Proposed Electrochemiluminescence Sensor Research Articles

Tailoring a novel all-in-one host-guest solid-state electrochemiluminescence platform for selective detection of spermine using cucurbit-[6]-uril modified [Ru(bpy)3]2+ electrode

Herein, a novel solid-state electrochemiluminescence (ECL) based on electrochemically incorporated [Ru(bpy)3]2+ on nafion modified glassy carbon electrode ([Ru(bpy)3]2+-Nafion/GCE) followed by chemisorption of cucurbit-[6]-uril (CB-[6]) on Ru(bpy)3]2+-Nafion/GCE (as CB-[6]-[Ru(bpy)3]2+-Nafion/GCE) has been developed for selective sensing of spermine (SPM) which belongs to the class of aliphatic biogenic amines and overexpression of SPM is associated with several cancers, particularly “Prostate Cancer” (PCa). Interestingly, the ECL emission of [Ru(bpy)3]2+ be enhanced significantly in the presence of CB-[6] modified [Ru(bpy)3]2+-Nafion/GCE. This is due to inherent ability of CB- [6] act as a co-reactant accelerator. Upon the addition of SPM, the ECL emission was further enhanced due to electron transfer reaction between SPM and [Ru(bpy)3]3+. Selectivity of the proposed ECL sensor towards SPM arises from the host-guest interaction between the CB-[6] and SPM, follows the anodic co-reactant ECL reaction (oxidative reduction mechanism) by confirmation of electrochemical and spectroscopic results like electron spin resonance (EPR) and ECL spectra. The proposed solid-state ECL sensor platform is selectively detect to SPM for a linear range of 10 nM - 5 mM with detection limit (LoD) of 1.4 nM at physiological pH conditions. In addition, the developed ECL platform of CB-[6]-[Ru(bpy)3]2+-Nafion/GCE has been successfully verified to the sensing of SPM in the urine sample, proving the practicability of the proposed sensor is suitable for clinical analysis.

A simplified molecularly imprinted ECL sensor based on Mn2SnO4 nanocubes for sensitive detection of ribavirin.

Conventional single-signal or emerging sandwich-type double-signal electrochemiluminescence (ECL) immunosensors/aptasensors have offered accurate detection of small molecules, yet suffer from complicated setup, long processing time, and non-reusability. Here, we demonstrate a simplified molecularly imprinted ECL sensor based on Mn2SnO4 nanocubes. As an n-type semiconductor, Mn2SnO4 has numerous active sites that can capture electrons to accelerate chemical reactions, resulting in enhanced ECL activity and stability. For the first time, we verify a robust cathodic ECL emission of Mn2SnO4 luminophores in the presence of K2S2O8 coreactants. The proposed ECL sensor applies to the sensitive detection of ribavirin (RBV), endowing a wide linear range (1-2000 ng mL-1), low detection limit (0.85 ng mL-1, S/N = 3), high stability, specificity, and reproducibility, and the detection capability in real milk and chicken samples. This work highlights single semiconductor luminophore-driven molecularly imprinted ECL sensors, meeting the original aspiration of uncomplicated but high-performance sensing in food safety inspection.

Highly Efficient Dual-Color Luminophores for Sensitive and Selective Detection of Diclazepam Based on MOF/COF Bi-Mesoporous Composites.

Currently, studies on electrochemiluminescence (ECL) mainly focused on the single emission of luminophores while those on multi-color ECL were rarely reported. Here, a bi-mesoporous composite of the metal-organic framework (MOF)/covalent-organic framework (COF) with strong and stable dual-color ECL was prepared to construct a novel ECL sensor for sensitive detecting targets. A PTCA-COF with excellent ECL performance was loaded with a great amount of another ECL emitter Cu3(HHTP)2. Remarkably, the integrated composite had both ECL properties of PTCA-COF at 520 nm and Cu3(HHTP)2 at 600 nm wavelengths. Furthermore, Cu3(HHTP)2 with good electron transfer ability can greatly enhance the electrical conductivity and promote electrochemical activation. Thus, the simultaneous enhanced two-color ECL intensity and the catalytic properties of the conductive MOF exerted a dual enhancement effect on the ECL signal of the composite. Significantly, diclazepam can not only be adsorbed well on the multi-stage porous structure MOF/COF composite by π-π interactions but also selectively quench the ECL signal of the PTCA-COF, realizing the sensitive detection. The ECL sensor showed a wide detection range from 1.0 × 10-13 to 1.0 × 10-8 g/L, and the limit of detection (LOD) was as low as 2.6 × 10-14 g/L (S/N = 3). The proposed ECL sensor preparation method was simple and sensitive, providing a new perspective for the potential application of multi-color ECL in the sensing field.

