Minipreps 
The term “miniprep” refers to a procedure or 
protocol used to purify plasmid DNA. 
If you have worked in a lab previously or if you end 
up working in a lab then you likely will have done or 
will do many, many minipreps.
Nucleic Acids Research (1979), 7: 1513 - 1523
http://tools.invitrogen.com/content/sfs/manuals/purelink%20_quick_plasmid_qrc.pdf
Protocol 
http://tools.invitrogen.com/content/sfs/manuals/purelink%20_quick_plasmid_qrc.pdf
http://tools.invitrogen.com/content/sfs/manuals/purelink%20_quick_plasmid_qrc.pdf
http://tools.invitrogen.com/content/sfs/manuals/purelink%20_quick_plasmid_qrc.pdf
One of the solutions (e.g., the Precipitation Buffer) 
contained a chaotropic agent or salt. 
What the heck is a chaotropic agent? 
“A chaotropic agent', also known as chaotropic 
reagent and chaotrope, is a substance which disrupts 
the three dimensional structure in macromolecules 
such as proteins, DNA, or RNA. Chaotropic agents 
interfere with stabilizing intramolecular interactions 
mediated by noncovalent forces such as hydrogen 
bonds, Van der Waals forces, and hydrophobic effects.” 
http://en.wikipedia.org/wiki/Chaotropic_agent
In the presence of a suitable chaotropic reagent, 
DNA will bind to siliceous materials. 
DNA remains bound to the resin when EtOH is 
used to rinse the resin because EtOH by itself 
will precipitate DNA. 
A final rinse in dH2O causes the DNA to elute 
from the resin.

Miniprep lecture