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The electronic control unit (ECU) broadcasts and receives data through the on-vehicle bus, enabling the management of the vehicle’s operations and associated functions. Nevertheless, the plaintext broadcast mechanism of the bus exposes the data to potential security threats. Consequently, researchers have explored incorporating technologies like encryption to ensure secure data transmission among various ECUs. However, due to the inherent constrained resources of ECUs and the imperative for low-latency communication, it is challenging to introduce secure mechanisms without causing excessive computational overhead or delays. In this paper, we present a novel lightweight and confidential communication (LiCoom) scheme for on-vehicle ECUs to address this challenge. Our scheme includes a non-interactive key generation and evolution scheme to facilitate key synchronization between different ECUs, followed by the design of a flexible communication scheme for ECUs based on the sensitivity on the transmitted data. Besides the security analysis according to the conceived threat models, we conducted extensive experiments by using various platforms, including laptops and several typical TBoxs. The experimental results show that our proposal imposes on ECUs neither significant computational overhead nor observable delays.

Although nanozymes with intrinsic enzyme-like characteristics have aroused great interest in the biosensing field, the challenge is to keep high enzyme-like activity of the nanozyme after the modification of biomolecules onto nanozymes. Herein, a functional zonation strategy of a heterodimer nanozyme was proposed to tackle the challenge and further construct a multiple chemiluminescence (CL) imaging immunoassay. Here Fe3O4-Au as a heterodimer nanozyme model was divided into two zones, in which Fe3O4nanoparticles (NPs) were regarded as a nanozyme zone and AuNPs were defined as an antibody immobilization zone. A signal amplification probe (Fe3O4-Au-Ab2) was prepared by modifying the secondary antibody (Ab2) on AuNPs of the Fe3O4-Au heterodimer owing to the Au–S bond. The exposed Fe3O4of the Fe3O4-Au-Ab2probe shows very high peroxidase-like activity and can efficiently catalyze H2O2-luminol to produce strong CL imaging signals for multiple antigens detection. Using chicken interleukin-4 (ChIL-4) and chicken gamma interferon (ChIFN-γ) as models, the proposed CL imaging immunoassay shows wide linear ranges (0.005–0.10 ng/mL for both ChIL-4 and ChIFN-γ) and low detection limits (0.58 pg/mL for ChIL-4, 0.47 pg/mL for ChIFN-γ) with the characteristics of high sensitivity, high specificity, and good stability. This work provides a promising functional zonation concept for nanozymes to construct new types of nanozyme probes for immunoassay of multiple biomolecules.

As the functions of connected vehicles become more complicated, the amount and type of data they generate during driving are increasing. Sharing the data among connected vehicles can improve users' driving experience and reduce traffic pressure. However, the leakage of users' private information caused by data sharing may harm the interest of vehicle users and even endanger their lives. Meanwhile, since the quality of data collected by vehicles varies, high-quality data sharing means users get more reliable services, while low-quality data can reduce service reliability, drive experience, or cause traffic accidents. Therefore, developing an effective and highly reliable privacy protection scheme for shared data becomes a pressing problem to be solved. At the same time, since data sharing requires low latency, it is also a challenge to introduce a privacy protection mechanism without significant delay. In this paper, we propose a decentralized federated learning-based data sharing scheme that provides strong privacy protection for data and improves the system's robustness. In particular, we decouple the data request process from the data sharing process to improve the sharing efficiency. Then we propose a TOP-K-based nodes selection scheme to improve the accuracy of the trained models and ensure data reliability. The security analysis shows that the scheme can resist attacks and achieve secure data sharing. Finally, the scheme's effectiveness and the model prediction's efficiency are verified through experiments. The results show that the scheme has high accuracy, efficiency, and security.

5G communication network has become a major pillar in the evolution of interconnected industrial systems. However, the introduction of 5G network may lead to unknown risks in the systems. To reveal the impact of network threats on 5G-based industrial systems, a 5G network security analysis approach combining formal modeling and attack penetration is proposed. Firstly, the 5G network models based on topology and transmission events are established to cope with diverse and hidden attack routes and behaviors. Then, the attack module is integrated into the network model. With attack penetration to the models, potential vulnerabilities are exploited and quantified based on the hierarchical-topology model, and network reliability is evaluated based on the transmission-event model. The simulation results identify and quantify network vulnerabilities under various attacks, including access authentication failure, destruction of data integrity, illegal control of Network Functions (NFs), and malicious consumption of shared slicing resources. Meanwhile, a more unpredictable outcome is that there is a threshold of access probability, $\alpha $ , to measure the impacts of attacks against the bearer network and core network on reliability. Finally, a practical case about the impact of network security on a 5G-based coupled-tank system is discussed, which further proves the feasibility of our approach.

