Vol 71, No 13 (2016)

A simple and rapid approach to obtaining target plates for the investigation of low-molecularweight compounds by surface-assisted laser desorption/ionization (SALDI) mass spectrometry is proposed. It consists in the vacuum sputtering of a carbon layer with a thickness of about 50 nm onto a metal surface. The resulting coatings are characterized by homogeneity, hydrophobicity, and high mechanical strength, which eliminates a possibility of mass spectrometer contamination. A comparison of the SALDI mass spectra of test compounds recorded using conventional carbon materials and carbon nanocoatings demonstrates advantages of the last named materials, such as high spectral resolution and the absence of spectral interferences at low m/z values.

Microbial alkaloid prodigiosin is proposed as a new effective matrix for the analysis of low-molecular- weight plant antioxidants by MALDI mass spectrometry in the negative ion detection mode. It is demonstrated that the physicochemical characteristics of prodigiosin, such as ability to activate ionization/ desorption of analyte, high absorption coefficient at the working wavelengths of lasers, good solubility in solvents used for analytes, uniformity of crystallization on the target, stability under working conditions, and the absence of interfering peaks of fragment and cluster ions, are consistent with the recommendations for effective matrices. Prodigiosin as a matrix ensures the high-resolution detection of various plant antioxidants in complex mixtures. The obtained mass spectra of flavonoid aglycones were characterized by high quality (signal-to-noise ratio higher than 10³) and reproducibility. The use of prodigiosin for analyzing a complex preparation of plant antioxidants ensures the simultaneous recording and interpretation of more than two dozens of ions corresponding to various antioxidants with the molecular weights of 100–500 Da.

A pulse microreactor implanted directly into a gas chromatograph injector combined with a mass spectrometer has been proposed for monitoring the activity of heterogeneous catalysts. The microreactor was made of a standard commercial liner for a particular gas chromatograph and contained a catalytic bed. A heated injector oven was used simultaneously for heating the catalytic region, rapid evaporation of the substrate, and pulsed introduction of reaction products into a chromatographic column. The temperature of the oven could be varied in the range 200–300°C. The method ensures the detailed description of the qualitative composition of the reaction products. The potential of the proposed microreaction system was demonstrated in the study of membrane-type catalysts (nanodiamonds modified by Pt–Ru and Pt–Ni and also catalytic phosphate systems with NASICON structure) in reactions of cyclohexanol, cyclopentanol, and cyclobutanol. The studied heterogeneous catalysts can be divided in two groups. One group (based on nanodiamonds) promotes dehydrogenation reactions. The NASICON catalytic group catalyzes dehydration reactions with the formation of cycloalkenes and dicycloalkyl ethers.

It is believed that information about the molecular structure of highly toxic O-alkyl-S-2(N,N-dialkylamino) ethyl alkylthiophosphonates (V-gases) obtained from their EI mass spectra is too insufficient. In particular, the determination of molecular weights and structures of radicals at phosphorus and oxygen atoms causes great difficulties. In this paper, solutions of these problems are proposed.

Static mass spectrometers are inconspicuous against the background of more modern and more sophisticated mass spectrometers, but their potentiality is far from being exhausted. One of the principle advantages of static mass spectrometers is that they are the only type of mass spectrometers with a “duty cycle” of 100%. However, to implement this advantage, a static mass analyzer should work in a spectrographic mode, covering a considerable range of masses in one measurement. However, systems with good spectrographic properties significantly differ from systems with good spectrometric properties from the optical point of view, and the development of such devices leads to completely new optical problems and, correspondingly, to new approaches to their solution. One of useful tools to solve these problems are specific electrostatic and magnetostatic fields, homogeneous in the Euler terms. In this paper, prospects for the use of Euler’s homogeneous fields in creating static mass analyzers of a new generation are discussed.