Electrochemical sensor for the detection of adrenaline at poly(crystal violet) modified electrode: optimization and voltammetric studies.

Herein, we report the electropolymerization of crystal violet (CRV) on a bare glassy carbon electrode (GCE) for the detection of adrenaline (AD). Electropolymerization parameters such as electrolyte pH, scan rate and monomer concentrations were optimized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The characterization of CRV and poly(crystal violet) (PCV) was done using FT-IR, UV-visible spectroscopy and EIS. More importantly, the charge transfer resistance (Rct) and other EIS data recorded from the EIS of various forms of the poly(crystal violet) (PCV) modified glassy carbon electrode (GCE) in AD were used for identifying the best PCV modified electrode. Subsequent application of the electrode prepared at optimum conditions (PGCE) for AD detection using the square wave voltammetry (SWV) gave a limit of detection (LOD) of 2.86 µM over a linear range of 10.3-102.7 µM. This sensor also showed considerable stability, good AD recovery from the real sample (98.9%), and excellent reproducibility, making it a suitable analytical tool for AD detection at the micromolar level.

Conductive Nanodiamond-Based Detection of Neurotransmitters: One Decade, Few Sensors.

Nanodiamond (ND) is a class of carbon nanomaterial with covalently connected sp3 carbon atoms in its core and an sp2 carbon adorned surface via edge defects or doping. Endogenous chemicals that provoke physiological responses in the human system called neurotransmitters (NTs) have been detected with several sensors with carbon-based nanomaterials. Nanodiamonds (NDs), another class of carbon nanomaterial, have shown the requisite surface area and electrocatalytic activity toward NTs in the past decade. Surprisingly, only a few electrochemical ND based NT sensors are available. This work briefly looked into the performance of the available sensors, NT and ND interactions, and the possible reason for data paucity on the subject matter.

Green and Traditional Synthesis of Copper Oxide Nanoparticles-Comparative Study.

The current study compared the synthesis, characterization and properties of copper oxide nanoparticles (CuO) based on green and traditional chemical methods. The synthesized CuO were confirmed by spectroscopic and morphological characterization such as ultraviolet-visible (UV-vis) spectroscopy, fourier transform infrared (FTIR) spectroscopy, zeta potential, scanning electron microscopy (SEM) and energy dispersed X-ray (EDX). Electrochemical behavior of the modified electrodes was done using cyclic voltammetry (CV) in ferricyanide/ferrocyanide ([Fe(CN)6]4-/[Fe(CN)6]3-) redox probe. As revealed by UV spectrophotometer, the absorption peaks ranged from 290-293 nm for all synthesized nanoparticles. Based on SEM images, CuO were spherical in shape with agglomerated particles. Zeta potential revealed that the green CuO have more negative surface charge than the chemically synthesized CuO. The potential of the green synthesized nanoparticles was higher relative to the chemically synthesized one. Cyclic voltammetry studies indicated that the traditional chemically synthesized CuO and the green CuO have electrocatalytic activity towards the ferricyanide redox probe. This suggests that the green CuO can be modified with other nanomaterials for the preparation of electrochemical sensors towards analytes of interest.

Carbon-Based Quantum Dots for Electrochemical Detection of Monoamine Neurotransmitters-Review.

Imbalance in the levels of monoamine neurotransmitters have manifested in severe health issues. Electrochemical sensors have been designed for their determination, with good sensitivity recorded. Carbon-based quantum dots have proven to be an important component of electrochemical sensors due to their high conductivity, low cytotoxicity and opto-electronic properties. The quest for more sensitive electrodes with cheaper materials led to the development of electrochemical sensors based on carbon-based quantum dots for the detection of neurotransmitters. The importance of monoamine neurotransmitters (NTs) and the good electrocatalytic activity of carbon and graphene quantum dots (CQDs and GQDs) make the review of the efforts made in the design of such sensors for monoamine NTs of huge necessity. The differences and the similarities between these two quantum dots are highlighted prior to a discussion of their application in electrochemical sensors over the last ten years. Compared to other monoamine NTs, dopamine (DA) was the most studied with GQDs and CQD-based electrochemical sensors.