Electrochemical sensing of bisphenol using a multilayer graphene nanobelt modified photolithography patterned platinum electrode

High-performance voltammetric sensor for dichlorophenol based on β-cyclodextrin functionalized boron-doped graphene composite aerogels

2, 2-methylenebis (4-chlorophenol) (dichlorophenol, Dcp) is a priority pollutant that poses a serious health threat to the public. Thus, the sensitive analysis of Dcp is of great significance. Heteroatom-doped carbon nanomaterials modified electrodes have been proven to be good electrocatalysts for electrochemical sensing application. β-cyclodextrin (β-CD) as a signal amplifier has also been utilized in biosensors. Inspired by these, in this study, a new composite of β-CD and three-dimensional (3D) boron-doped graphene aerogels (BGAs/β-CD) has been designed as a high-performance electrochemical sensing platform for Dcp determination. Graphene aerogels possess high specific surface area, large pore volume and good conductivity, which ensure rapid mass transfer and accelerated electron transfer. Besides, boron doping causes uneven charge distribution on the graphene lattice surface, producing a large amount of flowing π electrons, which provide abundant active sites for the catalytic oxidation reaction of Dcp. In addition, Dcp molecules could be captured into β-CD through host-guest recognition, which can effectively amplify the detection signal. Combining the merits of BGAs and β-CD, the BGAs/β-CD based sensor achieved sensitive detection of Dcp. Under optimized experimental conditions, the oxidation currents and the concentration of Dcp had a good linear relationship within 1.0 nM ∼ 21 μM. The detection limit was estimated as 0.33 nM (S/N = 3). This study might provide a new basis for the fabrication of 3D BG-based aerogel architectural material and its application in Dcp detection.

Selective electrochemical detection of bisphenol A using a molecularly imprinted polymer nanocomposite

A molecularly imprinted nanocomposite with covalently connected polyacrylate, β-cyclodextrin and graphene is synthesized for selective capture and electrochemical detection of bisphenol A.

Electrochemical sensor for facile detection of trace N-nitrosodiphenylamine based on poly(diallyldimethylammonium chloride)-stabilized graphene/platinum nanoparticles

A simple and sensitive electrochemical sensor for the detection of trace N-nitrosodiphenylamine was constructed based on PDDA-stabilized graphene/platinum nanoparticles.

Detection of Bisphenol A Using DNA-Functionalized Graphene Field Effect Transistors Integrated in Microfluidic Systems

Bisphenol A (BPA) detection has attracted much attention recently for its importance to food safety and environment. The DNA-functionalized solution-gated graphene transistors are integrated in microfluidic systems and used for recycling detections of BPA for the first time. In the presence of BPA, both single- and double-stranded DNA molecules are detached and released from the graphene surface in aqueous solutions, leading to the change of device electrical performance. The channel currents of the devices change monotonically with the concentration of BPA. Moreover, the devices modified with double-stranded DNA are more sensitive to BPA and show the detection limit down to 10 ng/mL. The highly sensitive label-free BPA sensors are expected to be used for convenient BPA detections in many applications.

Graphene and Graphene Analogs toward Optical, Electronic, Spintronic, Green-Chemical, Energy-Material, Sensing, and Medical Applications

This spotlight discusses intriguing properties and diverse applications of graphene (Gr) and Gr analogs. Gr has brought us two-dimensional (2D) chemistry with its exotic 2D features of density of states. Yet, some of the 2D or 2D-like features can be seen on surfaces and at interfaces of bulk materials. The substrate on Gr and functionalization of Gr (including metal decoration, intercalation, doping, and hybridization) modify the unique 2D features of Gr. Despite abundant literature on physical properties and well-known applications of Gr, spotlight works based on the conceptual understanding of the 2D physical and chemical nature of Gr toward vast-ranging applications are hardly found. Here we focus on applications of Gr, based on conceptual understanding of 2D phenomena toward 2D chemistry. Thus, 2D features, defects, edges, and substrate effects of Gr are discussed first. Then, to pattern Gr electronic circuits, insight into differentiating conducting and nonconducting regions is introduced. By utilizing the unique ballistic electron transport properties and edge spin states of Gr, Gr nanoribbons (GNRs) are exploited for the design of ultrasensitive molecular sensing electronic devices (including molecular fingerprinting) and spintronic devices. The highly stable nature of Gr can be utilized for protection of corrosive metals, moisture-sensitive perovskite solar cells, and highly environment-susceptible topological insulators (TIs). Gr analogs have become new types of 2D materials having novel features such as half-metals, TIs, and nonlinear optical properties. The key insights into the functionalized Gr hybrid materials lead to the applications for not only energy storage and electrochemical catalysis, green chemistry, and electronic/spintronic devices but also biosensing and medical applications. All these topics are discussed here with the focus on conceptual understanding. Further possible applications of Gr, GNRs, and Gr analogs are also addressed in a section on outlook and future challenges.

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.