In vivo monitoring of extracellular noradrenaline and glutamate from rat brain cortex with 2-min microdialysis sampling using capillary electrophoresis with laser-induced fluorescence detection

The measurement of neurotransmitters by capillary electrophoresis (CE) has emerged as a reliable and sensitive method for microdialysis sample analysis. This paper describes a method which employs laser-induced fluorescence detection (LIFD) of catecholamines and excitatory amino acid derivatives formed after reaction with naphthalene-2,3 -dicarboxaldehyde. On-line derivatization of very small volumes of microdialysis samples (500 nl) is developed before two off-line analyses (total run time of less than 10 min) are performed to detect derivatives of catecholamines and excitatory amino acids formed in each sample. High microdialysis temporal resolution is reached (2-min fractions) for the simultaneous monitoring of noradrenaline (NA) and glutamate concentrations from rat brain cortex microdialysates. The system performance is evaluated and pharmacological characterization of the determination of NA in cortical dialysates by CE-LIFD is reported.