化学
发色团
大气(单位)
紫外线
吸收(声学)
谱线
质谱法
吸收光谱法
环境化学
光化学
分析化学(期刊)
气象学
色谱法
光学
天文
物理
作者
XU Nan,Linghan Zeng,Xiao Li,Kai Song,Yanting Qiu,Hao Sun,Yujue Wang,Linghan Zeng,Mengren Li,Hui Wang,Shuya Hu,Taomou Zong,Yanping Bai,Zhou Zhang,Shuangde Li,Shijin Shuai,Yunfa Chen,Song Guo
标识
DOI:10.1021/acs.analchem.3c02700
摘要
Light-absorbing organic aerosols, referred to as brown carbon (BrC), play a vital role in the global climate and air quality. Due to the complexity of BrC chromophores, the identified absorbing substances in the ambient atmosphere are very limited. However, without comprehensive knowledge of the complex absorbing compounds in BrC, our understanding of its sources, formation, and evolution mechanisms remains superficial, leading to great uncertainty in climatic and atmospheric models. To address this gap, we developed a constrained non-negative matrix factorization (NMF) model to resolve the individual ultraviolet–visible spectrum for each substance in dissolved organic aerosols, with the power of ultrahigh-performance liquid chromatography-diode array detector-ultrahigh-resolution mass spectrometry (UHPLC-DAD-UHRMS). The resolved spectra were validated by selected standard substances and validation samples. Approximately 40,000 light-absorbing substances were recognized at the MS1 level. It turns out that BrC is composed of a vast number of substances rather than a few prominent chromophores in the urban atmosphere. Previous understanding of the absorbing feature of BrC based on a few identified compounds could be biased. Weak-absorbing substances missed previously play an important role in BrC absorption when they are integrated due to their overwhelming number. This model brings the property exploration of complex dissolved organic mixtures to a molecular level, laying a foundation for identifying potentially significant compositions and obtaining a comprehensive chemical picture.
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