Low Sulfur Detection

Many sources of natural and petroleum gas, from gas well, refinery or landfill, contain sulfur compounds that are odorous, corrosive and poisonous to catalysts used in gas processing. Further to that by-products from gas processing can occur in high purity grade of CO₂ which is produced for agricultural or beverage purposes.

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 of G.A.S. or the latest innovation of the integration of a miniaturized IMS into a channel of Agilent’s 490 Micro GC  allows to measure the relevant S-containing compounds at low ppb level. For both instruments relevant aspects for the low sulphur detection are respected e.g. by using inert sampling and internal gas pathways. By this absorption of compounds can be minimized and the power and outstanding sensitivity of the IMS as additional detector unit used in the best way.