1. What are the differences,in detail please, between analitical electrophoresis and preparative electrophoresis

 

2. What are the prons and cons in the usage of amonium sulphate, alcohol and acetone during the precipitation.

Not sure I understand what you mean by preparative and analytical? and what are you precipitating, DNA, RNA, protein? I sense you are seeking the answer to exam questions here...perhaps you need to do the reading? I'm sure you've been given the clues in your lecture notes, do the work...like I did.

At least if it's a homework question, put it in the homework section.

 

Anyway I think analytical is where you just which to find information out about the molecule, and preparative is where you want a functioning molecule once you've done electrophoresing. So SDS (detergent denatures the protein) would be analytical, PAGE would be preparative.