Problem with a diluent in a GC analysis

[chemistab]

I try to determine some solvents (methanol, Ethanol, Ethyl Acetate, toluene and DMSO) by GC-FID. I use NMP as diluent. My problem is that the diluent gives a not stable peak at the same retention time with DMSO. I changed some parameters of GC (for example the temperature program to the oven) but the problem was not solved.
Any suggestion please?

[chromatographer1]

Two of the obvious come to mind.

Use a different Diluent.

Use a different column.

Don't insist on science working as YOU want it to work to your convenience.

Sometimes, we ourselves have to realize that on occasion, sometimes:

You eat bear.

The bear eats you.

In other words, you may require a second method to do DMSO analysis using methyl alcohol, or methyl acetate or methylene chloride or some other solvent as a diluent.

best wishes,

Rod

[krickos]

Hi

Well some litterature/catalouge searching would perhaps avoided the problem.

Column manufactures like Agilent/J&W typically has retetion indexes for DB-1, WAX and 624 columns for the most common solvents.