This study developed an electrochemical sensor for the determination of Mn2+in Chinese liquor by modifying a glass carbon electrode with TiO2-NH2@COFDPTB, which was synthesized viathe controllable growth of COFDPTBonto the surface of TiO2-NH2using the Schiff-base condensation reaction between 2,5-dimethoxyterephthalaldehyde and 1,3,5-tris(4-aminophenyl)benzene. The morphological and structural characterization studies of the proposed TiO2-NH2@COFDPTBwere carried out by SEM, TEM, HRTEM, EDX, BET, XRD and FTIR techniques. Owing to the excellent properties and the synergism between TiO2and COFDPTB, the introduction of TiO2-NH2@COFDPTBimproved the electrochemical response significantly. By optimizing the experimental parameters, the sensor exhibited good linearity in the range of 0.1–1.0 nM and 0.08–10 μM with a detection limit of 2.83 × 10−11M and 9.50 × 10−9M, respectively, showing competitive performance for Mn2+determination. Besides, the proposed sensor was successfully applied to Mn2+detection in liquor samples, suggesting its practical application performance.

A new ratiometric fluorescent sensor based on the bifunctional carbon quantum dots (CQDs)@metal–organic framework (MOF) nanocomposite possessing peroxidase-mimicking catalytic and luminescent characteristics was developed for hydrogen peroxide (H2O2) and cholesterol detection. The incorporation of fluorescent CQDs into the cavities of MIL-101(Fe) MOF with peroxidase-like activities endows the nanocomposite with bifunctional properties. The CQDs@MOF can oxidize o-phenylene-diamine to 2,3-diaminophenolazine by H2O2with yellow fluorescence (556 nm). Meantime, the intrinsic fluorescence signal (455 nm) of CQDs@MOF is inhibited due to the inner filter effect. Therefore, the ratio of the fluorescent intensity is employed as the signal output to construct the H2O2ratiometric biosensor. In addition, the cholesterol can be determined by the ratiometric sensor with high sensitivity. In addition, the total cholesterol in human serum is determined with high accuracy using our ratiometric biosensor. This ratiometric fluorescent platform based on the bifunctional CQDs@MOF provides new insights in the field of bio-sensing.

A noninvasive fiber material-based wearable electrochemical sensor to continuously monitor the glucose level in sweat is highly desirable for smart fabrics for personal diabetes management. To achieve it, the key challenge is to construct fibers with high stretchability and excellent electrochemical performance. Herein, a highly stretchable Ni–Co metal–organic framework/Ag/reduced graphene oxide/polyurethane (Ni–Co MOF/Ag/rGO/PU) fiber-based wearable electrochemical sensor is fabricated for monitoring the glucose level in sweat continuously with high sensitivity and accuracy. The rGO/PU fiber was simply produced by an improved wet spinning technology, and the Ni–Co MOF nanosheet was coated on its surface to prepare the Ni–Co MOF/Ag/rGO/PU (NCGP) fiber electrode. The Ni–Co MOF has a large specific surface area and high catalytic activity, which enables the fiber sensors with good electrochemical performance with a high sensitivity of 425.9 μA·mM–1·cm–2and a wide linear range of 10 μM–0.66 mM. More importantly, the NCGP fiber electrode also shows extremely high stretching and bending stability under mechanical deformation. Also, the NCGP fiber electrode has high selectivity and long-time storage stability. Moreover, the NCGP fiber-based three-electrode system was sewn with an absorbent fabric and fixed on a stretchable polydimethylsiloxane film substrate to form a nonenzymatic sweat glucose wearable sensor, which realized real-time monitoring of glucose in human sweat with high accuracy. This indicates that our designed NCGP fiber can be used as a wearable electrochemical sensor for the bio-diagnostics of body sweat.

