Department of Civil and Environmental Engineering, Michigan Technological University, 1400 Townsend Dr., Houghton, MI 49931, USA.
J Chromatogr A. 2010 Jan 15;1217(3):256-63. doi: 10.1016/j.chroma.2009.11.049. Epub 2009 Dec 1.
A modeling approach is presented to predict the sorptive sampling collection efficiency of gaseous semivolatile organic compounds (SOCs) and the artifact caused by collection of particle-associated SOCs in multicapillary diffusion denuders containing polydimethylsiloxane (PDMS) stationary phase. Approaches are presented to estimate the equilibrium PDMS-gas partition coefficient (K(pdms)) from a solvation parameter model for any compound, and, for nonpolar compounds, from the octanol-air partition coefficient (K(oa)) if measured K(pdms) values are not available. These estimated K(pdms) values are compared with K(pdms) measured by gas chromatography. Breakthrough fraction was measured for SOCs collected from ambient air using high-flow (300 L min(-1)) and low-flow (13 L min(-1)) denuders under a range of sampling conditions (-10 to 25 degrees C; 11-100% relative humidity). Measured breakthrough fraction agreed with predictions based on frontal chromatography theory using K(pdms) and equations of Golay, Lövkvist and Jönsson within measurement precision. Analytes included hexachlorobenzene, 144 polychlorinated biphenyl congeners, and polybrominated diphenyl ethers 47 and 99. Atmospheric particle transmission efficiency was measured for the high-flow denuder (0.037-6.3 microm diameter), and low-flow denuder (0.015-3.1 microm diameter). Particle transmission predicted using equations of Gormley and Kennedy, Pich, and a modified filter model, agreed within measurement precision (high-flow denuder) or were slightly greater than (low-flow denuder) measured particle transmission. As an example application of the model, breakthrough volume and particle collection artifact for the two denuder designs were predicted as a function of K(oa) for nonpolar SOCs. The modeling approach is a necessary tool for the design and use of denuders for sorptive sampling with PDMS stationary phase.
提出了一种建模方法，用于预测气态半挥发性有机化合物（SOCs）的吸附采样收集效率，以及在含有聚二甲基硅氧烷（PDMS）固定相的多毛细管扩散除沫器中收集颗粒相关 SOCs 引起的假象。提出了从溶剂化参数模型估算任何化合物的 PDMS-气体分配系数（K(pdms)）的方法，如果没有测量的 K(pdms) 值，则对于非极性化合物，可以从辛醇-空气分配系数（K(oa)）估算。将这些估算的 K(pdms) 值与通过气相色谱法测量的 K(pdms) 值进行比较。在一系列采样条件下（-10 至 25°C；11-100%相对湿度），使用高流量（300 L min(-1)) 和低流量（13 L min(-1)) 除沫器从环境空气中收集 SOCs 测量了穿透分数。测量的穿透分数与基于 K(pdms) 和 Golay、Lövkvist 和 Jönsson 方程的前沿色谱理论预测相符，在测量精度范围内。分析物包括六氯苯、144 种多氯联苯同系物以及多溴二苯醚 47 和 99。高流量除沫器（0.037-6.3 µm 直径）和低流量除沫器（0.015-3.1 µm 直径）测量了大气颗粒传输效率。使用 Gormley 和 Kennedy、Pich 方程以及改进的滤膜模型预测的颗粒传输在测量精度内（高流量除沫器）或略高于（低流量除沫器）测量的颗粒传输相符。作为模型的一个应用实例，预测了两种除沫器设计的穿透体积和颗粒收集假象作为非极性 SOCs 的 K(oa)函数。该建模方法是使用 PDMS 固定相进行吸附采样的除沫器设计和使用的必要工具。
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