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Rationale: Complex plant‐derived polyphenols are promising for biomedical application. Their high complexity prevents the use of conventional pharmacopoeia techniques to perform quality control. The goal of this study was to apply ultra‐high‐resolution mass spectrometry to evaluate the batch‐to‐batch consistency of the molecular composition of a polyphenolic ligand using appropriate statistical metrics. Methods: Polyphenols were obtained by hydrolyzed‐lignin oxidation. Manufacturing was performed under a range of reaction conditions: heating cycles, oxygen flows, purification. Direct‐injection Fourier transform ion cyclotron resonance mass spectrometry (DI FTICR‐MS) was applied to analyze reaction products. For pairwise comparison Jaccard and Tanimoto similarities calculations were proposed. In addition, principal component analysis (PCA) was applied for sample grouping based on the molecular class contributions. Results: FTICR‐MS analysis revealed moderate Jaccard similarity of products synthesized under the same conditions, which shared about 50% of the formulae calculated in each sample. The intensity‐based Tanimoto index indicated high similarity of major components distribution of samples synthesized under standard conditions, while products obtained with variations in synthetic conditions were significantly different. PCA of molecular class contributions showed similar grouping with a high cumulative score. Conclusions: FTICR‐MS provides robust metrics for the examination of batch‐to‐batch consistency of synthetic polyphenol materials. This approach can be proposed for the analysis of reference samples and for development of complementary methods for quality control of medicinal agents based on various biologically active matrices. [ABSTRACT FROM AUTHOR]

Interlaboratory comparison on the determination of the molecular composition of humic substances (HS) was undertaken in the framework of IUPAC project 2016-015-2-600. The analysis was conducted using high resolution mass spectrometry, nominally, Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) with electrospray ionization. Six samples of HS from freshwater, soil, and leonardite were used for this study, including one sample of humic acids (HA) from coal (leonardite), two samples of soil HA (the sod-podzolic soil and chernozem), two samples of soil fulvic acids (FA) (the sod-podzolic soil and chernozem), and one sample of freshwater humic acids (the Suwannee River). The samples were analyzed on five different FTICR MS instruments using the routine conditions applied in each participating laboratory. The results were collected as mass lists, which were further assigned formulae for the determination of molecular composition. The similarity of the obtained data was evaluated using appropriate statistical metrics. The results have shown that direct comparison of discrete stoichiometries assigned to the mass lists obtained by the different laboratories yielded poor results with low values of the Jaccard similarity score – not exceeding 0.56 (not more than 56 % of the similar peaks). The least similarity was observed for the aromatics-rich HA samples from leonardite (coal) and the chernozem soil, which might be connected to difficulties in their ionization. The reliable similarity among the data obtained in this intercomparison study was achieved only by transforming a singular point (stoichiometry) in van Krevelen diagram into a sizeable pixel (a number of closely located stoichiometries), which can be calculated from the population density distribution. The conclusion was made that, so far, these are descriptors of occupation density distribution, which provide the metrics compliant with the data quality requirements, such as the reproducibility of the data measurements on different instruments. [ABSTRACT FROM AUTHOR]

Large scale isolation—in gram quantities—of dissolved organic matter (DOM) from natural waters is necessary for detailed investigation of its role in chemical and microbial processes driving carbon cycling under conditions of global climate change. The best candidate for a use in these large-scale experiments is a bulk sorbent Bondesil PPL, which has the same modification as the widely used Bond Elut PPL sorbent. There have been no studies so far reported on interchangeability of these sorbents with regard to DOM isolation. This work was devoted to comparative studies on sorption efficiency and molecular selectivity of these two sorbents—Bond Elut PPL and Bondesil PPL with regard to DOM components. Fulvic acids (FA) from peat water leachate were used as a model DOM. Laboratory solid phase extraction (SPE) setup was used for monitoring sorption recovery and extraction yield. It included three parallel experiments on pre-packed Bond Elut PPL cartridges (500 mg/3 mL) and three self-packed Bondesil PPL cartridges (500 mg/3 mL). Fourier transform ion cyclotron resonance mass spectrometry (FT ICR MS) and 13C/1H nuclear magnetic resonance (NMR) spectroscopy were used for determination of molecular and structural group compositions of the FA isolates obtained with a use of two different sorbents. The results of this study allowed a conclusion on interchangeability of the two sorbents used in this study for the purposes of DOM isolation from natural waters. This conclusion was backed up by similarity of sorption behavior of the peat FA components on both sorbents and by high similarity of molecular compositions and carbon distribution among the main structural groups. [ABSTRACT FROM AUTHOR]