Effects of Silcosteel® transfer line on the sampling of volatile organic compounds

A 150-ft section of 1/16-in. o.d. x 0.030-in i.d. fused-silica-lined stainless tubing (Silcosteel(R)) was studied to determine its suitability as a transfer line in the sampling and analysis of vapor samples of Volatile organic compounds (VOCs), principally in subsurface soil gases. A variety of test atmospheres of individual VOCs at concentrations ranging from 0.01 to 10,000 ppm were used to challenge the tubing. The adsorptive and desorptive properties of the tubing were characterized under conditions [14 degrees C (57 degrees F) end 90% RH] comparable to subsurface environments and also at temperatures of 2 degrees C (35 degrees F) and 46 degrees C (115 degrees F). Clearance rates of the selected VOCs from the tubing were also determined. Direct-sampling ion-trap mass spectrometry (DS-ITMS) real-time air monitoring was used to measure the effects of the transfer line on the vapor samples. (C) 1998 John Wiley & Sons, Inc.