Present Electrogenerated Chemiluminescence Sensor Research Articles

Enhanced cathodic electrogenerated chemiluminescence of luminol at a MXene–Nafion composite-modified electrode in neutral aqueous solution

Electrogenerated chemiluminescence (ECL) of luminol was studied on a two-dimensional titanium carbide (MXene)–Nafion composite-modified glassy carbon (GC) electrode in a neutral aqueous solution (pH 7). In the present work, Ti3C2Tx MXene was dispersed in a cation-exchange ionomer (Nation) and the resulting MXene–Nafion composite solution was drop-cast on the surface of GC electrode. Due to the strong electrocatalytic activity of the MXene towards the reduction reactions of oxygen and hydrogen peroxide, strong cathodic ECL emissions of luminol related to those reactions were obtained in a neutral aqueous solution. Based on the significant enhancement effect of hydrogen peroxide on the cathodic ECL, the present ECL sensor can detect hydrogen peroxide in the concentration range of 1.0 × 10−8 M ∼ 1.0 × 10−3 M with a detection limit of 3.1 × 10−9 M (S/N = 3). Furthermore, the present ECL sensor exhibits good selectivity towards hydrogen peroxide against interfering species such as glucose, ascorbic acid and uric acid. Therefore, the present ECL sensor could offer a good opportunity to be employed as an alternative transducer for the oxidase-based biosensors in biological fluids.

One-Step Fabrication of Highly Sensitive Tris(2,2'-bipyridyl)ruthenium(II) Electrogenerated Chemiluminescence Sensor Based on Graphene-Titania-Nafion Composite Film.

A highly sensitive tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy)32+) electrogenerated chemiluminescence (ECL) sensor based on a graphene-titania-Nafion composite film has been prepared in a simple one-step manner. In the present work, a highly concentrated 0.1 M Ru(bpy)32+ solution was mixed with an as-prepared graphene-titania-Nafion composite solution (1:20, v/v), and then a small aliquot (2 µL) of the resulting mixture solution was cast on a glassy carbon electrode surface. This one-step process for the construction of an ECL sensor shortens the fabrication time and leads to reproducible ECL signals. Due to the synergistic effect of conductive graphene and mesoporous sol-gel derived titania-Nafion composite, the present ECL sensor leads to a highly sensitive detection of tripropylamine from 1.0 × 10−8 M to 2.0 × 10−3 M with a detection limit of 0.8 nM (S/N = 3), which is lower in comparison to that of the ECL sensor based on the corresponding ECL sensor based on the titania-Nafion composite containing carbon nanotube. The present ECL sensor also shows a good response for nicotinamide adenine dinucleotide hydrogen (NADH) from 1.0 × 10−6 M to 1.0 × 10−3 M with a detection limit of 0.4 µM (S/N = 3). Thus, the present ECL sensor can offer potential benefits in the development of dehydrogenase-based biosensors.

Solid-state tris(2,2′-bipyridyl)ruthenium(II) electrogenerated chemiluminescence sensor based on ionic liquid/sol–gel titania/Nafion composite film

The feasibility of being able to control the selectivity of solid-state tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy)32+) electrogenerated chemiluminescence (ECL) sensor is proposed by selecting ionic liquids with appropriate hydrophobicity in the sol–gel titania/Nafion composite film. Four different kinds of ionic liquids with different hydrophobicity such as 1-butyl-3-methylimidazolium hexafluorophosphate (BMImPF6), 1-ethyl-3-methylimidazolium hexafluorophosphate (EMImPF6), 1-hexyl-3-methylimidazolium hexafluorophosphate (HMImPF6), 1-benzyl-3-methylimidazolium hexafluorophosphate (BnMImPF6) were incorporated in the sol–gel titania/Nafion composite films. The sequence of the observed ECL intensities for hydrophobic analytes is closely related to the sequence of the hydrophobicity of the ionic liquids used in the composite-based ECL sensor. In contrast, the observed ECL sequence for hydrophilic analytes such as ascorbic acid and oxalate is the opposite to the sequence of the hydrophobicity of the ionic liquids used in the composite film. Due to the decreased electron transfer resistance in the ionic liquid-based sol–gel titania/Nafion composite films, the present ECL sensor based on the BMImPF6/titania/Nafion composite film gave a remarkable detection limit (S/N=3) of 0.48nM for TPA.

