Electronic Transmission Rate Research Articles

Activation of peroxymonosulfate by β-FeOOH@Cia-MoS2 for enhancing degradation of tetracycline: Significant roles of surface functional groups and Fe/Mo redox reactions

Vertically oriented interstitial atom carbon-anchored molybdenum disulfide (Cia-MoS2) nanospheres loaded with iron oxyhydroxide (β-FeOOH) were proposed for modulating the surface catalytic activity and stability of the unsaturated catalytic system. The β-FeOOH@Cia-MoS2 efficiently activated peroxymonosulfate (PMS) to degrade 95.4% of tetracycline (TC) within 30 min, owing to the more sulfur vacancies, higher surface hydroxyl density, redox ability and electronic transmission rate of β-FeOOH@Cia-MoS2. According to the characterization and analysis data, the multiple active sites (Fe, Mo and S sites) and oxygen-containing functional groups (CO, –OH) of β-FeOOH@Cia-MoS2 could promote the activation of PMS to form reactive oxygen species (ROS). The oxidation cycle of Fe(II)/Fe(III) and Mo(IV)/Mo(VI), the electron transfer mediator of rich sulfur vacancies, as well as oxygen-containing functional groups on the surface of β-FeOOH@Cia-MoS2 synergistically promoted the formation of ROS (1O2, FeIVO, SO4•- and •OH), among which 1O2 was the main active oxidant. In particular, the β-FeOOH@Cia-MoS2/PMS system could still degrade pollutants efficiently and stably after five recycling cycles. Furthermore, this system had a strong anti-interference ability in the actual water body. This study provided a promising strategy for the removal of difficult-to-degrade organic pollutants.

Ti3C2 MXene-induced interface charge transferred in Z-scheme heterojunction for efficient photocatalytic removal of nitric oxide

Currently, NO pollution is an urgent challenge for us to face, and photocatalytic degradation has been recognized as one of the most promising methods to reduce it. As a representative photocatalyst, g-C3N4 has attracted researchers because of its low cost and excellent performance. In this work, a new triphasic Z-scheme heterostructure was built, TiO2/Ti3C2 MXene/g-C3N4, to improve the visible-light irradiation-induced NO removal efficiency of g-C3N4. In this Z-scheme heterostructure, Ti3C2 MXene could form a directional electron transfer thoroughfare between g-C3N4 and TiO2 to accelerate the electronic transmission rate, meanwhile, due to the specificity of the band structure, electrons on conduction band of g-C3N4 and holes on valence band of TiO2 can be well separated and react with the adsorbed species to achieve good photocatalytic performance. Because of the triphasic heterostructure formed by TiO2, Ti3C2 MXene and g-C3N4, the efficiency of this compound for visible-light irradiation-induced NO removal improves from 32% to 56%. This work provides a new strategy to improve NO removal efficiency and shows a broader application prospect of photocatalysts with a triphasic structure.

Introducing AgNPs-VB2 composites as the dual signal quenching of CeO2–AuNPs-g-CNQDs hybrids for ultrasensitive “on-off” electrochemiluminescence immunosensing of prostate specific antigen

An ultrasensitive resonance energy transfer based “on-off” switch electrochemiluminescence (ECL) immunosensing strategy was proposed and applied for prostate specific antigen (PSA) detection. In detail, self-enhancing nanohybrids of nano-CeO2 and AuNPs decorated graphitic carbon nitride quantum dots (CeO2–AuNPs–g-CNQDs) were synthesized, which produced high ECL emission with coreactant K2S2O8 for “switch-on” state. Noticeably, due to the reversible Ce3+↔ Ce4+ reaction, nano-CeO2 could serve as highly-efficient coreaction accelerator and induce the decomposition of S2O82− into SO4• -, which endowed the g-CNQDs/K2S2O8 system with enhanced ECL emission. Moreover, AuNPs acted crucial role in promoting the electronic transmission rate and providing sites to immobilize the biomolecules. On the other hand, the AgNPs-VB2 nanocomposites were used as dual labels to quench the ECL signal of g-CNQDs-K2S2O8 system via ECL-RET, leading to the decreased ECL for “switch-off” state. On the basis of sandwich-typed immunosensing strategy, the developed ECL immunosensing platform exhibited sensitive response to PSA in a linear range of 1.0 × 10−5 _ 50 ng mL−1 with a low detection limit of 0.0045 pg mL−1 (S/N = 3). This work provided a promising tool in early clinical diagnostics of prostate cancer.

