The Composition of Saturated Vapor over 1-Butyl-3-methylimidazolium Tetrafluoroborate Ionic Liquid: A Multi-Technique Study of the Vaporization Process.

A multi-technique approach based on Knudsen effusion mass spectrometry, gas phase chromatography, mass spectrometry, NMR and IR spectroscopy, thermal analysis, and quantum-chemical calculations was used to study the evaporation of 1-butyl-3-methylimidazolium tetrafluoroborate (BMImBF). The saturated vapor over BMImBF was shown to have a complex composition which consisted of the neutral ion pairs (NIPs) [BMIm][BF], imidazole-2-ylidene CNHBF, 1-methylimidazole CNH, 1-butene CH, hydrogen fluoride HF, and boron trifluoride BF. The vapor composition strongly depends on the evaporation conditions, shifting from congruent evaporation in the form of NIP under Langmuir conditions (open surface) to primary evaporation in the form of decomposition products under equilibrium conditions (Knudsen cell).

Adrenocorticotropic hormone-producing pheochromocytoma: A case report.

Introduction: Cases of ectopic production of adrenocorticotropic hormone are considerably rare, but persistent in clinical practice. Extremely rare cases of ectopic production, such as via pheochromocytoma secretion, require special clinical attention and prior knowledge. It is important to understand the diagnostic algorithm for identifying ectopic sources of adrenocorticotropic hormone production.

[Bioinorganic chemical composition of the lens and methods of its investigation].

Bioinorganic chemical composition of the lens of human and experimental animals (cows, dogs, rats, rabbits) have been analyzed in various studies. In most cases, the studies employed different methods to determine the gross (total) composition of chemical elements and their concentrations in the examined samples. Less frequently, they included an assessment of the distribution of chemical elements in the lens and correlation of their concentration with its morphological changes.

Thermal Emission of Alkali Metal Ions from Al-Pillared Montmorillonite Studied by Mass Spectrometric Method.

The thermal emission of alkali metal ions from Al-pillared montmorillonite in comparison with its natural form was studied by mass spectrometry in the temperature range 770-930 K. The measurements were carried out on a magnetic mass spectrometer MI-1201. For natural montmorillonite, the densities of the emission currents () decrease in the mass spectrum in the following sequence (T = 805 K, A/cm): K (4.

Knudsen effusion mass spectrometric determination of the complex vapor composition of samarium, europium, and ytterbium bromides.

Rationale: The vaporization of Sm, Eu, and Yb tri- and dibromides is accompanied by decomposition and disproportionation reactions. These result in complex vapor compositions whose analysis is an intricate problem for experimentalists. Approaches have been developed to interpret mass spectra and accurately determine the vapor composition of thermally unstable compounds.