Lower Limit Of Range Research Articles

Nanostructured copper selenide as an ultrasensitive and selective non-enzymatic glucose sensor

CuSe nanostructures exhibit high-efficiency for glucose detection with high sensitivity (19.419 mA mM−1 cm−2) and selectivity at low applied potential (0.15 V vs. Ag|AgCl), low detection limit (0.196 μM) and linear detection range (100 nM to 40 μM).

Novel methodology for anodic stripping voltammetric sensing of heavy-metal ions using Ti3C2Tx nanoribbons.

Conventional anodic stripping voltammetry (ASV) sensing of heavy-metal ions (HMIs) generally includes a two-step approach: (a) preconcentration via electrodeposition and (b) re-oxidation, while the requirement of the electrodeposition step makes the detection processes more complex. Herein, a novel methodology using self-reduction instead of electrodeposition was developed for the ASV sensing of HMIs (selecting Cd2+ as a representative analyte) by introducing Ti3C2Tx MXene nanoribbons (Ti3C2Tx NR) as a sensing element that can exhibit direct adsorption and reduction capabilities towards HMIs. Compared with conventional ASV technology, the proposed methodology is simpler and power-saving, and has a significant low detection limit (0.94 nM) and wide linear range (0.005-3.0 μM).

Nitrogen-doped carbon dodecahedron embedded with cobalt nanoparticles for the direct electro-oxidation of glucose and efficient nonenzymatic glucose sensing

Developing high-performance sensors for glucose detection is extremely desirable for clinical diagnostics and life sciences. Particularly, it is greatly attractive to exploit composite materials with large surface area, doped heterojunction and non-precious metal as highly active electro-catalysts for nonenzymatic glucose sensing. Herein, we reported a N-doped carbon dodecahedron embedded with Co nanoparticles (Co@NCD) for the direct electro-oxidation of glucose and efficient nonenzymatic glucose detection. Co@NCD was synthesized by the pyrolysis of zeolitic imidazolate framework (ZIF). Field emission scanning electron microscope, high-resolution transmission electron microscope, powder X-ray diffraction, X-ray photoelectron spectroscopy and nitrogen adsorption-desorption experiments were performed to investigate Co@NCD. A well-defined dodecahedron morphology with uniform size and shape was observed. Besides, the original framework was carbonized after pyrolysis leading to a hollow and porous graphite dodecahedron containing N-doped carbon heterojunction. Moreover, Co nanoparticles were evenly distributed into the dodecahedron. With porous structure, N-doped carbon and embedded Co nanoparticles, Co@NCD displayed a notable electro-catalysis towards the direct oxidation of glucose (onset potential: 0.20 V). By using Co@NCD as electro-catalyst, an efficient nonenzymatic glucose sensor was obtained with a rapid amperometric response (within 1 s), low detection limit (0.11 μM) and broad detection range (0.2 μM–12.0 mM). In addition, remarkable selectivity, repeatability, reproducibility and long-term stability were also observed. Finally, Co@NCD prepared sensor was also successfully applied to the detection of glucose in human serum. Our results suggested that ZIF templated method could be an innovative solution for active composite catalysts in biomolecular electro-catalysis and Co@NCD prepared sensor could be a substantial preferable sensing platform for the nonenzymatic glucose detection.

Investigation of electron–phonon interaction in bulk and nanoflakes of MoS2 using anomalous “b” mode in the resonant Raman spectra

Electron–phonon interaction in bulk and nanoflakes of MoS2 is investigated using Raman spectroscopy. Resonant Raman spectroscopic studies carried out on bulk and liquid exfoliated nanoflakes of MoS2 revealed a second order Raman mode (called the “b” mode), whose frequency in the case of nanoflakes was found to be largely different from that in bulk MoS2. Temperature dependent Raman spectra show larger variation in the frequency of the “b” mode in bulk MoS2 as compared to that in nanoflakes of MoS2. This anomalous behavior of the “b” mode could be attributed to the stronger electron–phonon coupling occurring in bulk MoS2, due to higher electron concentration in the same, as compared to that in nanoflakes of MoS2. A larger sulfur vacancy in bulk MoS2 as compared to that of nanoflakes was found to be responsible for higher electron concentrations. These findings are supported by energy dispersive x-ray analysis and x-ray photoelectron spectroscopic studies carried out on bulk and nanoflakes of MoS2. The present study suggests a more sensitive probe for the estimation of electron concentrations in the low limit range by following the “b” mode in resonance Raman spectra.

