Department of Civil and Environmental Engineering, Michigan Technological University, 1400 Townsend Dr., Houghton, Michigan 49931, USA.
Environ Sci Technol. 2010 Mar 15;44(6):2098-104. doi: 10.1021/es903002k.
A high flow rate (300 L min(-1)) multicapillary denuder was designed to collect trace atmospheric semivolatile organic compounds (SOCs). The denuder is coated with a reusable, polydimethylsiloxane stationary phase as a nonselective absorbent for SOCs. A solvent-free thermal desorption method was developed, including sample cleanup, that is selective for nonpolar SOCs, and has low consumables cost per sample. The entire sample is transferred into the gas chromatograph to minimize the sampling time required to collect detectable analyte mass. Trace concentrations (0.1-100 pg m(-3)) of polychlorinated biphenyls and hexachlorobenzene were measured in the atmosphere near Lake Superior in sample times of 3.2-6.2 h. Overall method precision was determined using field duplicates and compared to the conventional high-volume sampler method. Method precision (coefficient of variation) of 16% was found for the high-flow denuder compared to 21% for the high-volume method. The relative difference between the two methods was 25%, with the high-flow denuder method giving generally lower concentrations. The high-flow denuder is an alternative to high-volume or passive samplers when it is desirable to separate gaseous from particle-associated SOCs upstream of a filter. The method is advantageous for studies that require high temporal resolution.
一种高流量（300 L min(-1)）多毛细管吹脱管被设计用于采集痕量大气半挥发性有机化合物（SOCs）。吹脱管涂有可重复使用的聚二甲基硅氧烷固定相，作为 SOCs 的非选择性吸收剂。开发了一种无溶剂热解吸方法，包括样品净化，该方法对非极性 SOCs 具有选择性，且每个样品的消耗品成本低。将整个样品转移到气相色谱仪中，以最小化采集可检测分析物质量所需的采样时间。在苏必利尔湖附近大气中，使用该方法可在 3.2-6.2 h 的采样时间内测量痕量浓度（0.1-100 pg m(-3))的多氯联苯和六氯苯。使用现场重复样来确定整个方法的精密度，并与传统的大流量采样器方法进行比较。与大流量方法的 21%相比，高流量吹脱管方法的精密度（变异系数）为 16%。两种方法之间的相对差异为 25%，高流量吹脱管方法通常给出的浓度更低。当需要在过滤器上游将气态和颗粒相关 SOCs 分离时，高流量吹脱管是高流量或被动采样器的替代方法。该方法有利于需要高时间分辨率的研究。
