SCD355 for Nonhydrocarbon Gas based

[amrnassertk1]

I have issue with HP 7890A SCD355 for sulfur detection ,the issue is instability in result in sulfer mixture with helium balance , the result decreases and show big deviation along with runs

One more issue ,is there any formula to calculate sulfur conc. Of diffrent sulfur compunds by calibration only of one compound ( for example calculate conc. Of methyl and ethyl mercaptan by using gas STD. With hydrogen sulfide with nitrogen balance )

I need your help and support please

[amrnassertk1]

Please help

[Don_Hilton]

By what method are you introducing the gas mixture into the GC? And how are you handling from the gas cylinder to the instrument?

According to Agilent, the response factor for sulfur in independent of chemical composistion.http://www.chem.agilent.com/Library/tec ... 6785EN.pdf

[amrnassertk1]

I am working in speciality gases centre we are mixing gases with diffrent conc. As per custumer order .introduce the mixing gas to GC using gas regulator to regulate a gas pressure to GC
Thank you sir for your reply

[Don_Hilton]

I assume from a regulator through a gas sampling valve? I presume that you are using techniques which give good results with other gas mixtures. So, what surfaces is the gas mixture contacting? Sulfur compounds and surfaces such as metal can be a problem.