Development of an electrochemical sensor of endocrine disruptor bisphenol A by reduced graphene oxide for incorporation of spherical carbon nanoparticles

Cobalt-nickel phosphide supported on reduced graphene oxide for sensitive electrochemical detection of bisphenol A

Bisphenol A (BPA) is a commonly utilized phenolic contaminant in several manufacturing processes, contributing to environmental pollution. Therefore, the detection of BPA holds significant importance for monitoring water quality. In this work, we report a robust electrochemical detection method for BPA utilizing cobalt-nickel bimetal phosphide nanoparticles (CoNiP) supported on reduced graphene oxide (rGO). The CoNiP@rGO-modified glassy carbon electrode exhibits remarkable electrochemical activity in BPA detection. The detection mechanism is controlled by adsorption-mediated electron transfer, showcasing a low limit of detection (LOD) at 0.38 nM and a high sensitivity of 96.4 A M-1 cm-2 within the linear range of 0.001-8 μM. Furthermore, our developed sensor demonstrates good reproducibility and successfully detected BPA in actual water samples. The electrochemical activity of CoNiP@rGO was also characterized for hydroquinone (HQ) detected through a diffusion-controlled mechanism, displaying an excellent sensitivity of 36.4 A M-1 cm-2 across a broad linear range. These findings underscore the promising potential of CoNiP@rGO as a candidate for electrochemical detection of phenolic contaminants, especially in the sensing of BPA in environmental water samples. This efficacy is attributed to the modulation of its electronic properties, combined with its large electroactive surface area and low electron-transfer resistance.

Electrochemical (bio)sensors based on carbon quantum dots, ionic liquid and gold nanoparticles for bisphenol A

Electrochemical (bio)sensors were developed for bisphenol A (BPA) determination. Screen printed carbon electrode (SPCE) was modified with ionic liquid 1- butyl-3-methylimidazolium tetrafluoroborate (IL), carbon quantum dots (CQD) and gold nanoparticles (AuNP) for the fabrication of the BPA sensor. Electrode surface composition was optimized for the deposition time of AuNP, amount of CQD and percentage of IL using the central composite design (CCD) method. The results of the CCD study indicated that maximum amperometric response was recorded when 9.8 μg CQD, 3% IL and 284 s AuNP deposition time were used in modification. Tyrosinase (Ty) was further modified on the AuNP/CQD-IL/SPCE to fabricate the biosensor. Analytical performance characteristics of the BPA sensor were investigated by differential pulse anodic adsorptive stripping voltammetry and the AuNP/CQD-IL/SPCE sensor exhibited a linear response to BPA in the range of 2.0 × 10^-8 - 3.6 × 10^-6 M with a detection limit of 1.1 × 10^-8 M. Amperometric measurements showed that the linear dynamic range and detection limit of the Ty/AuNP/CQD-IL/SPCE were 2.0 × 10^-8 - 4.0 × 10^-6 M and 6.2 × 10^-9 M, respectively. Analytical performance characteristics such as sensitivity, reproducibility and selectivity were investigated for the presented (bio)sensors. The analytical applicability of the (bio)sensors to the analysis of BPA in mineral water samples was also tested.

Electrochemical determination of atenolol and propranolol using a carbon paste sensor modified with natural ilmenite

In this study, a simple voltammetric method was reported for independent determination of propranolol (PROP) and atenolol (ATN) in pharmaceutical tablets using carbon paste electrode modified with natural Ilmenite (CPE-I). The analytical performance of the modified sensor was evaluated using the square wave voltammetry and cyclic voltammetry for determination of both β(beta) blockers in 0.1 mol L−1 of sulfuric acid solution (H2SO4). The signal obtained with modified carbon paste electrode in 0.1 mol L−1 of H2SO4 showed a good electrocatalytic activity toward the oxidations of PROP and ATN compared with the bare one. The enhanced oxidation peak current response can be attributed to the catalytic effect of the ilmenite nanomaterial incorporated into the carbon paste electrode. Under optimal condition, good linear calibration curves were obtained ranging from 0.20 to 8.9 mmol L−1 for PROP and 2.0 to 9.9 µmol L−1 for ATN, with detection limits of 80 and 0.31 µmol L−1, respectively. The CPE-I sensor had good repeatability and reproducibility (RSD ≤ 3.2%) and high sensitivity for the detection of both ATN and PROP. The proposed sensor was applied for detection of these drugs in pharmaceutical tablets. The obtained results indicate that the voltammetric CPE-I sensor could be an alternative method for the routine quality control of the β blockers in complex matrices.

