Growth of 2D-layered double hydroxide nanorods heterojunctions with 2D tungsten carbide nanocomposite: An improving the electrochemical sensing in norfloxacin monitoring

Molecularly imprinted electrochemical sensor based on metal-covalent organic framework for specifically recognizing norfloxacin from unpretreated milk

Here, a molecularly imprinted electrochemical sensor (MIECS) was designed and fabricated for specifically monitoring norfloxacin (NFX), an entirely synthetic antibiotic. In which, Cu2+ dopped covalent organic framework (COF) was used to connect NFX imprinting layer and glassy carbon electrode through covalence. Under optimized conditions, the linear range is as wide as 5 orders of magnitude, and the detection limit is 5.94 × 10-3 μM (estimated based on S/N = 3). Average recoveries are among 92.4%-99.0% with relative standard deviations ≤ 4.05% (n = 3) in (spiked) whole, low-fat, and skimmed milk, validated by independent HPLC assays. The excellent performance can be ascribed to the significant recognition and enriching ability of the imprinting layer, improved conductivity of Cu2+ dopped covalent organic framework, and high stability of covalence between layers. We hope the work will act as a model of MIECSs for rapidly and selectively detecting trace drug residue in complex real samples.

Electrochemical determination of vanillin using 2D/2D heterostructure based on ZnCr-layered double hydroxide and g-CN

A ZnCr-LDH@g-CN composite was synthesized through a one-pot hydrothermal method to fabricate an effective sensor for detecting vanillin. The prepared material was investigated by using structural and physical studies. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) with applied potential (Epa =  + 0.68 V vs Ag/AgCl) were used to examine the electrochemical behavior of vanillin. The fabricated electrode exhibited a linear detection range of 0.001-143.2 μM, a low detection limit of 0.9 nM, sensitivity of 4.72 µA µM-1 cm-2, selectivity, stability, reproducibility (RSD = 4.40%), and repeatability (RSD = 4.46%). The optimized sensor was successfully applied to detect vanillin in real samples, including ice cream, chocolate, and water, and their recovery was 98.46-99.80%. Overall, the ZnCr-LDH@g-CN composite sensor offers a promising solution for precise vanillin detection.

Emerging carbonate anion intercalated- ZnCr-layered double hydroxide/vanadium carbide nanocomposite: Sustainable design strategies based on disposal electrochemical sensor for diethofencarb fungicide monitoring

Diethofencarb (DFC) is widely used in agriculture to fight against plant fungal attacks and enhance food crop production. On the other hand, the National food safety standard has set the overall maximum residual limit (MRL) of DFC to be 1 mg/kg. Hence it becomes essential to limit their usage, and it is vital to quantify the amount of DFC present in real-life samples to safeguard the health and environmental well-being. Here, we introduce a simple hydrothermal procedure for preparing vanadium carbide (VC) anchored by ZnCr-LDH. The sustainably designed electrochemical sensor for the detection of DFC portrayed high electro-active surface area, conductivity, rapid-electron transport ratio, and high ion diffusion parameters. The obtained structural and morphological information confirms the enriched electrochemical activity of the ZnCr-LDH/VC/SPCE towards DFC. The ZnCr-LDH/VC/SPCE electrode has displayed exceptional characteristics with DPV resulting in a vast linear response (0.01-228 μM), and lower LOD (2 nM) with high sensitivity. Real-sample analysis was carried out to demonstrate the specificity of the electrode with an acceptable recovery in both water (±98.75-99.70%) and tomato (±98.00-99.75%) samples.

Eutectic solvent mediated synthesis of carbonated CoFe-LDH nanorods: The effect of interlayer anion (Cl-, SO42-, CO32-) variants for comparing the bifunctional electrochemical sensing application

The unabated usage of priority anthropogenic stressors is a serious concern in the global environmental context. Pharmaceutical drugs such as furazolidone (FL) and nilutamide (NL) have far-reaching repercussions due to the presence of the reactive nitroaromatic moiety. Despite the widespread awareness regarding the dangers posed by nitroaromatic drugs, the promises to alleviate the environmental consequences of drug pollution are often unmet. Accordingly, implementing practices to monitor their presence in various media is a highly desirable, but challenging undertaking. With the advent of deep eutectic solvent-assisted synthesis, it has become possible to fabricate LDH-based sensor materials with minimal energy inputs in a sustainable and scalable manner. In this work, we have framed a series of CoFe-LDH electrocatalysts utilizing deep eutectic solvent-assisted hydrothermal strategies for the simultaneous detection of FL and NL. The CoFe-LDHs intercalated with three distinct anions, namely, (i) Cl^-, (ii) SO₄^2-, and (iii) CO₃^2- are compared so as to establish a relationship between anion intercalation and electrochemical activity. Amongst the prepared electrodes, the CF-LDH-ii/SPCE displays highly appreciable selectivity, linear response range (0.09-237.9 μM), low detetion limits (FL = 1.2 nM and NL = 3.8 nM), high sensitivity (FL = 29.71 μA μM⁻¹ cm⁻² and NL = 19.29 μA μM⁻¹ cm⁻²), good reproducibility and repeatability towards FL and NL in water and urine samples. Thus, with tailored gallery anions, the proposed electrocatalyst establishes enhanced electrocatalytic performance for the real-time analysis of pharmaceutical contaminants.