Vol 80, No 4 (2025)

The works of domestic and foreign scientists for 1999-2024 devoted to the development of new methods of observation of phosphorescence of natural and synthesized chemical compounds at room temperature in the presence of various supramolecular structures and nanostructured molecular ensembles are considered. The analysis of the results of studies has shown that the occurrence of phosphorescence at room temperature in the studied systems provides the creation of either self-organizing supramolecular structures with controlled spectral properties or nanostructured molecular ensembles. These structures provide the rigidity necessary to reduce the collisions suppressing phosphorescence and prevent the radiation-free deactivation of the triplet state of phosphors both in liquid and solid solutions and on the nanoparticle surface.

The characterization of highly dispersed materials and nanoparticles (NPs), as well as the investigation of their transformations in biological systems, constitute a critical aspect of research aimed at assessing the potential for active NP applications in biomedicine and pharmacology. A promising method for characterizing nanoparticles involves single particle inductively coupled plasma mass spectrometry (SP ICP MS). This technique enables the determination of nanoparticle masses at the femtogram level and gives information on their distribution by the analyte form (soluble ionic or nanoscale), size, and quantity within the analyzed sample. Sample preparation for an SP ICP MS analysis is based on the quantitative extraction of nanoparticles from a biological sample while preserving their characteristics. Liquid samples for analysis are prepared by dilutions, involving filtration, centrifugation, sedimentation, and various fractionation and separation techniques. Enzymatic and alkaline hydrolysis have been applied to the decomposition of biological tissues. The discussion addresses the capabilities and limitations of primary sample preparation methods, using biomaterials containing gold and silver nanoparticles as examples. Particular attention is given to techniques that do not alter the analyte, such as dilution and filtration. A possibility of analyzing iron oxide-based materials, relevant to biomedical research, using SP ICP MS is noted, along with the challenges associated with such analyses. The combination of laser ablation (as a sampling method) with SP ICP MS is shown to be a promising approach to studying the spatial distribution of nanoparticles in biological systems.

Magnetic effervescent tablets consisting of magnetic hypercrosslinked polystyrene, sodium bicarbonate, citric acid and EDTA are proposed for multicomponent isolation of residues of 55 veterinary drugs of different classes (sulfonamides and trimethoprim, amphenicols, nitroimidazoles, β-lactams, quinolones, macrolides, pleuromutilins and lincosamides) from river waters by magnetic solid-phase extraction before their HPLC-MS/MS determination. Due to the intensive release of carbon dioxide during dissolution of the tablet it is possible to do without the use of stirring devices, and the magnetic properties of the sorbent allow its separation without centrifugation and filtration; as a result, the sample preparation procedure (solid-phase extraction) takes less than 3 min. The method provides relative recoveries from 79 to 122 % and good reproducibility (s_r ≤ 0.12). Medicine substances were identified by the exact masses of analyte ions produced by electrospray ionisation with polarity switching. The matrix effect for all drugs is below 20 %. Determination was carried out by matrix calibration method and the limits of detection and quantification were 0.012 and 0.04 µg/L for most of the sulfonamides, trimethoprim, amfenicols, nitroimidazoles, macrolides, pleuromutilins and lincosamides and 0.06 and 0.2 µg/L for β-lactams and quinolones respectively.

A method for studying passive adsorption of organic substances on the surface of solids from room air is proposed. The method is based on the oxithermographic determination of organic matter on the surface of the material under study after the material has been in the room air for a fixed time. The method allows the total amount of carbon on the surface of a material to be determined and the contribution of ¹⁴C in low background measurements from surface organic matter to be estimated. The method was validated in laboratory facilities of two different organizations. The total content of organic substances extracted on the surface of platinum, palladium and quartz was determined after the samples had been exposed to air from 10 min to 34 days. Differences in adsorption were revealed depending on the composition of the surface material, as well as the cleanliness class of the premises where the analysis is carried out. The method allows carrying out studies without transporting samples to other rooms.