Sensors based on galvanic cell generated electrochemiluminescence and its application

Nano-assemblies consisting of Pd/Pt nanodendrites and poly (diallyldimethylammonium chloride)-coated reduced graphene oxide on glassy carbon electrode for hydrogen peroxide sensors

Non-enzymatic hydrogen peroxide (H2O2) sensors were fabricated on the basis of glassy carbon (GC) electrode modified with palladium (Pd) core-platinum (Pt) nanodendrites (Pt-NDs) and poly (diallyldimethylammonium chloride) (PDDA)-coated reduced graphene oxide (rGO). A facile wet-chemical method was developed for preparing Pd core-Pt nanodendrites. In this approach, the growth of Pt NDs was directed by Pd nanocrystal which could be regarded as seed. The PDDA-coated rGO could form uniform film on the surface of GC electrode, which provided a support for Pd core- Pt NDs adsorption by self-assembly. The morphologies of the nanocomposites were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction (spectrum). Electrocatalytic ability of the nanocomposites was evaluated by cyclic voltammetry and chronoamperometric methods. The sensor fabricated by Pd core-Pt NDs/PDDA-rGO/GCE exhibited high sensitivity (672.753 μA mM(-1) cm(-2)), low detection limit (0.027 μM), wider linear range (0.005-0.5mM) and rapid response time (within 5s). Besides, it also exhibited superior reproducibility, excellent anti-interference performance and long-term stability. The present work could afford a viable method and efficient platform for fabricating all kinds of amperometric sensors and biosensors.

Dual-channel cathodic electrochemiluminescence of luminol induced by injection of hot electrons on a niobate semiconductor modified electrode

In this paper, a new niobate semiconductor photocatalyst Sr(0.4)H(1.2)Nb(2)O(6)·H(2)O (HSN) nanoparticle was applied to investigate the cathodic electrochemiluminescent (ECL) behavior of luminol for the first time. The results presented here demonstrated that there were two ECL peaks of luminol at the cathodic potential attributed to immobilization of HSN on the electrode surface. It is implied that HSN can be electrically excited and injected electrons into aqueous electrolytes from this electrode under a quite low potential that only excites luminol. A mechanism for this luminol-ECL system on HSN/GCE has been proposed. Additionally, this HSN/GCE has lots of advantages, such as high stability, good anti-interference ability, simple instrumentation, rapid procedure and ultrasensitive ECL response. It is envisioned that this HSN/GCE has further applications in biosensors.

Developments and Applications of Electrogenerated Chemiluminescence Sensors Based on Micro- and Nanomaterials

A variety of recent developments and applications of electrogenerated chemiluminescence (ECL) for sensors are described. While tris(2,2′-bipyridyl)-ruthenium(II) and luminol have dominated and continue to pervade the field of ECL-based sensors, recent work has focused on use of these lumophores with micro- and nanomaterials. It has also extended to inherently luminescent nanomaterials, such as quantum dots. Sensor configurations including microelectrode arrays and microfluidics are reviewed and, with the recent trend toward increased use of nanomaterials, special attention has been given to sensors which include thin films, nanoparticles and nanotubes. Applications of ECL labels and examples of label-free sensing that incorporate nanomaterials are also discussed.

Effects of microstructure of carbon nanofibers for amperometric detection of hydrogen peroxide

Carbon nanofibers (CNFs) with three microstructures, including platelet-carbon nanofibers (PCNFs), fish-bone-carbon nanofibers (FCNFs), and tube-carbon nanofibers (TCNFs), were synthesized, characterized, and evaluated for electrochemical sensing of hydrogen peroxide. The CNFs studied here show microstructures with various stacked morphologies. The sizes and graphite-layer ordering of the CNFs can be well controlled. Glassy carbon (GC) electrodes modified by CNFs were fabricated and compared for amperometric detection of hydrogen peroxide. Sensors based on PCNFs/GC, FCNFs/GC, and TCNFs/GC were used in the amperometric detection of H2O2 in solution by applying a potential of +0.65 V versus Ag/AgCl at the working electrode. The highest electrocatalytic performance was observed for PCNFs/GC among the three types of hydrogen peroxide sensors. The amperometric response of PCNFs/GC retained over 90% of the initial current of the first day up to 21 days. The linear range is from 1.80x10(-4) to 2.62x10(-3) M with a correlation coefficient larger than 0.999 and with a detection limit of 4.0 microM H2O2 (S/N = 3). The relative standard deviation for detecting 1.80x10(-4) M H2O2 (N = 8) is 2.1% with an average response of 0.64 microA. The significant diversity of electrocatalytic activity of the CNFs toward the oxidation of hydrogen peroxide may result from the difference of morphologies, textural properties, and crystalline structures.