is presented. The method utilizes ion pairing with heptafluorobutyric acid (HFBA) to achieve HPLC separation with detection by positive ESI LC/MS/MS. The method does not require extraction or derivatization, utilizes a heavy labeled internal standard for each analyte, and allows for rapid throughput with a 5 min run time. The method was developed with particular attention taken to prevent conversion between analytes known to occur under certain conditions. The lower limit of quantitation is 7.8 ng/ml for all analytes, and the intra-day and inter-day accuracy (%RE) and precision (%R.S.D.) are defined for all analytes. The method was developed as a sensitive, selective, and robust method to investigate the excitatory and inhibitory neurotransmitters (glutamate and GABA) as biomarkers in drug development.

MeSH terms

  • Animals
  • Chromatography, High Pressure Liquid / methods*
  • Glutamic Acid / cerebrospinal fluid*
  • Glutamine / cerebrospinal fluid*
  • Humans
  • Pyrrolidonecarboxylic Acid / cerebrospinal fluid*
  • Rats
  • Spectrometry, Mass, Electrospray Ionization / methods*
  • gamma-Aminobutyric Acid / cerebrospinal fluid*


  • Glutamine
  • Glutamic Acid
  • gamma-Aminobutyric Acid
  • Pyrrolidonecarboxylic Acid