Evaluation of tubing losses during field sampling for hydrogen halide gases.
Buffington CO; Kneiss SC; Hornsby JL; Hoke SH
Field Anal Chem Tech 1998 Feb; 2(4):231-240
In field sampling for halogen acid gases, various types of tubing are used to transport the air sample from the source to the monitoring instrument or sampling container. During this process, losses of the analyte can occur through interaction with the component material of the tubing or sampling container. The purpose of this study was to investigate this interaction between hydrogen halide gases and various types of common laboratory tubing. A 20-ft length of tubing was placed between an acid gas diluter and the inlet port of a real-time gas analyzer. Electronic flow controllers provided a fixed concentration and flow rate. The acid gas was diluted with nitrogen. The concentration of and the time required for the gas to flow through the tubing was followed with a real-time halogen acid gas analyzer that was interfaced with a computer. By comparing the response characteristics with a calculated theoretical zero interaction, the amount of interaction can be estimated. The gases hydrogen fluoride, hydrogen chloride, hydrogen bromide, and hydrogen iodide were each studied with 24-26 types of common laboratory tubing, The best choices for use with any of the hydrogen halides would be either Norprene(TM) or any of the three Teflons(TM).
Laboratories; Laboratory-equipment; Laboratory-testing; Laboratory-work; Teflon-decomposition-products; Testing-equipment; Gas-sampling
SH Hoke, Center for Health Promotion and Preventive Medicine, Aberdeen Proving Ground, MD 21010
Field Analytical Chemistry and Technology