A Simple and Highly Stable Porous Gold‐based Electrochemical Sensor for Bisphenol A Detection

A porous gold electrode with a uniform pore size was prepared by a simple single potential step method. It provided around 19 times more surface area than a bare gold electrode. The porous gold electrode, without any modification, exhibited good electrocatalytic activity towards the oxidation of bisphenol A (BPA). The effect of the pH and scan rate, on the porous gold electrode was studied and discussed. Under optimum conditions of the flow system, the calibration plot of BPA was linear over a wide range of concentration, from 2.0 nM to 800 nM (R²=0.999), and the detection limit was 2.0 nM (s/n=3). It was of interest that, the porous gold electrode showed an exceptional result in minimizing the fouling from the oxidation product of BPA and led to a very high operational stability of the electrode for the detection of BPA (560 consecutive times). The porous gold electrode showed good fabrication reproducibility and can be used to detect bisphenol A that leached from baby bottles and drinking water bottles. The obtained results were in good agreement with the GC‐MS method (P >0.05).     

Sensitive Voltammetric Determination of Bisphenol A Based on a Glassy Carbon Electrode Modified with Copper Oxide‐Zinc Oxide Decorated on Graphene Oxide

A highly sensitive and selective chemical sensor was prepared based on metallic copper‐copper oxides and zinc oxide decorated graphene oxide modified glassy carbon electrode (Cu?Zn/GO/GCE) through an easily electrochemical method for the quantification of bisphenol A (BPA). The composite electrode was characterized via scanning electron microscopy (SEM), X‐Ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). The electrochemical behavior of BPA in Britton‐Robinson (BR) buffer solution (pH 7.1) was examined using cyclic voltammetry (CV). Under optimized conditions, the square wave voltammetry (SWV) response of Cu?Zn/GO/GCE towards BPA indicates two linear relationships within concentrations (3.0 nmol L^?1?0.1 μmol L^?1 and 0.35 μmol L^?1?20.0 μmol L^?) and has a low detection limit (0.88 nmol L^?1). The proposed electrochemical sensor based on Cu?Zn/GO/GCE is both time and cost effective, has good reproducibility, high selectivity as well as stability for BPA determination. The developed composite electrode was used to detect BPA in various samples including baby feeding bottle, pacifier, water bottle and food storage container and satisfactory results were obtained with high recoveries.     

Electrochemical behavior of bisphenol A at glassy carbon electrode modified with gold nanoparticles, silk fibroin, and PAMAM dendrimers

A glassy carbon electrode was modified with a composite made from gold nanoparticles and silk fibroin whose surface was further modified with amino-terminated G4 poly(amidoamine) dendrimer. This electrode shows distinct electrochemical response to bisphenol A (BPA). Electrochemical impedance spectroscopy was used to characterize the surface. The electrode displayed improved adsorption capacity and an increased response to BPA, compared to a surface without modification. Under the optimal detection conditions, the respeonse is linear in the concentration range from 1 nM to 1.3 μM, the correlation coefficient is 0.9991, and the detection limit is 0.5 nM (at an S/N of 3). The method was applied to the determination of BPA in water samples, and the recovery was in the range from 97% to 105%.     

Reduced Graphene Oxide/Carbon Nanotube/Gold Nanoparticles Nanocomposite Functionalized Screen‐Printed Electrode for Sensitive Electrochemical Detection of Endocrine Disruptor Bisphenol A

We fabricated a highly sensitive electrochemical sensor for the determination of bisphenol A (BPA) in aqueous solution by using reduced graphene oxide (RGO), carbon nanotubes (CNT), and gold nanoparticles (AuNPs)‐modified screen‐printed electrode (SPE). GO/CNT nanocomposite was directly reduced to RGO/CNT on SPE at room temperature. AuNPs were then electrochemically deposited in situ on RGO/CNT‐modified SPE. Under optimized conditions, differential pulse voltammetry (DPV) produced linear current responses for BPA concentrations of 1.45 to 20 and 20 to 1,490 nM, with a calculated detection limit of an ultralow 800 pM. The sensor response was unaffected by the presence of interferents such as phenol, p‐nitrophenol, pyrocatechol, 2,4‐dinitrophenol, and hydroquinone.     