Fabrication of Pt/CeO2/NCNFs with embedded structure as high-efficiency nanozyme for electrochemical sensing of hydrogen peroxide

The construction of nanozyme with stable structure and excellent analytical properties is urgently needed for non-enzymatic electrochemical sensing of H2O2. Herein, we prepared Pt particles/CeO2 plates embedded in N-doped carbon nanofibers (Pt/CeO2/NCNFs) by heat-treating electrospun composites as nanozyme for the detection of H2O2. Characterization results showed that Pt nanoparticles dispersed on or around CeO2 nanoplates and the composite embedded homogeneously in NCNFs matrix, which improved the structure stability and contributed to the synergistic effect of Pt, CeO2 and NCNFs, and further enhanced the enzyme-like electrocatalytic activity of as-prepared nanozyme for H2O2 reduction. Pt/CeO2/NCNFs-based sensors exhibited superior H2O2 analytical performances of low detection limit (0.049 μM), high sensitivity (185.6 μA mM−1 cm−2) and wide linear range (0.0005–15 mM). In addition, the sensor was possessed of high selectivity, anti-interference, excellent reproducibility and stability. These above results were attributed to the embedded structure and the synergistic effect of Pt nanoparticles, CeO2 nanoplates and NCNFs. More interestingly, the fabricated sensor showed satisfactory recoveries and RSD for H2O2 detection in cosmetics. These attractive properties manifested that Pt/CeO2/NCNFs had potential to be a candidate for fabricating H2O2 electrochemical sensor.

Hierarchical cage-frame type nanostructure of CeO2 for bio sensing applications: from glucose to protein detection

Self-assembled hierarchical nanostructures are slowly superseding their conventional counterparts for use in biosensors. These morphologies show high surface area with tunable porosity and packing density. Modulating the interfacial interactions and subsequent particle assembly occurring at the water-and-oil interface in inverse miniemulsions, are amongst the best strategies to stabilize various type of hollow nanostructures. The paper presents a successful protocol to obtain CeO2 hollow structures based biosensors that are useful for glucose to protein sensing. The fabricated glucose sensor is able to deliver high sensitivity (0.495 μA cm−2 nM−1), low detection limit (6.46 nM) and wide linear range (0 nM to 600 nM). CeO2 based bioelectrode can also be considered as a suitable candidate for protein sensors. It can detect protein concentrations varying from 0 to 30 µM, which is similar or higher than most reports in the literature. The limit of detection (LOD) for protein was ∼0.04 µM. Therefore, the hollow CeO2 electrodes, with excellent reproducibility, stability and repeatability, open a new area of application for cage-frame type particles.

Flexible enzyme cascade sensing platform based on a G-quadruplex nanofiber biohydrogel for target colorimetric sensing

Enzyme cascade reactions can greatly improve catalytic efficiency and achieve selective and sensitive detection of targets. This paper presents a novel strategy for colorimetric sensing of targets by loading natural enzymes into a hemin-doped G-quadruplex (G4-hemin) biohydrogel to form a flexible enzyme cascade sensing (FECS) platform. The biohydrogel has advantages of biocompatibility, printability and flexibility. The biohydrogel not only participates in the cascade reaction as the mimic enzyme but also provides a mild microenvironment for the natural enzyme. The FECS platform has a linear range from 0.4 μM to 120 μM and a detection limit of 3.6 × 10−6 M for hydrogen peroxide detection. Additionally, the FECS platform has a low detection limit and wide linear range for glucose and xanthine by loading xanthine oxidase (XOD) and glucose oxidase (GOD) into the biohydrogel, respectively. These results indicate that the novel FECS platform is an effective detection platform that can detect multiple targets and is expected to be widely used in flexible sensing.

Ventricular strain is compromised outside of the coronary autoregulatory range – assessment by cardiovascular magnetic resonance

