Low-flow active and passive sampling of VOCs using thermal desorption tubes: theory and application at an offset printing facility
Low-flow active and passive sampling of VOCs using thermal desorption tubes: theory and application at an offset printing facility
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DOI：
10.1039/b203289a
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发表时间：
2002-06-01
影响因子：
--
通讯作者：
Barnett, E
中科院分区：
文献类型：
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作者：
Batterman, S;Metts, T;Barnett, E
虽然基于吸附剂收集、热解吸和色谱分析的空气采样技术在环境空气采样中找到了合适的应用领域，但在职业应用方面却受到更多限制。本文评估了热解吸技术在低流量主动式和被动式采样配置中的应用，这种配置便于在职业环境和其他高浓度环境中进行长时间采样。使用孔口可使流量低至0.5毫升/分钟，采样周期可达数天，且无明显偏差。使用一个模型来预测包含孔口、空隙空间、玻璃棉和吸附剂的被动式采样器的采样速率。在一家商业胶印厂进行的实验室和现场测试用于评估该方法，该厂含有多种挥发性有机化合物（主要是芳香族化合物，还有一些氯化物和萜烯化合物，浓度从1到67000微克/立方米不等）。Tenax GR和Carbosieve SIII，单独使用或一起使用，被用作吸附剂。对高流量、低流量和被动式采样器进行的并排测试表明，在近五个数量级的浓度范围内，具有极好的一致性和高线性度（r = 0.95）。主动式采样器在低至0.5毫升/分钟的流量下进行了测试，而典型流量可达40毫升/分钟。被动式采样器在吸附质负载量从约1纳克到近10微克的范围内表现出线性范围，并与预测结果相符。使用化学质量平衡受体模型，将工厂中的浓度分配到溶剂、油墨以及其他室内外来源。总体而言，采用热解吸技术的低流量主动式和被动式采样方法具有良好的性能和极大的灵活性，便于在许多应用中使用，包括工作场所环境。
While air sampling techniques using adsorbent-based collection, thermal desorption and chromatographic analysis have found a niche in ambient air sampling, occupational applications have been more limited. This paper evaluates the use of thermal desorption techniques for low flow active and passive sampling configurations which allow conveniently long duration sampling in occupational settings and other high concentration environments. The use of an orifice enables flows as low as 0.5 ml min(-1) and sampling periods up to several days without significant biases. A model is used to predict sampling rates of a passive sampler encompassing an orifice, a void space, glass wool, and the adsorbent. Laboratory and field tests conducted at a commercial offset printing facility, which contained a variety of volatile organic compounds (primarily aromatic but also a few chlorinated and terpene compounds at levels from 1 to 67,000 mug m(-3)), are used to evaluate the approach. Tenax GR and Carbosieve SIII, both singly and together, were employed as adsorbents. Side-by-side tests comparing high flow, low flow and passive samplers show excellent agreement and high linearity (r = 0.95) for concentrations spanning nearly five orders of magnitude. Active samplers were tested at flows as low as 0.5 ml min(-1), compared to typical flows up to 40 ml min(-1). Passive samplers demonstrated a linear range and agreement with predictions for adsorbate loadings from similar to 1 ng to nearly 10 mug. Using a chemical mass balance receptor model, concentrations in the facility were apportioned to solvents, inks and other indoor and outdoor sources. Overall, the use of low flow active and passive sampling approaches employing thermal desorption techniques provides good performance and tremendous flexibility that facilitates use in many applications, including workplace settings.