Electrochemiluminescence biosensor for carcinoembryonic antigen detection based on Au-Ag/g-C3N4 nanocomposites

Herein, an electrochemiluminescence (ECL) aptasensor for carcinoembryonic antigen (CEA) detection was developed based on Au-Ag/g-C3N4 nanocomposites (NCs), which were synthesized by decorating graphitic carbon nitride (g-C3N4) nanosheets with alloy-structured Au-Ag bimetallic nanoparticles (NPs) via one-step in situ chemical reduction. As ECL sensing platform, Au-Ag/g-C3N4 NCs could significantly improve the ECL intensity of luminol due to the good conductivity of Au-Ag NPs, electrocatalytic activity for oxygen evolution reaction (OER) and the ability to adsorb luminol via π stacking interaction. In addition, it could load the thiol terminated aptamers of CEA via Au-S or Ag-S bonds. In the presence of CEA, the ECL response of the proposed biosensor decreased significantly due to the fact that the assembled protein layers hindered the electron transfer and the diffusion of ECL reactants toward the electrode surface. The proposed ECL sensor exhibited a good linear relationship with CEA in the range of 1.0–1.0 × 10−6 ng/mL with a detection limit of 8.9 × 10−7 ng/mL. The satisfactory results were obtained in the detection of CEA in human serum samples.

Ruthenium(II) complex encapsulated multifunctional metal organic frameworks based electrochemiluminescence sensor for sensitive detection of hydrogen sulfide

Metal organic frameworks (MOFs) based sensors exhibited a good deal of merits on sensitive detection like low reagent consumption, good chemical stability and high detection efficacy. Here, we reported a novel electrochemiluminescence (ECL) sensor which was based on tris(2,2′-bipyridyl) ruthenium(II) (Ru(bpy)32+) encapsulated multifunctional metal organic frameworks (Ru-MOFs) as nanocarrier and nanoreactor for sensitive detection of H2S. Moreover, novel co-reactants NBD-amine was introduced into the ECL sensor as recognition probe. The introducing of Ru-MOFs successfully increased the amount of luminescent probe in the sensing system. At the same time, the Ru-MOFs as nanoreactors improved the molecule reaction efficiency inside the MOFs, including Ru(bpy)32+/co-reactants, and NBD-amine/H2S. Furthermore, the Ru-MOFs has superior adsorption capacity for H2S, which will facilitate the enrichment of H2S at the sensing interface. These were all contributed to enhance the ECL signal and improve the sensitivity of proposed ECL sensor. As a result, the proposed ECL sensor had excellent detection performance for H2S with the dynamic range from 1.0 × 10−11 mol L−1 to 1.0 × 10−4 mol L−1 and the detection limit was 2.5 × 10−12 mol L−1.

Electrochemiluminescence Sensor Based on N-Doped Carbon Quantum Dots for Determination of Ceftazidime in Real Samples

In this work, we report an electrochemiluminescence (ECL) sensor based on nitrogen doped carbon quantum dots (N-CQDs), which has been synthesized by a solvothermal method. The N-CQDs were characterized using various techniques such as high-resolution transmission electron microscopy (HR-TEM), field emission scanning electron microscopy (FE-SEM), UV–vis absorption and photoluminescence spectroscopy, FT-IR spectroscopy, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The potential sweep range (−0.5 to −2.2 V) shows a stable and strong ECL signal. Interestingly, the ECL intensity only decreased by less than 20% after storing at 4 °C for 10 months. The applicability of the N-CQD sensor in electroanalytical chemistry was identified by the linear ECL on–off response for ceftazidime in a concentration range from 1 × 10−7 to 5 × 10−4 mol l–1 and a detection limit of 2.3 × 10−8 mol l–1. The results suggest that the proposed ECL sensor is robustly applicable for analysis of ceftazidime in real samples such as human serum, bovine milk and commercial milk powder.