Introduction Coronary autoregulation maintains near-constant myocardial blood flow in a range of approximately 60-140 mmHg of mean arterial pressure (MAP). Using oxygenation-sensitive (OS) cardiovascular magnetic resonance (CMR), we showed that myocardial oxygenation is compromised at MAP levels below the lower limit of this range. Above its upper limit we observed luxury perfusion and mild oxygen excess. There is a lack of data exploring the relationship between coronary autoregulation, myocardial oxygenation and ventricular function. CMR feature tracking software allows to quantify myocardial deformation and strain in OS images. Our aim was to explore our data from an animal study for associations between myocardial function, myocardial oxygenation and coronary blood flow (CBF) over a wide range of MAP levels. Methods In ten anaesthetized swine a flow probe was surgically attached to the proximal left anterior descending coronary artery before the animals were placed into a 3 Tesla MRI scanner. Starting from a baseline of 70 mmHg, MAP was varied in steps of 10-15 mmHg using phenylephrine and urapidil, respectively. At each MAP level, OS cine images and CBF readings of the anterior descending coronary artery were obtained, as well as arterial and coronary sinus blood gas samples to determine myocardial oxygen extraction ratio. Using feature tracking-software, strain data were acquired from images by tracing endo- and epicardial contours in end-diastole, from which peak global circumferential strain (GCS) was calculated for both ventricles. The relationships of peak GCS to MAP, CBF and myocardial oxygenation were established. Results We analysed 101 MAP levels, which ranged between 35 and 196 mmHg. Oxygenation as assessed by OS-CMR showed a curvi-linear relationship to MAP, with a steeper decrease below the lower limit of the autoregulatory range and an increase above its upper limit. Peak GCS of both ventricles became progressively impacted when MAP was forced from its baseline (70 mmHg) towards and beyond the lower and upper autoregulatory limit (dashed yellow lines in figure). There was no apparent association between changes of peak GCS and CBF. GCS of left ventricular myocardium decreased linearly with increasing myocardial oxygen extraction ratio (r=0.261, p=0.026), and in a non-linear fashion with decreasing myocardial tissue oxygenation. Discussion In a porcine model with non-diseased hearts, biventricular systolic function becomes compromised when MAP reaches levels either below or above coronary autoregulatory limits. Contractile dysfunction at pressures below the lower limit appears to be caused by myocardial deoxygenation. Conversely, hypertension-induced systolic dysfunction is associated with increased coronary flow and oxygen excess, which points to high afterload rather than O2 demand/supply imbalance as the most likely mechanism. We conclude that in hearts without coronary disease, global strain abnormalities elicited by hypotensive or hypertensive stress also differ in their underlying pathophysiological mechanisms.

Hierarchical MnS@MoS2 architectures on tea bag filter paper for flexible, sensitive, and selective non-enzymatic hydrogen peroxide sensors

We report here the rational development of MnO2 nanorods coated tea bag filter paper (TBFP) as a self-standing, bendable, and disposable electrochemical probe for the sensitive and selective H2O2 detection and addresses their challenges in H2O2 sensing via the replacement of ‘O’ with ‘S’ in the form of MnS microcubes and its core@shell architecture with MoS2. The as-configured MnS@MoS2/TBFP overwhelms the constrains of conventional electrochemical probes including time and cost consumed electrode surface renewability and catalyst loading progression, and the practice of an insulating binder. The hierarchical open porous architectures of MoS2-shell favour the diffusion of H2O2 into the core-MnS microcubes, facilitating an analyte utilization efficacy at both the core and shell architectures. The impacts of core@shell morphological features, replacement of ‘O’ with ‘S’, surface defects, and lattice distribution of MnS@MoS2 toward non-enzymatic H2O2 sensing performances are elucidated using variant electrochemical techniques. With the synergism of uniformly implanted and exposed metallic active sites, efficient electron transfer rate, and high analyte utilization efficiency, MnS@MoS2/TBFP exposes the low detection limit (120 nM), excellent sensitivity (650 μA mM−1 cm−2), and wide linear range (500 nM-5 mM) on H2O2 detection. Furthermore, the scrutinized non-enzymatic H2O2 detection concerts of MnS/MoS2/TBFP are selective, decisive, repeatable, and stable, constructing the excellent recovery rates in human urine sample analyses. Thus, the collective benefits of free-standing, flexible, binder-less, re-functional, and cost-efficient MnS@MoS2/TBFP probe actualize the evolution of affordable and high performance H2O2 sensors.

Extension of the Lower Range Limit Based on Industrial Studies of the Reliability of High-Power Unit Eqipment

For the 1200-MW power unit of the Kostroma SRPP, the lower limit of the lower range limit is 800 MW. This article presents the results of static field tests in unloading the power unit to 700 MW. Static and dynamic trials at the minimally achievable load with perturbations in the operating environment and fuel flow rate showed the reliability of operation of the power unit equipment in an expanded load range. Areliability assessment of the operation of components of the steam-and-water and air-gas paths, the feed-water pump group, and the draught equipment was conducted.

