Electrogenerated Chemiluminescence Sensor Research Articles

An electrogenerated chemiluminescence sensor prepared with a graphene/multiwall carbon nanotube/gold nanocluster hybrid for the determination of phenolic compounds

A dispersible graphene/multiwall carbon nanotube/gold nanocluster (GP/MWCNTs/AuNCs) hybrid in aqueous solution was prepared in situ, and characterized by transmission electron microscopy (TEM) and ultraviolet-visible (UV-vis) spectroscopy. Based on the fact that phenolic compounds can enhance the electrogenerated chemiluminescence (ECL) signal at the GP/MWCNTs/AuNCs modified glassy carbon electrode in the presence of peroxydisulfate, an ECL sensor was proposed for the determination of phenolic compounds with high sensitivity, good repeatability and stability. Due to its fascinating features, such as good water solubility and excellent stability, the GP/MWCNTs/AuNCs hybrid would offer a suitable catalytic platform for phenolic compounds and provide potential promise for the construction of ECL sensors.

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.

Electrogenerated chemiluminescence sensor for glutathione with $$ Ru\left( {bpy} \right)_3^{2+ } $$ -doped silica nanoparticles

An electrogenerated chemiluminescence (ECL) sensor for reduced glutathione was developed based on $$ \mathrm{Ru}\left( {\mathrm{bpy}} \right)_3^{2+ } $$ -doped silica nanoparticles-modified gold electrode (Ru-DSNPs/Au). These uniform Ru-DSNPs (about 58 + 4 nm) were prepared by a water-in-oil microemulsion method and characterized by transmission electron microscope and scanning electron microscope. With such a unique immobilization method, a considerable $$ \mathrm{Ru}\left( {\mathrm{bpy}} \right)_3^{2+ } $$ was immobilized three dimensionally on the electrode, which could greatly enhance the ECL response and thus result in an increased sensitivity. The ECL analytical performances of this sensor for reduced glutathione based on the quenched ECL emission of $$ \mathrm{Ru}\left( {\mathrm{bpy}} \right)_3^{2+ } $$ have been investigated in detail. Under the optimum condition, the ECL intensity was linear with the reduced glutathione concentration in the range of 1.0 × 10−9 to 1.0 × 10−4 mol L−1 (R = 0.9971). This method has been successfully applied for the determination of reduced glutathione in serum samples with satisfactory results. The as-prepared ECL sensor for the determination of reduced glutathione displayed good sensitivity and stability.

Preparation and Characterization of an Electrogenerated Chemiluminescence Sensor by Electrochemical Grafting of 4-Nitrophenyl Diazonium Salts Onto a Glass Carbon Electrode

An ECL sensor was fabricated by immobilization of a tris(2,2'-bipyridyl)ruthenium (II) complex (Ru(bpy)3(2+)) to an amine group-modified GC electrode (NH2-GC electrode). Here, the NH2-GC electrode was prepared by electrochemical reduction of a nitro group-modified GC electrode in 0.1 M KCl ethanol solution under H2 gas, which was followed by electrochemical grafting of 4-nitrophenyl diazonium salts in 0.1 M NBu4BF4 acetonitrile solution onto the GC electrode. The prepared ECL sensor was successfully confirmed via cyclic voltammetry, contact angle, scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and ECL spectrometry. The contact angle for the surface of the GC electrode, NO2-GC electrode, and NH2-GC electrod was 88.4 degrees, 67.4 degrees, and 52.4 degrees, respectively. The stability of the ECL sensor was investigated under continuous cyclic potential scanning for 55 cycles and the ECL intensity remained at 55%. The prepared ECL electrode can be expected to immobilize enzymes for preparation of the ECL biosensor to detect target molecules.

Electrogenerated chemiluminescence sensor for formaldehyde based on Ru(bpy)32+-doped silica nanoparticles modified Au electrode

A novel and sensitive electrogenerated chemiluminescence (ECL) sensor for formaldehyde was developed with the amine-functionalized Ru(bpy)32+-doped silica nanoparticles (Ru-DSNPs) as ECL emitter. Ru(bpy)32+ doped on the silica nanoparticle can maintain its electrochemical activities, which made silica nano-beads a excellent carrier of Ru(bpy)32+ species. The uniform Ru-DSNPs (about 75nm) were conjugated with Au electrode using mercaptoacetic acid as the intermediate to fabricate an ECL sensor for formaldehyde. The ECL analytical performances of this ECL sensor for formaldehyde based on its enhancement ECL emission of Ru(bpy)32+ were investigated in details. Under the optimum condition, the ECL intensity was linear with the formaldehyde concentration in the range of 1.0×10−8mol/L to 1.0×10−6mol/L. The detection limit was 6.0×10−9mol/L (S/N=3). This approach offered obvious advantages of being simpler, faster, and more stable compared with other sensors, and possessed great potential for formaldehyde detection which could be applied to determine directly the formaldehyde in real samples without pre-separation.

