Preparation and characteristic of cobalt phthalocyanine modified carbon paste electrode for bisphenol A detection

Synthesis of Metal–Organic Frameworks Quantum Dots Composites as Sensors for Endocrine-Disrupting Chemicals

Hazardous chemical compounds such as endocrine-disrupting chemicals (EDCs) are widespread and part of the materials we use daily. Among these compounds, bisphenol A (BPA) is the most common endocrine-disrupting chemical and is prevalent due to the chemical raw materials used to manufacture thermoplastic polymers, rigid foams, and industrial coatings. General exposure to endocrine-disrupting chemicals constitutes a serious health hazard, especially to reproductive systems, and can lead to transgenerational diseases in adults due to exposure to these chemicals over several years. Thus, it is necessary to develop sensors for early detection of endocrine-disrupting chemicals. In recent years, the use of metal–organic frameworks (MOFs) as sensors for EDCs has been explored due to their distinctive characteristics, such as wide surface area, outstanding chemical fastness, structural tuneability, gas storage, molecular separation, proton conductivity, and catalyst activity, among others which can be modified to sense hazardous environmental pollutants such as EDCs. In order to improve the versatility of MOFs as sensors, semiconductor quantum dots have been introduced into the MOF pores to form metal–organic frameworks/quantum dots composites. These composites possess a large optical absorption coefficient, low toxicity, direct bandgap, formidable sensing capacity, high resistance to change under light and tunable visual qualities by varying the size and compositions, which make them useful for applications as sensors for probing of dangerous and risky environmental contaminants such as EDCs and more. In this review, we explore various synthetic strategies of (MOFs), quantum dots (QDs), and metal–organic framework quantum dots composites (MOFs@QDs) as efficient compounds for the sensing of ecological pollutants, contaminants, and toxicants such as EDCs. We also summarize various compounds or materials used in the detection of BPA as well as the sensing ability and capability of MOFs, QDs, and MOFs@QDs composites that can be used as sensors for EDCs and BPA.

Developments and applications of nanomaterial-based carbon paste electrodes

This review summarizes the progress that has been made in the past ten years in the field of electrochemical sensing using nanomaterial-based carbon paste electrodes. Following an introduction into the field, a first large section covers sensors for biological species and pharmaceutical compounds (with subsections on sensors for antioxidants, catecholamines and amino acids). The next section covers sensors for environmental pollutants (with subsections on sensors for pesticides and heavy metal ions). Several tables are presented that give an overview on the wealth of methods (differential pulse voltammetry, square wave voltammetry, amperometry, etc.) and different nanomaterials available. A concluding section summarizes the status, addresses future challenges, and gives an outlook on potential trends.

A novel copper(ıı) phthalocyanine-modified multiwalled carbon nanotube-based electrode for sensitive electrochemical detection of bisphenol A

A novel copper(ii) phthalocyanine (CuPc)-modified multiwalled carbon nanotube-based electrode was prepared for the sensitive electrochemical detection of bisphenol A, by the modification of a pencil graphite electrode via the adsorption method.

Rational functionalization of reduced graphene oxide with an imidazole group for the electrochemical sensing of bisphenol A - an endocrine disruptor

Reduced graphene oxide has been rationally functionalized with histamine for the highly sensitive and selective electrochemical determination of bisphenol A (BPA). Histamine is covalently attached to graphene oxide by amide coupling and the oxygen functionalities of graphene oxide are partially reduced electrochemically. The facilitated electrochemical oxidation of BPA was achieved in neutral pH with functionalized reduced graphene oxide. The pH of the reaction controls the oxidation of BPA. Electrochemical oxidation is not favourable at pH less than the pKa of histamine due to the protonation of the imidazole nitrogen. The electrode is highly sensitive (1727.29 ± 12.48 nA μM-1 cm-2) towards BPA and shows a linear response up to 30 μM of BPA. It could detect as low as 0.03 nM of BPA (S/N = 5). The other coexisting analytes do not interfere with the voltammetric measurement of BPA.

Direct Electrochemical Detection of Bisphenol A Using a Highly Conductive Graphite Nanoparticle Film Electrode

We developed an accurate and sensitive sensor for electrochemical detection of bisphenol A (BPA) with a high-conductivity graphite nanoparticle (GN) film electrode. The GNs consisted of several stacked graphene sheets and showed a homogenous spherical shape, high conductivity, large surface area and good adsorption properties to BPA. The constructed GN film electrode exhibited improved amperometric current responses such as decreased impedance and lowered BPA oxidation potential compared with those of a pristine electrode, and also possessed a large surface area to allow fast electron transfer and BPA accumulation. A pre-accumulation process with BPA adsorption resulted in considerable current signal enhancement during BPA detection. The loading amount of GNs on the film electrode and the time for target BPA enrichment were optimized. The GN film electrode-based sensor showed high reproducibility and high selectivity for BPA over other reagents. Differential pulse voltammetry experiments revealed that the concentrations of BPA were linearly correlated with the current changes, and the lowest limit of detection of the sensor was 35 nM. Furthermore, the sensor showed great accuracy and reliability, as confirmed by high-performance liquid chromatography measurements. The sensor was also successfully used for BPA determination in groundwater samples, demonstrating its potential for real environmental analysis.

