Analysis of amino acid enantiomers in ambient aerosols:Effects and removal of coexistent aerosol matrix  

作　　者：Ying Li Xiaoying Li Libin Wu Luhan Shi ShanWang Pingqing Fu Yingyi Zhang Senchao Lai 

机构地区：[1]The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters,Ministry of Education,School of Environment and Energy,South China University of Technology,Guangzhou 510006,China [2]Institute of Surface-Earth System Science,School of Earth System Science,Tianjin University,Tianjin 300072,China [3]now at Hong Kong University of Science and Technology,Hong Kong 00852,China

出　　处：《Journal of Environmental Sciences》2024年第3期732-740,共9页环境科学学报（英文版）

基　　金：supported by the Natural Science Foundation of China (No.41975156)。

摘　　要：Amino acids(AAs)including D-and L-enantiomers are a group of organic nitrogen species in ambient aerosol.Due to the low abundances of AAs(level of ng/m^(3))and the matrix effects by coexistent components,it is challenging to quantify AA enantiomers in ambient aerosols especially under pollution conditions.In this study,we present an optimized method for analyzing AA enantiomers in atmospheric aerosol samples including a pretreatment process and the detection by high performance liquid chromatography coupled to a fuorescence detector(HPLC-FLD).Matrix effects caused by coexistent chemicals on AA enantiomers analysis in ambient aerosol samples were investigated especially for those collected in pollution episodes.The results revealed that the determination of AA enantiomers is significantly affected by the coexistent organic carbon(as a proxy of organic matter)and water-soluble ion of NH_(4)^(+).To remove the matrix effects,we applied a pretreatment using the solid phase extraction column coupled with alkaline adjustment to sample extract.After pretreatment,18 AAs including 6 pairs of D-and L-enantiomers(i.e.,leucine,isoleucine,valine,alanine,serine,and aspartic acid)can be successfully separated and quantified in aerosol samples by HPLC-FLD.The recoveries are in the range of 67%-106%.This method was successfully applied to the urban aerosol samples from pollution and non-pollution periods for AA enantiomers determination.We suggest that the concentrations of D-AAs and the ratio of D-AA/L-AA are indicative of the contribution of bacterial sources and the infuence of biomass burning.

关 键 词：Amino acid enantiomers Atmospheric aerosol Organic carbon AMMONIA Chiral ratio 

分 类 号：X513[环境科学与工程—环境工程]