Microplasma and quenching-induced Co doped NiMoO(4) nanorods with oxygen vacancies for electrochemical determination of glucose in food and serum

A novel hollow CuMn-PBA@NiCo-LDH nanobox for efficient detection of glucose in food

Designing a rapid and sensitive glucose detection method is of great significance to public health. Herein, hollow CuMn-PBA@NiCo-LDH nanoboxes (CuMn-PBA@NiCo-LDH NBs) were prepared using acid etching, cation exchange, and reflux method. The modified electrode exhibited outstanding electrocatalytic performance for glucose oxidation due to the unique hollow nanostructure and synergistic effects. The CuMn-PBA@NiCo-LDH NBs electrode displayed excellent electrocatalytic oxidation activity for glucose in an alkaline solution. Under optimal conditions, the electrode achieved a wide linear range (0.0005-1 mmol L-1, and 1-7 mmol L-1) and high sensitivity (10,300 μA L/mmol cm-2 and 5310 μA L/mmol cm-2), with a limit of detection (LOD) of 19 nmol L-1. The feasibility of the sensor applied to the detection of glucose was verified in real food samples through spiked recovery experiments. This electrode material offers an alternative method for the non-enzymatic glucose sensors.

NiCo-LDH coupled with 2D ZIF-derived Co nitrogen doped carbon nanosheet arrays as a self-supporting electrocatalyst for detection of formaldehyde

Formaldehyde is susceptible to illegal addition to foodstuffs to extend their shelf life due to its antimicrobial, preservative and bleaching properties. In this study, a self-supporting "nanosheet on nanosheet" arrays electrocatalyst with core-shell heterostructure was prepared in situ by coupling NiCo layer double hydroxide with 2D ZIF derived Co-nitrogen-doped porous carbon on carbon cloth (Co-N/C@NiCo-LDH NSAs/CC). Co-N/C nanosheet arrays act as a scaffold core with good electrical conductivity, providing more NiCo-LDH nucleation sites to avoid NiCo-LDH agglomeration, thus having fast mass/charge transfer performance. While the NiCo-LDH nanosheet arrays shell with high specific surface area provide more active sites for electrochemical reactions. As an electrocatalytic sensing electrode, Co-N/C@NiCo-LDH NSAs/CC has a wide linear range of 1 μM to 13 mM for formaldehyde detection, and the detection limit is 82 nM. Besides, the sensor has been applied to the detection of formaldehyde in food samples with satisfactory results.

Highly sensitive detection of glucose at a novel non-enzyme electrochemical sensing based on Mo-doped CoO Nanosheets

In this work, a Mo doped CoO nanosheet grown on nickel foam (labeled as: Mo-CoO) with defect-rich and improved electron transfer capacity was designed to be used as a novel non-enzyme electrode material. Physical characterizations demonstrated the Mo elements were doped inside of the samples and they were mutually stabilized with each other, resulting in a high structural stability electrochemical catalytical activity even if the content of Mo was low. For non-enzymatic glucose electrochemical sensing, the prepared Mo-CoO-1 showed a remarkable sensitivity of 89.3 mA cm-2  mM-1 , and a low detection limit of 0.43 μM. Density functional theory (DFT) studies revealed that the doped Mo atom exhibited a higher d-band center compared to the Co atom. A stronger p-d orbital hybridization between the glucose and the Mo atoms indicated the enhancement of glucose adsorption and activation. Importantly, Mo-CoO-1 provided a good selectivity and long-term stability, which can be expected to be used in future practical applications.

Layered bimetallic hydroxide nanocage assembled on MnO2 nanotubes: A hierarchical porous sugar gourd-like electrocatalyst for the sensitive detection of hydrogen peroxide in food

Hydrogen peroxide is used widely as a disinfection or bleaching additive during processing in the food industry. However, excessive residues of hydrogen peroxide in food have serious human health implications. In the present study, a novel electrochemical sensing electrode (MnO₂/ZIF-67@LDH) with hierarchical porous sugar gourd-like structure was fabricated through a multi-step hydrothermal method using ZIF as the precursor. The unique porous nanocage structure of the sensing electrode provided multidimensional charge transfer channels and accelerated the electron transfer rate. As a hydrogen peroxide sensor, the electrode had two detection linear ranges of 1×10^-3-4 mmol L^-1 and 4-8 mmol L^-1, and the detection limit was 0.26 µmol L^-1. The MnO₂/ZIF-67@LDH sensor was also applied to determine the content of hydrogen peroxide in actual food samples of juice and milk, and satisfactory recovery were achieved. The present study provides a novel and effective design strategy for the construction of electrochemical sensing electrodes.