‘On-off-on’ electrochemiluminescent aptasensor for Hg2+ based on dual signal amplification enabled by a self-enhanced luminophore and resonance energy transfer

• A dual signal amplification strategy was developed for ‘on–off-on’ ECL system. • Self-enhaced luminophore of Ru@SiO 2 -NGQDs provided the first ‘switch on’ signal. • The ‘switch off’ signal was obtained by the ERET between Ru@SiO 2 -NGQDs and AuNPs. • Hg 2+ induced the second ‘switch on’ signal with amplified ECL recovery efficiency. • The method exhibited wide linear range, low LOD and good selectivity for Hg 2+ assay. Divalent mercury ion (Hg 2+ ) is widely distributed in the ecological environment and harmful to the human body and the environment. Herein, a highly sensitive and selective ‘on–off-on’ electrochemiluminescence (ECL) aptamer sensing method based on the dual signal amplification strategy of a self-enhanced luminophore and ECL resonance energy transfer (ECL-RET) was developed to detect Hg 2+ . In detail, the first ‘switch-on’ state was obtained by the self-enhanced luminophore of Ru(bpy) 3 2+ -doped silica nanoparticle-nitrogen-doped graphene quantum dots (Ru@SiO 2 -NGQDs) modified glassy carbon electrode, which significantly amplified the ECL intensity compared with the mixture of Ru@SiO 2 and NGQDs. Later, the ‘switch-off’ state was induced by gold nanoparticles (AuNPs), which acted the acceptor in the ECL-RET system between AuNPs and Ru@SiO 2 -NGQDs due to their good spectral overlap. This combination of the self-enhanced luminophore and ECL-RET provided a novel dual signal amplification strategy, which led to a high signal-to-noise ratio and high analysis sensitivity. Finally, upon the addition of Hg 2+ , the formation of a stable T-Hg 2+ -T structure induced the release of AuNPs from the sensing interface and halted the ECL-RET process, resulting in ECL signal recovery (the second ‘switch-on’ state). For the detection of Hg 2+ , the proposed ECL sensor exhibited a wide linear range from 1 × 10 −14 to 1 × 10 −6 M and a highly sensitive detection limit of 3.0 fM. Finally, the feasibility of the developed method in water sample analysis was investigated.

Electrochemiluminescence Immunosensor Based on Nanobody and Au/CaCO3 Synthesized Using Waste Eggshells for Ultrasensitive Detection of Ochratoxin A.

A novel ultrasensitive electrochemiluminescence (ECL) immunoassay based on Au/CaCO3 was proposed for detecting ochratoxin A (OTA) in coffee. Au/CaCO3 nanocomposites synthesized using waste eggshells as the template with a large surface area and excellent electrochemical properties were applied for immobilizing a large amount of Ru(bpy)32+ and conjugating a high-affinity nanobody (prepared by the phage display technique). Coupling of the Au/CaCO3 nanocomposites and nanobody technologies provided an ultrasensitive and highly selective ECL immunosensor for OTA detection in the range of 10 pg/mL–100 ng/mL with a low detection limit of 5.7 pg/mL. Moreover, the as-prepared ECL immunosensor showed excellent performance and high stability. Finally, the proposed ECL sensor was applied to analyze OTA in coffee samples, confirming the desirable accuracy and practical applicability potential. Overall, this work presents a new nanomaterial for fabricating the sensing interface of immunosensors by harnessing natural waste as the source and a method for detecting toxic OTA in foods.

