Chromatography Forum

Hi all,

Im kinda tired replacing the septum on the wash vials for our GC's autosampler.

is there any fancy septum out there that is reusable?

Tarapan

How often are you doing this ? All septa are resusable - in that you can do more than one puncture, but I cannot imagine that that is your problem. Agilent do a diffusion cap for their wash vials, instead of replacing a septum you have to wash the crud off the cap every now and then, which I didn't find too tiring, but then I'm a big guy and I eat a healthy diet

Little bits of routine maintenance and cleaning are the price you have to pay for good results.

Peter

Alternatively, don't use any stoppers...just keep topping up or use a non volatile solvent. Personally I am with Peter, a little exercise is a good thing.

GCguy

Thanks Peter, the diffusion cap does seems promising alternative to those septum.

anyhow to clear the air a bit, what i meant was it gets pretty boring having to procure those septum when your stock gets too low. (thanks to the long winding and tedious procurement process).

Tarapan

Say you change wash vial septa once a day on two vials (which would be a pretty careful approach) - buy 'em in thousand packs, once every 18 months. Procurement processes are made by people, therefore they can be overcome by people !

Peter

Noting a comment above - a caution on topping off wash solvents: If you have samples with wide dynamic range, it is a good idea to dump solvent when about half to two thirds empty and fill fresh. It is possible to accumulate analytes from the high samples in the wash solvent vial and carry some into low concentration samples.

There is one place where a septum may be necessary - when the wash solvent or a solvent in the samples is noxious. The septum will keep the solvent out of the air and you will have fewer complaints from your lab mates. Otherwise, I allow the hole through the septum to be worn wide and I don't worry about it - it becomes like a diffusion cap (small hole limiting evaporation), but has some contact with the syringe needle.