Electrogenerated Chemiluminescence Behavior of Graphite-like Carbon Nitride and Its Application in Selective Sensing Cu2+

This paper reports for the first time the electrogenerated chemiluminescence (ECL) behavior of graphite-like carbon nitride (g-C(3)N(4)) with K(2)S(2)O(8) as the coreactant. The possible ECL reaction mechanisms are proposed. The spectral features of the ECL emission and photoluminescence (PL) of g-C(3)N(4) are compared, and their resemblance demonstrates that the excited states of g-C(3)N(4) from both ECL and photoexcitation are the same. The effects of K(2)S(2)O(8) concentration, pH, g-C(3)N(4)/carbon powder ratio, and scan rate on the ECL intensity have been studied in detail. Furthermore, it is observed that the ECL intensity is efficiently quenched by trace amounts of Cu(2+). g-C(3)N(4) is thus employed to fabricate an ECL sensor which shows high selectivity to Cu(2+) determination. The limit of detection is determined as 0.9 nM. It is anticipated that g-C(3)N(4) could be a new class of promising material for fabricating ECL sensors.

Graphene‐amplified electrogenerated chemiluminescence of CdTe quantum dots for H2O2 sensing

Electrogenerated chemiluminescence (ECL) of thiol-capped CdTe quantum dots (QDs) in aqueous solution was greatly enhanced by PDDA-protected graphene (P-GR) film that were used for the sensitive detection of H2 O2 . When the potential was cycled between 0 and -2.3 V, two ECL peaks were observed at -1.1 (ECL-1) and -1.4 V (ECL-2) in pH 11.0, 0.1 M phosphate buffer solution (PBS), respectively. The electron-transfer reaction between individual electrochemically-reduced CdTe nanocrystal species and oxidant coreactants (H2 O2 or reduced dissolved oxygen) led to the production of ECL-1. While mass nanocrystals packed densely in the film were reduced electrochemically, assembly of reduced nanocrystal species reacted with coreactants to produce an ECL-2 signal. ECL-1 showed higher sensitivity for the detection of H2 O2 concentrations than that of ECL-2. Further, P-GR film not only enhanced ECL intensity of CdTe QDs but also decreased its onset potential. Thus, a novel CdTe QDs ECL sensor was developed for sensing H2O2. Light intensity was linearly proportional to the concentration of H2 O2 between 1.0 × 10(-5) and 2.0 x 10(-7) mol L(-1) with a detection limit of 9.8 x 10(-8) mol L(-1). The P-GR thin-film modified glassy carbon electrode (GCE) displayed acceptable reproducibility and long-term stability.

Effective immobilization of Ru(bpy)32+ by functional composite phosphomolybdic acid anion on an electrode surface for solid-state electrochemiluminescene to sensitive determination of NADH

Phosphomolybdic acid anion ([PMo12O40]3−) was used for the immobilization of ruthenium(II) tris(bipyridine) (Ru(bpy)32+) on an electrode surface to yield a sensitive solid-state electrogenerated chemiluminescence (ECL) sensor. [PMo12O40]3− anion in the prepared sensor had catalytic ability to the NADH oxidation. The ECL signal of the Ru(bpy)32+/[PMo12O40]3− film was about 3-fold enhancement than that for the Ru(bpy)32+/Nafion film to NADH determination. The resulting ECL sensor exhibited a wide linear range from 2.5×10−7 to 5.0×10−3M (R=0.99) with the detection limit of 1.67×10−8M (S/N=3). In addition, it had good reproducibility and excellent long-term stability, and the relative average deviation was 0.77% of ECL intensity–time curve under continuous potential scanning for 21 cycles; after being used in two weeks, the sensor was able to keep over 90% activity toward 25μM NADH. Fabrication of the ECL sensor by this method is simple and easy. Such superior properties will promote the application of polyoxometalates in fabricating sensors for using in electroanalytical and biochemical analysis.

