Simple and sensitive fluorimetric method for determination of environmental hormone bisphenol A based on its inhibitory effect on the redox reaction between peroxyl radical and rhodamine 6G

Triple-signaling amplification strategy based electrochemical sensor design: boosting synergistic catalysis in metal-metalloporphyrin-covalent organic frameworks for sensitive bisphenol A detection

A covalent organic framework (COF) is a promising type of porous material with customizable surface characteristics. Confining multiple catalytic units within a mesoporous COF can generate abundant active sites and improve the catalytic performance. In this work, a COF with both metalloporphyrin and a metal nanoparticle complex denoted as hemin/TAPB-DMTP-COF/AuNPs (TAPB: 1,3,5-tris(4-amino-phenyl)benzene, DMTP: 2,5-dimethoxyterephaldehyde, AuNPs: Au nanoparticles) has been successfully fabricated through a hierarchical encapsulation method. The as-synthesized composite was then employed to construct an electrochemical sensing platform for the efficient detection of bisphenol A (BPA). Under the optimal conditions, the hemin/TAPB-DMTP-COF/AuNP sensor presented a linear range of 0.01-3 μmol L^-1 and a low detection limit of 3.5 nmol L^-1. The satisfactory signal amplification is based on a triple-signaling amplification strategy due to the abundant Fe³⁺ sites of Fe-porphyrin, high conductivity of AuNPs and a large specific surface area of the TAPB-DMTP-COF. The proposed method was used to measure the content of BPA in different water samples with a satisfactory recovery from 95.5 to 104.0%, suggesting the great potential of the sensor in practical applications.

A facile synthesis of nanostructured CoFe2O4 for the electrochemical sensing of bisphenol A

This work reports a novel, highly sensitive and cost-effective electrochemical sensor for the detection of bisphenol A in environmental water samples. Attractive non-noble transition metal oxide CoFe₂O₄ nanoparticles were successfully synthesized using a sol–gel combustion method and further characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. Under optimal conditions, the CoFe₂O₄ nanoparticle modified glassy carbon electrode exhibits high electrochemical activity and good catalytic performance for the detection of bisphenol A. The linear calibration curves are obtained within a wide concentration range from 0.05 μmol L⁻¹ to 10 μmol L⁻¹, and the limit of detection is 3.6 nmol L⁻¹ for bisphenol A. Moreover, this sensor also demonstrates excellent reproducibility, stability, and good anti-interference ability. The sensor was successfully applied to determine bisphenol A in practical samples, and the satisfactory recovery rate was between 95.5% and 102.0%. Based on the great electrochemical properties and practical application results, this electrochemical sensor has broad application prospects in the sensing of bisphenol A.

A new electrochemical sensor for bisphenol A is reported. CoFe₂O₄ nanoparticles were synthesized by a sol–gel combustion method. A nanoparticle-modified glassy carbon electrode exhibited outstanding electrochemical performance for the detection of bisphenol A.

Electrochemical Enzyme Biosensor Bearing Biochar Nanoparticle as Signal Enhancer for Bisphenol A Detection in Water

An electrochemical tyrosinase enzyme (Tyr) biosensor using a highly conductive sugarcane derived biochar nanoparticle (BCNP) as a transducer and signal enhancer (BCNPs/Tyr/Nafion/GCE) was developed for the sensitive detection of bisphenol A (BPA). The BCNPs/Tyr/Nafion/GCE biosensor exhibited improved amperometric current responses such as higher sensing signal, decreased impedance and lowered reduction potential compared with the Tyr/Nafion/GCE due to high conductivity property of the biochar nanoparticle. Under the optimized conditions, it could detect BPA in good sensitivity with linear range from 0.02 to 10 μM, and a lowest detection limit of 3.18 nM. Moreover, it showed a low K_m value, high reproducibility and good selectivity over other reagents, and the BCNPs/Tyr complex solution also showed good stability with 86.9% of sensing signal maintained after one month storage. The biosensor was also successfully utilized for real water detection with high accuracy as validated by high performance liquid chromatography. Therefore, the biochar nanoparticle based enzyme biosensor proved to be a potential and reliable method for high performance detection of pollutants in the environment.

Developing an integrated 3D-hydrodynamic and emerging contaminant model for assessing water quality in a Yangtze Estuary Reservoir

An integrated 3D-hydrodynamic and emerging contaminant model was developed for better understanding of the fate and transport of emerging contaminants in Qingcaosha Reservoir. The reservoir, which supplies drinking water for nearly half of Shanghai's population, is located in Yangtze Delta. The integrated model was built by Delft3D suite, a fully integrated multidimensional modeling software. Atrazine and Bisphenol A (BPA) were selected as two representative emerging contaminants for the study in this reservoir. The hydrodynamic model was calibrated and validated against observations from 2011 to 2015 while the integrated model was calibrated against observations from 2014 to 2015 and then applied to explore the potential risk of high atrazine concentrations in the reservoir driven by agriculture activities. Our results show that the model is capable of describing the spatial and temporal patterns of water temperature, salinity and the dynamic distributions of two representative emerging contaminants (i.e. atrazine and BPA) in the reservoir. The physical and biodegradation processes in this study were found to play a crucial role in determining the fate and transport of atrazine and BPA in the reservoir. The model also provides an insight into the potential risk of emerging contaminants and possible mitigation thresholds. The integrated approach can be a very useful tool to support policy-makers in the future management of Qingcaosha Reservoir.

