Classification of HULIS carbon from different atmospheric environments via a 2-D-Off-line chromatography

在大气颗粒的有机部分中，所谓的“腐殖质样物质”（HULIS）占了很大一部分。这部分的化学成分在很大程度上是未知的。分离技术，如相液相色谱（RP-LC）或毛细管电泳不允许成功分离这种复杂的部分。这就是为什么本项目建议应用基于极性（RP-LC）和分子大小（尺寸排除色谱）的二维分离。这两个维度（柱）将离线耦合，并收集馏分，通过飞行时间质谱（TOFMS）测定总有机碳（TOC）、UV-Vis吸光度和特征片段的元素组成。将对来自不同环境的颗粒进行采样（欧洲背景，亚洲大城市，具有强烈生物质燃烧影响的农村地区），以便识别和比较二维极性与尺寸空间内的模式。此外，离线表征的结果将与在线气溶胶质谱仪的数据进行比较。该项目的结果有望使人们更好地了解大气颗粒中重要的HULIS部分的浓度、组成和可能的来源。

Within the organic fraction of atmospheric particles, so-called "humic-like substances" (HULIS) make up a significant fraction. The chemical composition of this fraction is largely unknown. Separation techniques such as revered phase liquid chromatography (RP-LC) or capillary electrophoresis do not allow for a successful separation of this complex fraction. This is why the present projects suggests to apply a 2-dimensional separation based on polarity (RP-LC) and molecular size (size exclusion chromatography). The two dimensions (columns9 will be coupled offline and fractions will be collected to determine total organic carbon (TOC), UV-Vis absorbance, and elemental compositions of characteristic fragments by time-of-flight mass spectrometry (TOFMS). Particles from different environments will be sampled (European background, Asian megacity, rural location with strong biomass burning influence), in order to identify and compare patterns within the 2-dimensional polarity vs. size space. In addition, the results of the offline characterization will be compared with data from an online aerosol mass spectrometer. The results of this project are expected to allow for a better understanding of concentration, composition and possible sources of the important HULIS fraction of atmospheric particles.