Highly sensitive electrochemical sensor based on La3+-doped Co3O4 nanocubes for determination of sudan I content in food samples

Differential coulometry based on dual screen-printed strips for high accuracy levodopa determination towards Parkinson's disease management

As a vital therapeutic agent for Parkinson's disease, dosage control of levodopa has always been a major obstacle in ensuring efficacy and curbing side effects. Simple and fast electrochemical detection methods are the main force in this field. Here, we presented a differential dual-strip method based on the coulometry for high accuracy determination of levodopa. The difference between the two strip signals with or without the tyrosinase extracted the levodopa signal from the samples. The Prussian Blue modified carbon screen-printed electrode was used to convert and amplify the electrochemical signal upon the presence of levodopa. The system exhibited a linear behavior in the 0-10 μM concentration range and a detection limit of 0.25 μM. Furthermore, it was proved to be stable in effectively distinguishing levodopa from complex samples through anti-interference experiments and serum tests. We demonstrated the superiority of dual-strip differential coulometry for the determination of levodopa towards Parkinson's disease clinical management.

Fully-printed electrochemical sensors made with flexible screen-printed electrodes modified by roll-to-roll slot-die coating

The manufacture of sensors using large-scale production techniques, such as roll-to-roll (R2R) processing, may fulfill requirements of low-cost disposable devices. Herein, we report the fabrication of fully-printed electrochemical sensors using screen-printed carbon electrodes coated with carbon black inks through slot-die coating within an R2R process. As a proof of concept, sensors were produced to detect the neurotransmitter dopamine with high reproducibility and low limit of detection (0.09 μmol L^-1). Furthermore, fully-printed biosensors made with a tyrosinase-containing ink were used to detect catechol in natural water samples. Since slot-die deposition enables printing enzymes without significant activity loss, the biosensors exhibited high stability over a period of several weeks. Even more important, R2R slot-die coating may be extended to any type of sensors and biosensors with the possibility of large-scale manufacturing.

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.

Ultrasensitive electroanalytical sulfisoxazole sensors amplified with Pd-doped ZnO nanoparticles and modified with 1-hexyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)imide

In this study, an electrochemical sensor has been introduced by incorporating Pd-doped ZnO nanoparticles (ZnO–Pd/NPs) into a carbon paste (CP) matrix amplified by a conductive binder (1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (1H3MIBTMSI), in this case) to determine the concentration of the sulfisoxazole (SFX) drug in urine, tablet, and pharmaceutical wastewater samples.

The synergistic effect of Co/Ni in ultrathin metal–organic framework nanosheets for the prominent optimization of non-enzymatic electrochemical glucose detection

Co–Ni ultrathin metal organic framework nanosheets exhibited extremely high sensitivity, wide linear range, low detection limit and excellent selectivity as a glucose sensing electrode material.

Electrochemical Sensors, a Bright Future in the Fabrication of Portable Kits in Analytical Systems

Analysis of food, pharmaceutical, and environmental compounds is an inevitable issue to evaluate quality of the compounds used in human life. Quality of drinking water, food products, and pharmaceutical compounds is directly associated with human health. Presence of forbidden additives in food products, toxic compounds in water samples and drugs with low quality lead to important problems for human health. Therefore, attention to analytical strategy for investigation of quality of food, pharmaceutical, and environmental compounds and monitoring presence of forbidden compounds in materials used by humans has increased in recent years. Analytical methods help to identify and quantify both permissible and unauthorized compounds present in the materials used in human daily life. Among analytical methods, electrochemical methods have been shown to have more advantages compared to other analytical methods due to their portability and low cost. Most of big companies have applied this type of analytical methods because of their fast and selective analysis. Due to simple operation and high diversity of electroanalytical sensors, these types of sensors are expected to be the future generation of analytical systems. Therefore, many scientists and researchers have focused on designing and fabrication of electroanalytical sensors with good selectivity and high sensitivity for different types of compounds such as drugs, food, and environmental pollutants. In this paper, we described the mechanism and different examples of DNA, enzymatic and electro-catalytic methods for electroanalytical determination of drug, food and environmental compounds.

Bifunctional and highly sensitive electrochemical non-enzymatic glucose and hydrogen peroxide biosensor based on NiCo2O4 nanoflowers decorated 3D nitrogen doped holey graphene hydrogel

In this work, a simple strategy for fabricating a 3D nitrogen doped holey graphene hydrogel decorated with NiCo₂O₄ nanoflowers (NHGH/NiCo₂O₄) via a one-pot hydrothermal method with subsequent calcination is reported for the first time. The novel NHGH/NiCo₂O₄ nanocomposites featured high electrical conductivity, large and accessible surface areas, abundant active sites, and excellent electrocatalytic performance. Considering the excellent catalytic activity of NiCo₂O₄, a sensitive and bifunctional electrochemical non-enzymatic biosensor was established for the determination of glucose and hydrogen peroxide (H₂O₂). The obtained biosensor exhibited wide linear ranges (glucose: 0.005-10.95 mM; H₂O₂: 1-510 μM) and a low detection limits (glucose: 0.39 μM; H₂O₂: 0.136 μM) in alkaline solution (S/N = 3). Excellent electrocatalytic activity of this sensor was ascribed to the synergistic effects of the hybrid structure between the NiCo₂O₄ nanoflowers and NHGH. Furthermore, the sensitive biosensor also exhibited high selectivity and could be applied to determine glucose in real blood samples. Taken together, the results reveal that the proposed hybrid nanocomposite could be a promising electrochemical biosensor.