Simultaneous determination of mitotane,its metabolite,and five steroid hormones in urine samples by capillary electrophoresis using β-CD2SDS1 complexes as hydrophobic compounds solubilizers

Mitotane is a cytotoxic drug used in the treatment of inoperable adrenocortical carcinoma, it inhibits steroidogenesis as well, and therefore monitoring the level of steroid hormones in patients treated with mitotane is a crucial point of therapy. Hence, we have developed a simple, fast, and efficient electrophoretic method combined with reverse polarity sweeping as online preconcentration technique and dispersive liquid–liquid microextraction for the simultaneous determination of mitotane, its main metabolite DDA, and five steroid hormones (progesterone, testosterone, epitestosterone, cortisol, and corticosterone) in urine samples. In addition, a new sample matrix consisting of β-CD₂SDS₁ complexes for a high hydrophobic compounds solubilization was developed. Approach based on the application of β-cyclodextrin and SDS complex of a ratio 2:1 allowed for hydrodynamic injection into the capillary of a solution containing both mitotane and other analytes. The detection limits of the analytes for the reverse polarity sweeping-dispersive liquid–liquid microextraction method were found to be in the range of 1.5–3 ng/mL, which were approximately 1000 times lower than in the conventional hydrodynamic injection (5 s, 0.5 psi) without any preconcentration procedure. All analytes were completely resolved in less than 13 min by uncoated silica capillary with an inner diameter of 75 μm (ID) × 60 cm. Electrophoretic separation was performed in reverse polarity with a voltage of –25 kV with a background electrolyte (BGE) consisting of 100 mM SDS, 25% ACN, 25 mM phosphate buffer (pH 2.5), and 7 mM β-cyclodextrin.     

New Insight on Carbon Dioxide-Mediated Hydrogen Production**

A new approach to hydrogen production from water is described. This simple method is based on carbon dioxide-mediated water decomposition under UV radiation. The water contained dissolved sodium hydroxide, and the solution was saturated with gaseous carbon dioxide. During saturation, the pH decreased from about 11.5 to 7–8. The formed bicarbonate and carbonate ions acted as scavengers for hydroxyl radicals, preventing the recombination of hydroxyl and hydrogen radicals and prioritizing hydrogen gas formation. In the presented method, not yet reported in the literature, hydrogen production is combined with carbon dioxide. For the best system with alkaline water (0.2 m NaOH) saturated with CO₂ under UV-C, the hydrogen production amounted to 0.6 μmol h⁻¹ during 24 h of radiation.     

Tungsten and Molybdenum Heteropolyanions with Different Central Ions—Correlation between Theory and Experiment

Density functional theory calculations were carried out to investigate the electronic structures of Keggin-typed [XMo₁₂O₄₀]ⁿ⁻ and [XW₁₂O₄₀]ⁿ⁻ anions with different heteroatoms (X = Zn²⁺, B³⁺, Al³⁺, Ga³⁺, Si⁴⁺, Ge⁴⁺, P⁵⁺, As⁵⁺, and S⁶⁺). The influence of solvent on redox properties of heteropolyanions was discussed. For [XW₁₂O₄₀]ⁿ⁻ systems two linear correlation: first, between the experimental redox potential and energies of LUMO orbital; and second, between the experimental redox potential and total energy interaction (calculated between internal tetrahedron (XO₄ⁿ⁻), and rest of Kegging anion skeleton, (W₁₂O₃₆)) were designated. Taking into account the similarity of XW₁₂O₄₀ⁿ⁻ and XMo₁₂O₄₀ⁿ⁻ systems (in geometry and electronic structure), the estimated redox potential of molybdenum heteropolyanions (with X being p block elements) in different solvent were proposed.     