Catechin mediated green synthesis of Au nanoparticles: Experimental and theoretical approaches to the determination HOMO-LUMO energy gap and reactivity indexes for the (+)-epicatechin (2S, 3S)

This work suggests a green method for synthesizing Au nanoparticles (AuNPs) using the aqueous extract of Salix aegyptiaca extract. The mechanism of green synthesized AuNPs was examined by molecular electrostatic potential (MEP) calculations. AuNPs were characterized with different techniques such as Ultraviolet–visible spectroscopy (UV–vis), Fourier-transform infrared spectroscopy (FT-IR) spectroscopy, X-ray diffraction (XRD), and Transmission electron microscopy (TEM). Electrochemical investigation of modified glassy carbon electrode using AuNPs (AuNPs/GCE) shows that the electronic transmission rate between the modified electrode and [Fe (CN) 6 ] 3−/4− increased. Process of oxidation, energy gap, and chemical reactivity indexes of the (+)-epicatechin (2S,3S) were investigated using electrochemical techniques (cyclic voltammetry (CV) and differential pulse voltammetry (DPV) as well as UV–Visible spectroscopy and compared with quantum mechanical calculations. DPV and CV were used to obtain HOMO energies of the (+)-epicatechin (2S,3S), an optical energy gap was obtained from the UV–Vis spectroscopy. Frontier molecular orbitals analysis (FMO) and reactivity indexes such as chemical hardness (ŋ), electrophilicity (ώ), electronic chemical potential (μ), electron acceptor power (ώ + ), electron donor power (ώ − ) were determined with functional theory (DFT) calculations. In summary, the HOMO energy obtained from the experimental analyses (E HOMO (from DPV) = -5.24 eV, and E HOMO (from CV) = -5.28 eV) has a relative agreement with the HOMO energy calculated by B3LYP/6–31 g (d, p) including the solvent effect (water) (E HOMO (from B3LYP) = -5.75 eV). Also, UV–Vis spectroscopy gives the bandgap energy equal to 4.31 eV, while the 4.13 eV is calculated by TD-DFT-b3lyp/6–31 + g(d).

Improved NH3-N conversion efficiency to N2 activated by BDD substrate on NiCu electrocatalysis process

We developed a novel boron-doped diamond (BDD) electrode by the modification of bimetallic NiCu catalysts via electrochemical co-deposition method for improving the NH3-N conversion efficiency and selectivity to N2 in aqueous solution. It shows that the N2 selectivity of ammonia oxidation reaction (AOR) reached 88.62% with the NH3-N oxidation efficiency of 44.8% in 6 h. The high current efficiency of 84.17% was achieved at 1.2 V (vs Ag/AgCl), and the energy consumption was 8.19 kW·h/(kgN). Furthermore, the reaction mechanism has been investigated by in-situ Raman spectra, X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) during the reaction. It is verified that the BDD substrate plays a crucial role not only in the improvement of electronic transmission rate and but also the generation of abundant hydroxyl radicals (·OH) which provide proper hydrogen acceptors for the N-H bond activation processes. Theoretical calculations further reveal the doping effect of Cu(OH)2 with NiOOH that constructs the Cu/Ni concerted metal-nitrogen interaction, which stabilizes the relative energies of the intermediates thus promoting the reaction. This work sheds new light on the mechanism of selective electrochemical oxidation of NH3-N and develops an innovative technology of catalytic anode design toward wastewater treatment.