Acryl-modified diazabenzo[ghi]perylene for fast discrimination of Cys from GSH and Hcy with high quantum yield

A novel fluorescence probe (TIA) is designed and synthesized by grafting acryl on hydroxyl and diazabenzo[ghi]perylene, respectively. The acryl groups on hydroxyl act as a recognition site and fluorescence quencher. After a conjugated addition/cyclization reaction of Cys with TIA, the acryl groups on hydroxyl fall off and acryl conjugated perylene (TIA−OH) is released as the fluorophore with 70-fold increment of fluorescence in PBS. The short response time (less than 5 min) and high signal-noise-ratio endow the probe with fast detection, high sensitivity, low detection limit (0.11 μM) and wide linear range (10−100 μM). Interestingly, compared with the parent dihydroxy 1,2-diazabenzo[ghi]perylene, the introduction of acryl group on the perylene can modulate the fluorescence and increase the fluorescence quantum yield of TIA−OH by more than 10-fold (41 % in PBS). The TD-DFT calculations also reveal that the acryl group conjugated on the perylene can result intramolecular charge transfer and the calculated fluorescence is in good agreement with the experimental values. What’s more, the high cell membrane permeability and specificity for Cys of the probe ensure the application in fluorescence imaging of living cells to detect intracellular Cys.

Electrochemical Evaluation of Choline Oxidase on Modified Bamboo-Like CNTs Electrode: from Nano-Chemistry Towards Biotechnological Application

Carbon nanotube (CNT) can be considered as one of the best materials for enzyme nanobiosensor. In this study, we investigated comprehensively electron transfer properties in three kinds of carbon nanotubes for finding the best supporting material for comprising of the electrochemistry and electrocatalysis of enzymes in nano-dimension. Choline oxidase was selected as a sample enzyme for evaluating the performance of the electrodes. The enzyme was absorbed on modified SWCNT, MWCNT and Bamboo-like CNTs electrode in ionic liquid. Electron transfer and electroanalytical responses were investigated by Metrohm Autolab. Functionalization was studied by Raman spectroscopy and FTIR and also, the morphological evaluation was conducted by SEM. Raman spectroscopy showed that Bamboo-like CNTs had better properties in loading enzyme and other electrochemical properties for electron transfer. FTIR spectroscopy showed that Bamboo-like CNTs had high covalent binding on the surface wall of nanotubes. High loading of the enzyme was detected in Bamboo-like CNTs in comparison to two other nano-tubes by SEM. The electrochemical and amperometric response showed that Bamboo-like CNTs had a better response in different scan rates, wide linear range and detection limit. ChOx/RTIL/Bamboo-like CNTs/GC electrodes showed the high amounts of enzyme loading, high enzyme-substrate affinity, low detection limit, best sensitivity and wider linear range.

Co-embedded N-doped hierarchical carbon arrays with boosting electrocatalytic activity for in situ electrochemical detection of H2O2

In this work, self-supporting hierarchical Co-embedded N-doped carbon structures composed of leaf-like carbon sheets arrays and interconnected carbon nanotubes (CNTs) were synthesized on carbon cloth (CC) via dicyandiamide-assisted pyrolysis. The resultant composite is abbreviated as CC/Co@C-CNTs, in which Co nanoparticles are embedded both in carbon sheets and the tips of CNTs. The characterizations proved the hierarchical three-dimensional structure, large electroactive surface area of 4.71 cm−2, fast electron transfer, abundant Co/Co-Nx active sites, and synergistic effect between Co/Co-Nx species and CNTs in the CC/Co@C-CNTs-800-0.10 electrocatalyst. Benefiting from these unique superiorities, the CC/Co@C-CNTs-800-0.10 freestanding electrode exhibits excellent sensing performances of H2O2. It possesses a high sensitivity (388 μA mM-1 cm−2), fast response within 4 s, low detection limit (0.27 μM, S/N = 3) and wide linear range (0.40 μM–7.2 mM). More importantly, the freestanding electrode can be used to in situ detect H2O2 released from MDA-MB-231 cells and HeLa cells. This work provides a new design of nonenzymatic electrochemical sensing platform for amperometric determination of H2O2 in biological environment, which has great potential in cancer diagnosis, environmental monitoring and food analysis.

Sonochemical synthesis of samarium tungstate nanoparticles for the electrochemical detection of nilutamide.