Empirical parameters of lewis acidity and basicity for aqueous binary solvent mixtures

Empirical parameters of Lewis acidity, E^N_T, introduced by Reichardt et al., and Lewis basicity, B_KT , introduced by Kamlet and Taft, have been determined for mixtures of water with ten organic solvents. In the case of water/alcohol mixtures a distinct dependence between these acidity and basicity parameters have been found. For the other solvent mixtures the E^N_T on B_KT dependence is more complex even if these parameters are purified from non-specific solute/solvent interactions.     

Crystallographic characterization of three cathinone hydrochlorides new on the NPS market: 1-(4-methylphenyl)-2-(pyrrolidin-1-yl)hexan-1-one (4-MPHP), 4-methyl-1-phenyl-2-(pyrrolidin-1-yl)pentan-1-one (α-PiHP) and 2-(methylamino)-1-(4-methylphenyl)pentan-1-one (4-MPD)

Cathinones belong to a group of compounds of great interest in the new psychoactive substances (NPS) market. Constant changes to the chemical structure made by the producers of these compounds require a quick reaction from analytical laboratories in ascertaining their characteristics. In this article, three cathinone derivatives were characterized by X-ray crystallography. The investigated compounds were confirmed as: 1-[1-(4-methylphenyl)-1-oxohexan-2-yl]pyrrolidin-1-ium chloride ( 1 , C₁₇H₂₆NO⁺·Cl^?, the hydrochloride of 4-MPHP), 1-(4-methyl-1-oxo-1-phenylpentan-2-yl)pyrrolidin-1-ium chloride ( 2 ; C₁₆H₂₄NO⁺·Cl^?, the hydrochloride of α-PiHP) and methyl[1-(4-methylphenyl)-1-oxopentan-2-yl]azanium chloride ( 3 ; C₁₃H₂₀NO⁺·Cl^?, the hydrochloride of 4-MPD). All the salts crystallize in a monoclinic space group: 1 and 2 in P2₁/c, and 3 in P2₁/n. To the best of our knowledge, this study provides the first detailed and comprehensive crystallographic data on salts 1 – 3 .     

Analysis of NH3-TPD Profiles for CuSSZ-13 SCR Catalyst of Controlled Al Distribution – Complexity Resolved by First Principles Thermodynamics of NH3 Desorption,IR and EPR Insight into Cu Speciation**

NH₃ temperature-programmed desorption (NH₃-TPD) is frequently used for probing the nature of the active sites in CuSSZ-13 zeolite for selective catalytic reduction (SCR) of NO_x. Herein, we propose an interpretation of NH₃-TPD results, which takes into account the temperature-induced dynamics of NH₃ interaction with the active centers. It is based on a comprehensive DFT/GGA+D and first-principles thermodynamic (FPT) modeling of NH₃ adsorption on single Cu²⁺, Cu⁺, [CuOH]⁺ centers, dimeric [Cu-O-Cu]²⁺, [Cu-O₂²⁻-Cu]² species, segregated CuO nanocrystals and Brønsted acid sites (BAS). Theoretical TPD profiles are compared with the experimental data measured for samples of various Si/Al ratios and distribution of Al within the zeolite framework. Copper reduction, its relocation, followed by the intrazeolite olation/oxolation processes, which are concomitant with NH₃ desorption, were revealed by electron paramagnetic resonance (EPR) and IR. DFT/FPT results show that the peaks in the desorption profiles cannot be assigned univocally to the particular Cu and BAS centers, since the observed low-, medium- and high-temperature desorption bands have contributions coming from several species, which dynamically change their speciation and redox states during NH₃-TPD experiment. Thus, a rigorous interpretation of the NH₃-TPD profiles of CuSSZ-13 in terms of the strength and concentration of the active centers of a particular type is problematic. Nonetheless, useful connections for molecular interpretation of TPD profiles can be established between the individual component peaks and the corresponding ensembles of the adsorption centers.     

