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How To Condition 47mm Nylon Membranes for Use with the Mobile Phase Filter Degasser...

Reference Number: AA-00399 Created: 04/10/2012 09:34 PM Last Updated: 04/10/2012 09:44 PM

Filter membranes with smaller pores sizes such as 0.45µm have higher bubble points (the differential pressure required to draw air through a wet membrane). The bubble point is a function of the pore size and the surface tension and viscosity of the solvent wetting the membrane. With aqueous solvents a vacuum cannot always overcome the bubble point.

  1. Use an initially dry membrane and filter the entire required volume without breaking the vacuum. If this does not work...
  2. Remove the siphon tube from its assembly and fill the reservoir above the filter with approximately 25ml of the liquid to be filtered, reattach the siphon tube, re-immerse it in the solvent to be filtered and apply the vacuum. If this does not work, use a greater vacuum or a large pore size membrane.

Please note that unstirred and unsparged organic solvents such as methanol and acetonitrile become re-equilibrated with ambient gasses in a few hours while aqueous solutions require approximately 10 hours to re-equilibrate. Use a helium sparging device to keep your solvents degassed.

47mm Membranes

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