The Bio-fabrication of Gold Nanoparticles (AuNPs) by Green Method and Study of its Electrochemical Applications

This study reports a green method for the synthesis of gold nanoparticles (AuNPs) using the aqueous extract of Salix aegyptiaca extract. The effects of gold salt concentration, extract concentration and extract quantity were investigated on nanoparticles synthesis. Novel methods of ideally synthesizing AuNPs are thus thought that are formed at ambient temperatures, neutral pH, low costs and environmentally friendly fashion. AuNPs were characterized with different techniques such as UV–vis spectroscopy, FT-IR spectroscopy, X-ray diffraction, and TEM. FT-IR spectroscopy revealed that gold nanoparticles were functionalized with biomolecules that have primary carbonyl group, -OH groups and other stabilizing functional groups. TEM experiments showed that these nanoparticles are formed with various shapes and X-ray diffraction pattern showed high purity and face centered cubic structure of AuNPs. For electrochemical properties of AuNPs, a modified glassy carbon electrode using AuNPs (AuNPs/GCE) was investigated. The results show that electronic transmission rate between the modified electrode and [Fe (CN)6]3-/4- increased.

Emerging 2D-Layered MnPS3/rGO composite as a superior anode for sodium-ion batteries

Abstract Two-dimensional (2D) layered materials were widely investigated due to their unique sodium storage properties and rapid ion transport rates. Herein, we synthesized a 2D layered transition metal phosphorus sulfide MnPS3 by one step high-temperature solid-phase synthesis. After combining with graphene by high-energy ball milling followed by high-temperature argon calcination, the novel 2D/2D heterojunction of extra-thin MnPS3/rGO was successfully prepared. The resultant MnPS3/rGO hybrid can strengthen the conductivity of the material and ameliorate the volume change during the insertion/extraction process of the sodium-ion storage, compared to the pristine MnPS3. As a result, the 2D/2D heterojunction of ultra-thin MnPS3/rGO composite exhibits high cycling performance (290 mAh g−1 after 150 cycles at 0.2 A g−1), capacity retention rates up to 92%. The superior performance is ascribed to the combination of extra-thin MnPS3 nanosheets with graphene, which effectively enhances the interface contact area and the electronic transmission rate, greatly improving the adaptability of volume change and interfacial charge transfer abilities. This work provides a novel and promising MnPS3/rGO anode for sodium-ion batteries.

1T/2H MoS2 nanoflowers decorated amorphous Mo-CoSx skeleton: A ZIF-based composite electrocatalyst for the hydrogen evolution reaction

Electronic regulation through component precise control at the atomic level of electrocatalysts has a fundamental influence on the efficiency of hydrogen evolution reaction (HER). Herein, we successfully demonstrate a ZIF-based charge transfer medium for improving the electrocatalytic activity of MoS2 towards HER. Benefit for the enough porous structure, superior electron conductivity as well as the synergistic effect from the doped atoms, the hybrids phase (1T/2H) MoS2 nanoflowers decorated amorphous Mo-CoSx skeleton exhibited the promotional electrocatalytic performance in efficiency and stability. Specifically, an extremely low overpotential of 73 mV at the current density of −10 mA cm−2 and an impressive Tafel slope of 39.2 mV dec−1 had been achieved from the nanocomposites in an acidic condition (0.5 M H2SO4). The satisfactory activity improvement can be ascribed to the enhancement of electronic transmission rate as well as the synergistic effects between the doped Mo element and CoSx. This work might develop a new avenue to design highly efficient multicomponent electrocatalysts towards HER.

