Batterman Stuart, Metts Tricia, Kalliokoski Pentti, Barnett Emily
The University of Michigan, Ann Arbor 48109-2029, USA.
J Environ Monit. 2002 Jun;4(3):361-70. doi: 10.1039/b203289a.
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 microg 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 approximately 1 ng to nearly 10 microg. 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.
虽然基于吸附剂收集、热脱附和色谱分析的空气采样技术在环境空气采样中已占据一席之地，但在职业应用方面却较为有限。本文评估了热脱附技术在低流量主动和被动采样配置中的应用，这种配置能够在职业环境和其他高浓度环境中方便地进行长时间采样。使用孔板可实现低至0.5毫升/分钟的流量以及长达数天的采样周期，且偏差不显著。一个模型被用于预测包含孔板、空隙空间、玻璃棉和吸附剂的被动采样器的采样率。在一家商业胶印厂进行的实验室和现场测试被用于评估该方法，该厂含有多种挥发性有机化合物（主要是芳烃，但也有一些氯化物和萜烯化合物，浓度范围为1至67,000微克/立方米）。单独使用以及同时使用Tenax GR和Carbosieve SIII作为吸附剂。对高流量、低流量和被动采样器进行的并排测试表明，对于跨越近五个数量级的浓度，它们具有极好的一致性和高线性（r = 0.95）。主动采样器在低至0.5毫升/分钟的流量下进行了测试，而典型流量高达40毫升/分钟。被动采样器展示了线性范围，并与吸附质负载量的预测值相符，负载量范围约为1纳克至近10微克。使用化学质量平衡受体模型，将该厂中的浓度分配到溶剂、油墨以及其他室内和室外来源。总体而言，采用热脱附技术的低流量主动和被动采样方法具有良好的性能和极大的灵活性，便于在包括工作场所环境在内的许多应用中使用。
