Department of Environment & Energy, Sejong University, 98 Goon Ja Dong, Seoul 143-747, South Korea.
J Chromatogr A. 2011 Dec 30;1218(52):9328-35. doi: 10.1016/j.chroma.2011.11.007. Epub 2011 Nov 10.
A series of laboratory experiments were conducted to assess the accuracy of permeation tube (PT) devices using a calibration gas generator system to measure permeation rate (PR) of volatile organic compounds (VOCs). Calibration gas standards of benzene, toluene, and m-xylene (BTX) were produced from PTs at varying flow rates (FR) of 20-1200 mL min(-1) and constant temperature (30°C). Results indicate that changes in flow rate greatly affected the permeation rate of each VOC at this temperature. This paper presents experimental approaches to accurately measure actual permeation rate (APR) and the derivation of empirical equations for predicted permeation rate (PPR). If the magnitude of bias is defined as the difference between PPR and the manufacturer's permeation rate (MPR), the bias was typically 19-40% for toluene (T) and 31-54% for m-xylene (X). Benzene (B) exhibited the least bias of 1.4-18.8%, nevertheless our PPR values for benzene were more reliable at lower flow rates (0.75-1.20%). This study highlights the importance of flow rate and associated pressure changes as a key to accurate permeation rate estimation from permeation tube devices.
进行了一系列实验室实验，以评估使用校准气体发生器系统的渗透管（PT）设备的准确性，以测量挥发性有机化合物（VOC）的渗透速率（PR）。通过 PT 在 20-1200 mL min(-1) 的不同流速（FR）和恒定温度（30°C）下产生苯、甲苯和间二甲苯（BTX）的校准气体标准。结果表明，在该温度下，流速的变化极大地影响了每种 VOC 的渗透速率。本文介绍了准确测量实际渗透速率（APR）的实验方法和预测渗透速率（PPR）的经验方程的推导。如果偏差的大小定义为 PPR 与制造商的渗透速率（MPR）之间的差异，则甲苯（T）的偏差通常为 19-40%，间二甲苯（X）的偏差为 31-54%。苯（B）的偏差最小，为 1.4-18.8%，但我们对苯的 PPR 值在较低流速（0.75-1.20%）下更可靠。本研究强调了流速和相关压力变化作为从渗透管设备准确估计渗透速率的关键。