Sustainable Drying and Torrefaction Processes of Miscanthus for Use as a Pelletized Solid Biofuel and Biocarbon-Carrier for Fertilizers

Miscanthus is resistant to dry, frosty winters in Poland and most European Union countries. Miscanthus gives higher yields compared to native species. Farmers can produce Miscanthus pellets after drying it for their own heating purposes. From the third year, the most efficient plant development begins, resulting in a yield of 25–30 tons of dry matter from an area of 1 hectare. Laboratory scale tests were carried out on the processes of drying, compacting, and torrefaction of this biomass type. The analysis of the drying process was conducted at three temperature levels of the drying agent (60, 100, and 140 °C). Compaction on a hydraulic press was carried out in the pressure range characteristic of a pressure agglomeration (130.8–457.8 MPa) at different moisture contents of the raw material (0.5% and 10%). The main interest in this part was to assess the influence of drying temperature, moisture content, and compaction pressure on the specific densities (DE) and the mechanical durability of the pellets (DU). In the next step, laboratory analyses of the torrefaction process were carried out, initially using the Thermogravimetric Analysis TGA and Differential Scaning Calorimeter DSC techniques (to assess activation energy (EA)), followed by a flow reactor operating at five temperature levels (225, 250, 275, 300, and 525 °C). A SEM analysis of Miscanthus after torrefaction processes at three different temperatures was performed. Both the parameters of biochar (proximate and ultimate analysis) and the quality of the torgas (volatile organic content (VOC)) were analyzed. The results show that both drying temperature and moisture level will affect the quality of the pellets. Analysis of the torrefaction process shows clearly that the optimum process temperature would be around 300–340 °C from a mass loss ratio and economical perspective.     

Targeted Hybrid Nanocarriers as a System Enhancing the Skin Structure

The skin is constantly exposed to external and internal factors that disturb its function. In this work, two nanosystems-levan nanoparticles and a surfactin-stabilized nanoemulsion were preserved (tested for microbial growth) and characterized (size, polydispersity, Zeta potential, and stability). The nanosystems were introduced in the model formulations-cream, tonic, and gel, and confirmed by TEM. The analysis showed that nanoemulsion has a spherical morphology and size 220–300 nm, while levan nanoparticles had irregular shapes independently of the use of matrix and with particle size (130–260 nm). Additionally, we examined the antiradical effect of levan nanoparticles and nanoemulsion in the prototype of formulations by scavenging DPPH (2,2-diphenyl-1-picrylhydrazyl; EPR spectroscopy). The model cream with both nanosystems and the whole range of products with nanosystems were evaluated in vivo for hydration, elasticity, smoothness, wrinkles and vascular lesions, discoloration, respectively. The cream improved skin condition in all tested parameters in at least 50% of volunteers. The use of more comprehensive care, additionally consisting of a tonic and gel, reduced the previously existing skin discoloration to 10.42 ± 0.58%. The presented prototype formulations are promising in improving skin conditions.     

Unravelling Structural Mysteries of Simple Organozinc Alkoxides

Simple RZnOR’ alkoxides are among the first known organozinc compounds, and widespread interest in their multifaced chemistry has been driven by their fundamental significance and potential applications including various catalytic reactions. Nevertheless, their chemistry in solution and in the solid state remains both relatively poorly understood and a subject of constant debate. Herein, the synthesis and structural characterization of long-sought structural forms, a roof-like trimer [(tBuZn)₃(μ-OC(H)Ph₂)₂(μ₃-OC(H)Ph₂)] and a ladder-type tetramer [(PhZn)₄(μ-OC(H)Ph₂)₂(μ₃-OC(H)Ph₂)₂], incorporating diphenylmethanolate as a model alkoxide ligand, are reported. Both novel aggregates are robust in the solid state and resistant towards mechanical force. By using ¹H NMR and diffusion-order spectroscopy, it is demonstrated that new RZnOR’ alkoxides are kinetically labile in solution and readily undergo ligand scrambling, such as in the case of Schlenk equilibrium. The elucidated key structural issues, which have remained undiscovered for decades, significantly advance the chemistry of RZnOR’ alkoxides and should support the rational design of zinc alkoxide-based applications.