Electrogenerated chemiluminescence of a cationic cyclometalated iridium complex–Nafion modified electrode in neutral aqueous solution

Electrogenerated chemiluminescence (ECL) of a cationic cyclometalated iridium complex, [(pqcm)2Ir(bpy)](PF6) (1, pqcmH=2-phenyl-quinoline-4-carboxylic acid methyl ester, bpy=2,2′-bipyridine), was investigated at a bare glassy carbon electrode in CH3CN solution and 4 ECL peaks were observed. Then, the ECL of the iridium complex was studied in neutral phosphate buffer solution (PBS) by immobilizing it on a glassy carbon electrode. Two closely located ECL peaks were obtained at 1.07 and 1.40V when the potential was scanned from −3.00V to 2.20V, while only one broad ECL peak located around −2.0V was obtained when the potential was scanned from 2.20V to −3.00V. In the presence of oxalate, one ECL peak located around 1.22V could be obtained except the broad ECL peak located at −2.00V. The ECL peak at positive potential range was enhanced more than one magnitude in the presence of Nafion and was nearly 5-times higher than that of Ru(bpy)32+–Nafion modified electrode, suggesting that the synthesized iridium complex has great application potential in ECL detection. The ECL spectra of iridium complex were identical to its photoluminescence spectrum, indicating the same metal-to-ligand charge transfer (MLCT) excited states. The mechanisms of ECL were proposed based on the experimental results. The present ECL sensor gave a linear response for the oxalate concentration from 1.0×10−6 to 1.0×10−4molL−1 with a detection limit (S/N=3) of 9.1×10−7molL−1.

Tris(2,2′‐bipyridyl)ruthenium(II) Electrogenerated Chemiluminescence Sensor Based on Platinized Carbon Nanotube–Zirconia–Nafion Composite Films

AbstractMesoporous films of platinized carbon nanotube–zirconia–Nafion composite have been used for the immobilization of tris(2,2′‐bipyridyl)ruthenium (II) (Ru(bpy)32+) on an electrode surface to yield a solid‐state electrogenerated chemiluminescence (ECL) sensor. The composite films of Pt–CNT–zirconia–Nafion exhibit much larger pore diameter (3.55 nm) than that of Nafion (2.82 nm) and thus leading to much larger ECL response for tripropylamine (TPA) because of the fast diffusion of the analyte within the films. Due to the conducting and electrocatalytic features of CNTs and Pt nanoparticles, their incorporation into the zirconia–Nafion composite films resulted in the decreased electron transfer resistance within the films. The present ECL sensor based on the Pt–CNT–zirconia–Nafion gave a linear response (R2=0.999) for TPA concentration from 3.0 nM to 1.0 mM with a remarkable detection limit (S/N=3) of 1.0 nM, which is much lower compared to those obtained with the ECL sensors based on other types of sol‐gel ceramic–Nafion composite films such as silica–Nafion and titania–Nafion.

Electrogenerated Chemiluminescence Sensor Based on Tris(2,2'-bipyridyl) ruthenium(II) Immobilized in the Composite Film of Multi-walled Carbon Nanotube/Sol-gel Zinc oxide/Nafion

A composite film of multi-walled carbon nanotube (MWCNT)/sol-gel-derived zinc oxide(ZnO)/Nafion has been utilized as an efficient immobilization matrix for the construction of a highly sensitive and stable tris(2,2'-bipyridyl) ruthenium(II) (Ru(bpy) 3 2+ ) electrogenerated chemiluminescence (ECL) sensor. The electrochemical and ECL behaviors of Ru(bpy) 3 2+ ion-exchanged into the composite film were strongly dependent upon the sol-gel preparation condition, the amount of MWCNT incorporated into the ZnO/Nafion composite film, and the buffer solution pH. The synergistic effect of MWCNTs and ZnO in the composite films increased not only the sensitivity but also the long-term stability of the ECL sensor. The present ECL sensor based on the MWCNT/ZnO/Nafion gave a linear response (R 2 = 0.999) for tripropylamine concentration from 500 nM to 1.0 mM with a remarkable detection limit (S/N = 3) of 15 nM. The present ECL sensor showed outstanding long-term stability (94% initial signal retained for 5 weeks). Since the present ECL sensor exhibits large response towards NADH, it could be applied as a transduction platform for the ECL biosensor in which the NADH is produced from the dehydrogenase-based enzymatic reaction in the presence of NAD + cofactor.

