Purifying PCR product from 2% agarose gel

[ChenHA]

Ednot wrote:

> 
> On Feb 18, 10:46 am, "hilary cassidy" <cass... from gmail.com> wrote:
>> Hi
>>
>> I've been trying to purify my PCR product from a 2% agarose gel all
>> week now as it needs to be purified prior to Topo cloning. I've used
>> both the QIAEX II Gel Purification kit by Qiagen and the Illustra DNA
>> and Gel Band Purification Kit by GE Healthcare. Each time I have
>> strong bands on the gel prior to cutting the bands, but everytime I
>> purify and run the DNA on a gel to check there is nothing!!!

I stopped using QIAEX because it doesn't work well all the time, 
especially for small fragments.  I use Geneclean and it hasn't failed me 
yet.  Geneclean has a special kit for very small fragment (Mermaid if I 
remember correctly), although trying this and the normal kits for ~200bp 
fragments doesn't seem to make much difference (both worked equally well).

How big is your fragment?  If you fragment is very small, check that you 
haven't mistaken your oligos for PCR products.