An immobilization-free and homogeneous electrochemiluminescence assay for detection of environmental pollutant graphene oxide in water

• An immobilization-free and homogeneous ECL sensor for GO detection was proposed. • The fabricated ECL sensor has the merits of simplicity and sensitivity. • The proposed ECL sensor avoids the complex process of electrode modification. • Satisfactory recoveries were obtained for GO detection in river water and wastewater. As a new type of environmental pollutant, the toxicity of graphene oxide (GO) has been worldwide concerned, however, studies on detection of such pollutant is rarely studied up to date. In this work, an immobilization-free homogeneous electrochemiluminescence (ECL) method for effective detection of GO was developed based on the quenched ECL signal of luminol induced by GO. As an important luminophor, luminol possessed super ECL performance in alkaline buffer solution at bare glassy carbon electrode; while after GO was added, the inhibited ECL signal was obtained due to the dynamic quenching process between luminol emitter and GO quencher. More interestingly, the inhibited ECL signal of the luminol was depended on the concentration of the added GO. Under optimal conditions, a good linear relationship between the inhibited ECL signal of luminol versus the logarithm of the concentration of GO was obtained in the range of 0.08 ~ 800 μg mL −1 with a detection limit of 0.03 μg mL −1 (S/N = 3). Moreover, the method provided recoveries of 103 ~ 107.5% for river water and 108 ~ 110.6% for chemical wastewater when applied to spiked samples of real environmental water.

Electrochemiluminescence sensor based on the target recognition-induced aggregation of sensing units for Hg2+ determination

Abstract In this work, the target recognition-induced aggregation of sensing units was initiated on a solid electrode to develop an enhanced surface-tethered electrochemiluminescence (ECL) sensor for Hg2+ analysis. Thymine (T) was assembled on upconversion nanoparticles (UCNP) as sensing units (T-UCNP). In the presence of Hg2+, the T monolayer-modified Au electrode (AuE/T) absorbed Hg2+ and T-UCNP by T-Hg2+-T matching. Surface-tethered T-UCNP further recruited more Hg2+, as well as T-UCNP, thus forming a UCNP-T-Hg2+-T-UCNP reticular architecture on the surface of the electrode. Hg2+ quantification was subsequently conducted by detecting the ECL signal amplified by the captured UCNP. During ECL analysis, target recognition and signal accumulation were simultaneously realized by the target-induced aggregation of T-UCNP. The simple and flexible strategy proposed in this work immobilized ECL emitters efficiently and simplified the preparation procedure of the sensor. The proposed ECL sensor displayed a low limit of detection (LOD) of 0.4 pmol L−1 and favorable recoveries (84.8 %–98.7 %) during real-sample analysis.

Multifunctional Zinc Oxide Promotes Electrochemiluminescence of Porphyrin Aggregates for Ultrasensitive Detection of Copper Ion.

The design and exploration of highly efficient organic luminophores for an electrochemiluminescence (ECL) sensor is a fascinating and promising subject. Herein, we present a surfactant-assisted self-assembly of 5,10,15,20-tetrakis (4-carboxyphenyl) porphyrin (TCPP) J-aggregate as a robust organic luminophore to construct the solid-state ECL sensing platform with significantly enhanced and constantly stable signals, by using peroxydisulfate (S2O82-) as the coreactant, and l-cysteine capped zinc oxide nanoflowers (ZnO@Cys NFs) as the multifunctional energy donor and coreactant accelerator. Compared with TCPP monomer, this TCPP J-aggregate possesses a unique aggregation-induced electrochemiluminescence (AIECL) performance, which results in 5-fold enhancement in red-light ECL emission at 675 nm. The resonance energy transfer from the ZnO@Cys NFs (energy donor) to the TCPP J-aggregate (energy acceptor) substantially improves the ECL intensity and stability. ZnO@Cys NFs have also been used as a coreactant accelerator to promote the conversion of more S2O82- into SO4•-. The corresponding ECL mechanism has been investigated by UV-vis absorption spectrum, photoluminescence, ECL, and density functional theory. Since l-cysteine on ZnO@Cys NFs can efficiently realize bidentate chelation with Cu2+, the proposed ECL sensor shows a highly selective and sensitive quenching effect for the detection of Cu2+ with a wide linear range from 1.0 pmol·L-1 to 500 nmol·L-1 and a detection limit of 0.33 pmol·L-1, paving a bright research direction for the development of TCPP aggregates in ECL field.

