Zhou Yue, West Christopher P, Hettiyadura Anusha P S, Pu Wei, Shi Tenglong, Niu Xiaoying, Wen Hui, Cui Jiecan, Wang Xin, Laskin Alexander
Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China.
Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States.
Environ Sci Technol. 2022 Apr 5;56(7):4173-4186. doi: 10.1021/acs.est.1c07972. Epub 2022 Mar 15.
This study reports molecular-level characterization of brown carbon (BrC) attributed to water-soluble organic carbon in six snowpack samples collected from northern Xinjiang, China. The molecular composition and light-absorbing properties of BrC chromophores were unraveled by application of high-performance liquid chromatography (HPLC) coupled to a photodiode array (PDA) detector and high-resolution mass spectrometry. The chromophores were classified into five major types, that is, (1) , (2) , (3) , (4) , and (5) . Identified chromophores account for ∼23-64% of the total light absorption measured by the PDA detector in the wavelength range of 300-370 nm. In the representative samples from urban and remote areas, and dominate the absorption in the wavelengths below and above 320 nm, respectively. The highly polluted urban sample shows the most complex HPLC-PDA chromatogram, and more other chromophores contribute to the bulk absorption. are the most light-absorbing species in the soil-influenced sample. Chromophores in two remote samples exhibit ultraviolet-visible features distinct from other samples, which are attributed to . Identification of individual chromophores and quantitative analysis of their optical properties are helpful for elucidating the roles of BrC in snow radiative balance and photochemistry.
本研究报告了对从中国新疆北部采集的六个积雪样本中归因于水溶性有机碳的棕碳（BrC）的分子水平特征。通过应用与光电二极管阵列（PDA）检测器和高分辨率质谱联用的高效液相色谱（HPLC），揭示了BrC发色团的分子组成和光吸收特性。发色团分为五种主要类型，即（1）、（2）、（3）、（4）和（5）。在300 - 370 nm波长范围内，已鉴定的发色团占PDA检测器测量的总光吸收的约23 - 64%。在城市和偏远地区的代表性样本中， 和 分别在320 nm以下和以上波长的吸收中占主导地位。污染严重的城市样本显示出最复杂的HPLC - PDA色谱图，更多其他发色团对总体吸收有贡献。 是受土壤影响样本中吸光性最强的物种。两个偏远样本中的发色团呈现出与其他样本不同的紫外 - 可见特征，这归因于 。鉴定单个发色团并对其光学性质进行定量分析有助于阐明BrC在雪辐射平衡和光化学中的作用。
