Determination of in vivo amino acid neurotransmitters by high-performance liquid chromatography with o-phthalaldehyde-sulphite derivatisation

• Published in: Journal of neuroscience methods 1995-03, Vol.57 (1), p.93-99
• Main Authors: Rowley, Helen L., Martin, Keith F., Marsden, Charles A.
• Format: Article
• Language: English
• Subjects: Amino acid neurotransmitter; Animals; Chromatography, High Pressure Liquid; Electrochemical detection; Electrochemistry; Extracellular Space - chemistry; gamma-Aminobutyric Acid - analysis; Glutamic Acid - analysis; High-performance liquid chromatography; Hippocampus - chemistry; Male; Microdialysis; Neurotransmitter Agents - analysis; Neurotransmitter Agents - cerebrospinal fluid; o-Phthalaldehyde; o-Phthalaldehyde-sulphite derivatisation; Rats; Sulfites
• ISSN: 0165-0270; 1872-678X
• DOI: 10.1016/0165-0270(94)00132-Z

The measurement of amino acid neurotransmitters by high-performance liquid chromatography (HPLC) has emerged as a reliable and sensitive method. This paper describes a method which employs electrochemical (EC) detection of amino acid derivatives formed by a reaction with o-phthalaldehyde (OPA) in the presence of sulphite ions. This is discussed in relation to the problems of previously reported methods based on OPA derivatisation. Precise separation of the following 7 amino acid standards is achieved using isocratic elution: serine, glycine, taurine, glutamate, arginine, alanine and GABA, in order of increasing retention time. Total elution time is 25 min. Derivatisation proceeds at room temperature and the derivatives are stable for up to 5 h. This technique has the sensitivity to determine the concentrations of amino acid neurotransmitters in cerebrospinal fluid (CSF) and an in vivo microdialysis method is discussed for the detection of basal and potassium-stimulated levels of γ-aminobutyric acid and glutamate from rat hippocampus.