Jianzhen Kang

[Ru(bpy)3]2+‐Doped Silica Nanoparticles within Layer‐by‐Layer Biomolecular Coatings and Their Application as a Biocompatible Electrochemiluminescent Tag Material

[Ru(bpy)3]2+-doped silica (RuSi) nanoparticles were synthesized by using a water/oil microemulsion method. Stable electrochemiluminescence (ECL) was obtained when the RuSi nanoparticles were immobilized on a glassy carbon electrode by using tripropylamine (TPA) as a coreactant. Furthermore, the ECL of the RuSi nanoparticles with layer-by-layer biomolecular coatings was investigated. Squential self-assembly of the polyelectrolytes and biomolecules on the RuSi nanoparticles gave nanocomposite suspensions, the ECL of which decreased on increasing the number of bilayers. Moreover, factors that affected the assembly and ECL signals were investigated. The decrease in ECL could be assigned to steric hindrance and limited diffusion of the coreactant molecules in the silica matrix after they were attached to the biomolecules. Since surface modification of the RuSi nanoparticles can improve their biocompatibility and prevent leaking of the [Ru(bpy)3]2+ ions, the RuSi nanoparticles can be readily used as efficient and stable ECL tag materials in immunoassay and DNA detection.

Dynamic coating for resolving rhodamine B adsorption to poly(dimethylsiloxane)/glass hybrid chip with laser-induced fluorescence detection.

In this paper a method was described about dynamic coating for resolving rhodamine B (RB) adsorption on a hybrid poly(dimethylsiloxane) (PDMS)/glass chip. The results showed that when the non-ionic surfactant Triton X-100 was higher than 0.5% (v/v) into the phosphate buffer, the adsorption of RB appeared. Besides, some separation conditions for RB were investigated, including concentration of Triton X-100, concentration and pH value of running buffer, separation voltage and detection site. Through comparing electroosmotic flow, plate numbers and other parameters, an acceptable separation condition was obtained. Under optimized conditions, the precisions of RB detection (R.S.D., n=10) were 2.62% for migration time, 4.78% for peak height respectively. Additionally, RB concentration linearity response was excellent with 0.9996 of correlation coefficient between 1 and 100muM, and a limit of detection (S/N=3) was 0.2muM. Finally, we separated rhodamine B isothiocyanate and lysine deriving from the fluorescent probe, and the result displayed that the dynamic coating method was applicable by CE separations using PDMS/glass chip.

Capillary Electrophoresis with Indirect Electrochemiluminescence Detection

Abstract An indirect electrochemiluminescence (IECL) detection for capillary electrophoresis (CE) is presented in this article. IECL is based on the inhibition of Ru(bpy)3 2+/TPA system. The developed technique is successfully applied to the analysis of phenolic compounds: phenol, o‐chlorophenol, p‐nitrophenol, and 2,4,6‐trinitrophenol. The factors that influenced the separation and detection were investigated in detail. On the optimized condition, the tested phenols (phenol, o‐chlorophenol, p‐nitrophenol, and 2,4,6‐trinitropheno) could inhibit the ECL signal from the luminescence reagent, and the components of the mixture could be separated and recognized. In addition, when 2 mM phenol was the analyte, the relative standard deviations for migration time and negative peak height were 0.27% and 2.29%, respectively (n=6). And the linear correlation coefficient was 0.996 for phenol (0.5–5 mM). The preliminary results showed that the CE‐IECL might be applied to the detection of phenolic compounds or other samples. Supported by the National Natural Science Foundation of China (No. 20299030 and 20335040), and National Key Basic Research Program 2001CB5102.