Electrochemical synthesis of phosphorus and sulfur co-doped graphene quantum dots as efficient electrochemiluminescent immunomarkers for monitoring okadaic acid

In this study, water-dispersed, uniform-sized phosphorus and sulfur co-doped graphene quantum dots (P, S-GQDs) were prepared by the one-step electrolysis of a graphite rod in an alkaline solution containing sodium phytate and sodium sulfide. Compared with GQDs and mono-doped GQDs (P-GQDs and S-GQDs), the P, S-GQDs dramatically improved the electrochemiluminescence (ECL) performance. Therefore, they were used as bright ECL signaling markers through conjugation with a monoclonal antibody against okadaic acid (anti-OA-MAb). Moreover, as an effective matrix for OA immobilization, the carboxylated multiwall carbon nanotubes-poly(diallyldimethylammonium) chloride-Au nanocluster (CMCNT-PDDA-AuNCs) composite promoted electron transfer and enlarged the surface area. Owing to the multiple amplifications, a competitive indirect ECL immunosensor for highly sensitive quantitation of OA has been developed. Under the optimized conditions, the 50% inhibitory concentration (IC50) of the immunosensor was 0.25 ng mL−1, and its linear range was 0.01–20 ng mL−1 with a low detection limit of 0.005 ng mL−1. Finally, the proposed ECL sensor was successfully utilized to detect OA contents in mussel samples. Therefore, this study provides new insights into the designation of ECL luminophores and expands application of co-doped GQDs in fabrication of ECL immunosensors for shellfish toxin determination.

Facile electrochemiluminescence sensing platform based on water-soluble tungsten oxide quantum dots for ultrasensitive detection of dopamine released by cells

This report outlines an ultrasensitive electrochemiluminescence (ECL) sensing platform based on water-soluble tungsten oxide quantum dots (WOx QDs) for the detection of dopamine (DA) released from P12 cells. The WOx QDs with good stability and water solubility were prepared by a facile and green hydrothermal method, and used to modify a glassy carbon electrode (WOx QDs/GCE). The proposed ECL sensor exhibited a stable and strong cathodic ECL signal when potassium peroxodisulfate (K2S2O8) as the coreactant in aqueous solution. The possible ECL mechanism was studied and deduced, and the ECL response signal of the proposed sensor decreased rapidly in the presence of dopamine (DA). Under optimal conditions, the ECL signals of WOx QDs linearly decreased with the increase of DA concentration in the range of 10−15 M to 10−9 M and 10−9 M to 10−5 M, respectively. The detection limit was as low as 10−15 M (S/N = 3). Based on these results, this method has been successfully applied to the determination of DA released by PC12 cells. The detection linear range for the detection of DA released by PC12 cells was from 0.1 to 0.9 μM with a detection limit of 0.045 μM. Therefore, the proposed ECL sensor displayed high sensitivity, good specificity and long-term stability, which may shed light on a new way to construct other high-performance ECL detection systems based on WOx or WOx QDs-based nanocomposites.

A novel ECL sensor based on a boronate affinity molecular imprinting technique and functionalized SiO2@CQDs/AuNPs/MPBA nanocomposites for sensitive determination of alpha-fetoprotein

In this work, a boronate-affinity sandwich electrochemiluminescence (ECL) sensor was constructed to detect alpha-fetoprotein (AFP) based on a multiple signal amplification strategy. Gold nanoparticles (AuNPs) were utilized and modified on the surface with chitosan in order to facilitate electron transfer. The composite of the molecularly imprinted polymer (MIP) enhanced the selectivity of alpha-fetoprotein detection. 4-mercaptophenylboronic acid (MPBA) was used as the tracing tag for capture of alpha-fetoprotein. SiO2 nanoparticles carried carbon quantum dots (CQDs) labeled with gold nanoparticles and produced an ECL signal. Under the optimum experimental conditions, the linear range for alpha-fetoprotein was between 0.001 and 1000 ng/mL with a correlation coefficient of 0.9952, and the detection limit was 0.0004 ng/mL (S/N = 3). This proposed ECL sensor displayed several advantages, including outstanding selectivity, fine reproducibility, high sensitivity, low detection limit and wide linear range. Furthermore, the newly constructed boronate-affinity sandwich ECL sensor was successfully applied to the determination of alpha-fetoprotein in serum samples, indicating great potential for application in clinical diagnostics.

