Measurement of gas-phase ammonia and amines in air by collection onto an ion exchange resin and analysis by ion chromatography
Measurement of gas-phase ammonia and amines in air by collection onto an ion exchange resin and analysis by ion chromatography
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DOI：
10.5194/amt-7-2733-2014
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发表时间：
2014-01-01
影响因子：
3.8
通讯作者：
Finlayson-Pitts, B. J.
中科院分区：
文献类型：
--
作者：
Dawson, M. L.;Perraud, V.;Finlayson-Pitts, B. J.
氨和胺是大气中常见的痕量气体，有各种生物和人为来源，主要来自农业场所。除了它们的恶臭性质外，氨和胺都被证明会增强硝酸、硫酸和甲磺酸等酸的颗粒形成，这对能见度、人类健康和气候都有影响。量化这些物质对颗粒形成的影响的一个关键组成部分是在实验室和现场研究中进行精确的气相测量。然而，众所周知，这些物质难以测量，因为它们容易从水溶液中吸附在表面上，包括吸附在玻璃表面上，如本研究中所确定的。我们在这里描述了一种新的技术，用于测量气相氨和胺，涉及吸收到弱阳离子交换树脂，然后提取和分析，使用离子色谱法。两个变量之一的十亿分之一的浓度在空气中，第二个较低的（万亿分之一）检测限进行了说明。后者涉及使用定制设计的高压筒来容纳树脂以进行在线提取。这些方法避免了使用采样管线，这可能导致这些化合物的显著入口损失。它们还具有相对简单和便宜的优点。在加利福尼亚州奇诺的一个养牛场附近进行的测量证明了这种技术对环境空气的适用性。
Ammonia and amines are common trace gases in the atmosphere and have a variety of both biogenic and anthropogenic sources, with a major contribution coming from agricultural sites. In addition to their malodorous nature, both ammonia and amines have been shown to enhance particle formation from acids such as nitric, sulfuric and methanesulfonic acids, which has implications for visibility, human health and climate. A key component of quantifying the effects of these species on particle formation is accurate gas-phase measurements in both laboratory and field studies. However, these species are notoriously difficult to measure as they are readily taken up on surfaces, including onto glass surfaces from aqueous solution as established in the present studies. We describe here a novel technique for measuring gas-phase ammonia and amines that involves uptake onto a weak cation exchange resin followed by extraction and analysis using ion chromatography. Two variants one for parts per billion concentrations in air and the second with lower (parts per trillion) detection limits are described. The latter involves the use of a custom-designed high-pressure cartridge to hold the resin for in-line extraction. These methods avoid the use of sampling lines, which can lead to significant inlet losses of these compounds. They also have the advantages of being relatively simple and inexpensive. The applicability of this technique to ambient air is demonstrated in measurements made near a cattle farm in Chino, CA.