Energy-Level-Related Response of Cathodic Electrogenerated-Chemiluminescence of Self-Assembled CdSe/ZnS Quantum Dot Films

A strategy for construction of a solid-state electrogenerated chemiluminescence (ECL) sensor based on a self-assembled film of core/shell structural CdSe/ZnS quantum dots (QDs) is presented in this work for the first time. The surface coverage of CdSe/ZnS QDs is about 2.2 × 1012 NPs/cm2, which is on the level of a submonolayer. This self-assembled CdSe/ZnS QD film has shown a strong and efficient cathodic ECL with peroxydisulfate and hydroperoxide as coreactants in aqueous solution. The quenching effect with hydroperoxide as the coreactant reveals an energy-level-related mechanism for the QD ECL processes. The energy levels of QDs and coreactants determine ECL responses. This insight provides a universal guide to select proper coreactants for the QD ECL sensors. In addition, the self-assembled CdSe/ZnS QD ECL sensor has the potential to detect energy-level-related analytes, such as dopamine.

Electrogenerated Chemiluminescence Sensor Based on a Self‐Assembled Monolayer of Ruthenium(II)‐bis(2,2′‐bipyridyl)(aminopropyl imidazole) on Gold Deposited Screen Printed Electrode

AbstractA new electrogenerated chemiluminescence (ECL) sensor based on a self‐assembled monolayer (SAM) of Ru(II)‐bis(2,2′‐bipyridyl)(aminopropyl imidazole) on a gold‐deposited screen printed electrode (SPE) has been developed. Since the ECL emission of the Ru(II)‐bis(2,2′‐bipyridyl)(aminopropyl imidazole) complex can be easily obtained at an applied potential of less than +0.8 V, the possibility of the oxidation of the Ru‐complex SAM formed on gold‐deposited SPE electrode surface was greatly diminished and thus the stability of the resulting Ru‐complex SAM‐based ECL sensor was enormously enhanced compared to the previously reported Ru(bpy)32+‐derivative monolayer‐based ECL sensors with applied potentials of more than +1.0 V. In the present study, the gold deposited SPE with carbon nanotube paste was used in order to increase the amount of Ru‐complex immobilized on the electrode surface through a large surface area of deposited gold nanoparticles causing good charge transport and thus leading to the increased sensitivity of the ECL sensor. The ECL characteristics obtained with the present Ru‐complex SAM‐based ECL sensor are compared with those obtained with other Ru(bpy)32+‐SAM‐based ECL sensors.

Electrogenerated chemiluminescence sensor for the determination of.

An electrogenerated chemiluminescence (ECL) sensor for the determination of propranolol hydrochloride was fabricated by employing tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)32+) as an ECL signal producer and graphene as a modified material. The ECL sensor was fabricated by adsorbing Ru(bpy)32+ onto a mixture of graphene and Nafion. The introduction of conductive graphene into Nafion was found to greatly enhance the ECL intensity of Ru(bpy)32+ and the ECL intensity of Ru(bpy)32+ decreased in the presence of propranolol hydrochloride. Based on this phenomenon, a sensitive and stable ECL method was developed for the determination of propranolol hydrochloride by employing a Ru(bpy)32+-graphene-Nafion modified electrode. Under the optimized conditions, the ECL intensity was linear with the concentration of propranolol hydrochloride over a range of 1.0 × 10-10 to 5.0 × 10-9 mol L-1 with a detection limit of 3 × 10-11 mol L-1. The ECL sensor exhibited long-term stability with a relative standard deviation of 4.1% for sixteen continuous determinations of 2.0 × 10-9 mol L-1 propranolol hydrochloride. The developed method has been successfully applied to the determination of propranolol hydrochloride in pharmaceutical samples.

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.

Double Covalent Coupling Method for the Fabrication of Highly Sensitive and Reusable Electrogenerated Chemiluminescence Sensors