An Electrochemiluminescence Sensor Based on Nafion/Magnetic Fe₃O₄ Nanocrystals Modified Electrode for the Determination of Bisphenol A in Environmental Water Samples.

The well-dispersive and superparamagnetic Fe3O4-nanocrystals (Fe3O4-NCs) which could significantly enhance the anodic electrochemiluminescence (ECL) behavior of luminol, were synthesized in this study. Compared to ZnS, ZnSe, CdS and CdTe nanoparticles, the strongest anodic ECL signals were obtained at +1.6 V on the Fe3O4-NCs coated glassy carbon electrode. The ECL spectra revealed that the strong ECL resonance energy transfer occurred between luminol and Fe3O4-NCs. Furthermore, under the optimized ECL experimental conditions, such as the amount of Fe3O4-NCs, the concentration of luminol and the pH of supporting electrolyte, BPA exhibited a stronger distinct ECL quenching effect than its structural analogs and a highly selective and sensitive ECL sensor for the determination of bisphenol A (BPA) was developed based on the Fe3O4-NCs. A good linear relationship was found between the ECL intensity and the increased BPA concentration within 0.01–5.0 mg/L, with a correlation coefficient of 0.9972. The detection limit was 0.66 × 10−3 mg/L. Good recoveries between 96.0% and 105.0% with a relative standard deviation of less than 4.8% were obtained in real water samples. The proposed ECL sensor can be successfully employed to BPA detection in environmental aqueous samples.

Versatile Electrochemiluminescence Assays for PEDV Antibody Based on Rolling Circle Amplification and Ru-DNA Nanotags.

The sensitive and accurate detection methods for PEDV antibody have practical significance for the prevention and treatment of PEDV. In this work, a new multiple pathways signal amplification method was proposed to construct a sensitive electrochemiluminescence (ECL) platform for the detection of PEDV antibody. Using Au NP-modified graphene nanosheet (Au-GN) as the substrate, antibody-antigen reaction as the recognition unit, rolling circle amplification (RCA) for signal enhancement, and assembled cascade Ru-DNA nanotags as signal label, the proposed platform behaved with good specificity and sensitivity. The binding system of biotin-streptavidin, RCA, and Ru(bpy)32+-doped silica nanoparticles (Ru SNPs) showed remarkable amplification efficiency, low background signal, and little nonspecific adsorption. Moreover, the proposed ECL sensor exhibited good analytical performance for PEDV antibody with a wide linear range from 0.1 pg mL-1 to 5000 pg mL-1 with a detection limit of 0.05 pg mL-1 ( S/ N = 3). The proposed strategy exhibited the advantages of excellent stability and sensitivity for determination of the PEDV antibody, which was easy to prepare and had a good application prospect.

Sensitive detection of hydroquinone based on electrochemiluminescence energy transfer between the exited ZnSe quantum dots and benzoquinone

We proposed a signal amplification strategy designed for sensitive electrochemiluminescence (ECL) detection of hydroquinone (HQE) in water. The detection mechanism is based on the ECL energy transfer (ET) can generate between the excited ZnSe quantum dots (QDs) and the benzoquinone (BQE) obtained by oxidation of hydroquinone. The ECL-ET resulted in the quenching effect of the cathodic ECL of ZnSe QDs using S2O82− as co-reactant. Because the graphene of outstanding electronic conductivity can accelerate the electron transfer rate between the ZnSe QDs on electrode and S2O82− in the electrolyte solution, so that larger than 3-fold enhance in ECL intensity was obtained after ZnSe QDs decorated on graphene. Under the optimal conditions, the linear range for hydroquinone was 1 × 10−9–1 × 10−6 mol/L with a detection limit of 3.4 × 10−10 mol/L (S/N = 3). The proposed ECL sensor showed the performance advantages of fine selectivity, high sensitivity, low detection limit, wide linear range and good reproducibility. It will hold an enormous potential in the field of environmental analysis.

