I have a question.
how I can change the column in the gc/ms without stopped turbopump ? It is possible?
regards Azrael ?
I believe what @mhardacker is referencing with the flow calculation is that as soon as the restriction capillary is cut, the EPC is no longer controlling the amount of flow to the MSD, i.e. atmospheric pressure…
There is a product for this.
i can not to tell how often will change the column because other people will work. I just want to improve what is. I was asked about it. I would not touch this system. But there is interest in doing several tasks on one detector. i have two columns - polar and not polar and one port for the injector on analysis pesticide and lipid. and I am thinking how to implement this task. can buy another injector and a ferrule with two holes (what you talked about yestarday) and use two columns at once. And it is also possible to change columns, which is what James gave the link about, but I haven't looked into that yet. Therefore, I am interested in whether this can be done and how to do it correctly so as not to harm the detector (turbomolecular pump).
The only really fast & SAFE column change is only possible with Quick Swap technique suggested by james_jenkins.
On one hand, a restriction capillary is used to limit the flow to the pump & to stabilise the vacuum. In order to avoid a large O2/H20 entry in the short time: a "protective makeup gas" feed is used.
If my customers want to be particularly careful, I recommend to reduce the MS temperatures to 100°C before column change. This prevents ion source oxidation effects if the column change process takes longer (e.g. ferrule defective, column broken.. etc).