An on-line instrument for mobile measurements of the spatial variability of hexavalent and trivalent chromium in urban air
An on-line instrument for mobile measurements of the spatial variability of hexavalent and trivalent chromium in urban air
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DOI：
10.1016/j.atmosenv.2006.09.030
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发表时间：
2006-12-01
影响因子：
5
通讯作者：
Ma, Yilin
中科院分区：
文献类型：
--
作者：
Khlystov, Andrey;Ma, Yilin
蒸汽喷射气溶胶收集器-长光程吸收光谱（SJAC-LPAS），一个在线连续的移动的测量的空间分布的水溶性六价铬和三价铬在环境气溶胶中，已经开发和介绍在这里。该系统使用SJAC收集颗粒，并使用二苯卡巴肼（DPC）比色法在线分析收集的样品。通过使用聚四氟乙烯AF（无定形含氟聚合物）液芯波导，检测极限已显着提高，允许在环境浓度的在线测量。Cr（VI）的检测限为0.2 ng m（-3）。水溶性Cr（III）也可以在DPC法检测前用过氧化氢平行氧化成Cr（VI）进行测定。然后将Cr（III）的浓度确定为两条线之间的差（Cr（VI）和Cr（VI）加Cr（III））。该仪器是专门设计用于移动的平台上，以研究污染物的空间分布在一个城市内的规模为100米。特别注意的时间分辨率和稳定性的仪器性能在驾驶条件下。仪器的时间分辨率为15 s。在30 km h（-1）的典型行驶速度下，该仪器可以检测到约150 m尺度上的铬浓度变化（“热点”）。该仪器已被证明能够可靠地运行，并在四个移动的测量活动期间捕获Cr（VI）浓度的时间和空间变异性在威尔明顿，DE。(c)2006爱思唯尔有限公司保留所有权利。
The Steam-Jet Aerosol Collector-long Pathlength Absorbance Spectroscopy (SJAC-LPAS), an on-line continuous instrument for mobile measurements of spatial distribution of water-soluble hexavalent and trivalent chromium in ambient aerosols, has been developed and is presented here. The system collects particles with the SJAC and analyzes the collected sample on-line using the diphenycarbazide (DPC) colorimetric method. By using a Teflon AF (Amorphous Fluoropolymer) liquid core wave guide, the limit of detection has been significantly improved, allowing on-line measurements at ambient concentrations. The limit of detection for Cr(VI) is 0.2 ng m(-3). Water-soluble Cr(III) can also be measured by oxidizing it to Cr(VI) in a parallel line using hydrogen peroxide before the detection with the DPC method. The concentration of Cr(III) is then determined as the difference between the two lines (Cr(VI) and Cr(VI) plus Cr(III)). The instrument was specifically designed to be used on a mobile platform to study spatial distribution of the pollutant within a city on a scale of 100 m. Special attention was given to the time resolution and the stability of the instrument performance under driving conditions. The time resolution of the instrument is 15 s. At a typical driving speed of 30 km h(-1) the instrument can detect variations in chromium concentration ("hot spots") on the scale of about 150 m. The instrument has proven to operate reliably and capture temporal and spatial variability of Cr(VI) concentration during four mobile measurement campaigns in Wilmington, DE. (c) 2006 Elsevier Ltd. All rights reserved.