Journal of Analytical Chemistry最新文献

Among the numerous applications of 3D printing technology in chemistry, data visualization is one of the most unusual as people are typically accustomed to the idea that digital data exist in a purely abstract form. Gas chromatography—mass spectrometry (GC-MS) data are unsuitable for 3D printing without preliminary data processing, as neighboring extracted ion chromatograms merge into a single structure. In this work, we developed an R script (https://osf.io/djkyz) to convert a fragment of raw GC-MS data into an STL file suitable for 3D printing. A series of test prints was conducted to determine the optimal profile for mass spectral peaks, as well as the width and height of chromatographic peaks. A GC-MS fragment containing a group of five closely eluting compounds was 3D-printed using a fused deposition modeling technique and served as a tangible model in mass spectrometry classes. Students reported enhanced clarity and a better understanding of the concept of deconvolution after interacting with the 3D-printed models.

To improve the accuracy of determining low (ng/g) concentrations of noble metals (Au, Pd, Pt, Rh, Ru, and Ir) in geological samples, we experimentally assessed mass spectral overlapping due to certain rock components. It was found that the ion exchange separation of the matrix does not eliminate the interferences from Zr, Hf, and Ta oxides, and in some cases, the complete removal of these elements from the test solution is required. An analysis of SRMs SChS-1, SLg-1, TDB-1, OPY-1, and SBC-1 demonstrated that the use of a Ln-resin as an additional sorbent in combination with the subsequent ICP–MS determination in the low and/or medium resolution mode offers promise.

The review describes the current state of research into the analysis of sulfur-containing compounds in crude oils and their refined products by various methods of chromatography and mass spectrometry. However, the absence of universal analysis methods necessitates employing a diverse array of techniques to detect specific groups of sulfur containing compounds (SCCs).

A sample containing microparticles of two different uranium materials with distinct uranium isotopic compositions was analyzed during an international experiment. Mass spectrometric analysis of 25 particles revealed that, within the measurement error, six particles had an isotopic composition consistent with that of the first material, and three particles were consistent with the second material. However, the uranium isotopic composition of the remaining 16 particles did not match either of the known materials. This indicates that the preliminary examination of uranium microparticles by scanning electron microscopy can identify particles carrying information about the isotopic composition of the source materials.

An ion optical analysis of a static mass analyzer, based on a second-order focusing magnetic mirror, was conducted while accounting for aberrations caused by the movement of ions outside the mean plane of the mass analyzer. As part of this study, an optimization algorithm was developed for the four-dimensional acceptance of the mass analyzer at a fixed resolution, formulated within the framework of the inverse problem.

Diarylheptanoids (DAH) are a class of phenolic secondary plant metabolites possessing a wide range of biological activities and pronounced antioxidant properties. This study proposes an original approach to the rapid screening of diarylheptanoids in plant extracts, based on surface-assisted laser desorption/ionization (SALDI) mass spectrometry on target plates with carbon nanocoating and cationization with lithium ions. The test sample was an extract of birch phloem containing centrolobol (CL) and platyphyllonol (PF), the structures of which were confirmed by NMR spectroscopy. The high intensity of diarylheptanoid signals in the resulting mass spectra made it possible to use tandem mass spectrometry for their search and identification. Using the developed approach, four glycosylated derivatives of CL and PF were discovered and tentatively identified in the studied extract, including those containing monosaccharide and disaccharide residues with pentose and hexose sugars.

The results of measurements of ²³⁵U/²³⁸U isotope ratios in microparticles of a reference material performed by Cameca IMS-4f and Cameca IMS 1280-HR mass spectrometers are compared. Twenty-eight particles of various shapes and sizes and also one spherical uranium oxide particle approximately 0.6 μ in size were analyzed by both instruments. These particles were selected based on a preliminary SEM–EDX analysis. The results indicate that the Cameca IMS-1280 HR mass spectrometer can measure uranium isotope ratios with precision up to thousandths of percent, while the Cameca IMS-4f mass spectrometer can measure only up to tenths of percent. For measurements of uranium-235 concentrations at the 0.7% level, the error range for mass spectrometers with a “large” magnet is two orders of magnitude smaller than the errors from mass spectrometers with a “small” magnet, with measurement errors more than ten times lower. Additionally, while mass spectrometers with a small magnet cannot measure minor isotope concentrations at the 5 × 10^–3% level in submicrometer particles, mass spectrometers with a large magnet can achieve this with an error of less than 10%.

Potato, like other Solanaceae plants, have a small family of eukaryotic translation initiation factors 4E (eIF4E), including four proteins eIF4E-1, eIF4E-2, eIF(iso)4E, and the novel cap-binding protein (nCBP). These factors play roles in the process of the post-transcriptional regulation of gene expression. The eIF4Es are also used by numerous RNA viruses to synthesize their proteins. The quantitative detection of eIF4Es at the proteome level yields data about their abundances and the involvement of each factor in the process of translation initiation under normal and stress conditions. To quantify eIF4Es, we have developed a mass spectrometry protocol for the detection of isoforms in potato S. tuberosum leaf tissues by multiple reaction monitoring (MRM) assay. As a result, we have detected all potato eIF4Es and determined their amounts with the most abundant protein, eIF4E-1.

Studying the chemical composition of snow as an indicator of atmospheric pollution at high latitudes is crucial for understanding the transport processes of pollutants in the atmosphere and assessing the anthropogenic impact on Arctic ecosystems. This study proposes a method for detecting and quantifying semi-volatile micropollutants in snow by combining stir-bar sorptive extraction (SBSE) with thermal desorption (TD) gas chromatography–high resolution mass spectrometry (Orbitrap). Optimizing of SBSE conditions using 76 test priority atmospheric pollutants allowed detection limits to be achieved for most non-polar and weakly polar semi-volatile compounds at the levels ranging from 0.01 to 1 ng L^–1. The method demonstrated the ability of detecting 62 analytes and achieving the highly sensitive determination of 32 analytes, with low labor costs using a minimum amount of sample (100 g). The SBSE-TD-GC–HRMS method for snow analysis was developed and validated. Tests on real samples from the Novaya Zemlya and Franz Josef Land archipelagos detected 29 pollutants from various classes, including polycyclic aromatic hydrocarbons, phenols, phthalates, nitro- and chloro-organic compounds, and their derivatives, with concentrations ranging from 0.1 to 50 ng kg^–1.