Sample filtration

<p>I am having a hard time deciding how to filter my samples for UPLC analysis.  Has anyone had success using microcentrifuge filters for sample prep?  I have been looking into:</p><p></p><p>Costar<small><sup>®</sup></small> Spin-X<small><sup>®</sup></small> Centrifuge Tube Filters - Spinfilter Ny 0.22um from Cole Parmer </p><p>Ultrafree-MC microcentrifuge filters - Durapore PVDF membrane, pore size 0.22um from Sigma</p><p></p><p>These would be used as an alternative to using syringe filters.  I have to filter out possible particulate contiminants from my sample which have not been problematic (binding to, or clogging my column or tubing) for HPLC analysis, but am concerned that they may gum up my new H-Class. </p><p></p><p>I am thinking that microcentrifuge filtering would be so much more cost/time efficient and generate less waste than purchasing filter units, syringes and then still having the additional cost of storage vials.  But I have no experience using these units.</p><p></p><p>Thanks for any advice you may have!</p>


  • Do your samples have to be centrifuged?  I have used Whatman Mini-UniPrep 0.2um filters and worked out great for my application (rat urine). The nice thing about this device is that the filter is built-in to the autosampler vial, so the filtered sample goes straight to the autosampler tray. They are a bit pricey, but I thought it was worth it saving separate filter and syringe and vial costs and the time for multiple transfer. You need to set the needle depth higher than usual so that the needle does not penetrate the filter in the vial. Hope it helps.