Problems with Zero Gases for Ultra-Low Level Measurements of Air Pollutants

Publisher Website
Google Scholar
Abstract
The replacement of wet-chemical methods of measuring air pollutants by more sophisticated instruments has introduced a number of new problems. Most of the new analytical instruments do not give absolute results. Instead, their measurements are relative to a reference standard containing a “known” concentration of the pollutant of interest and to a “zero” standard containing neither the pollutant of interest nor interfering components. As the attempt is made to measure pollutants at very low levels, it becomes more difficult not only to produce reference standards, but also equally difficult to establish the zero level. The specific requirements for ultra-pure zero gases, including carrier gases employed in Chromatographic measurements, are illustrated for many instruments in use today. Problems in the handling of zero gases are discussed. Results of tests demonstrate the ease of contamination of zero gases by regulators, sample lines, syringes, etc. Solutions to many of these handling problems are presented.

This publication has 3 references indexed in Scilit: