The method of extending the proportionality - region of a flame-ionization detector and apparatus for carrying out the method

摘要

922,910. Determining relative quantities of fluid mixture constituents. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. June 1, 1961 [June 3, 1960], No. 19865/61. Class 37. In a method of detecting the presence of organic material in gases supplied to the flame of a flame ionisation detector which burns hydrogen or a mixture of hydrogen and other gases such as nitrogen, argon or helium in the presence of a separately supplied combustion supporting gas, the combustion supporting gas consists of a mixture containing carbon dioxide in addition to oxygen or a compound giving off oxygen. The carbon dioxide concentration of the mixture lies between 10-40% by volume with 20-35 % by volume as the preferred range. The oxygen content is kept lower than about 16% by volume, with a lower limit such that the flame is able to burn steadily. It is stated that compared with previous methods the method disclosed provides constant sensitivity of the flame detector over a greater range of concentration of organic material in gases to be tested. Specification 900,981 is referred to.