Monitoring of Sulfur Compounds in the Ambient Air. Synspec GC 955 810 gas chromatograph is specifically designed and built for the measurement of sulfur compounds in the ambient air. The two prominent groups of sulfur compounds that can be detected with this GC are mercaptans and sulfides but additional components such as benzene can be added also. The instrument is equipped with a built-in cooled pre-concentration system and PID detector. The analyser holds a CE approval for EMC conformity.