Synergetic activation of peroxymonosulfate by MnO2-loaded β-FeOOH catalyst for enhanced degradation of organic pollutant in water

In this paper, manganese dioxide (MnO2) loaded iron oxyhydroxide (β-FeOOH) was synthesized aiming to improve the catalytic performance of β-FeOOH as peroxymonosulfate activator. The β-FeOOH@MnO2/PMS system exhibited excellent performance and its reaction rate constant of Acid Orange 7 (AO7) degradation (0.0533 min−1) was approximately 2.3 times as that in β-FeOOH/PMS system (0.0232 min−1). β-FeOOH@MnO2 possessed superior properties as catalyst than β-FeOOH, owing to the higher surface hydroxyl density with higher specific surface area, redox ability and electronic transmission rate. Moreover, on the basis of the analysis from FTIR and XPS, it was found that the redox reaction of Fe3+/Fe2+ and Mn4+/Mn3+ synergistically activated PMS as well as the generation of FeOH+ and MnOH2+ accelerated activating PMS in the β-FeOOH@MnO2/PMS system. Thus, MnO2 and FeOOH synergistically activated PMS to reactive oxygen species (ROS). And 1O2, O2− and OH were identified as predominant ROS in the β-FeOOH@MnO2/PMS system on the basis of the result from quenching experiments and ESR. As a result, TOC removal rate was increased up to 22.62%. Additionally, β-FeOOH@MnO2 exhibited good stability with low iron dissolution and manganese dissolution. Generally, this study proposed that β-FeOOH@MnO2 was an efficient and environmental catalyst as PMS activator for organic pollutant degradation in water.

An electrochemiluminescence immunosensor based on ZnSe@ZnS QDs composite for CEA detection in human serum

ZnSe@ZnS QDs were synthesized by a simple one-step method. The prepared ZnSe@ZnS quantum dots (ZnSe@ZnS QDs) composite showed a strong cathode ECL emission using potassium persulfate (K2S2O8) as a co-reactant. The poly-(diallyldimethylammonium chloride) (PDDA) reduced graphene oxide (PDDA-rGO) composite provided a larger activity site could conjugate more ZnSe@ZnS QDs and second antibody (Ab2) to improve the sensitivity of the ECL immunosensor. The electrode modified with Au NPs was employed for immobilization of primary antibodies (Ab1) and enhancing the electronic transmission rate of the immunosensor. A novel ECL immunosensor was constructed using Au NPs as a sensing platform and PDDA-rGO/ZnSe@ZnS QDs composite as signal probe for highly-sensitive carcinoembryonic antigen (CEA) detection in human serum. Under optimal conditions, a range of 0.0001–100ng/mL and the detection limit of 0.029pg/mL for CEA were obtained. This ECL immunosensor possesses long-term stability, good reproducibility and high sensitivity. These are promising qualities for detecting biomarkers, drugs, and environmental pollutants.

A H2O2-free electrochemiluminescence immunosensor constructed on all-in-one bioprobe comprised of TiO2-B supported fluoro-coumarin silicon phthalocyanine for deoxynivalenol sensing

A highly sensitive electrochemiluminescence (ECL) immunosensor was fabricated for the quantitative analysis of deoxynivalenol (DON) based on an effective all-in-one bioprobe that composed of TiO2-B with Fluoro-coumarin silicon phthalocyanine (F-couSiPc) and luminol. Herein, TiO2-B with large specific area was served as a favorable carrier, greatly increased the loading of enhancer F-couSiPc and luminophore luminol, resulting in the tremendous enhancement of ECL signal. Specifically, F-couSiPc as coreaction accelerator could facilitate the decomposition of dissolved O2 to generate substantial reactive oxygen species (ROS) to participate in the ECL reaction of luminol. Additionally, the prepared PEDOT/HA@mp MnO2 was employed as the sensing platform of biosensor, which can not only capture substantial antibody to improve the sensitivity, but also could expedite the electronic transmission rate to make the ECL intensity further amplified. Ultimately, the proposed immunosensor presented favorable performance for the determination of DON, such as high sensitivity, good stability, wide liner range (from 1.0*10−6 ng/mL to 10 ng/mL) and a low detection limit of 3.3*10-7 ng/mL.