This study reports the sonochemical synthesis of samarium tungstate nanoparticles (SWNPs) for applications in electrochemical sensors. The synthesis process is based on a precipitation reaction, which was investigated by ultrasound and compared with the effect of stirring. A bath sonicator operated at a frequency and power of 37/100kHz and ~60W, respectively, was employed to prepare the material. The shock waves efficiently irradiated the reaction conditions as much as possible, resulting in the good crystallinity of the monoclinic phase of the SWNPs, which was confirmed by XRD analysis. The surface morphology and structural composition was further evaluated by HRTEM, EDS and XPS. The good crystallinity and uniform distribution of elements in the nanoparticles were confirmed. The performance of the SWNPs to electrochemically sense nilutamide (NLT) was studied, which revealed a good electrochemical signal. As a result, the SWNPs were applied to an electrode material for the detection of NLT. This study revealed the excellent activity of the SWNPs for NLT detection, resulting in a low detection limit (0.0026µM) and good linear range (0.05-318µM). Furthermore, the results show appreciable analytical performances, which could be applied to electrochemical anti-androgen drug nilutamide sensors.

Synthesis and crystal structure of a novel pyridine acylhydrazone derivative as a “turn on” fluorescent probe for Al3+

A novel acylhydrazone-based fluorescent probe HL was synthesized and characterized by 1H NMR, 13C NMR, mass spectrum (MS) and x-ray diffraction analysis. HL showed high selectivity and sensitivity towards Al3+ over other metal ions based on excited-state intramolecular proton transfer (ESIPT) and photo-induced electron transfer (PET) processes with a low detection limit (2.14 × 10−8 M) and reasonable pH application range (4.0–7.5). HL and Al3+ formed a 1:1 complex, leading to a remarkable fluorescence enhancement, which was confirmed by Job’s plot experiments, 1H NMR and MS. Fluorescence titration experiments showed the fluorescence intensity of HL had good linearity with Al3+ concentration and can be used to detect Al3+ in real water samples.

One-Step Green Preparation of N-Doped Silicon Quantum Dots for the on-off Fluorescent Determination of Hydrogen Peroxide

By using (3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane) and o-phenylenediamine as the reaction substrate, N-doped silicon quantum dots (N-SiQDs) with high quantum yield and excellent optical properties were synthesized by a one-step, simple, low-cost, and green method. Sequentially a N-SiQDs/silver nanoparticles (N-SiQDs/Ag NPs) nanocomplex was constructed as a nanoprobe to develop an “on-off” fluorescent sensing platform for hydrogen peroxide (H2O2). The produced N-SiQDs was characterized by various methods such as transmission electron microscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. Due to the surface plasmon-enhanced energy transfer from donor N-SiQDs to acceptor Ag NPs, the fluorescence of N-SiQDs is quenched (“off”) by Ag NPs. In the presence of hydrogen peroxide, it etches the Ag NPs to release N-SiQDs and further increases the fluorescence intensity from N-SiQDs (“on”). Based on this principle, an “on-off” fluorescent sensing platform for hydrogen peroxide was successfully developed. Under the optimized experimental conditions, the results show that the developed sensing platform has a low detection limit (1.5 μM) and wide linear range (5.0 to 200.0 µM) for the determination of hydrogen peroxide.

Electrochemical Immunosensors for Sensitive Detection of Neuron-Specific Enolase Based on Small-Size Trimetallic Au@Pd^Pt Nanocubes Functionalized on Ultrathin MnO2 Nanosheets as Signal Labels.

Medically, neuron-specific enolase (NSE) as a specific tumor marker has become an important indicator to diagnose small-cell lung carcinoma. In this study, a sandwich-type electrochemical immunosensor was designed to determine NSE sensitively. Au nanoparticle (Au NP)-embedded zinc-based metal-organic frameworks (Au@MOFs) were prepared as the substrate materials to modify the electrode and immobilize the primary antibody (Ab1). The Au@MOFs with the free amino groups on the MOF surface could effectively increase the immobilization amount of Ab1 through covalent linkage. Simultaneously, the embedding of Au NPs improved the conductivity of MOFs and accelerated interface electron transfer. Sub-30 nm trimetallic Au@Pd^Pt nanocubes (Au@Pd^Pt NCs) loaded onto ultrathin MnO2 nanosheets (MnO2 UNs/Au@Pd^Pt NCs) acted as the labels of secondary antibodies. The small-size Au@Pd^Pt NCs enhanced atomic utilization efficiency and offered more catalytic active sites. The MnO2 UNs with high external surface areas could improve the dispersion of Au@Pd^Pt NCs. The MnO2 UNs/Au@Pd^Pt NCs could catalyze the H2O2 reduction and promote the oxidation of hydroquinone to quinone effectively because of their synergistic effect; thus, the generated quinone achieved amplification of the highly reductive peak current. Furthermore, under the optimal conditions, the immunosensor exhibited a low detection limit (4.17 fg/mL) and broad linear range (10 fg/mL to 100 ng/mL). The results were satisfactory for NSE detection in human serum samples, implying that the presented method had great application potential in clinical bioanalysis.

