Gaseous standard mixtures - the challenge of obtaining small amounts of measurands

Commonly used methods of generating gaseous standard mixtures require complex apparatus during both preparation and storage. Using the proposed indirect method of generating gaseous standard mixtures, an analytical instrument can be calibrated by connecting it directly to a furnace in which thermal decomposition of a sample of chemically modified silica gel takes place. In this case, the furnace acts as a sampling device. This approach has a number of advantages, such as the possibility of preparing toxic or malodorous analytes just prior to investigations or calibration of a measuring device. (C) 2004 Published by Elsevier B.V.