Developments toward a low-cost approach for long-term, unattended vapor intrusion monitoring.
Developments toward a low-cost approach for long-term, unattended vapor intrusion monitoring.
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开发一种低成本方法来进行长期、无人值守的蒸汽入侵监测。
DOI：
10.1039/c4an00736k
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Tolley,WilliamK
中科院分区：
文献类型：
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作者：
Patel,SanjayV;Tolley,WilliamK
美国有超过 450 000 个地点受到化学品污染。大量的污染场地和化学物质在地下迁移的速度给附近的住宅和商业建筑带来了相当大的风险。这些地点周围监测的高成本源于放置和更换被动吸附剂蒸气采样器以及由此产生的实验室分析所涉及的劳动力。这种监控产生的稀疏数据集不能很好地跟踪时间变化。为了大幅降低成本并更好地跟踪暴露情况，需要成本较低、无人值守的系统来监测土壤气体和蒸汽侵入家庭和企业，以帮助修复污染场地。本文描述了专门用于监测蒸汽入侵的廉价系统的开发进展；该系统可以重复运行，无需用户干预，检测限较低（1 × 10−9，或十亿分之一）。目标分析物包括氯化烃（二氯乙烯、三氯乙烷、三氯乙烯和全氯乙烯）和苯。该系统由用于收集蒸汽的捕集和吹扫预浓缩器以及用于分离单个化合物的紧凑型气相色谱仪组成。化学检测是通过化学电容器阵列和金属氧化物半导体可燃物传感器完成的。预浓缩器和色谱柱均采用电阻加热。所有组件均与环境空气兼容，环境空气可作为气相色谱仪和检测器的载气。
There are over 450 000 sites contaminated by chemicals in the US. This large number of contaminated sites and the speed of subsurface migration of chemicals pose considerable risk to nearby residences and commercial buildings. The high costs for monitoring around these sites stem from the labor involved in placing and replacing the passive sorbent vapor samplers and the resultant laboratory analysis. This monitoring produces sparse data sets that do not track temporal changes well. To substantially reduce costs and better track exposures, less costly, unattended systems for monitoring soil gases and vapor intrusion into homes and businesses are desirable to aid in the remediation of contaminated sites. This paper describes progress toward the development of an inexpensive system specifically for monitoring vapor intrusion; the system can operate repeatedly without user intervention with low detection limits (1 × 10−9, or 1 part-per-billion). Targeted analytes include chlorinated hydrocarbons (dichloroethylene, trichloroethane, trichloroethylene, and perchloroethylene) and benzene. The system consists of a trap-and-purge preconcentrator for vapor collection in conjunction with a compact gas chromatography instrument to separate individual compounds. Chemical detection is accomplished with an array of chemicapacitors and a metal-oxide semiconductor combustibles sensor. Both the preconcentrator and the chromatography column are resistively heated. All components are compatible with ambient air, which serves as the carrier gas for the gas chromatography and detectors.