Recent Advances on Electrochemical Sensors for Detection of Contaminants of Emerging Concern (CECs).

Contaminants of Emerging Concern (CECs), a new category of contaminants currently in the limelight, are a major issue of global concern. The pervasive nature of CECs and their harmful effects, such as cancer, reproductive disorders, neurotoxicity, etc., make the situation alarming. The perilous nature of CECs lies in the fact that even very small concentrations of CECs can cause great impacts on living beings. They also have a nature of bioaccumulation. Thus, there is a great need to have efficient sensors for the detection of CECs to ensure a safe living environment. Electrochemical sensors are an efficient platform for CEC detection as they are highly selective, sensitive, stable, reproducible, and prompt, and can detect very low concentrations of the analyte. Major classes of CECs are pharmaceuticals, illicit drugs, personal care products, endocrine disruptors, newly registered pesticides, and disinfection by-products. This review focusses on CECs, including their sources and pathways, health effects caused by them, and electrochemical sensors as reported in the literature under each category for the detection of major CECs.

Detection of Environmentally Harmful Malathion Pesticides Using a Bimetallic Oxide of CuO Nanoparticles Dispersed over a 3D ZnO Nanoflower.

Super-sensitive malathion detection was achieved using a nonenzymatic electrochemical sensor based on a CuO/ZnO-modified glassy carbon electrode (GCE). Due to the high affinity between the Cu element and the sulfur groups in malathion, the developed CuO-ZnO/GCE sensor may bond malathion with ease, inhibiting the redox signal of the Cu element when malathion is present. In addition to significantly increasing the ability of electron transfer, the addition of 3D-flower-like ZnO enhances active sites of the sensor interface for the high affinity of malathion, giving the CuO-ZnO/GCE composite an exceptional level of sensitivity and selectivity. This enzyme-free CuO-ZnO/GCE malathion sensor demonstrates outstanding stability and excellent detection performance under optimal operating conditions with a wide linear range of malathion from 0 to 200 nM and a low detection limit of 1.367 nM. A promising alternative technique for organophosphorus pesticide (OP) determination is offered by the analytical performance of the proposed sensor, and this method can be quickly and sensitively applied to samples that have been contaminated with these pesticides.

Sonochemical synthesis of silver nanoparticles anchored reduced graphene oxide nanosheets for selective and sensitive detection of glutathione.

Developed here an eco-friendly, one-pot approach toward rapid synthesis of silver nanoparticles anchored reduced graphene oxide (AgNPs(TMSPED)-rGO) nanosheets via sonochemical irradiation method, using an aqueous solution mixture of GO and AgNO3 in the presence of N-[3(trimethoxysilyl)propyl] ethylenediamine (TMSPED) without any reducing agent. As synthesized decorated nanosheets was thoroughly characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Pristine AgNPs(TMSPED), pristine rGO(TMSPED) and as prepared AgNPs(TMSPED)-rGO materials were employed to modify the glassy carbon (GC) electrode and demonstrated its excellent electrocatalytic activities towards glutathione (GSH). Voltammetry and amperometry measurements were utilized to assess the electrochemical properties towards the glutathione detection. When the Ag nanoparticles were anchored onto the rGO surface, the observed results illustrated that the electrocatalytic properties of rGO might be enhanced. The resulting sensor exhibits excellent repeatability and long-term stability. Furthermore, AgNPs(TMSPED)-rGO/GC electrode able to be employed for the selective determination of GSH in amperometric analysis in the presence of ascorbic acid (AA), dopamine (DA), uric acid (UA) and glucose. Finally, this modified electrode was effectively applied to determine glutathione in real samples with good recoveries.

Chemiluminescence studies between aqueous phase synthesized mercaptosuccinic acid capped cadmium telluride quantum dots and luminol-H2O2.

Mercaptosuccinic acid capped Cadmium telluride quantum dots have been successfully synthesized via aqueous phase method. The products were well characterized by a number of analytical techniques, including FT-IR, XRD, HRTEM, and a corrected particle size analysis by the statistical treatment of several AFM measurements. Chemiluminescence experiments were performed to explore the resonance energy transfer between chemiluminescence donor (luminol-H2O2 system) and acceptor CdTe QDs. The combination of such donor and acceptor dramatically reduce the fluorescence while compared to pristine CdTe QDs without any exciting light source, which is due to the occurrence of chemiluminescence resonance energy transfer (CRET) processes.