还原氧化石墨烯-多壁碳纳米管复合膜负载金纳米粒子修饰玻碳电极检测双酚A

以水合肼为还原剂,采用均相还原法制备还原氧化石墨烯-多壁碳纳米管复合材料(rGO-MWCNTs),通过滴涂法将其修饰到玻碳电极(GCE)表面.以此复合材料为载体,采用电化学方法制备了金纳米粒子-还原氧化石墨烯-多壁碳纳米管复合膜修饰电极(AuNPs-rGO-MWCNTs/GCE).通过扫描电镜(SEM)、EDS能谱技术和电化学方法对此电极进行了表征.研究了双酚A在修饰电极上的电化学行为.结果表明,此电极对双酚A的电极过程具有良好的电化学活性,在0.10 mol/L PBS溶液(pH 7.0)中,微分脉冲伏安法测定双酚A的线性范围为5.0 × 10-9~1.0 × 10-7 mol/L和1.0 × 10-7~2.0 × 10-5 mol/L,检出限为1.0 ×10-9 mol/L(S/N=3). 将此电极用于模拟水样和超市购物小票样品中双酚A含量的测定,加标回收率分别为97%~110%和98%~104%.     

Label‐Free Detection of Bisphenol A Using a Potentiometric Immunosensor

A potentiometric immunosensor for the label‐free detection of bisphenol A (BPA) was developed by covalently immobilizing a polyclonal antibody (PAb) onto the surface of a carboxylated poly(vinyl chloride) (PVC‐COOH) membrane. The immunosensor was characterized using scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS), and electrochemical impedance spectroscopy. The immobilization of PAb and its interaction with antigen (Ag) and BPA were also confirmed by quartz crystal microbalance (QCM) studies. Experimental parameters affecting the immuno‐interaction between PAb and its Ag or BPA were examined in terms of pH, antibody concentration, and temperature. The immunosensor showed a specific recognition of BPA with less interference than 4.8% from other common phenolic compounds. A calibration plot was obtained between 1.0 and 30.0 ng/mL and the detection limit was determined to be 0.6 ng/mL. The proposed immunosensor was applied for a real water sample spiked with BPA and the recoveries were in the range between 102.5 and 105.7%.     

An Electrochemical Sensor Based on Nitrogen‐doped Carbon Nanofiber for Bisphenol A Determination

In this paper, bisphenol A was determined by electrochemical method at a nitrogen‐doped carbon nanofiber modified carbon paste electrode (NCNF/CPE) with high sensitivity and good selectivity. NCNF was obtained by a simple electrospinning followed by carbonization procedure, in which polyacrylonitrile (PAN) as precursor and nitrogen doping was realized by re‐utilizing the tail gas that produced in the thermal pretreatment process. Good reproducibility and high stability were obtained for BPA detection at NCNF modified CPE. Current response plotted with BPA concentration was linear in the range of 0.1–60 μM with LOD of 0.05 μM. The proposed electrochemical sensor was employed for BPA determination with satisfactory recoveries for real water samples, indicating the practical applicability of NCNF/CPE.     

A Simple and Renewable Nanoporous Gold‐based Electrochemical Sensor for Bisphenol A Detection

A sensitive and simple electrochemical sensor based on nanoporous gold (NPG) was developed for the detection of bisphenol A (BPA). NPG was prepared by the dealloying method. The NPG modified glassy carbon electrode (GCE) displayed excellent catalytic activity towards the electrooxidation of BPA. The mechanism of the electrooxidation of BPA on NPG/GCE sensor was inferred. The sensor showed a linear range from 0.1 μM to 50 μM with a detection limit of 12.1 nM BPA. Specially, a simple but effective approach was attempted to renew the used sensor. The application of the sensor for real sample analysis was demonstrated.     

