Hydrogensulfide, COS and total sulphur requirements in natural gas and CO2 often list sub-ppm maximum sulfur levels which are difficult to achieve using conventional GC sulfur selective detectors such as FPD or PFPD. Not only detection is a challenge, also the introduction of the gas samples is a concern, as H2S and mercaptanes by nature adsorp to active spots of various surfaces, including steel sample cyliners, tubings, GC inlets and liners. Permanent deactivation of surfaces is a requirement to ensure repeatable data at low concentration levels. Moreover, care should be taken with stability and reactivity of sulphur compounds during sample introduction, as they intend to form other molecules.
Using the GC-IMS set-up of G.A.S. allows to measure the relevant S-containing compounds at low ppb level and by that addresses the sampling concerns using an inert sampling path and a the high sensitivity of its IMS as detector coupled to the GC.
Gas Chromatograph - Ion Mobility Spectrometer (GC-IMS) of G.A.S. combines the
high selectivity of a Gas Chromatograph with the extraordinary sensitivity of
an IMS (typically low ppbv range)
read more ...