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A thermally-enhanced membrane-based flow-through extraction system for the on-line determination of volatile organic compounds in water.

机译：一种基于热增强膜的流通提取系统，用于在线测定水中的挥发性有机化合物。

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摘要

A heated, flow-through, membrane-based extraction cell has been designed for the extraction of volatile organic compounds (VOCs) from aqueous solutions. A stream of aqueous sample was pumped through a temperature-controlled channel in the extraction cell, where it was in contact with a polydimethylsiloxane membrane. The VOCs in the sample passed through the membrane and into a gas stream. The air sample containing the VOCs was either detected directly, or it was trapped and desorbed onto a gas chromatography column equipped with a mass selective detector (GC-MS). The extraction cell characteristics and optimum operating conditions were studied. Higher extraction cell temperatures and sample flow rates were found to result in larger analyte responses. Increases in air flow rate in the acceptor channel resulted in a decrease in response. Detection limits using GC-MS were at or below 0.08 microg/L for aromatic hydrocarbons, 2.73 microg/L for THMs, and 0.34 microg/L for the odor causing compounds geosmin and 2-methylisoborneol.;Resistances to mass transfer in the extraction cell were studied using theoretical and experimental data. Both the water and membrane phase resistances were predicted to be significant to mass transport. Three extraction cell variables were examined: sample flow rate, air flow rate, and cell temperature. Boundary layer thickness of the water phase was estimated to be 32 microm at water flow rates of 15 mL/min, and < 10 um when water flow rates exceeded 30 mL/min. Experimental data indicated that under the normal operating conditions of a 15 mL/min sample flow rate at 85 °C, both the membrane and water resistances were significant.;The system was used to monitor the City of Syracuse, New York drinking water in the distribution system for the presence of VOCs related to gasoline contamination and disinfection byproducts formed during chlorination during the summers of 2010 and 2011. The water originated from Skaneateles Lake, an oligotrophic lake used for recreational boating. Aromatic hydrocarbon concentrations were found to fluctuate day to day and were largely associated with summer holiday weekends, likely due to increased motorboat traffic.
机译：设计了一个加热的，流通的，基于膜的萃取池，用于从水溶液中萃取挥发性有机化合物（VOC）。将含水样品流泵送通过萃取室中的温度控制通道，使其与聚二甲基硅氧烷膜接触。样品中的VOC穿过膜进入气流。可以直接检测包含VOC的空气样品，或者将其捕获并解吸到配备有质量选择检测器（GC-MS）的气相色谱柱上。研究了萃取池的特性和最佳操作条件。发现较高的萃取室温度和样品流速会导致较大的分析物响应。受体通道中空气流速的增加导致响应降低。使用GC-MS的检出限为芳烃为0.08 microg / L或以下，THMs为2.73 microg / L，以及引起气味的化合物土臭素和2-甲基异冰片酚为0.34 microg / L。使用理论和实验数据进行了研究。预测水和膜的相电阻对传质都很重要。检查了三个萃取池变量：样品流速，空气流速和池温。在水流速为15 mL / min时，水相的边界层厚度估计为32微米，当水流速超过30 mL / min时，其边界层厚度小于10 um。实验数据表明，在85°C的15 mL / min样品流速的正常操作条件下，膜和水的阻力均很显着。该系统用于监测纽约州锡拉丘兹市的饮用水分配系统中存在的挥发性有机化合物的存在，这些挥发性有机物与汽油污染和在2010年和2011年夏季加氯过程中形成的消毒副产物有关。水源自Skaneateles湖，这是一种用于休闲划船的贫营养湖。发现芳香烃的浓度每天都在波动，并且与暑假周末有关，这很可能是由于摩托艇交通的增加。

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  • 作者

    Harrington, Lindsay A.;

  • 作者单位

    State University of New York College of Environmental Science and Forestry.;

  • 授予单位 State University of New York College of Environmental Science and Forestry.;
  • 学科 Analytical chemistry.;Polymer chemistry.;Environmental science.
  • 学位 Ph.D.
  • 年度 2012
  • 页码 236 p.
  • 总页数 236
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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