An ultrasensitive electrochemiluminescent immunosensor based on graphene oxide coupled graphite-like carbon nitride and multiwalled carbon nanotubes-gold for the detection of diclofenac

In this study, a novel competition-type electrochemiluminescent (ECL) immunosensor for detecting diclofenac (DCF) was fabricated with graphene oxide coupled graphite-like carbon nitride (GO-g-C3N4) as signal probe for the first time. The ECL intensity of carboxylated g-C3N4 was significantly enhanced after being combined with graphene oxide (GO) which exhibited excellent charge-transport property. The sensing platform was constructed by multiwalled carbon nanotubes and gold nanoparticles (MWCNTs-AuNPs), which not only provided an effective matrix for immobilizing a large amount of coating antigen but also facilitated the electronic transmission rate to enhance the ECL intensity. Based on the synergistic effect of GO-g-C3N4 and MWCNTs-AuNPs composite, the proposed sensor showed high sensitivity, good stability, and wide linearity for the detection of DCF in the range of 0.005–1000ngmL−1 with a detection limit of 1.7pgmL−1. Furthermore, the developed immunoassay has been applied to real samples with satisfactory results. Therefore, this work provided a promising method for the detection of DCF and other small molecular compounds in the future.

Enhanced electrochemical performance of LiFePO4 cathode with synergistic modification of Na3V2(PO4)3 and carbon network

A high performance 9LiFePO4–Na3V2(PO4)3/C composite is successfully prepared by a sol–gel technique followed by subsequent carbonthermal reduction process. The structure and performance of 9LiFePO4–Na3V2(PO4)3/C composite have been investigated by XRD, SEM, TEM, EDS, CV and EIS. The result shows that the Na3V2(PO4)3 acting as ionic conductor improves the lithium ion transmission rate, while a thin amorphous carbon layer on the surface of nanoparticles and interfacial structure between the two phase enhances the electronic transmission rate of the composite. The synergistic effect of continual conductive carbon network and Na3V2(PO4)3 phase facilitates the diffusion of lithium ion and electron, ensures the stability of the LiFePO4 nanoparticles by limiting the direct contact of LiFePO4 particle with the electrolyte and ultimately improve the rate capability and long-cycling life of the material. The 9LiFePO4–Na3V2(PO4)3/C composite delivers discharge capacities of 151.2, 144.9 and 118.1mAhg−1 at 1.0, 2.0, 5.0 C, respectively, with high capacity retention up to 88.2% after 2000cycles at 2.0 C, exhibiting good electrochemical performance compared with that of the pristine one.

Ultrasensitive amperometric immunosensor for PSA detection based on Cu2O@CeO2-Au nanocomposites as integrated triple signal amplification strategy

In this work, a novel label-free electrochemical immunosensor was developed for the quantitative detection of prostate specific antigen (PSA). To this end, the amino functionalized cuprous oxide @ ceric dioxide (Cu2O@CeO2-NH2) core-shell nanocomposites were prepared to bond gold nanoparticles (Au NPs) by constructing stable Au-N bond between Au NPs and -NH2. Because the synergetic effect presents in Cu2O@CeO2 core-shell loaded with Au NPs (Cu2O@CeO2-Au), it shows better electrocatalytic activity towards the reduction of hydrogen peroxide (H2O2) than single Cu2O, Au NPs and Cu2O@CeO2. Featured by large specific surface area, good biocompatibility and good electrochemical properties which can greatly improve the electronic transmission rate, Cu2O@CeO2-Au was used as transducing materials to achieve efficiently capture antibodies and triple signal amplification of the proposed immunosensor. Under the optimal conditions, the proposed immunosensor exhibited a wide linear range from 0.1pg/mL to 100ng/mL with a low detection limit of 0.03pg/mL (S/N=3). Furthermore, the proposed label-free immunosensor has been used to determine PSA in human serum with satisfactory results. Meanwhile, it displayed good reproducibility, acceptable selectivity, and long-term stability, which had promising application in bioassay analysis.

