Dear Giuseppe,

the answer to your question is dependent upon a number of parameters, none of which you have provided. I tried to look up the characteristics of your syringe, but did not get a hit. Regardless of that, have you considered that injecting air/water vapour onto your GCMS is a wise thing to do? From your question, it is not clear to me that you have a complete helium or hydrogen flushing system for your sample. We have a CombiPal headspace sampling system, which allows to flush the sample with helium, take a heated syringe headspace sample and inject this onto the GCMS. No oxygen, no water will get onto the column. And as for needle lifetime: they will all fail, sooner or later. But it does matter to optimize injection parameters for maximum needle life time. Please provide some more details, so I can be more helpful. Kind regards, Harrie verhoeven.

You are asking a question about your needle, but didn't tell us which needle you have. In general, for headspace analysis (which is what you are describing) you want to use a side-port needle. Harrie is off base about the O2; obviously you have O2 in your vial headspace (as does he). You will cause no harm by injecting it.

You need a gas-tight syringe for headspace, so that part of the syringe description is good.

In my experience, I think that you need to do it mannually. Taking 1 or 2 samples first to discharge and purge any gas on your syringe. Then, a third intent allow you to put your sample in the injection port.

Good luck

SAM