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

2008; Elsevier BV; Volume: 171; Issue: 2 Linguagem: Inglês

10.1016/j.jneumeth.2008.02.019

1872-678X

James A. Eckstein, Gina M. Ammerman, Jessica M. Reveles, Bradley L. Ackermann,

Molecular Sensors and Ion Detection

A simple and sensitive method for the separation and quantitation of glutamine, glutamate, pyroglutamate, and γ-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.