Deviceless decoupled electrochemical detection of catecholamines in capillary electrophoresis using gold microband array electrodes

Abstract

Samples containing microM concentrations of dopamine, (+/-)-isoproterenol, para-aminophenol and chlorogenic acid have been separated by capillary electrophoresis (CE) and detected using end-column amperometric detection based on a novel decoupling method. The present decoupling approach involves the use of an electrochemical detector chip containing an array of microband electrodes where the working and reference electrodes are positioned only 10 microm from each other. The short distance between the working and reference electrodes ensures that both electrodes are very similarly affected by the presence of the CE electric field. With this method, no shift in the detection potential was seen when the CE high voltage was applied. This eliminated the need for a reoptimization of the detection potential to compensate for the influence of the separation voltage on the detection. It is also demonstrated that catecholamines can be detected using gold microband electrodes by careful adjustment of the detection potential to avoid the formation of gold oxide. Such careful adjustments of the detection potential are straightforward using the present decoupling method.

Determination of catecholamines by CE with direct chemiluminescence detection

“…Several detection techniques in CE, including LIF [20][21][22], UV [23,24], MS [25], EC [26][27][28], and fluorescence [29], have been developed to determine catecholamines. Although LIF detection has the advantage of high sensitivity, the disadvantages are expensive instrumentation and complicated approach.…”

Simultaneous determination of catecholamines and polyamines in PC-12 cell extracts by micellar electrokinetic capillary chromatography with ultraviolet absorbance detection

“…Due to the unique advantages of CE in bioanalysis, determination of catecholamines in biological samples with CE has been demonstrated by using various detection techniques [48][49][50][51][52][53][54]. Amperometric detection of polyamines [55][56][57] and catecholamines [58][59][60][61][62][63] have been accomplished after HPLC or CE separations. However, the simultaneous detection of both polyamines and catecholamines were not performed due to their different detection conditions, such as buffer types, pH values and applied voltages.…”

Evaluation of fused-core and monolithic versus porous silica-based C18 columns and porous graphitic carbon for ion-pairing liquid chromatography analysis of catecholamines and related compounds

“…Concerning separation techniques for neurotransmitter analysis, liquid chromatography (LC) is widely used but capillary electrophoresis has been also reported [5][6][7]. Different LC systems have been described using UV [8] or fluorescence [9] detection however today, the most widespread technique for the investigation of these molecules in biological samples is ion-pairing chromatography (IPLC) associated with an electrochemical detection (ECD) [10][11][12][13][14].…”