双酚A在氮掺杂多壁碳纳米管修饰电极上的电化学行为及测定

构建了不同百分含量的氮掺杂的多壁碳纳米管化学修饰石墨电极,利用线性扫描伏安法及循环伏安法研究了双酚A(BPA)在修饰电极上的电化学行为。提出了一种灵敏、简便的直接检测双酚A的电化学分析方法。在pH6.98的PBS缓冲溶液中,在电位0.20 V富集后,该修饰电极在0.680 V出现一个灵敏的、峰形好的氧化峰。表明氮掺杂多壁碳纳米管薄膜对双酚A的氧化表现出一定的催化作用,能显著提高双酚A的氧化峰电流。在优化条件下,采用线性扫描伏安法对双酚A进行测定。双酚A的氧化峰电流与其浓度在2.5×10-7～1.0×10-4 mol/L之间有很好的线性关系(R为0.996),检出限为5.0×10-8mol/L。电极已初步用于实际样品中BPA的测定。     

Label‐free Electrochemical Bisphenol A Aptasensor Based on Designing and Fabrication of a Magnetic Gold Nanocomposite

The present study focuses on designing and fabricating an electrochemical aptasensor for the label free detection of bisphenol A (BPA) using gold nanoparticles (Au NPs) immobilized on functional cupper magnetic nanoparticles (CuFe₂O₄‐SH) and multiwall carbon nanotubes (MWCNTs) modified with aptamer and 6‐mercapto‐1‐hexanol (MCH). A number of analysis techniques were used to characterize the nanocomposite, including Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometer, elemental mapping analysis and energy dispersive x‐ray diffraction. The results of the analyses revealed that the fabricated aptasensor had an acceptable linearity index (0.05‐9 nM) with an ultralow detection limit (25.2 pM) when used to determine BPA. Electrochemical experiments were conducted using a [Fe(CN)₆]³⁻/[Fe(CN)₆]⁴⁻ redox system. The results of the electrochemical tests indicated that the existence of Au NPs along with magnetic nanoparticles and MWCNTs in nanocomposite led to a synergistic augmentation on the surface of the modified electrode, thus facilitating the efficient sensing of BPA. This method is highly selective, sensitive and environmentally friendly. Moreover, proposed aptasensor has valuable potential applications in medical diagnostics and food industries where a fast and reliable detection of BPA is of paramount importance for the health of the public.     

Electrochemical sensor based on f-SWCNT and carboxylic group functionalized PEDOT for the sensitive determination of bisphenol A

A simple,sensitive,and reliable method for the voltammetric determination of bisphenol A(BPA) by using carboxylic group functionalized single-walled carbon nanotubes(f-SWCNT)/carboxylic-functionalized poly(3,4-ethylenedioxythiophene)(PC4) complex modified glassy carbon electrode(GCE) has been successfully developed.The electrochemical behavior of BPA at the surface of the modified electrode is investigated by electrochemical techniques.The cyclic voltammetry results show that the as-prepared electrode exhibits strong catalytic activity toward the oxidation of BPA with a well-defined anodic peak at 0.623 V in PBS(0.1 mol/L,pH 7.0).The surface morphology of the 3D network of composite film is beneficial for the adsorption of analytes.Under the optimized conditions,the oxidation peak current is proportional to BPA concentration in the range between 0.099 and 5.794 μmol/L(R~2 = 0.9989),with a limit of detection of 0.032 μmol/L(S/N = 3).The enhanced performance of the sensor can be attributed to the excellent electrocatalytic property of/-SWCNT and the extraordinary conductivity of PC4.Furthermore,the proposed modified electrode displays high stability and good reproducibility.The good result on the voltammetric determination of BPA also indicates that the asfabricated modified electrode will be a good candidate for the electrochemical determination and analysis of BPA.     