Two-dimensional (2D) ultrathin nickel–cobalt phosphate nanosheets were synthesized using a simple one-step hydrothermal method. The morphology and structure of nanomaterials synthesized under different Ni/Co ratios were investigated by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Moreover, the influence of nanomaterials’ structure on the electrochemical performance for glucose oxidation was investigated. It is found that the thinnest nickel–cobalt phosphate nanosheets synthesized with a Ni/Co ratio of 2:5 showed the best electrocatalytic activity for glucose oxidation. Also, the ultrathin nickel–cobalt phosphate nanosheet was used as an electrode material to construct a nonenzymatic electrochemical glucose sensor. The sensor showed a wide linear range (2–4470 μM) and a low detection limit (0.4 μM) with a high sensitivity of 302.99 μA·mM–1·cm–2. Furthermore, the application of the as-prepared sensor in detection of glucose in human serum was successfully demonstrated. These superior performances prove that ultrathin 2D nickel–cobalt phosphate nanosheets are promising materials in the field of electrochemical sensing.

Existing electrochemical biosensing platforms, using traditional rigid and unstretchable electrodes, cannot monitor the biological signaling molecules released by cells in a mechanically deformed state in real time. Here, a stretchable and flexible electrochemical sensor was developed based on nickel metal–organic framework composite/Au nanoparticle-coated carbon nanotubes (Ni-MOF composite/AuNPs/CNTs) for sensitive detection of dopamine (DA) released by C6 living cells in real time. A Ni-MOF composite was obtained by introducing Ni, NiO, and a carbon frame onto the surface of two-dimensional (2D) Ni-MOF nanosheets using an efficient one-step calcination method. The hybrid of Ni-MOF composite/AuNPs/CNTs that deposited on the poly(dimethylsiloxane) (PDMS) film endowed the sensor with excellent electrochemical performance with a wide linear range of 50 nM to 15 μM and a high sensitivity of 1250 mA/(cm2M) and also provided the sensor with desirable stability against mechanical deformation. Furthermore, the stretchable electrode also displayed good cellular compatibility while C6 living cells can be cultured and proliferated on it with strong adhesion. Then, the DA released by C6 living cells with chemical induction in both natural and stretched states was monitored using our stretchable and flexible electrochemical sensor in real time. This indicates that our new design of flexible Ni-MOF composite/AuNPs/CNTs/PDMS (NACP) film electrodes provides more opportunities for the detection of chemical signals released from cells and soft living organisms even under mechanically deformed states.

Covalent organic frameworks functionalized carbon fiber paper was developed as a simple and sensitive platform for determining atmospheric OH quickly.

The detection of cytokines plays an important role in clinical diagnosis and immune mechanism research of chicken diseases. In this work, a novel and ultrasensitive chemiluminescent (CL) imaging array immunosensor was proposed to detect multiple chicken cytokines based on DNAzyme@CuS nanoparticles (DNAzyme@CuSNPs) dual mimic enzyme signal amplification strategy. DNAzyme@CuSNPs owns excellent peroxidase property, which was modified with second antibody (Ab2) to prepare DNAzyme@CuSNPs detection probe, and demonstrated high catalysis CL imaging signal due to synergistic catalysis. Chicken interleukin-4 (ChIL-4) and chicken interferon-γ(ChIFN-γ) were used as model analysis samples, the DNAzyme@CuSNPs-based CL imaging immunosensor achieved simultaneous and high-throughput detection of ChIL-4 and ChIFN-γwith wide linear range of 10−3–102 ng/mL, and the detection limits are 0.41 pg/mL and 0.36 pg/mL, respectively. The multiplex chicken cytokines CL imaging array immunosensor shows a high sensitivity, wide linear range, excellent specificity and acceptable stability. This research opens dual mimic enzyme signal-amplified strategy to develop sensitive CL imaging immunoassay for chicken diseases detection application.

In this work, a kind of molecularly imprinted polymer (MIP) was prepared by using metronidazole (MNZ) as the template, pyrrole as the functional monomer and vertically cross-linked two-dimensional Sn3O4(2D Sn3O4) nanoplates as the support. The developed MIP/2D Sn3O4was characterized by SEM, XRD, XPS and FT-IR. It was used to modify a glassy carbon electrode (GCE) to construct a novel MNZ electrochemical sensor. Parameters affecting the performance of the sensor were thoroughly investigated and optimized. The results revealed that 2D Sn3O4is promising as a support for MNZ imprinting. Owing to the 2D structure, large active surface, functionalization and high electrical conductivity, the MIP/2D Sn3O4modified electrode showed a wide linear range and low detection limit. The differential pulse voltammetric peak currents produced on the MIP/2D Sn3O4electrochemical sensor showed a linear relationship for concentrations of MNZ in the range of 0.025–2.5 μM. The detection limit of this sensor was down to 0.0032 μM (S/N = 3). This MIP/2D Sn3O4sensor was successfully used to detect MNZ in honeybee samples without any separation or accumulation processes, demonstrating that MIP/2D Sn3O4is a promising biomimetic material for use in electroanalysis and other relevant fields.

