Indigenously synthesized nanocomposite materials: Use of nanocomposite as novel sensing platform for trace detection of Pb2+

Fluorescence Detection of Pb2+ in Environmental Water Using Biomass Carbon Quantum Dots Modified with Acetamide-Glycolic Acid Deep Eutectic Solvent

In this study, a novel green fluorescent probe material, nitrogen-doped carbon quantum dots (N-CQDs), was prepared by a one-step hydrothermal synthesis method using walnut green skin as a carbon source and acetamide-glycolic acid deep eutectic solvent (AGADES) as a modifier. By covalent coupling, the amide chromophore in AGADES is designed to cover the surface of walnut green skin carbon quantum dots (W-CQDs), forming a fluorescence energy resonance effect and improving the fluorescence performance of the carbon quantum dots. The prepared N-CQDs have a uniform particle size distribution, and the fluorescence quantum efficiency has increased from 12.5% to 32.5%. Within the concentration range of 0.01~1000 μmol/L of Pb2+, the linear detection limit is 1.55 nmol/L, which can meet the trace detection of Pb2+ in the water environment, and the recycling rate reaches 97%. This method has been successfully applied to the fluorescence detection and reuse of Pb2+ in actual water bodies, providing new ideas and methods for the detection of heavy metal ions in environmental water.

Recent advances in the modification of electrodes for trace metal analysis: a review

This review paper summarizes the research published in the last five years on using different compounds and/or materials as modifiers for electrodes employed in trace heavy metal analysis. The main groups of modifiers are identified, and their single or combined application on the surface of the electrodes is discussed. Nanomaterials, film-forming substances, and polymers are among the most used compounds employed mainly in the modification of glassy carbon, screen-printed, and carbon paste electrodes. Composites composed of several compounds and/or materials have also found growing interest in the development of modified electrodes. Environmentally friendly substances and natural products (mainly biopolymers and plant extracts) have continued to be included in the modification of electrodes for trace heavy metal analysis. The main analytical performance parameters of the modified electrodes as well as possible interferences affecting the determination of the target analytes, are discussed. Finally, a critical evaluation of the main findings from these studies and an outlook discussing possible improvements in this area of research are presented.

Simultaneous electrochemical detection of gallic acid and uric acid with p-tert-butylcalix[4]arene-based coordination polymer/mesoporous carbon composite

Design and synthesis of an efficient electrocatalyst for simultaneous determination of gallic acid (GA) and uric acid (UA) is vital in the biological field. Herein, we synthesized a new p-tert-butylcalix[4]arene-based metal-organic electrocatalyst (Mn-L@MC) by combining Mn-L (H₄L = tetrakis[(2-biphenylcarboxyl)oxy]-p-tertbutylcalix[4]arene) and mesoporous carbon (MC) via a simple mechanical grinding method. Synergistic effect between Mn-L and MC made the Mn-L@MC composite behave high-efficiency electrocatalytic performance toward simultaneous detection of GA and UA. Under optimal experimental conditions, the Mn-L@MC-2 electrode material featured relatively wide linear range (0.5-90 µM) for the two analytes, and low determination limits of 0.043 µM for GA and 0.059 µM for UA. The remarkable electrochemical detection behavior of Mn-L@MC-2 electrode material toward GA and UA are comparable to those known sensors containing precious metals. The Mn-L@MC-2 material exhibited high selectivity, superior reproducibility, and acceptable stability during the determination of the two analytes. The sensor was assembled to simultaneously detect GA and UA in healthy human urine with satisfactory recoveries.