A double covalent coupling method for the fabrication of a highly sensitive and reusable electrogenerated chemiluminescence (ECL) chemical sensor for the detection of tertiary amines and ECL aptamer-based (ECL-AB) biosensor for the detection of cocaine is reported. The ECL sensors were constructed by covalent coupling of amino-containing Ru(bpy)(3)(2+) derivatives (Ru1, Ru(bpy)(3)(2+) = tris(2,2'-bipyridyl)ruthenium(II)) or cocaine aptamer-Ru1 to the surface of a paraffin-impregnated graphite electrode that had been covalently modified with a monolayer of 4-aminobenzene sulfonic acid via electrochemical oxidations. ECL performance of the newly developed chemical sensors was evaluated using tri-n-propylamine (TPrA) and metoclopramide (MCP) as model analytes. The sensors exhibited excellent sensitivity, stability, and reproducibility with a detection limit of 30 nM for TPrA and 2.0 nM for MCP, and relative standard deviations (RSDs) of 2.1% over 90 cyclic potential cycles (0 to 1.50 V vs Ag/AgCl) and 2.6% over 45 cycles (0.60 to +1.30 V vs Ag/AgCl) at 400 mV/s for 50 nM TPrA and 200 nM MCP, respectively. For the ECL-AB biosensor, it showed an extremely low detection limit of 10 pM for cocaine, and offered a good selectivity toward cocaine, heroin, and caffeine. This detection limit was about 4-6 orders of magnitude lower than that reported on the basis of alternating current (AC) voltammetry and optical aptamer-based cocaine biosensors. Additionally, the ECL-AB biosensor was highly reusable (RSD = 2.8%, n = 7) and possessed long-term storage stability (96.8% initial ECL recovery over 21 days storage). A binding constant of 4.6 +/- 0.3 x 10(9) M(-1) between cocaine and its aptamer was estimated using an ECL based Langmuir isotherm approach. Wide ranging applications of the presently reported strategy in fabricating various chemical sensors or biosensors are expected.

Electrogenerated Chemiluminescence Sensor Based on Tris(2,2′‐bipyridine)ruthenium(II)‐Immobilized Natural Clay and Ionic Liquid

AbstractA novel electrogenerated chemiluminescence (ECL) sensor based on natural clay and ionic liquid was fabricated. Tris(2,2′‐bipyridine)ruthenium(II) (Ru(bpy)32+) was immobilized on natural clay surface through simple adsorption. An ECL sensor was prepared by mixing Ru(bpy)32+‐incorporated clay, graphite powder and an ionic liquid (1‐butyl‐3‐methylimidazolium hexafluorophosphate) as the binder. The electrochemical behavior and ECL of the immobilized Ru(bpy)32+ was investigated. It was observed that the ECL of immobilized Ru(bpy)32+ was activated by the ionic liquid. The proposed ECL sensor showed high sensitivity to tri‐n‐propylamine (TPrA) and the detection limit was found to be 20 pM. In addition, the ECL sensor displayed good stability for TPrA detection and long‐term storage stability.

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%).

Layer-by-layer assembly of functional silica and Au nanoparticles for fabricating electrogenerated chemiluminescence sensor

We described the use of silica nanoparticles as building blocks for the immobilization of electrogenerated chemiluminescence (ECL) reagent Ru(bpy)32+ and the fabrication of layer-by-layer assembly film by alternating the deposition of the Ru(bpy)32+-doped silica nanoparticles and Au nanoparticles. UV–vis absorption spectroscopy, scanning electron microscopy (SEM), cyclic voltammetry and ECL were used to characterize the uniform growth of the multilayer film. Since Ru(bpy)32+ could still maintain its ECL property when doped into the silica nanoparticles, the as-prepared multilayer film could be used as an effective ECL sensor, and the sensor showed high sensitivity and good stability.

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 sensor for metoclopramide determination based on Ru(bpy) 32+-doped silica nanoparticles dispersed in Nafion on glassy carbon electrode

A novel method for the determination of metoclopramide (MCP) using electrogenerated chemiluminescence (ECL) is presented. A tris(2,2′-bipyridyl)dichlororuthenium(II) (Ru(bpy) 3 2+)-doped silica (RuDS) nanoparticle/perfluoinated ion-exchange resin (Nafion) with nanocomposite membrane modified glassy carbon electrode (GCE) is used. The Ru(bpy) 3 2+ encapsulation interior of the silica nanoparticle maintains its electrochemical activities and also reduces Ru(bpy) 3 2+ leaching from the silica matrix when immersed in water due to the electrostatic interaction. The analytical performance of this ECL sensor for MCP is shown in detail. Under optimal experimental conditions, it has good linearity in the concentration range from 2 × 10 −8 mol/L to 1 × 10 −5 mol/L ( R = 0.9989) with a detection limit of 7 × 10 −9 mol/L. The relative standard deviation ( n = 11) is 3.2% for detecting 1.2 × 10 −6 mol/L MCP. The recoveries are in the range of 97.0–104.4% for sample measurements by standard-addition method. This method has been applied successfully to determine MCP in pharmaceutical preparations and in human urine. Statistical analysis (Student's t-test and variance ratio F-test) of the obtained results show no significant difference between this proposed method and the reference method.