Economic dispatch is one of the fundamental problems in the power system research. The existing algorithms are either discrete iterative algorithms or continuous-time dynamical algorithms. By virtue of the hybrid techniques, a hybrid consensus-based algorithm is proposed in this paper, which consists of a finite-time continuous-time algorithm and a discrete-time interacted scheme. Moreover, inspired by the cluster synchronization and the benefit of the projection operator, a supervised strategy is carried out to ensure that each generator unit will work within its power generation constraint. For a better understanding of the supervised hybrid distributed algorithm, the detailed pseudo-code is presented. Finally, a numerical example is given to illustrate the effectiveness of the algorithm.

Ni-MOF (metal–organic framework)/Ni/NiO/carbon frame nanocomposite was formed by combing Ni and NiO nanoparticles and a C frame with Ni-MOF using an efficient one-step calcination method. The morphology and structure of Ni-MOF/Ni/NiO/C nanocomposite were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and energy disperse spectroscopy (EDS) mapping. Ni-MOF/Ni/NiO/C nanocomposites were immobilized onto glassy carbon electrodes (GCEs) with Nafion film to construct high-performance nonenzymatic glucose and H2O2electrochemical sensors. Cyclic voltammetric (CV) study showed Ni-MOF/Ni/NiO/C nanocomposite displayed better electrocatalytic activity toward glucose oxidation as compared to Ni-MOF. Amperometric study indicated the glucose sensor displayed high performance, offering a low detection limit (0.8 μM), a high sensitivity of 367.45 mA M–1cm–2, and a wide linear range (from 4 to 5664 μM). Importantly, good reproducibility, long-time stability, and excellent selectivity were obtained within the as-fabricated glucose sensor. Furthermore, the constructed high-performance sensor was utilized to monitor the glucose levels in human serum, and satisfactory results were obtained. It demonstrated the Ni-MOF/Ni/NiO/C nanocomposite can be used as a good electrochemical sensing material in practical biological applications.

MicroRNAs (miRNAs) in tumor-derived extracellular vesicles (tEVs) are important cancer biomarkers for cancer screening and early diagnosis. Multiplex detection of miRNAs in tEVs facilitates accurate diagnosis but remains a challenge. Herein, we propose an encoded fusion strategy to profile the miRNA signature in tEVs for pancreatic cancer diagnosis. A panel of encoded-targeted-fusion beads was fabricated for the selective recognition and fusion of tEVs, with the turn-on fluorescence signals of molecule beacons for miRNA quantification and barcode signals for miRNA identification using readily accessible flow cytometers. Using this strategy, six types of pancreatic-cancer-associated miRNAs can be profiled in tEVs from 2 μL plasma samples (n= 36) in an isolation-free and lysis-free manner with only 2 h of processing, offering a high accuracy (98%) to discriminate pancreatic cancer, pancreatitis, and healthy donors. This encoded fusion strategy exhibits great potential for multiplex profiling of miRNA in tEVs, offering new avenues for cancer diagnosis and screening.

The inhibition mechanism of 2,4-dichlorophenoxyacetic acid (2,4-D) to catalase was studied by a catalase biosensor in a flow-injection analysis (FIA) system. This system provides an ideal sensing platform to electrochemically evaluate the chemical mechanism of enzyme inhibition. Hierarchical porous calcium phosphate (hp-CaP), as a biocompatible nanomaterial, was used to immobilize catalase for repeat use. 2,4-D together with H2O2was injected into the bioreactor of the immobilized catalase-FIA system during the experimental procedure. The activity of the immobilized catalase was inhibited, which caused a decrease of the catalase-catalyzed H2O2reduction current. Lineweaver–Burk, Dixon, and Cornish–Bowden plots confirmed that the inhibition of catalase by 2,4-D followed an competitive mechanism with a inhibition constant of 4.78 × 10–7M. Based on this inhibition characters, a biosensor for 2,4-D detection was constructed. This biosensor showed a linear range from 0.03 to 3.00 μM with a detection limit of 0.015 μM. It demonstrated good stability, acceptable reproducibility and low cost for 2,4-D screening. It has been successfully applied for the determination of 2,4-D in commercial bean sprouts samples. It is anticipated that a rapid evaluation of the chemical mechanism of catalase inhibition by the FIA system could pave the way to rationally designing biosensors.

