Continuous monitoring of ambient ammonia with a membrane-electrode-based detector.
Continuous monitoring of ambient ammonia with a membrane-electrode-based detector.
复制标题
使用基于膜电极的检测器连续监测环境氨。
DOI：
10.1021/ac00146a007
复制
发表时间：
1987
影响因子：
7.4
通讯作者：
Meyerhoff,ME
中科院分区：
文献类型：
--
作者：
Pranitis,DM;Meyerhoff,ME
介绍了一种适用于大气氨浓度在0.4-260 ppbv范围内直接连续测量的新型探测系统。在所提出的系统中，适当的缓冲剂流经一个窄口径的气体渗透“嗅探器”管，然后流到一个流过的Am-选择性膜电极上。试剂流中电极检测到的氨活度与嗅探管周围的气相氨浓度成正比。仅通过改变试剂缓冲液的流速和/或嗅探器的长度就可以改变系统的检测范围。对其他大气气体(CO_2、NO_2、SO_2、N_2)没有观察到直接的电位响应，尽管某些酸性气体的存在似乎减少了游离氨的量。结果表明，在优化的操作条件下，该系统可以很容易地检测到室内空气中氨含量的微小波动，测量范围为2-10ppbv。大气中的氨是空气中的主要碱性物种，在污染化学中起着重要的作用。事实上，人们认为主要酸性污染物(NO*和S02)的最终命运在一定程度上受控于这些物质与空气中的氨的反应(1-3)。大气中的氨也被认为是平流层NO*物种的前身(1)。因此，准确测量周围环境中的氨浓度对于研究酸雨的化学以及大气的光化学很重要(4-8)。环境氨的连续监测仪也可用于使用氨的封闭区域(例如，镀铜工艺)或
A novel detection system suitable for the direct and continu-ous measurement of atmospheric ammonia levels In the 0.4-260 ppbv range Is described. In the proposed system, an appropriate buffer reagent flows through a narrow-bore gas-permeable" sniffer” tube and on to a flow-through am-monium-selective membrane electrode. The ammonium ac-tivity detected by the electrode In the reagent stream is di-rectly proportional to the gas-phase ammonia concentrations surrounding the sniffer tube. The detection range of the system can be varied merely by changing the flow rate of the reagent buffer and/or the length of the sniffer. No direct potentiometric response to other atmospheric gases (C02, N02, S02, N2) is observed, althoughthe presence of certain acidic gases appears to diminish the amount of free gaseous ammonia. It Is shown that under optimized operating con-ditions, the system can readily detect small fluctuations In room-air ammonia levels which are measured to be In the 2-10 ppbv range.Atmospheric ammonia, being the major alkaline species in air, plays an important role inpollution chemistry. Indeed, it is believed that the ultimate fate of major acidic pollutants (NO* and S02) is controlled to some extent by the reaction of these species with ammonia in air (1-3). Atmospheric ammonia is also thought to be a precursor to stratospheric NO* species (1). Consequently, accurate measurement of ambient ammonia concentrations is important in the study of the chemistry of acid rain, as well as the photochemistry of the atmosphere (4-8). A continuous monitor for ambient ammonia might also find applications in enclosed areas where ammonia is being used (eg, copper-plating processes) or