Miniaturization of batch- and flow-type chemiluminescence detectors in capillary electrophoresis

Electrogenerated Chemiluminescence Detection of Amino Acids Based on Precolumn Derivatization Coupled with Capillary Electrophoresis Separation

A novel method for highly sensitive detection of primary and secondary amino acids with selective derivatization using acetaldehyde as a new derivatization reagent was proposed by capillary electrophoresis (CE) coupled with electrogenerated chemiluminescence (ECL) of tris(2,2'-bipyridine)ruthenium(II). The precolumn derivatization of these amino acids with acetaldehyde was performed in aqueous solution at room temperature for 1 h. Upon optimized derivatization, the ECL intensities and detection sensitivities of the amino acids were significantly enhanced by 20-70 times. Using four amino acids, arginine, proline, valine, and leucine, as model compounds, their derivatives could be completely separated by CE and sensitively detected by ECL within 22 min. The linear ranges were 0.5-100 microM for arginine and proline and 5-1000 microM for valine and leucine with the detection limits of 1 x 10(-7) (0.5 fmol, arginine), 8 x 10(-8) (0.4 fmol, proline), 1 x 10(-6) (5 fmol, valine), and 1.6 x 10(-6) M (8 fmol, leucine) at a signal-to-noise ratio of 3. The derivatization reactions and ECL process of amino acids were also proposed based on in situ Fourier transform infrared and ultraviolet spectrometric analyses.

Simultaneous operation of plural separation modes in capillary electrophoresis with a chemiluminescence detector possessing a micro-space area for reaction/detection

Analysis of alpha-amino acids, proteins, and phenolic compounds was simultaneously performed using three capillaries in capillary electrophoresis with chemiluminescence detection, taking advantage of the micro-space area for reaction/detection at the tip of the capillary. The three capillaries included usual, polymer-containing, and sodium docley sulfate (SDS)-containing migration buffers for separation. The eluted samples from the capillaries, which were inserted into the chemiluminescence detection cell, were mixed with chemiluminescence reagent at the tips of the capillaries to generate visible light. The specific micro-space area for reaction/detection at the tips of the capillaries enabled the simultaneous operation of the three separation modes in the present system.

Derivatization of biomolecules for chemiluminescent detection in capillary electrophoresis

An overview is presented on the power and drawbacks of the relatively unfamiliar chemiluminescence-based detection technique applied in analysis by capillary electrophoresis, for determining chemically derivatized biomolecules. Examples of the most common systems are given for many series of biologically active compounds as well as for some pharmaceuticals. The most common chemiluminescent systems include the application of peroxyoxalate ester chemiluminescence, acridinium esters, luminol and derivatives, detection based on the tris(2,2'-bipyridine)ruthenium(III) system, the huge potentials offered by direct oxidations-though often with still unelucidated reaction mechanisms-and the powerful area of bioluminescence techniques, revealing as well the fast developing area of microchip-based analysis employing this specific luminescence principle.

Separation of biogenic amines by micellar electrokinetic chromatography with on-line chemiluminescence detection

A method of on-line chemiluminescence detection with capillary electrophoresis for biogenic amines (diaminopropane, putrescine, cadaverine and diaminohexane) labeled with N-(4-aminobutyl)-N-ethylisoluminol is reported for the first time. Two separation modes, capillary zone electrophoresis and micellar electrokinetic chromatography (MEKC), were studied. The results show that excellent resolution was achieved in MEKC. Parameters affecting separation process and chemiluminescence detection have been examined in detail. Under the optimum conditions, the baseline separation of four amines was obtained within 7.5 min. The detection limits (S/N=3) of diaminopropane, putrescine, cadaverine and diaminohexane are 3.5 x 10(-8), 3.5 x 10(-8), 3.9 x 10(-8) and 1.2 x 10(-7) M, respectively. The method was applied to the analysis of biogenic amines in lake water.

Microfabricated On-Chip-Type Electrochemical Flow Immunoassay System for the Detection of Histamine Released in Whole Blood Samples

This paper describes an on-chip-type electrochemical flow immunoassay system with a multichanneled matrix column. The multichanneled matrix column was functionally coated with cation-exchange resin and used for separation of proteins. Antihistamine immunoglobulin G (IgG) antibody conjugated with ferrocenemonocarboxylic acid (Fc) was also prepared and used as a novel analytical reagent. Antibody-antigen complexes were separated from free Fc-conjugated IgG antibody (Fc-IgG) on the basis of differences in isoelectric point (pI) using the multichanneled matrix column coated with cation-exchange resin. The assay yields a good relationship between current and histamine concentration in the range of 200-2000 ng/mL. This simple technique enables the assay of histamine released in whole blood within 2 min. Furthermore, a good correlation was found between the response of the electrochemical immunoassay described in this paper and the conventional RIA (radioimmunoassay). This on-chip-type electrochemical flow immunoassay requires only minute quantities of whole blood samples and generates highly reproducible results.

Simultaneous Analysis of Plural Samples in a CE-CL Detector Possessing Micro-Space Area for Reaction/Detection

Plural samples were simultaneously analyzed in a capillary electrophoresis (CE)-chemiluminescence (CL) detector system, taking advantage of a micro-space area for reaction/detection at the tip of the capillary. The CL reaction of 1,10-phenanthroline and hydrogen peroxide was adopted and a Cu(II) sample was used as a model. Three different length capillaries were inserted into a flow-type CL detection cell made of a Teflon tube. Three samples migrated in the corresponding capillaries at the same time and mixed with the CL reagent at the tip of capillary to produce CL. The simultaneous analysis of plural samples in the present system supported the possibility that a real sample could be determined more easily, rapidly, and precisely with the calibration curve.