Efficient Determination of PML/RARα Fusion Gene by the Electrochemical DNA Biosensor Based on Carbon Dots/Graphene Oxide Nanocomposites

Purpose

The PML/RARα fusion gene as a leukemogenesis plays a significant role in clinical diagnosis of the early stage of acute promyelocytic leukemia (APL). Here, we present an electrochemical biosensor for PML/RARα fusion gene detection using carbon dots functionalized graphene oxide (CDs/GO) nanocomposites modified glassy carbon electrode (CDs/GO/GCE).

Materials and Methods

In this work, the CDs/GO nanocomposites are produced through π-π stacking interaction and could be prepared in large quantities by a facile and economical way. The CDs/GO nanocomposites were decorated onto electrode surface to improve the electrochemical activity and as a bio-platform attracted the target deoxyribonucleic acid (DNA) probe simultaneously.

Results

The CDs/GO/GCE was fabricated successfully and exhibits high electrochemical activity, good biocompatibility, and strong bioaffinity toward the target DNA sequences, compared with only the pristine CDs on GCE or GO on GCE. The DNA biosensor displays excellent sensing performance for detecting the relevant pathogenic DNA of APL with a detection limit of 83 pM (S/N = 3).

Conclusion

According to the several experimental results, we believe that the simple and economical DNA biosensor has the potential to be an effective and powerful tool for detection of pathogenic genes in the clinical diagnosis.

A Silver-Loaded Exfoliated Graphite Nanocomposite Anti-Fouling Electrochemical Sensor for Bisphenol A in Thermal Paper Samples

Silver nanoparticles (AgNPs) were synthesized separately and loaded onto the expanded layers of exfoliated graphite (EG) to form a silver nanoparticle-exfoliated graphite nanocomposite (AgNPs-EG). The AgNPs-EG was compressed into a pellet (0.6 cm in diameter) and used to prepare an electrochemical sensor for bisphenol A (BPA) in standard samples and in thermal paper. The synthesized materials were characterized by ultraviolet-visible spectrophotometry, X-ray diffraction spectroscopy, scanning electron microscopy, and energy-dispersive X-ray. The electrochemical behavior of BPA on the AgNPs-EG sensor was investigated by cyclic voltammetry and square wave voltammetry. Under optimized experimental conditions, the oxidation peak current was linearly proportional to bisphenol A concentrations in the range from 5.0 to100 μM, with a coefficient of determination (R2 ) of 0.9981. The obtained limit of detection of the method was 0.23 μM. The fabricated sensor was able to overcome electrode fouling with good reproducibility (RSD = 2.62%, n = 5) by mechanical polishing of the electrode on emery paper. The proposed method was successfully applied to determine bisphenol A in thermal paper samples and demonstrated good accuracy of 93.1 to 113% recovery.

Simultaneous adsorption and determination of bisphenol compounds in water medium with a Zr(IV)-based metal-organic framework

A chemically stable Zr(IV)-based metal-organic framework (BUT-17) has been explored for simultaneous adsorption and determination of bisphenol compounds (BPs) in aqueous medium. The prepared BUT-17 possesses a large surface area (2936 m² g^-1) and excellent fluorescent performance. An adsorption capacity of 111 mg g^-1 for bisphenol A (BPA) with a rapid adsorption rate (1.76 g mg^-1 min^-1) is achieved by BUT-17. The excellent adsorption performance could be attributed to the hydrogen bond interaction between BPs and BUT-17. Furthermore, the fluorescent intensity of BUT-17 was quenched up to 92% due to the formation of complexes between BPs and BUT-17. Thus, a BUT-17-based fluorescent sensing method for the rapid determination of BPs has been established with the limit of detection of 10.0 ng mL^-1 for BPA and a linear range from 2.0 to 23.0 μg mL^-1. These results indicate that as an outstanding multifunctional platform, BUT-17 is promising for the simultaneous removal and determination of BPs in water medium. Simultaneous removal and detection of BPs with BUT-17.

