00411umb_Srivastava_3.3.qxd

Abstract The feasibility of fabricating copper-sensitive chemically modified electrodes (CMEs) for trace analysis in aqueous and in 40% (v/v) ethanol-water media was investigated. Carbon paste electrodes modified with crown ethers were constructed by mixing the crown ethers into a graphite powder-paraffin oil matrix. The electrodes so formed were able to bind Cu(II) ions chemically and gave better voltammetric responses than the unmodified ones. The crown ethers studied and compared were 15-crown-5, benzo-15-crown-5 and dibenzo-18-crown-6. With a 3% benzo-15-crown-5 CME, Cu(II) could be quantified at sub-ppm levels by differential pulse voltammetry with a detection limit of 0.05 ppm. By differential pulse anodic stripping voltammetry Cu(II) could be quantified over the range 1 to 100 ppb. Interference from metal ions like Ni(II), Co(II), Mn(II), Fe(II), etc. have also been studied. The method was successfully applied to artificial as well as commercial samples of alcoholic beverages

Electrogenerated Chemiluminescence for bio-assay: from single Molecule to Nano-structured tracers (Global journal of physical chemistry)

This review provides a basic introduction to the Electrogenerated Chemiluminescence (ECL) technique. The fundamental concepts, mechanisms and bio-analytical applications are briefly discussed. In addition, the trends of current ECL materials research are summarized in relation to their potential use in biological systems. Particular emphasis is given to new water soluble ECL labels and to encapsulation of emitting materials in nanostructures including silica nanoparticles, carbon nanotubes and quantum dots