Online derivatization for hourly measurements of gas- and particle-phase semi-volatile oxygenated organic compounds by thermal desorption aerosol gas chromatography (SV-TAG)
Online derivatization for hourly measurements of gas- and particle-phase semi-volatile oxygenated organic compounds by thermal desorption aerosol gas chromatography (SV-TAG)
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DOI：
10.5194/amt-7-4417-2014
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发表时间：
2014-01-01
影响因子：
3.8
通讯作者：
Goldstein, A. H.
中科院分区：
文献类型：
--
作者：
Isaacman, G.;Kreisberg, N. M.;Goldstein, A. H.
实验室氧化研究已经确定了大量的含氧有机化合物，可用作示踪剂，以了解大气颗粒物的来源和氧化化学。这些化合物在周围环境中的定量传统上依赖于低时间分辨率收集过滤器样品，然后用衍生剂进行离线样品处理，以允许通过气相色谱法分析具有羟基的其他不可洗脱的有机化学品。我们在这里提出了一个自动化的原位仪器，用于测量高极性有机半挥发性和低挥发性化合物在气相和颗粒相的质量浓度和气体颗粒分区的每小时定量。具有衍生作用的双池半挥发性热解吸气溶胶气相色谱仪（SV-TAG）在两个平行的采样池上收集仅颗粒和组合颗粒加蒸气样品，通过热解吸到用衍生剂饱和的氦气中进行串联分析。引入甲硅烷基化剂MSTFA（N-甲基-N-（三甲基甲硅烷基）三氟乙酰胺）可使所有测试化合物（包括链烷酸、多元醇、二酸、糖和多功能化合物）完全衍生化。在实验室测试中，发现衍生化具有高度重现性（
Laboratory oxidation studies have identified a large number of oxygenated organic compounds that can be used as tracers to understand sources and oxidation chemistry of atmospheric particulate matter. Quantification of these compounds in ambient environments has traditionally relied on low-time-resolution collection of filter samples followed by offline sample treatment with a derivatizing agent to allow analysis by gas chromatography of otherwise non-elutable organic chemicals with hydroxyl groups. We present here an automated in situ instrument for the measurement of highly polar organic semi-volatile and low-volatility compounds in both the gas-and particle-phase with hourly quantification of mass concentrations and gas-particle partitioning. The dual-cell semi-volatile thermal desorption aerosol gas chromatograph (SV-TAG) with derivatization collects particle-only and combined particle-plus-vapor samples on two parallel sampling cells that are analyzed in series by thermal desorption into helium saturated with derivatizing agent. Introduction of MSTFA (N-methyl-N-(trimethylsilyl) trifluoroacetamide), a silylating agent, yields complete derivatization of all tested compounds, including alkanoic acids, polyols, diacids, sugars, and multifunctional compounds. In laboratory tests, derivatization is found to be highly reproducible (