A simple and effective capillary electrophoresis–chemiluminescence (CE–CL) detection system was developed based on an ultra-fast bis(2,4,6-trichlorophenyl)oxalate (TCPO) chemiluminescence (CL) reaction (0.6 s duration) that avoided overlapping peaks and peak tailing. Through a series of static injection experiments, this unusually rapid CL reaction was ascribed to the catalytic effect of imidazole in the tetrahydrofuran solvent, which has been rarely utilized in such investigations. A possible mechanism is given to explain the results. Under the optimized conditions, rhodamine 6 G (R6G) and its hydrolysis product (R6G-COOH) could be efficiently separated through electrophoresis in 7 min, with sensitive CL detection in the proposed CE–CL system. In this way, the alkaline hydrolysis of R6G was monitored, followed by estimation of relative rate constants and activation energy. This finding and application should be helpful in further study for the TCPO CL reaction, and revealed an attractive opportunity for simplifying the CE–CL system, such as in a microchip device. Copyright © 2011 John Wiley & Sons, Ltd.

A form of single-strand DNA-conformation polymorphism analysis (SSCP) employing nondenaturing slab gel electrophoresis is applicable to the genetic diagnosis of mutations at exons 7, 8 and 9 of the p53 gene. Recently, microchip electrophoresis (ME) systems have been used in SSCP analysis instead of conventional slab gel electrophoresis in terms of speed, sensitivity and automation. The aim of the present study was to investigate the application of SSCP and ME analysis as a rapid and effective method to the detection of mutations for exons 7, 8 and 9 of the p53 gene. It was found that using the electric field strength 260 V/cm and the sieving matrix of 4 mg/mL poly(ethylene oxide) was very useful to achieve better resolution and fast detection of mutations at exons 7, 8 and 9 of p53 gene. Under the optimized conditions, mutations at exons 7–9 of p53 gene were analyzed within 60 s and the relative standard deviation values of the migration times were less than 5.81% (n=5). The detection limit can be as low as 1 ng·L⁻¹.

Thionine molecules have been electropolymerized onto different types of carbon nanotubes (CNT) using a cyclic voltammetry scanning technology, including multi-walled carbon nanotubes, single-walled carbon nanotubes and aligned carbon nanotubes. Results indicate that such prepared nanocomposites have combined the intrinsic faradic capacitance of polythionine with the double layer capacitance of polythionine-CNT, and thus the polythionine modification obviously enhanced the CNT capacitance. Especially the carboxyl group modified multi-walled carbon nanotubes, which have made their nanotube tips opened, allowed much more electropolymerization cycles and then obtained a most significant increment in capacitance than the other three ones.

Copolymers of poly(vinylpyrrolidone) (PVP) and hydroxyethylcellulose (HEC) were synthesized, with PVP to HEC molar ratios of 3:1, 2:1 and 1:1. The copolymers were tested as separation media in DNA fragment separation analysis by microchip electrophoresis (MCE). Separation efficiency over 3.8×10⁵ for 118 bp has been reached by using the bare channels without the additional polymer coating step. Under optimized separation conditions for longer read length DNA sequencing, the separation ability of the copolymers decreased with decreasing (PVP-co-HEC) molar ratio from 3:1 to 2:1 and 1:1. In comparison with (PVP-co-HEC) 1:1, the copolymer with (PVP-co-HEC) 3:1 ratio showed high separation efficiency. By using a 20 g·L⁻¹ copolymer with (PVP-co-HEC) 3:1 ratio, ΦΧ174-HaeIII digest DNA marker was successfully separated within 3 min.

The major bioactive components in a Chinese herb named Polygonum perfoliatum L. including ferulic acid, vanillic acid, quercetin, caffeic acid and protocatechuic acid were simultaneously determined by capillary electrophoresis with electrochemical detection (CE-ED) in this paper. The effects of working electrode potential, pH and concentration of running buffer, separation voltage, and injection time on CE-ED were investigated. Under the optimum conditions, the five analytes could be separated within 17 min at a separation voltage of 18 kV in 10 mmol· L⁻¹ phosphate buffer (pH 9.2). A 300 µm diameter carbon disk electrode generated good responses at +0.95 V (vs. SCE) to the five analytes. The response was linear over three orders of magnitude with detection limits (S/N=3) ranging from 7.1×10⁻⁸ to 9.3×10⁻⁸ g·mL⁻¹ for the analytes. This proposed method could be successfully applied to the analysis of the real samples with relatively simple extraction procedures and satisfactory results.