Analysis of serotonin in brain microdialysates using capillary electrophoresis and native laser-induced fluorescence detection

Abstract

Serotonin or 5-hydroxytryptamine (5-HT) is a major neurotransmitter in the central nervous system. In this work, a method for analyzing 5-HT in brain microdialysis samples using a commercially available capillary electrophoresis (CE) system has been developed. A pH-mediated in-capillary preconcentration of samples was performed, and after separation by capillary zone electrophoresis, native fluorescence of 5-HT was detected by a 266 nm solid-state laser. The separation conditions for the analysis of 5-HT in standard solutions and microdialysates have been optimized, and this method has been validated on both pharmacological and analytical bases. Separation of 5-HT was performed using a 80 mmol/L citrate buffer, pH 2.5, containing 20 mmol/L hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and +30 kV voltage. The detection limit was 2.5 x 10(-10) mol/L. This method allows the in vivo brain monitoring of 5-HT using a simple, accurate CE measurement in underivatized microdialysis samples.

An ellipsoidal mirror for detection of laser‐induced fluorescence in capillary electrophoresis system: Applications for labelled antibody analysis

“…The use of a 'ball lens' is very useful because it allows the use of a very stable excitation beam and the collection is better than without a ball lens using a simple microscope [2]. In addition, this setup can be easily used with UV lasers [3,4]. In a previous review article, a number of different 'homemade' LIF detectors were described in detail [5].…”

Analytical Considerations for Microdialysis Sampling

“…Off -line analysis using CE -LIF has been performed for the detection of amino acids [120] , neurotransmitters [121] , and neuropeptides [16,17] . The Philips lab has employed microdialysis with off -line CE for the analysis of cytokines and chemokines from cultured astrocytes.…”

A new evaluation technique for the detection of impurities in purified proteins via CE with native UV‐LIF

“…These compounds can be excited in the visible range and have high fluorescence yield to obtain very good sensitivity (in the range 100 to 10 pM). In the same vein, the native fluorescence of catecholamines was monitored by a UV laser to obtain nM concentration LODs [13,14]. While most proteins are not fluorescent in the visible spectrum, the native fluorescence of tryptophan (Trp), tyrosine (Tyr) and phenylalanine (Phe) allow for UV detection of proteins.…”