Diamond-based electrochemical aptasensor realizing a femtomolar detection limit of bisphenol A

In this study, we designed and fabricated an electrochemical impedance aptasensor based on Au nanoparticles (Au-NPs) coated boron-doped diamond (BDD) modified with aptamers, and 6-mercapto-1-hexanol (MCH) for the detection of bisphenol A (BPA). The constructed BPA aptasensor exhibits good linearity from 1.0×10^-14 to 1.0×10^-9molL^-1. The detection limitation of 7.2×10^-15molL^-1 was achieved, which can be attributed to the synergistic effect of combining BDD with Au-NPs, aptamers, and MCH. The examine results of BPA traces in Tris-HCl buffer and in milk, UV spectra of aptamer/BPA and interference test revealed that the novel aptasensors are of high sensitivity, specificity, stability and repeatability, which could be promising in practical applications.

Rapid and sensitive detection of bisphenol a from serum matrix

Bisphenol A (BPA) is an endocrine disrupting compound that may have adverse developmental, reproductive, neurological, and immune system effects. Low-level exposure to BPA is ubiquitous in human populations due to its widespread use in consumer products. Therefore, highly sensitive methods are needed to quantify BPA in various matrices including water, serum, and food products. In this study, we developed a simple, rapid, highly sensitive and specific sensor based on an aptamer probe and AC electrokinetics capacitive sensing method that successfully detected BPA at femto molar (fM) levels, which is an improvement over prior work by a factor of 10. We were able to detect BPA spiked in human serum as well as in maternal and cord blood within 30s. The sensor is responsive to BPA down to femto molar levels, but not to structurally similar compounds including bisphenol F (BPF) or bisphenol S (BPS) even at much higher concentration. Further development of this platform may prove useful in monitoring exposure to BPA and other small molecules in various matrices.

AuNp@MOF composite as electrochemical material for determination of bisphenol A and its oxidation behavior study

A hybrid material on the carbon paste electrode exhibited a greater electroactivity for the determination of an endocrine disruptor.

A nitrogen and sulfur co-doped graphene-supported nickel tetrapyridyloxyphthalocyanine hybrid fabricated by a solvothermal method and its application for the detection of bisphenol A

A novel hybrid consisting of nickel tetrapyridyloxyphthalocyanine (NiTPPc) and nitrogen and sulfur co-doped graphene (N-S-G) was obtained via a solvothermal method and applied for the determination of BPA.

Azo dye functionalized graphene nanoplatelets for selective detection of bisphenol A and hydrogen peroxide

A new electrochemical sensor is developed based on graphene nanoplatelets functionalized with tri-azo dye (direct blue 71) for selective and highly sensitive detection of bisphenol A and hydrogen peroxide in pH 7 phosphate buffered saline solution.

A highly sensitive electrochemical sensor for simultaneous determination of hydroquinone and bisphenol A based on the ultrafine Pd nanoparticle@TiO2 functionalized SiC

A titanium dioxide-silicon carbide nanohybrid (TiO2-SiC) with enhanced electrochemical performance was successfully prepared through a facile generic in situ growth strategy. Monodispersed ultrafine palladium nanoparticles (Pd NPs) with a uniform size of ∼2.3 nm were successfully obtained on the TiO2-SiC surface via a chemical reduction method. The Pd-loaded TiO2-SiC nanohybrid (Pd@TiO2-SiC) was characterized by transmission electron microscopy and X-ray diffractometry. A method for the simultaneous electrochemical determination of hydroquinone (HQ) and bisphenol A (BPA) using a Pd@TiO2-SiC nanocomposite-modified glassy carbon electrode was established. Utilizing the favorable properties of Pd NPs, the Pd@TiO2-SiC nanohybrid-modified glassy carbon electrode exhibited electrochemical performance superior to those of TiO2-SiC and SiC. Differential pulse voltammetry was successfully used to simultaneously quantify HQ and BPA within the concentration range of 0.01-200 μM under optimal conditions. The detection limits (S/N=3) of the Pd@TiO2-SiC nanohybrid electrode for HQ and BPA were 5.5 and 4.3 nM, respectively. The selectivity of the electrochemical sensor was improved by introducing 10% ethanol to the buffer medium. The practical application of the modified electrode was demonstrated by the simultaneous detection of HQ and BPA in tap water and wastewater samples. The simple and straightforward strategy presented in this paper are important for the facile fabrication of ultrafine metal NPs@metal oxide-SiC hybrids with high electrochemical performance and catalytic activity.