Latest Advances in Determination of Bisphenols with Nanomaterials, Molecularly Imprinted Polymers and Aptamer Based Electrochemical Sensors

Contamination of environmental sources such as soils, sediments and rivers and human exposure caused by several endocrine disrupting compounds (EDCs) are considered as the most challenging issues of today's world. EDCs cover a wide variety of compounds ranging from phthalates to parabens and bisphenols (BPs) are the leading group among them. BPs are widely used during the production of different plastic materials such as food and beverage containers, toys, medical equipment and baby bottles that we use in every aspect of our lives. BPs may migrate from those products to different media under certain conditions and this situation causes chronic exposure for humans and other creatures in the environment. Especially bisphenol A (BPA) and its other analogues such as bisphenol F, bisphenol S and tetrabromobisphenol that have similar structures and are preferred as alternatives to BPA cause harmful adverse effects such as endocrine disruption, neurotoxicity, genotoxicity and cytotoxicity. There are legal restrictions and prohibitions by the European Union (EU) in order to prevent possible harmful effects. Therefore, it is important to develop highly sensitive, fast, easy to use and cheap sensors for the determination of BPs in biological, environmental and commercial samples. Electrochemical sensors, which are one of the most widely, used analytical techniques, provide these conditions. Additionally, it is possible to enhance the performance of electrochemical sensors with nanomaterials, molecularly imprinted polymers or aptamer based technologies. This review aims to give comprehensive information about BPs with summarizing most recent applications of electrochemical sensors for their determination in different samples.

Conducting chitosan/hydroxylethyl cellulose/polyaniline bionanocomposites hydrogel based on graphene oxide doped with Ag-NPs

The current work focuses on a cheap and simple preparation of highly conducting chitosan/hydroxyl ethylcellulose/polyaniline loaded with graphene oxide doped by silver nanoparticles (CS/HEC/PAni/GO@Ag) bionanocomposite as a biodegradable and biocompatible hydrogel for energy storage technology. Scanning electron microscopy (SEM) displays the compatibility of chitosan, hydroxyl ethyl cellulose, and polyaniline and a good distribution of GO@Ag-NPs in bionanocomposite hydrogels. X-ray diffraction (XRD) displayed the structure and existence of GO@Ag-NPs in the matrix. The swelling percentage and the antibacterial activities slightly increased with raising the content of GO@Ag-NPs. Also, the presence of both chitosan and cellulose improves the biodegradation of the fabricated bionanocomposites, which is increased by adding GO. Moreover, the incorporation of 5% GO@Ag-NPs in hydrogels enhances dc-conductivity by about 25 times from 3.37 × 10^-3 to 8.53 × 10^-2 S/cm. The fabricated hydrogels are inexpensive, eco-friendly, and have high capacitance and permittivity, and so they can store electrical energy.

New trends in the electrochemical detection of endocrine disruptors in complex media

Endocrine disruptors (EDCs) are substances existing in the environment which affect animal and human endocrine functions and cause diseases. A small quantity of EDCs can have a serious impact on the body. Currently, enzyme-linked immunosorbent assay (ELISA), high-performance liquid chromatography (HPLC), and other traditional methods are used to detect EDCs. Although their sensitivity and reliability are good, these methods are complex, expensive, and not feasible to use in the field. Electrochemical techniques present good potential for the detection of EDCs owing to their low cost, simple, and wearable instrumentation. This paper presents the new trends in this field over the last 3 years. Some simple materials can allow some EDCs to be directly detected. New designs of biosensors, such as aptasensors, allow a femtomolar limit of detection to be reached. Many types of nanomaterial-based sensors were tested; carbonaceous nanomaterials, such as multiwalled carbon nanotubes (MWCNTs) and reduced graphene oxide (rGO), associated or not with other types of nanoparticles were included in numerous designs. Molecularly imprinted polymer (MIP)-based sensors constitute an emerging field. All the presented electrochemical sensors were successfully tested for the detection of EDCs in different types of real samples.

Synergistic design of a tin phosphate-entrapped graphene flake nanocomposite as an efficient catalyst for electrochemical determination of the antituberculosis drug isoniazid in biological samples

A SnP/GRF-modified electrode has potential application in the electrochemical detection of ISZ.