Chromatography Forum

Hi everyone,

We are trying to analyze sulfolane (boiling point 285C) and are getting poor reproducibility. Peak area RSD = around 10%.

We suspect that this is due to inlet discrimination so we've tried many different things (split, splitless, varying purge time etc..) We also tried to raise ion source temperature to 285C) but we are getting the same RSD.

Any suggestion?

We followed the method reported in a paper. The method is as follows:

Solvent: toluene
Injection temperature : 250C (we used 285C)
Oven temperature (80C for 2 min, then 160C at 10C/min, then to 280C at 20C/min
Ion source temperature: 285C (we used both 250C and 285C)

Thank you everyone!

Did you try the inlet at 250C as in the method? It could be some type of breakdown at 285C that is causing the problem.

Add an internal standard with a similar boiling point and look at the repeatability of peak area ratio. What column are you using, and what are the gas flow rates. What inlet liner do you have, and when was it last cleaned or replaced ?

Peter

Thanks for the suggestions. We have figured it out - the only option is splitless, increase purge time and set ion source temperature to 285C.

Adding an internal standard is a great idea, although will be a bit tricky to find a compound that is also very hydrophilic and has similar boiling point.