[rjb]

I am interested in trying out a ‘novel’ purge and trap headspace recovery process which involves drawing headspace though a narrow tube containing a custom made adsorbent. In the literature, the authors used an air sampling pump to provide a flow rate of ~1.5 Litres per minute through the device. The trouble is, I don’t have the budget to be able to justify buying a dedicated pump for testing (they’re expensive!), so figured that it might be possible to test the technique using a lab vacuum line and a bit of fettling.

I propose to hook up the device to a simple and cheap air flow meter (as used for medical oxygen etc.). This will connect to something like a Y shaped 3 way valve (to act as a bleed to allow better flow control) one end of which will go to the vacuum line, the other to the atmosphere. I have attached a sketch below:

Before I start spending any money, I would very much appreciate any opinions on whether this likely to work (or not) as well as any suggestions of alternative ways of achieving the same goal, you are after all rather a creative bunch of people...

Thanks in advance

p.s. I hope you don't mind be adding this to the Organic Chem. Forum (rather than somewhere else), but the analyte is organic and more importantly I suspect organic chemistry types are etc most likely to have experience of using vacuum/Schlenk lines etc.