sucrose gradient - how to get fractions from the top (May/13/2003 )

We want to fraction a DNA sample with sucrose gradient. After centrifugation, we will have to get each fractions from the TOP. We don't know what is the best way doing this without disturbing the gradient. Would you please give us some tips on that?

I have only done CsCl gradient centrifugation. I don't know the difference between
them.So you'd better see Molecular Cloning for help, I extract my sample in guidance of it and get good result.