A sensitive solid-state electrochemiluminescence sensor for clenbuterol relying on a PtNPs/RuSiNPs/Nafion composite modified glassy carbon electrode

In this work, a highly sensitive electrochemiluminescence (ECL) sensor for the detection of clenbuterol (CBT) in pork is reported. The fabrication of the sensor was carried out by modification of a glassy carbon electrode (GCE) with platinum nanoparticles (PtNPs)/silica nanoparticles doped with [Ru(bpy)3]2+ (RuSiNPs)/Nafion composite. The morphology, composition and electrochemical behavior of the PtNPs/RuSiNPs were characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy and electrochemical impedance spectroscopy, respectively. It was found that all the PtNPs are formed on the surface of RuSiNPs and the electron transfer resistance was obviously reduced on the PtNPs/RuSiNPs GCE. Taking the advantage of the Si-O-Si grid of RuSiNPs, the [Ru(bpy)3]2+ luminophore leaching from the modified electrode could largely be prevented, benefiting the ECL signal stability. Moreover, due to the enhanced electron transfer rate and electrocatalytical property of the PtNPs, the sensitivity of the PtNPs/RuSiNPs-based sensor was greatly improved. Under optimized conditions, the ECL peak intensity was linear with the concentration of CBT in the range of 5–100ngmL−1, with a detection limit as low as 0.8ngmL−1. The recoveries of the CBT obtained from spiked pork samples at PtNPs/RuSiNPs/Nafion GCE were between 89.5% and 106.3% and the RSDs were lower than 6.21%. The proposed ECL sensor based on PtNPs/RuSiNPs composite presented good characteristics for CBT determination in terms of rapid, high sensitivity and good stability, promising the applicability of this sensor in real samples.

Electrochemiluminescence behavior of meso-tetra(4-sulfonatophenyl)porphyrin in aqueous medium: its application for highly selective sensing of nanomolar Cu(2.).

The cathodic electrochemiluminescence (ECL) behavior of meso-tetra(4-sulfonatophenyl)porphyrin (TSPP) with potassium peroxydisulfate (K2S2O8) as the coreactant in aqueous solution with strong and stable emission was exploited to determine Cu(2+) down to nanomolar concentration. Two possible reaction mechanisms have been proposed to understand the generation of ECL by the TSPP/K2S2O8 system. The effects of the concentration of TSPP and K2S2O8, pH of the medium, and scan rate on the ECL intensity were studied in detail. The ECL intensity was efficiently quenched by trace amounts of Cu(2+). This phenomenon was used to develop a new method, which can offer rapid, reliable, and selective detection of Cu(2+). Under the optimum conditions, plots of the ECL of the TSPP/K2S2O8 system versus the concentration of Cu(2+) are linear in the range of 5 to 160 nM with a detection limit of 1.56 nM (S/N = 3). The proposed ECL sensor was successfully applied for analysis of tap and river water samples. It is anticipated that TSPP could be a new class of promising luminescent agent for ECL sensors. Graphical Abstract A two-step cathodic elelctrochemiluminescence (ECL) behavior of TSPP/K2S2O8 system in the aqueous solution and Cu(2+) determination using the same.

Electrolytic exfoliation synthesis of boron doped graphene quantum dots: a new luminescent material for electrochemiluminescence detection of oncogene microRNA-20a

In this work, boron doped graphene quantum dots (BGQDs) with the atomic percentage of boron (B) of 0.67-2.26% were synthesized by electrolytic exfoliation of B doped graphene rods. X-ray photoelectron spectroscopy of BGQDs confirmed that the B atoms have been successfully incorporated into the GQDs. Characterizations by transmission electron microscopy, photoluminescence (PL) spectra and UV-visible spectra demonstrated that BGQDs had a consistent lattice spacing with the plane of graphene and possessed good luminous performance. The PL stability, the electrochemical impedance and Zeta potential test indicated that the 60 days-PL stability of BGQDs was improved by 51% and the resistance of BGQDs was decreased by 11% compared with that of the pure GQDs when 1.29% (atomic percentage) of B was doped. Electrochemiluminescence (ECL) sensing results showed that the ECL sensor with BGQDs as luminescent material exhibited an excellent analytical property for the detection of miRNA-20a in a linear range of 0.1-1×104 pM with a quantification limit of 0.1 pM. Specificity tests showed that this ECL sensor could distinguish the target miRNAs-20a with several similar bases strand. The obtained results in this study prove that the proposed ECL sensor provides a high sensitively, specifically and simply platform for detection of miRNAs-20a.