concentrate DNA - (Dec/31/2014 )

I have used DNeasy to extract DNA. I eluted in 200uL volume. The extracted DNA concentration is 25ng/ul in Buffer AE. I need the concentration higher than this and want to reconcentrate the DNA. I don't have a speedvac. The DNA is already purified. I just want to reelute the DNA in a smaller buffer volume (100uL or 75uL). What is a good column-based DNA concentration kit to use to do this? I looked at the Zymo DNA Clean and Concentrator -25. But can that be used for reconcentration of already purified DNA?

Old school, but still effective: Add a layer of 2-butanol above your DNA. Water will dilute the butanol, leaving the DNA concentrated in a smaller volume of water. See a detailed protocol here:

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCAQFjAA&url=http%3A%2F%2Fopenwetware.org%2Fimages%2F4%2F43%2FMoore.pdf&ei=mS2kVLWYIIehNvurgaAC&usg=AFQjCNFZ1Zm6UNfyq4kfb1FTciwk-QoOvQ&sig2=1KuZg_xV0JoNo-bl4xJSjg&bvm=bv.82001339,d.eXY

Also you can use an Amicon centrifugal filter.  You place the sample, centrifuge, discard elute, add the volume of buffer or water that you want place the filter upside down, centrifuge and you will have your DNA concentrated and with a minimal of loss.  If you use a clean kit you will loose materials.  If you don't have those ask to other people usually somebody have.  And buy some, always a good idea to have on hand.  

Thanks. The amicon filters should work.