Carbon-dot-based dual-emission silica nanoparticles as a ratiometric fluorescent probe for Bisphenol A

A simple and effective strategy for designing a ratiometric fluorescent nanosensor is described in this work. A carbon dots (CDs) based dual-emission nanosensor for Bisphenol A (BPA) was prepared by coating CDs on the surface of dye-doped silica nanoparticles. The fluorescence of dual-emission silica nanoparticles was quenched in hydrochloric acid by potassium bromate (KBrO₃) oxidation; BPA inhibited KBrO₃ oxidation, resulting in the ratiometric fluorescence response of dual-emission silica nanoparticles. Several important parameters affecting the performance of the nanosensor were investigated and optimized. The detection limit of this nanosensor was 0.80ng mL^-1 with a linear range from 10 to 500ng mL^-1. This was applied successfully to determine BPA in the leached solution of different plastic products with satisfactory results.

Sensing Estrogen with Electrochemical Impedance Spectroscopy

This study demonstrates the application feasibility of electrochemical impedance spectroscopy (EIS) in measuring estrogen (17β-estradiol) in gas phase. The present biosensor gives a linear response (R² = 0.999) for 17β-estradiol vapor concentration from 3.7 ng/L to 3.7 × 10^-4 ng/L with a limit of detection (3.7 × 10^-4 ng/L). The results show that the fabricated biosensor demonstrates better detection limit of 17β-estradiol in gas phase than the previous report with GC-MS method. This estrogen biosensor has many potential applications for on-site detection of a variety of endocrine disrupting compounds (EDCs) in the gas phase.

Global Assessment of Bisphenol A in the Environment: Review and Analysis of Its Occurrence and Bioaccumulation

Because bisphenol A (BPA) is a high production volume chemical, we examined over 500 peer-reviewed studies to understand its global distribution in effluent discharges, surface waters, sewage sludge, biosolids, sediments, soils, air, wildlife, and humans. Bisphenol A was largely reported from urban ecosystems in Asia, Europe, and North America; unfortunately, information was lacking from large geographic areas, megacities, and developing countries. When sufficient data were available, probabilistic hazard assessments were performed to understand global environmental quality concerns. Exceedances of Canadian Predicted No Effect Concentrations for aquatic life were >50% for effluents in Asia, Europe, and North America but as high as 80% for surface water reports from Asia. Similarly, maximum concentrations of BPA in sediments from Asia were higher than Europe. Concentrations of BPA in wildlife, mostly for fish, ranged from 0.2 to 13 000 ng/g. We observed 60% and 40% exceedences of median levels by the US Centers for Disease Control and Prevention's National Health and Nutrition Examination Survey in Europe and Asia, respectively. These findings highlight the utility of coordinating global sensing of environmental contaminants efforts through integration of environmental monitoring and specimen banking to identify regions for implementation of more robust environmental assessment and management programs.

Detection of bisphenol A in food packaging based on fluorescent conjugated polymer PPESO3 and enzyme system

Bisphenol A (BPA) is a kind of carcinogen, which can interfere with the body's endocrine system. In this paper, a new kind of fluorescent sensor for BPA detection was established based on the fluorescent conjugated polymer PPESO3. The oxidative product of BPA is able to quench PPESO3 in the presence of HRP and H2O2, and the quenched PL intensity of PPESO3 was proportionally to the concentration of BPA in the range of 1-100 μmol/L with a detection limit of 4 × 10(-7) mol/L. The proposed method has been applied to detect BPA in eight food packaging samples with satisfactory results. The proposed method has the potential for the assay of BPA in food or food packaging samples.

Spectrophotometric and high performance liquid chromatographic methods for sensitive determination of bisphenol A

A new spectrophotometric method for the determination of trace amounts of bisphenol A based on a diazotization-coupling reaction was developed. In acidic solution, clenbuterol was first diazotized with sodium nitrite, then coupled with bisphenol A to from an azo-compound [I] in NH3-NH4Cl buffer, which shows a maximum absorption at 410 nm. The effects of the amount of sodium nitrite, diazo reaction time, the amount of clenbuterol, coupling reaction time and coupling reaction temperature have been examined. Under the optional conditions, the determination of the linear range of bisphenol A is 0.24-8.4 μg/mL, correlation coefficient is 0.9905 and detection limit of this method is 0.15 μg/mL. The spectrophotometric method is simple, rapid, high sensitivity with better accuracy. High performance liquid chromatography (HPLC) technique combined with this new spectrophotometric method has been also developed for the measurement of bisphenol A. The analysis was achieved on a C18 column using water and methanol as a mobile phase and the detection was done spectrophotometrically at 410 nm. These reported methods were applied to the determination of bisphenol A in hot water in contact with commercially available table-water bottle samples.

Facile synthesis of chitosan-capped ZnS quantum dots as an eco-friendly fluorescence sensor for rapid determination of bisphenol A in water and plastic samples

Quantitative detection of BPA in water and plastic samples was developed based on fluorescence quenching of eco-friendly chitosan-capped ZnS QDs.

Determination of Bisphenol A by Fluorescence Immunoassay Based on Quantum Dots as Probe

A sensitive and selectivity fluoroimmunoassay was established for the determination of bisphenol A, on the basis of being labeled quantum dots. Anti-rabbit IgG conjugated by quantum dots were regarded as a probe in this system. The presented method produced a widely linear range from 0.0001 to 100.0 ng mL-1, with detection limit of 0.078 pg mL-1. The method was applied to determine bisphenol A in plastic leach liquor, with the recoveries from 99.8% to 102.5%. The results were similar to those obtained from a high performance liquid chromatography method, while this method is simple, rapid, sensitive and accurate.