Chromatography Forum

Greetings!

Your headspace system it's automated? The analysis it's from gc/ms or gc/fid?

It's dimethylsulfoxide or dimethlyformamide ? N,N-Dimethylsulfoxide is commonly expressed by DMSO. Either way i think the procedure will be the same for both.

If it's automated , remove the syringe, rinse the syringe about 3 times with acetone and 3 times with methanol. I reccomend a five minutes ultrassonic bath in methanol too, if you have this equipment of course. Put the syringe in the automated headspace and purge it for 5 minutes with nitrogen or other (cheap) gas that you use, run a blank.

if it's not automated, rinse with the solvents listed above about 5 times each. Wait the syringe to get dry and run a blank.

If in both cases you see something indicating contamination, consider change the septum and liner too.



t.b.

Ops!

your equipment is this : http://www.chem.agilent.com/Library/bro ... 6491EN.pdf
right?

I have a CTC-pal system coupled with a 5975C-7890A Agilent, an automated headspace system pretty simple acctually. I don't know if the procedure i listed will be able to clean your system. I really don't know how your system works.

Sorry.... ....

DMF is miscible with water, just put a mL of water in 10 vials and then equilibrate them in the oven at like 110 for a few minutes and inject, set the other heated zones to elevated temp and your GC's inlet to split mode with a few hundred mL of split flow. Set the oven above 100 C too, so no water collects anywhere. You could even remove your column if you want, just install an inch of two of column with a column nut into the inlet so it holds pressure.

If you still see DMF peaks after cleaning you may need to run more vials but I would bet it will be gone. The syringe is more difficult to get to in a G1888 than a CTC sampler. There is also significant flow path and a 6 port valve. All of it is heated so a bit u very of steam should help purge everything out, but I wouldn't go taking anything apart unless I needed to.