State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China.
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China.
J Environ Sci (China). 2020 Nov;97:67-74. doi: 10.1016/j.jes.2020.05.008. Epub 2020 Jun 7.
Molecular level characterization of dissolved organic sulfur (DOS) by electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR MS) is necessary for further understanding of the role of DOS in the environment. Here, ESI spray solvent, a key parameter for ion production during ESI process, was investigated for its effect on the molecular characterization of DOS by ESI-FTICR MS. 100% MeOH as spray solvent was found for the first time to remarkably enhance the ionization efficiency of the majority of CHOS-molecules in NOM, which facilitated a total of 1473 CHOS-molecular formulas with one sulfur atom to be detected. The number of CHOS-molecular formulas obtained using 100%MeOH as spray solvent increased notably over 740 in comparison with those using 50% MeOH aqueous solution (731) or 50% ACN aqueous solution (653). Moreover, due to the enhancement of ionization efficiency of DOS during ESI processes, the tandem mass spectra of the NOM CHOS-molecules could be easily obtained using 100% MeOH as spray solvent, which were hardly obtained using 50% MeOH aqueous solution as spray solvent. The results of the tandem mass spectra suggested the first discovery of organosulfates or sulfonic acids in Suwannee River NOM sample. A simple method based on 100% MeOH as ESI spray solvent for advanced molecular characterization of DOS by ESI-FTICR MS was proposed and applied, and the results revealed more molecular information of DOS in sea DOM samples.
采用电喷雾电离-傅里叶变换离子回旋共振质谱（ESI-FTICR MS）对溶解有机硫（DOS）进行分子水平的表征，对于进一步了解 DOS 在环境中的作用是必要的。在此，研究了 ESI 喷雾溶剂（ESI 过程中离子产生的关键参数）对 ESI-FTICR MS 中 DOS 分子表征的影响。首次发现 100%甲醇作为喷雾溶剂可显著提高 NOM 中大多数 CHOS 分子的离子化效率，共检测到 1473 个含一个硫原子的 CHOS 分子公式。与使用 50%甲醇水溶液（731）或 50%乙腈水溶液（653）作为喷雾溶剂相比，使用 100%甲醇作为喷雾溶剂时，获得的 CHOS 分子公式数量显著增加，超过了 740。此外，由于在 ESI 过程中 DOS 的离子化效率得到提高，因此可以使用 100%甲醇作为喷雾溶剂轻松获得 NOM CHOS 分子的串联质谱，而使用 50%甲醇水溶液作为喷雾溶剂则很难获得。串联质谱的结果表明，首次在苏万尼河 NOM 样品中发现了有机硫酸盐或磺酸。提出并应用了一种基于 100%甲醇作为 ESI 喷雾溶剂的简单方法，通过 ESI-FTICR MS 对 DOS 进行高级分子表征，结果揭示了海洋 DOM 样品中更多的 DOS 分子信息。