Electroanalysis of Bisphenol A at a Multiwalled Carbon Nanotubes‐gold Nanoparticles Modified Glassy Carbon Electrode

A sensitive electrochemical method was developed for the determination of bisphenol A (BPA) at a glassy carbon electrode (GCE) modified with a multiwalled carbon nanotubes (MWCNTs)‐gold nanoparticles (GNPs) hybrid film, which was prepared based on the electrostatic interaction between positively charged cetyltrimethylammonium bromide (CTAB) and negatively charged MWCNTs and GNPs. The MWCNT‐GNPs/GCE exhibited an enhanced electroactivity for BPA oxidation versus unmodified GCE and MWCNTs/GCE. The experimental parameters, including the amounts of modified MWCNTs and GNPs, the pH of the supporting electrolyte, scan rate and accumulation time, were examined and optimized. Under the optimal conditions, the differential pulse voltammetric anodic peak current of BPA was linear with the BPA concentration from 2.0×10^?8 to 2×10^?5 mol L^?1, with a limit of detection of 7.5 nmol L^?1. The proposed procedure was applied to determine BPA leached from real plastic samples with satisfactory results.     

双酚A在SDS现场自组装膜与[bupy]PF6复合修饰碳糊电极上的电催化氧化及电分析方法

研究了双酚A(BPA)在十二烷基硫酸钠(SDS)现场自组装膜与离子液体N-丁基吡啶夫氟磷酸盐([ bupy]PF6)复合修饰碳糊电极(SDS-[ bupy]PF6/CPE)上的电催化氧化行为和电化学动力学性质.实验结果表明,在SDS-[ bupy]PF6/CPE上BPA发生了一受扩散控制的不可逆电化学氧化过程,用循环伏安(CV)法和计时电流(CA)法测得BPA在SDS-[bupy]PF6/CPE上的电极反应过程动力学参数.用方波伏安(SWV)法测得BPA氧化峰电流(Ipa)与其浓度在1.0×10-5～ 1.0×10-3 mol/L范围内呈良好的线性关系,线性方程为Ipa(μA) =2.635 +51.30c( 10-3 mol/L),r =0.998 1,检测限(S/N=3)为3.01×10-7 mol/L,同时运用SWV法对湖水样品中双酚A的含量进行了电化学定量测定.     

双酚A在纳米金-离子液体复合修饰电极上的电化学行为及测定

该文制备了纳米金-离子液体修饰电极(GNP-[BMIM]PF6/GCE),用红外光谱对GNP和[BMIM]PF6进行了表征.采用交流阻抗法研究了GNP-[BMIM]PF6/GCE的表面电化学特性,同时研究了双酚A(BPA)在该修饰电极上的循环伏安行为.结果表明,BPA在该修饰电极上出现1个氧化峰,无还原峰,为不可逆电化...     

Biomolecule‐Doped Organic/Inorganic Hybrid Nanocomposite Film for Label‐Free Electrochemical Immunoassay of α‐1‐Fetoprotein

A new electrochemical immunosensor for the detection of α‐1‐fetoprotien (AFP) was developed based on AFP antibody (anti‐AFP)‐functionalized organic/inorganic hybrid nanocomposite membrane. To fabricate such a hybrid composite membrane, 3,4,9,10‐perylenetetracarboxylic acid‐bound thionine molecules (PTCTH) were initially doped into titania colloids (TiO₂), and then gold nanoparticles and anti‐AFP were immobilized onto the composite film in turn. Comparison with the electrode fabricated only with thionine not 3,4,9,10‐perylenetetracarboxylic acid, the immunosensor with PTCTH exhibited high sensitivity and fast electron transfer. The presence of gold nanoparticles provided a good microenvironment for the immobilization of biomolecules, enhanced the surface coverage of protein, and improved the sensitivity of the immunosensor. The modified process was characterized by scanning electron microscope (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The surface topography of the membrane was investigated by scanning electron microscopy (SEM). Under optimal conditions, the proposed immunosensor exhibited a wide linear range from 2.5 to 200.0 ng/mL towards AFP with a detection limit of 0.5 ng/mL (S/N=3). The stability, reproducibility and precision of the immunosensor were acceptable. Comparison with the conventional enzyme‐linked immunosorbent assay (ELISA), the present method did not require more labeled procedures and washing steps. Significantly, the detection methodology provides a promising approach for other proteins or biosecurities.     