Electrogenerated chemiluminescence for the sensitive detection of leucine using Ru(bpy) 32+ immobilized on dendritic Pd nanoparticle

A novel electrogenerated chemiluminescence (ECL) sensor for the detection of amino acid based on the immobilized Ru(bpy) 3 2+ on dendritic Pd nanoparticle was firstly developed. The primary amino acid (leucine) was derivatized by reacting with acetaldehyde. The electrochemical and ECL behaviors of the immobilized Ru(bpy) 3 2+ were investigated. The modified electrode showed an increased electrocatalytic response to the oxidation of the derivatized leucine, producing a sensitized ECL signal probably since a high fraction of surface atoms located on the tips of the dendrites and a large amount of Ru(bpy) 3 2+ was immobilized on the electrode. Under optimal conditions, the sensor could be used for the determination of leucine with a linear range from 3.0 to 182 μM and a detection limit of 1.0 μM at 3 σ. Furthermore, the present ECL sensor displayed a long-term stability. Our interference experiments indicated that acetaldehyde derivatives of other amino acids, such as proline and valine can be completely separated by electrophoresis (CE).

Functionalized magnetic nanoparticle with poly(3-thiopheneacetic acid) and its application for electrogenerated chemiluminescence sensor

Polymer-coated magnetic nanoparticles (MNPs) have been prepared and used as an immobilization matrix for the fabrication of solid-state tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy) 3 2+) electrogenerated chemiluminescence (ECL) sensor. The pre-synthesized maghemite (γ-Fe 2O 3) MNPs were coated with poly(3-thiopheneacetic acid) based on an oxidative polymerization method using KMnO 4. The poly(3-thiopheneacetic acid)-coated MNPs have formed the clusters with average diameter of 200–500 nm. The multilayer films of poly(3-thiopheneacetic acid)-coated MNPs were uniformly formed on the surface of a Pt electrode by an external magnet. The Ru(bpy) 3 2+ was rapidly incorporated into the multilayer films within 5 min through the electrostatic interaction between the Ru(bpy) 3 2+ and the negatively charged carboxylates of 3-thiopheneacetic acid at pH 7.0. Due to the fast mass transport in the multilayer films of the functionalized MNPs, the present Ru(bpy) 3 2+ ECL sensor based on the functionalized MNPs showed improved ECL sensitivity for tripropylamine (TPA) compared to the Nafion-based ECL sensor. The present ECL sensor exhibited a quite low limit of detection for TPA (49 nM). The sensor-to-sensor reproducibility was very good (R.S.D. = 5%).

A Novel Electrogenerated Chemiluminescence (ECL) Sensor Based on Ru(bpy)32+‐Doped Titania Nanoparticles Dispersed in Nafion on Glassy Carbon Electrode

AbstractA novel electrogenerated chemiluminescence (ECL) sensor based on Ru(bpy)32+‐doped titania (RuDT) nanoparticles dispersed in a perfluorosulfonated ionomer (Nafion) on a glassy carbon electrode (GCE) was developed in this paper. The electroactive component‐Ru(bpy)32+ was entrapped within the titania nanoparticles by the inverse microemulsion polymerization process that produced spherical sensors in the size region of 38±3 nm. The RuDT nanoparticles were characterized by electrochemical, transmission electron and scanning microscopy technology. The Ru(bpy)32+ encapsulation interior of the titania nanoparticles maintains its ECL efficiency and also reduces Ru(bpy)32+ leaching from the titania matrix when immersed in water due to the electrostatic interaction. This is the first attempt to prepare the RuDT nanoparticles and extend the application of electroactive component‐doped nanoparticles into the field of ECL. Since a large amount of Ru(bpy)32+ was immobilized three‐dimensionally on the electrode, the Ru(bpy)32+ ECL signal could be enhanced greatly, which finally resulted in the increased sensitivity. The ECL analytical performance of this ECL sensor for tripropylamine (TPA) was investigated in detail. This sensor shows a detection limit of 1 nmol/L for TPA. Furthermore, the present ECL sensor displays outstanding long‐term stability.

Electrogenerated Chemiluminescence Sensors Using Ru(bpy)32+ Doped in Silica Nanoparticles

A novel electrogenerated chemiluminescence (ECL) sensor based on Ru(bpy)3(2+)-doped silica (RuDS) nanoparticles conjugated with a biopolymer chitosan membrane was developed. These uniform RuDS nanoparticles (approximately 40 nm) were prepared by a water-in-oil microemulsion method and were characterized by electrochemical and transmission electron microscopy technology. The Ru(bpy)3(2+)-doped interior maintained its high ECL efficiency, while the exterior nanosilica prevented the luminophor from leaching out into the aqueous solution due to the electrostatic interaction. This is the first attempt to branch out the application of RuDS nanoparticles into the field of ECL, and since a large amount of Ru(bpy)3(2+) was immobilized three-dimensionally on the electrode, the Ru(bpy)3(2+) ECL signal could be enhanced greatly, which finally resulted in the increased sensitivity. This sensor shows a detection limit of 2.8 nM for tripropylamine, which is 3 orders of magnitude lower than that observed at a Nafion-based ECL sensor. Furthermore, the present ECL sensor displays outstanding long-term stability.