Highly sensitive electrochemiluminescent immunosensor based on gold nanoparticles-functionalized zinc oxide nanorod and poly(amidoamine)-graphene for detecting brombuterol

β-adrenergic agonists (β-agonists) recognized as a growth promoter will reflect the health of human. Sensitive detection of β-agonists in foodstuff is valuable for the health of animals and human. A novel ultrasensitive competition-type electrochemiluminescent (ECL) immunosensor was developed for detecting brombuterol (Brom) based on CdTe Quantum dot (QDs) and polyamidoamine dendrimer (PAMAM, G2) modified graphene oxide (GO) (CdTe QDs-PAMAM-GO composite) as bioprobe for the first time. The surface of glassy carbon electrode (GCE) was coated with AuNPs–ZnO NRs composite film as the platform, which facilitated the electronic transmission rate to enhance the ECL intensity and provide enough active sites for capturing antibody. The resulting ECL immunosensor enabled the real samples detection of Brom with a lower detection limit of 0.3pgmL−1 (S/N=3) and a wider linear range from 0.001 to 500ngmL−1. The proposed immunosensor coupled with the excellent advantages of CdTe QDs-PAMAM-GO and AuNPs–ZnO NRs composite displayed high sensitivity and long-term stability, and provided an approach for determining other important biomarkers.

Highly selective and sensitive electrochemical sensor for l -cysteine detection based on graphene oxide/multiwalled carbon nanotube/manganese dioxide/gold nanoparticles composite

Abstract A highly selective and sensitive electrochemical sensor for detection of l -cysteine based on a graphene oxide/carboxylated multiwalled carbon nanotube/manganese dioxide/gold nanoparticles composite (GO/CCNTs/AuNPs@MnO 2 ) was developed. The property of the glassy carbon electrode which was modified by GO/CCNTs/AuNPs@MnO 2 contributed to increasing the sensing surface area and the electronic transmission rate. Besides, the addition of MnO 2 could effectively improve the selectivity and specificity of l -cysteine determination. The morphology and composition of GO/CCNTs/AuNPs@MnO 2 were characterized by scanning electron microscope, energy dispersive spectrometer, fourier transform infrared spectroscopy and X-ray diffractometer and the results evidenced that GO/CCNTs/AuNPs@MnO 2 flower-like structure was efficiently synthesized. The determination results of l -cysteine indicated that the surface area, electronic transmission rate and sensitivity of GO/CCNTs/AuNPs@MnO 2 sensor were highly increased. Under the optimal conditions, the electrochemical sensor exhibited excellent analytical performance with good selectivity, reproducibility and stability. The linear range of l -cysteine was from 1.0 × 10 − 8 to 7.0 × 10 − 6 mol L − 1 and the detection limit was 3.4 × 10 − 9 mol L − 1 (3δ). The proposed electrochemical sensor was successfully applied to the determination of trace l -cysteine in spiked water samples.

Application of Au cage/Ru(bpy)32+ nanostructures for the electrochemiluminescence detection of K562 cancer cells based on aptamer

In this work, an electrochemiluminescence (ECL) cytosensor for ultrasensitive and selective cytosensing of K562 cancer cells was developed. Pt nanoparticles (PtNPs) dotted carbon nanotubes (CNTs) was immobilized on the working electrode which can not only improve the electronic transmission rate but also increase the surface area. And aptamers modified electrode was employed for specific and efficient cancer cell capture. A new class of nanoprobes were also prepared by integrating the functions of specific recognition of concanavalin A (Con A) and signal amplification of Au cage/Ru(bpy)32+ nanostructures. With a sandwich-type cytosensor format, the amount of Au cage/Ru(bpy)32+-labeled Con A increased with the increment of K562 cancer cells in the samples, resulting in the increase of ECL signals. The as-proposed cytosensor exhibited excellent analytical performance toward the cytosensing of K562 cells in a wide detection linear range from 500 to 5.0×106cellsmL−1 with a detection limit of 500cellsmL−1. Moreover, the proposed method showed good precision, acceptable stability and reproducibility.

