Ying Dong

Carcass decomposition is a natural process that is characterized by a series of chemical transformations. During postmortem degradation, macromolecules are broken down into smaller molecules. Because proteins constitute a large proportion of the dry cell mass, protein degradation is the dominant postmortem decomposition process. Currently, the characteristics of protein degradation postmortem are largely unknown. Metabolomics enables the quantitative analysis of all metabolites within organisms or cells and has been used to investigate metabolite changes during physiological and pathological processes. Recently, forensic researchers have also applied metabolomics to postmortem challenges. In this study, we used targeted metabolomics with gas chromatography–mass spectrometry (GC–MS) to quantitatively analyze amino acid changes in rat myocardial tissue and assess protein degradation with the postmortem interval (PMI). First, the GC–MS method was validated and yielded satisfactory results. Quantitative analysis revealed good correlations between the concentrations of 14 amino acids (alanine, glycine, valine, leucine, isoleucine, proline, methionine, phenylalanine, tryptophan, glutamine, tyrosine, glutamic acid, histidine, and arginine) and early PMI. Among the 14 amino acids, the concentrations of nearly all neutral nonpolar amino acids consistently increased during the 0–6 days postmortem, while that of glutamic acid increased up to 10 days postmortem. Higher ambient temperatures increased the rate of protein degradation. A total of 9 amino acids (alanine, glycine, valine, leucine, isoleucine, phenylalanine, tryptophan, tyrosine, and glutamic acid) that exhibit regular increases at different temperatures during specific PMI show potential as biomarkers for PMI estimation.

In this work, a green, stable and versatile organic-solvent-free electromembrane extraction (EME) system based on semi-interpenetrating polymer networks (semi-IPN) is proposed for the extraction and enrichment of both basic and acidic drugs from human urine. Because of its non-toxicity and high affinity in target separation, semi-solid polypropylene glycol (PPG) was selected as a component for the synthesis of semi-IPN networks via an ultrasonic-assisted blending (UAB) method. Using the homogeneous semi-IPN membrane as the supported liquid membrane (SLM), the organic-solvent-free EME system was obtained. Under the optimized conditions, the organic-solvent-free EME system showed high recovery efficiency for both basic analytes (70–97%) and acidic analytes (86–100%). Moreover, the organic-solvent-free EME set-up could be reused in eight successive extraction batches without an obvious decrease in extraction efficiency. In addition, the EME system could be conveniently stored at ambient temperature for a long time, which will greatly promote the commercialization of EME. We believe this study provides new insights and attempts in the development of green sample preparation approaches.

Metal–organic frameworks (MOFs) are promising materials in the separation and catalysis fields. However, traditional MOFs usually show limited defects and poor binding selectivity. Designing a versatile strategy to address these issues is therefore a great challenge. In this work, by integrating molecular imprinting and MOF fabrication, imprinted MOFs with specific recognition defects were generated. An adsorption isotherm study indicated that the imprinted UiO-66_NH₂ had a binding capacity of 295.2 mg g⁻¹ towards the ketoprofen template, which is much higher than that of traditional molecularly imprinted polymers (MIPs). The universality of this synthetic strategy was verified by creating specific cavities in different types of imprinted MOFs (e.g., MIL-101_NH₂ and UiO-66_NH₂). Remarkably, the imprinted MOFs (represented by imprinted MIL-101_NH₂) exhibited significantly enhanced photocatalytic activity for target sulfadimidine degradation. In comparison with the non-imprinted MIL-101_NH₂ system, the imprinted MIL-101_NH₂ showed much higher photocatalytic activity (∼64%) and larger photocatalytic selectivity (4.74). We believe that this versatile strategy provides new insights into the design of enzyme-like MOFs with many defects and high binding selectivity.

Hierarchical porous graphene based materials are explored for their application as electrochemical storage devices due to their large specific surface area, high electrical and thermal conductivity, and excellent specific capacity.

Mesoporous silica has been widely used for wastewater treatment due to its high adsorption capacity in theory. However, limited by the adsorption–desorption equilibrium, it still remains a challenge to remove heavy metal ions from the polluted water. In this work, graphene oxide (GO)-coated mesoporous silica spheres were prepared by an electrostatic self-assembly method, and these showed excellent Pb(II) ion removal efficiency. The escape of Pb(II) ions adsorbed on mesoporous silica could be suppressed by the GO coating, resulting in the enhanced adsorption performance.

In this work, water-soluble ZnS:Ni/ZnS quantum dots (QDs) with core/shell structure were obtained successfully using mercaptoacetic acid as dressing agent, which were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, atomic force microscopy and transmission electron microscopy. A highly sensitive and stable electrochemical sensor was developed by immobilizing L-cysteine and ZnS:Ni/ZnS QDs on the surface of glassy carbon electrode. The sensor showed excellent catalytic activity to catechol (CC). Experimental results showed that the oxidation peak current of CC was linear over the range from 0.5 to 100 μM, and the detection limit (S/N = 3) for CC was 32 nM. The developed sensor was successfully used for determination of CC in lake water samples with satisfactory recoveries.