This paper describes the immobilization of gold nanoparticles on metal–metalloporphyrin frameworks (AuNPs/MMPF-6(Fe)) through electrostatic adsorption. The composites were characterized by powder X-ray diffraction, zeta potential, transmission electron microscopy, electrochemical impedance spectroscopy, and voltammetric methods. MMPF-6(Fe) exhibited a pair of redox peaks of the Fe(III)TCPP/Fe(II)TCPP redox couple. The AuNPs/MMPF-6(Fe)-based electrochemical sensor demonstrates a distinctly higher electrocatalytic response to the oxidation of hydroxylamine due to the synergic effect of the gold metal nanoparticles and metal–metalloporphyrin matrix. The voltammetric current response exhibits two linear dynamic ranges, 0.01–1.0 and 1.0–20.0 μmol L–1, and the detection limit was as low as 0.004 μmol L–1(S/N = 3). Moreover, the biosensor exhibits high reproducibility and stability in acid solution. Our work not only offers a simple way to achieve the direct electrochemical behavior of metalloporphyrin but also expands the potential applications of MOFs-based composites in bioanalysis.

In the present work, a novel label-free chemiluminescent (CL) immunoassay method was designed by employing smart CuS nanoparticles (CuSNPs) as peroxidase mimetics. The CuSNPs were synthesized through a simple coprecipitation method, and showed high catalytic activity and stability. This efficient label-free CL immunoassay could be easily achieved through a simple strategy. First, CuSNPs dispersed in chitosan were modified on the epoxy-functionalized glass slide to form a solid CL signal interface. Streptavidin was then used to functionalize CuSNPs to capture the biotinylated antibody, further producing a sensing interface. After online incubation with antigen molecules, the formed antibody–antigen complex on the biosensing substrate could prevent the diffusion channel of CL substrate toward the signal interface, and restrained the mimic enzyme-catalyzed CL reaction, finally resulting in the decrease of CL signals of the assay system. Compared to the label-based CL immunoassay, the proposed label-free assay mode is more simple, cheap and fast. Using a model analyte alpha-fetoprotein, the label-free CL immunoassay method had a linear range of 0.1–60 ng/mL and a low detection limit of 0.07 ng/mL. Moreover, the peroxidase mimetic-based label-free CL immunoassay system showed good specificity, acceptable repeatability, and good accuracy. The study provided a promising strategy for the development of highly efficient label-free CL immunoassay system.

A simple cyclic voltammetric method was applied to assemble and orient a model protein, namely, myoglobin (Mb), into a biocompatible Brij 56 film. Ultraviolet–visible and circular dichroism spectra indicated that Mb in Brij 56 matrix preserved its secondary structure. Fourier transform infrared spectra confirmed the formation of hydrogen bonds between Mb and Brij 56. These hydrogen bonds acted as the electron tunnel to transfer electrons from Mb’s active sites to the underlying glassy carbon electrode. Effective direct electron transfer of Mb was realized with the presence of a couple of quasi-reversible and well-defined redox peaks at −310 mV (vs standard calomel electrode) in the studied potential range. The peaks were attributed to the redox couple of heme Fe(II)/Fe(III) of the well-oriented Mb in Brij 56 matrix. The surface coverage and the electron transfer rate (ks) of Mb immobilized into the Brij 56 film was ∼4.9 × 10–11mol cm–2and 72.6 ± 3.0 s–1, respectively. An excellent electrocatalytic response of the immobilized Mb toward nitrite in the absence of electron transfer mediators was observed. These results emphasized that the biomimetic Brij 56 could be used as an attractive material for immobilizing proteins and constructing biosensors.