Biogenic Preparation of Gold Nanostructures Reduced from Piper longum Leaf Broth and Their Electrochemical Studies.

Exploitation of green chemical procedures for the synthesis of metal nanoparticles by biological process has received great attention in the field of nanotechnology. To demonstrate a biogenic method that involves the reduction of aqueous gold ions by the extract of Piper longum leaves leading to the formation of different morphological gold nanoparticles (AuNPs). The formation of gold nano-structures has been characterized by UV-Vis absorption spectroscopy. The X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns indicates the AuNPs are highly crystalline nature with the face-centered cubic (111), (200), (220) and (311) facets, respectively. The AuNPs have different sizes and morphologies that are identified by TEM studies. The involvement of water soluble bio-molecules such as carboxylic acids, flavonoids, proteins and terpenoids were identified by Fourier transform infrared (FT-IR) and Raman spectrum. The responsible mechanism of improving acidic nature and the process of encapsulation of gold nanoparticles by Piper longum extract was discussed. Additionally, we have demonstrated the modified carbon paste electrode using gold nanoparticles by means of cyclic voltammetry in a solution of 1 M KCI and 1 mM [Fe(CN)6]3-/4-. The analysis of cyclic voltammetry shows electronic transmission rate between modified Au-CPE and Bare-CPE electrode increased.

Ultrasensitive molecularly imprinted electrochemical sensor based on magnetism graphene oxide/β-cyclodextrin/Au nanoparticles composites for chrysoidine analysis

A imprinted electrochemical sensor based on glassy carbon electrode (GCE) for ultrasensitive detection of chrysoidine was fabricated. A GCE was modified by magnetic graphene oxide/β-cyclodextrin/gold nanoparticles composites (MGO/β-CD@AuNPs). The sensing surface area and electronic transmission rate were increased, which was benefited from the distribution property of MGO/β-CD@AuNPs. The MGO/β-CD@AuNPs composite improved electrochemical response and sensitivity of the sensor. The molecularly imprinted electrochemical sensor was prepared by electropolymerization on modified electrode. Chrysoidine and pyrrole were used as template molecule and functional monomer, respectively. Under the optimization experimental conditions, the electrochemical sensor exhibited excellent analytical performance: the detection of chrysoidine ranged from 5.0×10−8mol/L to 5.0×10−6mol/L with the detection limit of 1.7×10−8mol/L. The sensor was applied to determine chrysoidine in spiked water samples and showed high selectivity, good sensitivity and acceptable reproducibility. The proposed method provides a promising platform for trace amount detection of other food additives.

Gold–silver nanocomposite-functionalized graphene based electrochemiluminescence immunosensor using graphene quantum dots coated porous PtPd nanochains as labels

In this paper, the electrochemiluminescence (ECL) detection of a tumor marker by using gold–silver nanocomposite-functionalized graphene as a sensing platform, which increased the surface area to capture a large number of primary antibodies as well as improving the electronic transmission rate. The graphene quantum dots (GQDs) were high quantum yield and high biocompatible which obtained by one-pot simple synthetic strategy. With property of good conductivity and large surface area, porous PtPd nanochains can conjugate more GQDs and second antibody to improve the sensitivity of the immunoassay. As a proof-of-concept, carbohydrate antigen 199 was used as a model analyte. Under optimal conditions, the ECL immunosensors exhibited a wide detection range (0.002–70 UmL−1) and a low detection limit (0.96 mUmL−1). Such immunosensor showed good precision, acceptable stability and reproducibility. In addition, the proposed method provided a new promising platform of clinical immunoassay for other biomolecules.