Capillary electrophoresis of neurotransmitters with amperometric detection at melanin-type polymer-modified carbon electrodes

Abstract This paper reports on the advantages of combining the separation capability of capillary electrophoresis using a novel home-made electrochemical cell adapted to commercially available capillary electrophoresis equipment with the permselective properties of melanin-type polymer-modified carbon electrodes as amperometric detectors. The excellent permselective properties of the melanic polymer have allowed a large improvement on the quantification of dopamine, epinephrine and norepinephrine. A linear response was obtained in the range 8–200 pg of dopamine with sensitivities between 3- and 5-times higher than those at the bare carbon electrodes and detection limits at submicromolar level (41 fmol in the volume injected). The effect of the carbon electrodes size, and capillary electrophoresis parameters on the analytical performance is also discussed.

[1]  D. B. Hibbert,et al.  Electrodeposited polytyramine as an immobilisation matrix for enzyme biosensors. , 1998, Biosensors & bioelectronics.

[2]  M. Smyth,et al.  Capillary electrophoresis with electrochemical detection employing an on-column Nafion joint , 1992 .

[3]  S. Lunte,et al.  Membrane-Based On-Column Mixer for Capillary Electrophoresis/Electrochemistry , 1995 .

[4]  P. D. Voegel,et al.  Integrated Capillary Electrophoresis/Electrochemical Detection with Metal Film Electrodes Directly Deposited onto the Capillary Tip. , 1997, Analytical chemistry.

[5]  M. Chicharro,et al.  Multiresidue Analysis of Pesticides in Environmental Waters by Capillary Electrophoresis Using Simultaneous UV and Electrochemical Detection , 2004 .

[6]  D. M. Morgan,et al.  Theoretical and practical limitations on the optimization of amperometric detectors. , 1984, Analytical chemistry.

[7]  Andrew G. Ewing,et al.  Improved method for end-column amperometric detection for capillary electrophoresis , 1993 .

[8]  G. Rivas,et al.  Highly selective dopamine quantification using a glassy carbon electrode modified with a melanin-type polymer , 2001 .

[9]  P. D. Voegel,et al.  Electrochemical detection in capillary electrophoresis , 1997, Electrophoresis.

[10]  S. Lunte,et al.  Chemically modified microelectrodes for capillary electrophoresis/electrochemistry , 1994 .

[11]  R. Baldwin,et al.  Amperometric detection in capillary electrophoresis with normal size electrodes , 1993 .

[12]  G. Rivas,et al.  Dopamine and Glucose Sensors Based on Glassy Carbon Electrodes Modified with Melanic Polymers , 2004 .

[13]  S. Cosnier.  Biomolecule immobilization on electrode surfaces by entrapment or attachment to electrochemically polymerized films. A review. , 1999, Biosensors & bioelectronics.

[14]  James P. Landers,et al.  Handbook of Capillary Electrophoresis , 1993 .

[15]  M. Chicharro,et al.  Simultaneous UV and electrochemical determination of the herbicide asulam in tap water samples by micellar electrokinetic capillary chromatography , 2002 .

[16]  Xinjian Huang,et al.  Determination of thiols by capillary electrophoresis with electrochemical detection using a palladium field-decoupler and chemically modified electrodes , 1995 .

[17]  Swee Ngin Tan,et al.  Amperometric detection for capillary electrophoresis at a sol–gel carbon composite electrode , 2000 .

[18]  S. Lunte,et al.  Capillary electrophoresis with pulsed amperometric detection of carbohydrates and glycopeptides , 1996, Electrophoresis.

[19]  Frank-Michael Matysik,et al.  End‐Column Electrochemical Detection for Capillary Electrophoresis , 2000 .

[20]  Linan Song,et al.  Simultaneous determination of sugars and organic acids by co-electroosmotic capillary electrophoresis with amperometric detection at a disk-shaped copper electrode , 1998 .

[21]  Hsuan‐Jung Huang,et al.  Application of a nickel-microelectrode-incorporated end-column detector for capillary electrophoretic determination of alditols and alcohols , 1997 .

[22]  Christine Kranz,et al.  Controlled Electrochemical Preparation of Amperometric Biosensors Based on Conducting Polymer Multilayers , 1998 .

[23]  S. Lunte,et al.  Pharmaceutical and biomedical applications of capillary electrophoresis/electrochemistry , 1994, Electrophoresis.