The weak interfacial binding affinities of the inorganic perovskite core with ligands and high density of surface defect states induce the facile detachment of surface ligands from nanocrystals (NCs), resulting in their poor colloidal stability and fluorescence in aqueous. In this work, a powerful ligand engineering strategy was proposed for eliminating the surface defects and aggregation of the NCs. Using an amphiphilic polymer octylamine-modified polyacrylic acid (OPA) as a capping ligand, the as-synthesized CsPbBr3NCs retain high photoluminescence intensity and stability by the modified ligand-assisted reprecipitation method. The increase in the fluorescence lifetime and NC size could also be observed, and how the NC particle size influences fluorescence lifetime was further studied. In addition, the water stability, photostability, and thermal stability were significantly improved, and the fluorescence of NCs can maintain 80.13% of the original value in water for 15 d. We further validated that the strong binding affinity of OPA and oleylamine ligands with CsPbBr3NCs leads to a reduction in surface trap states, and a large amount of carboxyl groups of the OPA made the NCs preserve good water solubility. In addition, the OPA has the ability of adjusting the particle size of NCs. Furthermore, a wavelength-shifted colorimetric sensor based on these NCs was constructed for detection of Cl–in sweat, which enables the rapid and visual detection of Cl–with high accuracy and stability. Overall, these CsPbBr3NCs synthesized by the ligand engineering strategy validated their wide applications in biomedical sensing fields.

Here we report a method to prepare protein-imprinted polymers in the presence of a real sample (chicken egg white), rather than any known purified proteins. By comparing the electrophoretic separation of the sample in the imprinted polymer and a control capillary, it's found such a sample-imprinted polymer could retain abundant species. As a result the signals of abundant proteins in the sample were removed or reduced in the electropherogram. Meanwhile new peaks appeared to stand for enrichment of the minor proteins in the same sample. This suggests a new way to investigate molecular imprinting, which means analyzing complicated samples based on their instinctive complexities, i.e., a series of polymers just imprinted by themselves.

A rapid and sensitive approach for the determination of trace levels of cadmium using stripping voltammetry coupled with a sequential injection lab-on-valve system was developed. The proposed method was based on the accumulation of cadmium on the multi-walled carbon nanotubes/Fe3O4nanoparticles modified electrode where iodide was used as the induced adsorption media. Different parameters such as supporting electrolyte and its pH, concentration of KI, amounts of modifier, accumulation potential, accumulation time, and flow rate were investigated to enhance the analytical performance. Under the optimum conditions, the signal intensity shows a linear relationship with the concentration of cadmium over the range of 5 × 10−9to 2 × 10−7mol L−1. A sampling frequency of 24 per hour and a detection limit of 2.7 × 10−9mol L−1were obtained with an accumulation time of 120 s. The relative standard deviation for 11 repeated measurements of 1 × 10−8mol L−1cadmium was 3.2%. The analytical use of the established method was validated by applying it to the determination of cadmium in natural waters samples and certified reference materials.

In this study, a method for the determination of alkylamine carbonate (AAC) nonionic–anion oil displacement agent in oil-field water was developed for the first time, involving pre-column derivatization using a novel labeling agent and HPLC with diode-array detection. The derivatization and chromatographic separation conditions were investigated thoroughly. The analyte was labeled with 4-methoxybenzenesulfonyl fluoride at 50 °C for 20 min. When the method was applied in the determination of C18A5C (an AAC oil displacement agent containing eighteen alkyl and five amino groups) a linear calibration curve was obtained from 1.0 to 100.0 μg mL−1with a correlation coefficient of more than 0.999 and a detection limit of 0.05 μg mL−1. In the determination of real oil-field water samples, the recovery range of C18A5C was 91.8% to 96.2%, and the intra-day and inter-day relative standard deviations were 2.9–3.5% and 3.8–4.3%, respectively. The experimental results demonstrate that this method, with its merits of simplicity in pretreatment, rapidity in derivatization, and stability of the derivatives, can be employed in the analysis of C18A5C and has potential application in the detection of other oil displacement surfactants containing amino groups. It is of great significance to develop a fast, easy-to-operate, sensitive and reliable method for environmental impact assessment.