Study of the microstructure and particles of vanadium (III) oxide, vanadium (V) oxide and lithium aluminate powders

Powder materials are widely used in the manufacture of electrochemical elements of thermal chemical sources of current. Electrochemical behavior of the powders depends on the shape and size of their particles. The results of the study of the microstructure and particles of the powders of vanadium (III), (V) oxides and lithium aluminate obtained by transmission electron and atomic force microscopy, X-ray diffraction and gas adsorption analyses are presented. It is found that the sizes of vanadium (III) and vanadium (V) oxide particles range within 70 – 600 and 40 – 350 nm, respectively. The size of the coherent-scattering regions of the vanadium oxide particles lies in the lower range limit which can be attributed to small size of the structural elements (crystallites). An average volumetric-surface diameter calculated on the basis of the surface specific area is close to the upper range limit which can be explained by the partial agglomeration of the powder particles. Unlike the vanadium oxide particles, the range of the particle size distribution of the lithium aluminate powder is narrower — 50 – 110 nm. The values of crystallite sizes are close to the maximum of the particle size distribution. Microstructural analysis showed that the particles in the samples of vanadium oxides have a rounded (V2O3) or elongated (V2O5) shape; whereas the particles of lithium aluminate powder exhibit lamellar structure. At the same time, for different batches of the same material, the particle size distribution is similar, which indicates the reproducibility of the technologies for their manufacture. The data obtained can be used to control the constancy of the particle size distribution of powder materials.

A graphene quantum dots-Pb2+ based fluorescent switch for selective and sensitive determination of D-penicillamine.

Taking consideration of metal-induced fluorescence quenching and excellent coordination effect of D-penicillamine (D-PA), a graphene quantum dots (GQDs)-based fluorescent switch for D-PA detection was designed and established firstly with the help of lead ions. GQDs obtained from citric acids made them rich in carboxyl and hydroxyl groups, giving GQDs the ability to combine with lead ions. As anticipated, the fluorescence intensity was quenched by Pb2+ through electron transfer process. Further, the addition of D-PA effectively recovered the fluorescence due to the departure of Pb2+ from GQDs aroused by the strong coordination between D-PA and Pb2+. Thus, a fluorescent switch was activated for D-PA detection. The fluorescence recovery efficiencies were found to be proportional to the concentration of D-PA in the range of 0.6-50μmolL-1 and the detection limit was 0.47μmolL-1. The real sample detection was performed in human urea sample and satisfactory recoveries of 96.84%-102.13% were obtained. The GQDs-Pb2+ based fluorescent switch sensing method was firstly established with low detection limit and wide linear range, making it a supplement and improvement for D-PA detection.

Poly(sulfosalicylic acid)-functionalized gold nanoparticles for the detection of tetrabromobisphenol A at pM concentrations

Developing a sensitive, simple and fast sensing system for 3,3′,5,5′-tetrabromobisphenol A (TBBPA) is important because of its ubiquitousness and high toxicity. In this work, a gold nanoparticles (AuNPs) and poly(sulfosalicylic acid) (PSSA) composite film (AuNPs-PSSA) is fabricated in-situ on an electrode surface via cyclic voltammetry scanning. The characterization via scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray (EDX) analysis and Fourier transform infrared (FTIR) spectroscopy indicate that the PSSA film is homogeneously decorated with AuNPs, and a highly uniform and thin composite film is obtained. Electrochemical tests reveal that the AuNPs-PSSA film exhibits larger active surface area, lower charge transfer resistance and higher accumulation efficiency toward TBBPA than single AuNPs and PSSA film. As a result, the oxidation signals and sensing sensitivity of TBBPA are significantly enhanced on the surface of the AuNPs-PSSA. The developed TBBPA sensing platform using AuNPs-PSSA composite film, with low detection limit (25 pM) and wide linear range (0.1−10 nM), is successfully utilized to measure TBBPA level in wastewater samples. The results are highly consistent with those that obtained from high-performance liquid chromatography. The preparation and reusability of the TBBPA sensor can be automatically achieved through CV scanning, providing a promising on-line monitoring system for wastewater samples.