Biomedical subjects

Jianzhen Kang

Publications and source records attributed to Jianzhen Kang.

4 recordsLinked to original sources

PubMed2006

CE coupling with end-column electrochemiluminescence detection for chiral separation of disopyramide.

CE with electrochemiluminescence (ECL) detection technique was successfully applied for the chiral separation of a kind of class IA antiarrhythmic racemic drug. To the best of our knowledge, this is the first report of ECL detection used in chiral CE. To get better detection sensitivity and good enantioresolution at the same time, the conditions of capillary inlet and outlet buffer were systematically optimized. Unlike the traditional chiral separation method, the buffers we used in the capillary inlet and outlet differed from each other in terms of buffer pH, ionic strength, type of BGE as well as buffer composition. Under the optimum conditions, baseline enantioseparation and highly sensitive detection of the enantiomers were achieved. Wide linear relationship of each enantiomer was achieved in the range of 5 x 10(-7) to 2 x 10(-5) mol/L with relative coefficients of 0.996 and 0.997, respectively. The detection limits were estimated to be 8 x 10(-8) and 1.0 x 10(-7) mol/L (S/N = 3) for the enantiomers, respectively. In addition, a successful application of this new method to the chiral separation of the racemic drug in spiked plasma samples confirmed the validity and applicability of the chiral CE-ECL method.

Anti-Arrhythmia Agents↗

PubMed2005

Microchip capillary electrophoresis with solid-state electrochemiluminescence detector.

We report microchip capillary electrophoresis (CE) coupling to a solid-state electrochemiluminescence (ECL) detector. The solid-state ECL detector was fabricated by immobilizing tris(2,2'-bipyridyl)ruthenium(II) (TBR) into an Eastman AQ55D-silica-carbon nanotube composite thin film on an indium tin oxide (ITO) electrode. After being made by a photolithographic method, the surface of the ITO electrode was coated with a thin composite film through a micromolding in capillary (MIMIC) technique using a poly(dimethylsiloxane) (PDMS) microchannel with the same pattern as an ITO electrode. Then the TBR was immobilized via ion exchange by immersing the ITO electrode containing the thin film in TBR aqueous solution. The whole system was built by reversibly sealing the TBR-modified ITO electrode plate with a PDMS layer containing electrophoresis microchannels. The results indicated that the present solid-state ECL detector displayed good durability and stability in the microchip CE-ECL system. Proline was selected to perform the microchip device with a limit of detection of 2 microM (S/N=3) and a linear range from 25 to 1000 microM. Compared with the CE-ECL of TBR in aqueous solution, while the CE microchip with solid-state ECL detector system gave the same sensitivity of analysis, a much lower TBR consumption and a high integration of the whole system were obtained. The present system was also used for medicine analysis.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed2005

Electrochemiluminescence quenching as an indirect method for detection of dopamine and epinephrine with capillary electrophoresis.

An electrochemiluminescence (ECL) inhibition method was developed as an indirect detection method for the determination of dopamine and epinephrine separated by capillary electrophoresis (CE). When the concentration of Ru(bpy)(3) (2+) was 50 muM diluted by 50 mM phosphate (pH 8.5) in the cell and 0.5 M tripropylamine (TPA) was added to the running buffer (10 mM phosphate, pH 9.0), an inhibition of ECL of the Ru(bpy)(3) (2+)/TPA system by the analytes was observed. Under the optimized conditions, the relative standard deviations of migration time and negative peak area were less than 1% and 3%, respectively, for 1 microM dopamine or 1 microM epinephrine (n = 10). Linear ranges of 0.1-10 microM for both analytes and the detection limits (signal-to-noise ratio S/N = 3) of 10 nM for dopamine and 30 nM for epinephrine were obtained.

Dopamine↗

PubMed2004

Short-capillary electrophoresis with electrochemiluminescence detection using porous etched joint for fast analysis of lidocaine and ofloxacin.

Fast analysis of ofloxacin and lidocaine, as bactericide and analgesic or anesthetics, is of clinic importance for understanding the patient's medical process. This paper presented a high throughput, simple analysis method of lidocaine and ofloxacin by capillary electrophoresis coupled with electrochemiluminescence (ECL) using porous etched joint. To shorten the analysis time and to improve the analytical performance, a capillary with 10 cm in length was used as the separation channel. The cyclic voltammograms of Ru(bpy)3(2+) with different capillary length at same field strength showed that the porous etched joint eliminated the effect of electrophoretic current on the ECL detection. Following micro total analysis systems (microTAS), some advantages of which this approach has, the fabrication of channel in chip was not needed. Compared with capillary electrophoresis with 40-cm-long capillary, the high sample throughput and low zone broadening may be the main advantage of the present system. Under optimal condition, the detection limits of lidocaine and ofloxacin based on peak height were 3.0 x 10(-8) and 5.0 x 10(-7) molL(-1) and a 60 h(-1) of sampling frequency was obtained. The precision (R.S.D.) of the migration time and the peak height for five replicate injections of a mixture of lidocaine (1.0 x 10(-6) molL(-1)) and ofloxacin (4.0 x 10(-6) molL(-1)) were 3.2-3.9% and 4.7-5.3%, respectively.

Electrophoresis, Capillary↗