A novel graphene–Au nanoparticles (AuNPs) composite film modified glassy carbon electrode (GCE) was proposed for selective detection of dopamine (DA). The resulting electrode was characterized using transmission electron microscopy, cyclic voltammetry and differential pulse voltammetry. Compared to bare and graphene modified electrodes, this nanocomposite modified electrode not only significantly improved the electrochemical peak potential difference between DA and ascorbic acid (AA), but also noticeably enhanced the current response. The constructed DA sensor showed a wide linear range (5–1000 μM) and a low detection limit (1.86 μM). The graphene–AuNPs composite, which was obtained by assembling AuNPs onto the graphene surface, could provide a promising platform to develop excellent electrochemical sensors for detecting DA.

A new facile method of preparing porous spherical silica particles as stationary phase for high performance liquid chromatography (HPLC) separations was developed. In this method, monolithic silica columns whose skeletons contained weakly connected porous silica microspheres were prepared first using the aging temperature and mass ratio of PEG to TMOS in the range of 25–30 °C and 0.10–0.20, respectively, and mass ratio of TMOS to H2O less than 0.5. Then, dispersed porous silica spheres were obtained by gentle grinding of the monolithic column. After surface modification with C18, silica microspheres with an average diameter of 5.4 μm were packed and used in HPLC for separation of neutral, acidic, and basic compounds. The retention behavior is similar to the column packed with commercially available 5 μm C18 silica particles while column efficiency is only about a half of the latter. The results demonstrate that the microspheres are a promising alternative packing material for HPLC.

A thermally responsive polymer, termed as P(IPAAm-AM-BisAM), was prepared by the copolymerization of N-isopropyl acrylamide, acrylamide, and N,N′-methylenebisacrylamide. At room temperature this polymer was dissolved in water to form a low viscous solution so that it could be loaded in a capillary easily. When a high voltage was applied on the capillary, the polymer was stimulated by the Joule heat and transferred from a liquid state into a solid state, acting as a sieving matrix for the separation of proteins according to their molecular weights. The logarithm values of the molecular weights of the proteins correlated linearly with the migration times. This capillary gel electrophoresis of proteins was carried out using a conventional instrument. Using such a copolymer, we can easily realize high-speed, high-efficiency and reproducible capillary gel electrophoresis for proteins without any instrumental rebuilding or investment.

Abstract: The electrochemical behavior of ortho-phenylphenol (OPP) at a disposable electrode (an improved wax-impregnated graphite electrode) in the presence of sodium dodecyl sulfate (SDS) was studied for the first time. The results demonstrated that the electrocatalytic oxidation process of OPP was accompanied with two-charge-two-proton transference. The electronic transmission coefficient (α) and diffusion coefficient (D R) for OPP were calculated to be 0.8126 and 3.61 × 10−2 cm2/s, respectively. The electrochemical signal was apparently improved by SDS at the disposable electrode and the oxidative peaks current was proportional to the concentration of OPP over the range from 1.0 × 10−9 to 4.0 × 10−6 mol/L with the detection limit of 8.7 × 10−10 mol/L. This novel and highly sensitive method can be successfully applied to detect OPP in the orange rind sample.

A stripping voltammetric assay using a morin modified electrode in a sequential injection lab-on-valve system was developed for the determination of trace amounts of cadmium. The sample and reagent arrangements were achieved by a syringe pump. The target metal ions were accumulated on the morin modified glassy carbon electrode surface, and the quantification step was performed by subsequent anodic stripping voltammetry. The key experimental variables relevant to the voltammetric measurement procedure were optimized. For a 100 s preconcentration time, a linear calibration curve was obtained for a concentration range of 1 to 125 μg L−1with a detection limit of 0.41 μg L−1. The analytical use of the established method was assessed by applying it to the determination of cadmium in real samples and carrying out recovery experiments. The method was subsequently validated by comparing the results with those given by ICP-OES.

Abstract: A sub-picomole level topotecan hydrochloride determination method was first proposed using sodium dodecyl sulfate (SDS) as a sensitized reagent at a novel disposable electrode (an improved wax-impregnated graphite electrode). The effects of different kinds of surfactants on the electrochemical response to topotecan hydrochloride were examined. The results indicate the electrochemical signal was apparently improved by SDS. At optimal conditions, the oxidative peak current increased linearly with the logarithm of concentrations for topotecan hydrochloride in the ranges of 2.0 × 10−12 to 1.0 × 10−11 mol/L and 8.0 × 10−11 to 8.0 × 10−10 mol/L with a detection limit of 6.4 × 10−13 mol/L. The proposed method could be applied in determining topotecan hydrochloride in urine.

