N, S co-doped lignin-based carbon microsphere functionalized graphene hydrogel with ‘‘sphere-in-layer” interconnection as electrode materials for supercapacitor and molecularly imprinted electrochemical sensors

(Bio)Electroanalysis of Tetracyclines: Recent Developments

Tetracyclines (TCs) are antibiotics used extensively in medicine, veterinary science, and animal husbandry. Their overuse and the widespread presence of their residues in the environment contribute to intensifying the phenomenon of antibiotic resistance (ABR). The efforts are being made to reduce the spread of antibiotics and control the phenomenon of ABR, and one of the key methods is monitoring the presence of antibiotic residues in the environment and food of animal origin. Herein, we provide the overview of the recent developments in electrochemical (bio)sensing of tetracyclines in different types of samples. The review presents a comprehensive view of such aspects of the practical (bio)sensor application as sample preparation, the reusability of (bio)sensors, and the possibility of determining antibiotics at levels required by regulations. Advances, existing challenges, and future trends in the development of novel (bio)electrochemical methods of tetracycline quantification were discussed.

Hierarchical porous sulfur self-doped lignin carbon derived from full component utilization of black liquor for high-performance supercapacitors

Black liquor, primarily consisting of lignin, polysaccharides, and inorganic substances, is a potential precursor of porous carbon materials for high-performance supercapacitors. However, the laborious purification of black liquor lignin and the introduction of exogenous heteroatoms have hindered their practical applications. Herein, the full components of black liquor were utilized to synthesize hierarchical porous sulfur self-doped lignin carbons (S-LCs) through a self-activation process aimed at improving the performance of supercapacitors. Benefiting from the intensified reactivity and crosslinking degree of the polysaccharide component and the sulfur self-doping and self-activation effect of inorganic substances, the resulting S-LCs exhibit a high specific surface area (SSA), abundant porous structure, and enhanced defect activity, all contributing toward increasing the energy storage capacity of supercapacitors. The as-obtained S-LC-G250/700 features a high SSA of 892.94 m2 g-1 and a sulfur content of 3.3 at.%. The S-LC-G250/700 demonstrates excellent specific capacitance (e.g., 405.06 F g-1 at 0.5 A g-1), remarkable stability (103 % capacity retention after 10,000 cycles), and high energy density of 30.4 Wh kg-1. Density functional theory calculations verified the advantages of the high-content sulfur self-doping of black liquor, suggesting that self-doped sulfur contributes to charge adsorption on porous carbon surfaces and promotes electron transfer in the electrolyte.

A simple molecularly imprinted electrochemical sensor for determination of propyl gallate in food samples

Propyl gallate (PG), a prevalent synthetic phenolic antioxidant found in food products, has generated considerable apprehension owing to its potential adverse impacts on human health. Therefore, as a result of the current inquiry, an innovative electrochemical sensor with improved sensitivity and selectivity for PG detection has been created. Under optimal conditions, the manufactured sensor exhibits the capability to identify PG within a broad range from 0.01 μM to 5 μM and from 5 μM to 1000 μM with a limit of detection (LOD) of 6 nM, demonstrating exceptional levels of reproducibility, repeatability, stability, and selectivity. The sensor demonstrated successful detection of PG in edible oils and mayonnaise, with good recoveries ranging from 98.44 % to 101.37 %.

Sustainable lignin precursors for tailored porous carbon-based supercapacitor electrodes

Sustainable materials are attracting a lot of attention since they will be critical in the creation of the next generation of products and devices. In this study, hydrogels were effectively synthesized utilizing lignin, a non-valorised biopolymer from the paper industry. This study proposes a method based on utilizing lignin to create highly swollen hydrogels using poly(ethylene) glycol diglycidyl ether (PEGDGE) as a crosslinking agent. The influence of different crosslinker ratios on the structural and chemical properties of the resultant hydrogels was investigated. Pore size was observed to be lowered when the amount of crosslinker was increased. The inclusion of additional hydrophilic groups in the hydrogel network decreased the swelling capacity of the hydrogels as the crosslinking density increases. These precursor materials were carbonised and electrochemically tested for application as electrodes for supercapacitors with capacitance characterized as a function of crosslinker ratio.