Interlaboratory comparison on the determination of themolecular 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 (FTICRMS) 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 sodpodzolic 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 datawas 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 (notmore than Article note: Sponsoring body: IUPAC Chemistry and the Environment Division: see more details on page 1466. *Corresponding author: Irina V. Perminova, Lomonosov Moscow State University, Department of Chemistry, Moscow, Russia, e-mail: iperm@med.chem.msu.ru Alexander Zherebker: Skolkovo Institute of Science and Technology, Skolkovo, Russia; Lomonosov Moscow State University, Department of Chemistry, Moscow, Russia Sunghwan Kim and Nissa Nurfajin: Kyungpook National University, Department of Chemistry, Daegu, South Korea Philippe Schmitt-Kopplin, Norbert Hertkorn and Mourad Harir: Helmholtz Zentrum-Muenchen, Research Unit Analytical Biogeochemistry, Munich, Germany Robert G. M. Spencer: Florida State University, Earth, Ocean & Atmospheric Science, Tallahassee, FL, USA Oliver Lechtenfeld: Helmholtz Zentrum-Leipzig, Leipzig, Germany. https://orcid.org/0000-0001-5313-6014 David C. Podgorski: University of New Orleans, Pontchartrain Institute for Environmental Sciences, Department of Chemistry, New Orleans, LA, USA Boris Koch: Alfred Wegener Institute for Marine and Arctic Research, Bremerhaven, Germany Eugene N. Nikolaev: Skolkovo Institute of Science and Technology, Skolkovo, Russia Evgeny A. Shirshin: Lomonosov Moscow State University, Department of Physics, Moscow, Russia Sergey A. Berezin and Dmitry S. Kats: Lomonosov Moscow State University, Department of Computing Mathematics, Moscow, Russia Gleb D. Rukhovich: Lomonosov Moscow State University, Department of Chemistry, Moscow, Russia Pure Appl. Chem. 2020; 92(9): 1447–1467 © 2020 Walter de Gruyter GmbH. This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. For more information, please visit: http://creativecommons.org/licenses/by-nc-nd/4.0/ 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 studywas 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 wasmade 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.

中文翻译：

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通过傅里叶变换离子回旋共振质谱法测量腐殖质成分空间的实验室间比较（IUPAC 技术报告）

在 IUPAC 项目 2016-015-2-600 的框架内进行了测定腐殖质 (HS) 分子组成的实验室间比较。使用高分辨率质谱法进行分析，名义上是具有电喷雾电离的傅立叶变换离子回旋共振质谱法(FTICRMS)。本研究使用了来自淡水、土壤和风化岩的 6 个 H2S 样品，包括来自煤（风化岩）的腐植酸 (HA) 样品，两个土壤 HA 样品（草灰土和黑钙土），两个土壤黄腐酸样品。酸（FA）（草皮灰化土和黑钙土），以及淡水腐植酸样品（Suwannee 河）。使用每个参与实验室采用的常规条件，在五种不同的 FTICR MS 仪器上分析样品。结果被收集为质量列表，这些列表被进一步指定用于确定分子组成的公式。使用适当的统计指标评估获得的数据的相似性。结果表明，分配给不同实验室获得的质量列表的离散化学计量的直接比较产生了较差的结果，Jaccard 相似性分数的值较低 - 不超过 0.56（不超过文章注释：赞助机构：IUPAC 化学和环境部：详见第 1466 页。 *通讯作者：Irina V. Perminova，罗蒙诺索夫莫斯科国立大学化学系，俄罗斯莫斯科，电子邮箱：iperm@med.chem.msu.ru Alexander Zherebker：斯科尔科沃科学研究所和技术，俄罗斯斯科尔科沃；罗蒙诺索夫莫斯科国立大学，俄罗斯莫斯科化学系 Sunghwan Kim 和 Nissa Nurfajin：韩国大邱庆北国立大学化学系 Philippe Schmitt-Kopplin、Norbert Hertkorn 和 Mourad Harir：Helmholtz Zentrum-Muenchen，德国慕尼黑分析生物地球化学研究组 Robert GM Spencer：佛罗里达州立大学地球、海洋与大气科学，美国佛罗里达州塔拉哈西 Oliver Lechtenfeld：德国莱比锡亥姆霍兹中心莱比锡。https://orcid.org/0000-0001-5313-6014 David C. Podgorski：新奥尔良大学，庞恰特雷恩环境科学研究所，化学系，美国路易斯安那州新奥尔良 Boris Koch：Alfred Wegener 海洋与研究所北极研究，德国不来梅哈芬 Eugene N. Nikolaev：俄罗斯斯科尔科沃斯科尔科沃科学技术研究所 Evgeny A. Shirshin：罗蒙诺索夫莫斯科国立大学物理系，莫斯科，俄罗斯 Sergey A. Berezin 和 Dmitry S. Kats：罗蒙诺索夫莫斯科国立大学，计算数学系，莫斯科，俄罗斯 Gleb D. Rukhovich：罗蒙诺索夫莫斯科国立大学，化学系，莫斯科，俄罗斯纯应用程序。化学 2020 年；92(9): 1447–1467 © 2020 Walter de Gruyter GmbH。本作品采用知识共享署名-非商业性使用-禁止衍生 4.0 国际许可协议进行许可。有关更多信息，请访问：http://creativecommons.org/licenses/by-nc-nd/4.0/ 56% 的相似峰值）。从风化岩（煤）和黑钙土中富含芳烃的 HA 样品观察到的相似性最小，这可能与它们的电离困难有关。本次比对研究中获得的数据之间的可靠相似性仅通过将 van Krevelen 图中的奇异点（化学计量）转换为可从人口密度分布计算的相当大的像素（许多紧密定位的化学计量）来实现。得出的结论是，到目前为止，这些是职业密度分布的描述符，它们提供了符合数据质量要求的指标，例如不同仪器上数据测量的可重复性。