Cysteic acid, containing negatively charged sulfonic ligand, has been deliberately modified on the electrode by the electrochemical oxidation method. It could promote the accumulation of adenine on the electrode because of the electrostatic interaction between the negatively charged cysteic acid and the positively charged adenine at pH 6.0. After accumulation at the potential of 0.2 V for 300 s, adenine produced well-defined oxidation peaks at about 1000 mV. Cyclic voltammetric study indicated that the oxidation process was irreversible and adsoption-controlled. Based on the differential pulse voltammetric (DPV) procedure, the linear calibration curve for the detection of adenine over the range 2.0 x 10-7 -1.0 x 10-4 M was obtained. The detection limit (3σ) was down to 5.9 x 10-8 M. Such modified electrode was also successfully applied for the determination of adenine in Vitamin B4 tablet.

This minireview summarized several examples to illustrate the application of electrochemical methods for pharmaceutical and drug analysis. Special attentions were devoted to the voltermmetric and potentiometric techniques. A section dedicated to the application of the electrochemical detectors coupled with flow system was also presented. Finally, we briefly outline future trends of the electrochemical methods for drug analysis.

Polycysteic acid based electrochemical oxidation of L-cysteine (CySH) and carbon nanotubes (CNTs) formed a composite thin film material at a glassy carbon electrode (GCE) that was used a novel modifier for electroanalytical determination of sinomenine which is used for rheumatoid arthritis treatment. The determination of sinomenine at the composite modified electrode was studied by differential pulse voltammetry (DPV). The peak current obtained at + 0.632 V (vs SCE) from DPV was linearly dependent on the sinomenine concentration in the range of 1.0 x 10-7 to 6.0 x 10-5 M in a B-R buffer solution (0.04 M, pH 1.81) with a correlation coefficient of 0.998. The detection limit (S/N = 3) was 5.0 x 10-8 M. The electrochemical reaction mechanism of sinomenine was also discussed. This new method was then applied to the high-throughput determination of sinomenine in human serum samples with satisfactory results. This polycysteic acid/CNTs composite film may be considered to be a promising, low-cost, durable, and biocompatible material for the modification of sensors in applications to pharmaceutical and biomedical analysis.

Recent advances in electrochemical detection techniques coupled with high-performance liquid chromatography (HPLC-ECD) in pharmaceutical and biomedical analysis are reviewed. ECD classification and modes including common amperometric, coulometric, conductimetric, and potentiometric detector, are outlined and the some typical examples of determinations in pharmaceutical and biomedical analysis are described. The electrochemical detection system can offer superior merits over other detectors commonly used with HPLC. These techniques have great potential owing to their prominent characteristics in high-throughput screening procedures of drugs in various matrices. Fundamental 67 references from last 5 years related with a field are cited in this review.

Fused‐silica capillaries were packed with porous 1 μm bare silica microspheres and immobilized by potassium silicate–formamide in order to obtain columns with silica‐based monolithic packing. After curing, the particle‐fixed monolithic columns were octadecylated in situ with dimethyloctadecylchlorosilane. The columns were mechanically strong and permeable. No noticeable loss in efficiency was found after using a column continuously for 1 month. The performances of the particle‐fixed silica monolithic columns were evaluated for CEC under RP conditions. High separation efficiency (about 125 200 plates/m) was obtained by using these new types of columns.

This paper introduces a novel method for packing Capillary Electrochromatography Columns (CEC). Using vacuum packing methodology, silica particles as small as 1 μm were successfully packed into the capillary columns with 75 μm inner diameter. The columns are very stable and show no noticeable loss in efficiency after 200 sample injections. The performance of these vacuum packed capillary columns was evaluated with a mixture of aromatic and non‐aromatic compounds. A 24 cm long capillary column can produce peak efficiencies of around 45 000 plates for benzene.

•An interpolation method is adopted to reconstruct the voltage curve.•A health indicator extracting framework is proposed.•Four features are extracted from ICA curve to characterize the battery degradation.•An Outliers processing method is developed to suppress measurement noise.

This paper describes a potentiometric method for the determination of Cu2+ in 0.1mol/L HAc-NaAc -1.0mol/L NaCl buffer, pH 5.00, using a carbon paste electrode, whose linear range is 1.0 × 10-6∼1.0×10-3 mol/L with 61mV/decade of calibration slope. It exhibits high selectivity and desired reproducibility.