Analysis of Substances in the Gaseous Phase

The period up to the beginning of the twentieth century is characterized by ever-increasing interest in absorption gas analysis, from the points of view both of instrumentation and the method itself, as well as considerations of its usefulness. At the end of the 19th century, Hempel, Winkler, Bunte, and Orsat carried out important work and, together with Bunsen, laid the foundations for classical gas analysis. Absorption by solid substances was gradually replaced by the use of solutions of reagents that were easier to prepare and often more effective. This change required the development of new apparatus. Hempel described a basic apparatus for volumetric absorption and combustion analysis. His monograph, “Gasanalytische Methoden”, which was published in several editions, gives a good review of classical methods. In 1875, Orsat constructed an apparatus for the complete analysis of various gas mixtures which is still used with only slight modification.