Determination of glycine, gaba, glutamate and serine FROM microdialysis samples using liquid chromatography with coulometric detector

Amino acids are the most abundant neurotransmitters in the brain. Therefore, the measurement of Amino acids concentrations in the brain extracellular is of importance in the field of neuroscience. Epilepsy occurs whenever an increase in the level of excitatory amino acids or a decrease in the level of inhibitory acids. In this study, the reverse-phase high-performance liquid chromatography-electrochemical detection method has been developed for the determination of amino acids in microdialysis samples of brain tissues, utilized derivatization with front column o- ftalaldehit and electrochemical detection. The chromatographic separation was performed on, a silica Agilent Zorbax Eclipse C18 (3.0mm x 150 mm, 5 µm particle size) column, using phosphate buffer (50 mM, pH: 6,5) was determined as a working buffer. The method was conducted in a gradient mode with a flow rate of 0.8 ml/min,10 µL injection volume, and 40°C. The values of the detection limit and quantity limitations were calculated as follows 0.02 µg/mL, 0.06 µg/mL for Glutamic Acid, 0.05µg/mL, 0.02µg/mL for Glisine, 0.3µg/mL, 1.01µg/mLfor Gamma_aminobutiric acid, 0.13 µg/mL, 0.4 µg/mL for Serine.The linearity range of the method was 0.05-2 μg/mL.