Chromatography Forum

I have to analyze for something out of certain matrix... the only solvent I know of that boils above he analyte AND solvates the matrix as well a she analyte is DMSO.

I am using an Agilent ( therefore a loop design) headspace sampler.

In the past when I tried using DMSO as the solvent i headspace I ran into reproducibility issues which I am reasonably sure were due to the DMSO condensing in the vent line.

Has anybody had any luck with using DMSO as a solvent for headspace analysis with a loop style headspace sampler? If so at what temperature did you keep the HS oven?

Thanks,
- Karen

Hi Karen,

I kept the transfer line at 110C and the oven at 80C

But my carrier flow through the loop was at least 5mL per min.

Also, I was beta-testing Tekmar's fused silica coated needle, and connecting lines, including the transfer line into the GC which was directly connected to the analytical column.

Any metal in your system which comes in contact with DMSO will tend to retain the DMSO.

I would also suggest if possible you use the minimum amount of DMSO to dissolve your sample (not at room temperature but in your equilibrating oven temperature) when mixed with water.

I found that some difficult drugs would not dissolve in water or in DMSO, but WOULD dissolve if mixed 50/50.

Likewise you may not need 100% DMSO but perhaps a 30/70 or less may be enough to dissolve your matrix.

Just a suggestion. Good luck in your research.

Rod, retired but ready.

100%+
During the government's checking I did test the purity of the sample transport and 7694E showed the rest of the previous samples of toluene (in water) 0.63% and the remainder of DMSO (as solvent) at 0.8%.
Generally speaking DMSO hard boiling, but very volatile compound (you know how to flavor spreads). So if DMSO is not sorbed (on that metall or resine), and through the line goes a constant stream of gas (nitrogen) DMSO previous sample is removed almost completely.