Online gas chromatographs are installed in all kind of industries mainly for process monitoring or emission control applications.

The example shows continuous monitoring of trichloroethylene and methyl i-butyl ketone in the exhaust air of an industrial plant using a GC 4000 analyzer. Both components are commonly used as organic solvents and can be easily separated even on isothermal conditions using a non-polar capillary column.

For occupational safety reasons harmful and toxic organic compounds, such as epichlorhydrine or methylisocyanide, often have to be monitored at extremely low concentrations. Therefore, these kinds of application ask for excellent detection sensitivity of the analytical monitoring system.

The example shows a chromatogram recorded during monitoring of indoor air for vinyl chloride. Due to its carcinogenic nature, vinyl chloride is particularly injurious to human health. For this application the GC 5000 system is provided with a single stage enrichment module. Such a monitoring system allows for safe detection of vinyl chloride even at concentration levels in the ppt-range.

Gas chromatographs are used for monitoring of aromatic hydrocarbons and other ozone precursors in ambient air in order to observe the compliance with environmental regulations.

The chromatogram shown was acquired with a GC 5000 BTX analyzer and gives an example for monitoring of benzene, toluene, ethyl benzene and xylene in ambient air. During the measuring cycle, benzene was present at a concentration level of 2 µg/m³ only. This detected concentration falls well below the legally permitted value according to the directives of the European Community.