Tris(2,2′-bipyridyl)ruthenium(II) electrogenerated chemiluminescence sensor based on carbon nantube dispersed in sol–gel-derived titania–Nafion composite films

A highly sensitive and stable tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy) 3 2+) electrogenerated chemiluminescence (ECL) sensor was developed based on carbon nanotube (CNT) dispersed in mesoporous composite films of sol–gel titania and perfluorosulfonated ionomer (Nafion). Single-wall (SWCNT) and multi-wall carbon nanotubes (MWCNT) can be easily dispersed in the titania–Nafion composite solution. The hydrophobic CNT in the titania–Nafion composite films coated on a glassy carbon electrode certainly increased the amount of Ru(bpy) 3 2+ immobilized in the ECL sensor by adsorption of Ru(bpy) 3 2+ onto CNT surface, the electrocatalytic activity towards the oxidation of hydrophobic analytes, and the electronic conductivity of the composite films. Therefore, the present ECL sensor based on the CNT–titania–Nafion showed improved ECL sensitivity for tripropylamine (TPA) compared to the ECL sensors based on both titania–Nafion composite films without CNT and pure Nafion films. The present Ru(bpy) 3 2+ ECL sensor based on the MWCNT–titania––Nafion composite gave a linear response ( R 2 = 0.999) for TPA concentration from 50 nM to 1.0 mM with a remarkable detection limit (S/N = 3) of 10 nM while the ECL sensors based on titania–Nafion composite without MWCNT, pure Nafion films, and MWCNT–Nafion composite gave a detection limit of 0.1 μM, 1 μM, and 50 nM, respectively. The present ECL sensor showed outstanding long-term stability (no signal loss for 4 months).

Tris(2,2′‐bipyridyl)ruthenium(II) Electrogenerated Chemiluminescence Sensor Based on Sol–Gel‐Derived V2O5/Nafion Composite Films

AbstractMesoporous V2O5/Nafion composite films have been used for the immobilization of tris(2,2′‐bipyridyl)ruthenium (II) (Ru(bpy)$\rm{ {_{3}^{2+}}}$) on an electrode surface to yield a solid‐state electrogenerated chemiluminescence (ECL) sensor. The electrochemical and ECL behavior of Ru(bpy)$\rm{ {_{3}^{2+}}}$ ion‐exchanged into the composite films has been characterized as a function of the amount of Nafion incorporated into the V2O5/Nafion composite. The composite film with 80% Nafion content has the largest pore diameter (4.19 nm) and yields the maximum ECL response for tripropylamine (TPA) because of the fast diffusion of analyte into the film with large pores. Due to the enlarged pore size and enhanced conductivity of the V2O5/Nafion composite, the present ECL sensor based on the composite films exhibited around 2 orders of magnitude higher ECL response and one order of magnitude lower detection limit for TPA (10 nM) compared to those obtained with the ECL sensors based on other types of sol–gel ceramic/Nafion composite films such as SiO2/Nafion and TiO2/Nafion.

Electrogenerated chemiluminescence from tris(2,2'-bipyridyl)ruthenium(II) immobilized in titania-perfluorosulfonated ionomer composite films.

Electrochemical behavior and electrogenerated chemiluminescence (ECL) of tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)3(2+)) immobilized in sol-gel-derived titania TiO2)-Nafion composite films coated on a glassy carbon electrode have been investigated. The electroactivity of Ru(bpy)3(2+) ion exchanged into the composite films and its ECL behavior were strongly dependent upon the amount of Nafion incorporated into the TiO2-Nafion composite films. The ECL sensor of Ru(bpy)32+ immobilized in a TiO2-Nafion composite with 50% Nafion content showed the maximum ECL intensities for both tripropylamine (TPA) and sodium oxalate in 0.05 M phosphate buffer solution at pH 7. Detection limits were 0.1 microM for TPA and 1.0 microM for oxalate (S/N = 3) with a linear range of 3 orders of magnitude in concentration. The present ECL sensor showed improved ECL sensitivity and long-term stability, as compared to the ECL sensors based on pure Nafion films. The present Ru(bpy)3(2+) ECL sensor based on TiO2-Nafion (50%) composite films was applied as an HPLC detector for the determination of erythromycin in human urine samples. The present Ru(bpy)3(2+) ECL sensor was stable in the mobile phase containing a high content of organic solvent (30%, v/v), in contrast to a pure Nafion-based Ru(bpy)3(2+) ECL sensor. The detection limit for erythromycin was 1.0 microM, with a linear range of 3 orders of magnitude in concentration.