Reassessment of the antioxidative mixture for the challenging electrochemical determination of dopamine, noradrenaline and serotonin in microdialysis samples.
In recent years, the simultaneous monitoring of the monoamine neurotransmitters dopamine, noradrenaline and serotonin in vivo is advancing due to innovations in miniaturized and fast chromatographic techniques. However, the determination of the most hydrophilic compound, noradrenaline, in microdialysis samples by (ultra-)high performance liquid chromatography ((U)HPLC) with electrochemical detection (ECD) is impeded by a broad solvent front, caused by the addition of antioxidative agents. Hence, an elaborate reassessment of currently used antioxidative mixtures is necessary for further analytical improvements. The proposed mixture, containing 100mM acetic acid, 0.27mM Na2EDTA and 12.5μM ascorbic acid (pH 3.2), is less complex than previously described mixtures and shows minimal ECD interference. It stabilizes the three monoamines in standard solutions and in microdialysis samples, considering both autosampler stability at 4°C for 48h and long term stability at -20°C for a duration of six months. An in vivo microdialysis experiment demonstrates the possibility to monitor changes in extracellular levels of the three monoamines simultaneously in the rat hippocampus with UHPLC-ECD using the optimized antioxidative mixture.
['Van Schoors|Jolien|J|', 'Lens|Charlotte|C|', 'Maes|Katrien|K|', 'Michotte|Yvette|Y|', 'Smolders|Ilse|I|', 'Van Eeckhaut|Ann|A|']
D000818:Animals D000975:Antioxidants D002851:Chromatography, High Pressure Liquid D004298:Dopamine D004355:Drug Stability D006624:Hippocampus D008297:Male D017551:Microdialysis D018377:Neurotransmitter Agents D009638:Norepinephrine D051381:Rats D017208:Rats, Wistar D012701:Serotonin
Monoamine neurotransmitters Electrochemical detection Stability In vivo microdialysis UHPLC