Chromatography Forum

Could someone please offer me some direction in selecting a bench top vacuum pump. I work in a lab where we have no in-house vacuum system and must rely on diaphragm vacuum pumps to filter mobile phase preparations. However, the pumps that are currently in use have a hell of a time to pull solvent through a 0.2 micron filter which is needed for UPLC. I've checked Restek, Vacuubrand and there are many to pick from. I contacted them if they can recommend one that will perform the task above and cant get a straight answer. I want one that will be powerful enough to filter but wont be so strong to change the percent composition. I would prefer diaphragm since they don't require oil and are quieter and I think have improved their vacuum efficiency. More helpful might be some insight as to what parameters I should look for. House vacuum is about 100-250mbar. So I'm considering a pump that can pump to 100 mbar with an adjustable vacuum gauge. However, should I consider horsepower? Or Max flow rate? Any advice would be welcomed.

We used house vacuum when filtering mobile phase. Of course maintenance turned off such vacuum on weekends.

So I bought an air-conditioning vacuum pump and used that on weekends when needed. I believe I bought the least expensive one on this page http://www.ackits.com/vacuum-pumps-and-oil-mastercool

$141 http://www.ackits.com/vacuum-pumps-and- ... pump-33434

Thanks Consumer Product Guy:

Good price, however I think I would rather stay away from an oil vacuum pump. Our lab area is small and the pump will get lots of use, hence it will be very noisy.
Besides, I think the diaphragm pumps, albeit a bit more pricey, should get me down to 70mbar which I think will filter fairly well.

Appreciate the reply and suggestions.