A Novel Electrochemical Aptasensor for Carcinoembryonic Antigen Detection Based on Target‐induced Bridge Assembly

The present study describes a novel electrochemical aptasensor for detection of carcinoembryonic antigen (CEA), a key cancer biomarker. The sensing strategy relied on the CEA‐induced bridge assembly, as a physical barrier, on the surface of gold electrode, resulting in a significant increase of the sensor sensitivity. Under optimal conditions, the aptasensing platform showed a wide linear range (3 pg/mL to 40 ng/mL) and a low detection limit (0.9 pg/mL). Some possible interfering materials were also assessed and the results indicated that the designed aptasensor had good specificity toward CEA. The quantitation of CEA in the spiked human serum samples confirmed the reliability and applicability of the electrochemical aptasensor. So, the developed sensing method has a potential application in the clinical diagnosis.     

Electrochemical aptasensor for the determination of bisphenol A in drinking water

We present an electrochemical aptasensor for rapid and ultrasensitive determination of the additive bisphenol A (BPA) and for screening drinking water for the presence of BPA. A specific aptamer against BPA and its complementary DNA probe were immobilized on the surface of a gold electrode via self-assembly and hybridization, respectively. The detection of BPA is mainly based on the competitive recognition of BPA by the immobilized aptamer on the surface of the electrode. The electrochemical aptasensor enables BPA to be detected in drinking water with a limit of detection as low as 0.284 pg?mL^?1 in less than 30 min. This extraordinary sensitivity makes the method a most powerful tool for on-site monitoring of water quality and food safety.

POMs as Active Center for Sensitively Electrochemical Detection of Bisphenol A and Acetaminophen

A new type of electrochemical sensor based on multi-walled carbon nanotubes(MWCNTs), K2H4SiW11CuO39-6H2O(SiW11Cu) and gold nanoparticles(AuNPs) was prepared for the simultaneous detection of bisphenol A and acetaminophen. Differential pulse voltammetry(DPV), cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) were used for electrochemical characterization, and Fourier transfonn infrared spectroscopy(FTIR) was used to characterize the structure of polyoxometalates. Electrochemical experimental results show that the composite modified electrodes have good electrochemical activity as well as current response values of bisphenol A and acetaminophen when pH=7.0. At the same time, the modified electrode exhibits good stability and reproduction, and has good anti-interference ability to other substances. In practical application, the sensor obtained satisfactory results.     

Non‐Covalent Functionalization of Graphene with Bisphenol A for High‐Performance Supercapacitors

The reduced graphene oxide (RGO)/bisphenol A (BPA) composites were prepared by an adsorption‐reduction method. The composites are characterized by X‐ray diffraction (XRD), UV‐vis, thermogravimetric (TG) analysis, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM). The results confirm that BPA is adsorbed on the basal plane of RGO by π‐π stacking interaction. Furthermore, the electrochemical behaviors were evaluated by cyclic voltammetry, galvanostatic charge/discharge techniques and electrochemical impedance spectroscopy (EIS). The results show that the RGO/BPA nanocomposites exhibit ultrahigh specific capacitance of 466 F·g^?1 at a current density of 1 A·g^?1, excellent rate capability (more than 81% retention at 10 A·g^?1 relative to 1 A·g^?1) and superior cycling stability (90% capacitance decay after 4000 cycles). Consequently, the RGO/BPA nanocomposites can be regarded as promising electrode materials for supercapacitor applications.     

Electrochemical detection of DNA damage induced by in situ generated bisphenol A radicals through electro-oxidation

A glassy carbon electrode was modified with dsDNA and a nanocomposite composed of multi-walled carbon nanotubes and chitosan (MWNT-chit). The electrode was applied to the electrochemical detection of DNA damage as induced by in situ generated bisphenol A (BPA) radicals through electro-oxidation. The modified electrode was characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The results indicate that MWNT-chit nanocomposite represents a viable platform for the immobilization of DNA that effectively promotes electron transfer between DNA and the electrode. The mode of interaction between DNA and BPA was investigated by differential pulse voltammetry and UV-vis spectrophotometry, indicating that the dominant interaction is intercalation. In order to explore the mechanism of damage caused by BPA radicals, the electro-oxidation of BPA at the modified glass electrode was investigated. Based on the signal for guanine without any other external indicator, DNA damage was investigated through the electro-oxidation of BPA.