青岛大气气溶胶中氨基化合物的分布特征

氨基化合物是大气气溶胶和雨水中常被检出的一类有机氮化合物,由于其可作为生物生长直接的氮源,因此可能对海洋生态系统产生直接作用.利用2008年1～12月在青岛采集的66个总悬浮颗粒物样品,采用邻苯二甲醛/N-乙酰-L-半胱氨酸柱前衍生高效液相色谱法,分析了其中溶解态(DAC)和颗粒态氨基化合物(PAC)的浓度.气溶胶中DAC浓度为2.4～40.9nmol·m-3,在春季最高,夏季次之,秋季、冬季最低.PAC浓度为0.7～76.1nmol·m-3,呈现春季冬季秋季夏季的变化趋势.不同季节氨基化合物的组成不同.依据气团的后向轨迹,气溶胶样品可分为受北方陆源、南方陆源和海洋源影响,DAC和PAC在受南方陆源影响的气溶胶中浓度最高,北方陆源次之,海洋源气溶胶中最低.不同来源的气溶胶中氨基化合物的组成不同,蛋白质类氨基化合物对总氨基化合物的贡献在海洋源气溶胶中最高,在南方源气溶胶中最低.

Distributions of Dissolved and Particulate Amino Compounds in Atmospheric Aerosols at Qingdao

Amino compounds is one class of organic nitrogen compounds that has been measured extensively in aerosols and rainwater. These compounds in atmospheric deposition might have a potential role in marine ecosystem since it can be directly utilizable sources of nitrogen for microorganisms and plants. 66 total suspended particles samples were collected at Qingdao from January to December in 2008. Concentrations of dissolved amino compounds (DAC) and particulate amino compounds (PAC) were analyzed using precolumn fluorescence derivatization with o-phthaldialdehyde and N-isobutyryl-L-cysteine, combined with reverse-phase high performance liquid chromatography. Concentrations of DAC in Qingdao aerosols ranged from 2.4 to 40.9 nmol·m^-3, with highest values occurring in spring, followed in summer and lowest values in autumn and winter. PAC concentration were from 0.7 to 76.1 nmol·m^-3, presenting the seasonal trend of spring > winter > autumn > summer. Compositions of amino compounds in aerosols varied seasonally. By classifying air mass back trajectories during each sampling period, the aerosol samples in Qingdao were mainly influenced by northerly continental source, southerly continental source and marine source. Concentrations of DAC and PAC were found highest in the samples influenced by southerly continental source, followed by northerly continental source and lowest in the samples by marine source. Compositions of amino compounds were also influenced by the sources. Contributions of protein-type to total amino compounds were highest in the aerosols from marine source and lowest in the aerosols from southerly continental source.