[Joeyboy]

I'm wanting to extract free cholesterol from egg yolks and I need some help in figuring out the process, I'll explain what I understand already and I would ask anyone who can correct or suggest anything to improve this method would be a great help.
Basically I want to start off with the egg yolk seperated from it's white, I then would put the egg yolk into a tube of methanol and methylene chloride with a ratio of 1/2 total 15ml, then shake the tube and add 5ml water and shake again and centrifuge for around 5/10 minutes then using a pipette extract the bottom layer which would contain lipids and methylene chloride and put into another tube. Then add K0H, pottasium hydroxide with methanol ( methanolic K0H ) and add to a container on a heat of 90 degrees c for an hour. I should then be left with glycols and other things which I will seperate using a solution of saline ( salt water ) and stir, now I was wondering whether I still need a non polar solvent like heptane or butane or if I can skip this and the residue on top of the saline would be free cholesterol which I could then filter through filter paper to obtain free cholesterol?

*{MOD Edit -- an actually useful title}*

[Arkcon]

A couple of questions for you:

Where did you find this procure?  Why are you following it diligently, to start with, and then want to change it later? 

You have two liquids, one floating on another, why do you want to use filter paper to separate them?  Can you think of better laboratory equipment to use?  Do you really think filter paper will work? 

Why are you executing this procedure?  You seem to have very specific procedures, then you suddenly seem to not understand the basics.  Are you expecting to use this isolated product as a medicine or food?  Because we're not allowed to help, in that case.  If this is a gee-wiz lookit whaticando sort of question, we're still glad to help, but you may have to put up with us actually trying to teach you something about chemistry as we go along.

[Joeyboy]

Hello and thanyou for your reply, I found this procedure as an improvement to folch's 1957 polar lipid extraction, This is purely knowledge I am wanting to gain to further my education in chemistry I am just wanting to understand that if I have lipids extracted via the methylene chloride instead of chloroform and I have then put them through the process of seperating them with the methylenic K0H, would I be left with free cholesterol? If so how can I extract it? I understand the saline will draw the stuff I don't need as it's highly polar and hexane/butane/naptha/toluene would be used as a non polar which could be extracted and then dried leaving pure cholesterol but is hexane or butane or a non polar really needed? If so why? Or will the residue on the top of the saline be free cholesterol and how would it be stored, extracted  or turned into a crystal form? Ie for lab use or is it already in a crystal form after extraction? Anything you can teach me will be highly appreciated and help me understand this procedure in more detail, it caught my interest as there are different methods and I want to know which one is best/would work and leave the cholesterol. On this topic I have read that a tubar of a certain wild yam using this process would yield Diosgenin is this extracted using the same technique yielding Diosgenin instead of cholesterol? As I understand Diosgenin undergoes a process using the p450scc ( side chain clevege ) enzyme to turn this into progesterone/pregesterone, how is this done whats the method Ie how is the p450 enzyme extracted in the first place and p450scc isolated and how is it introduced to the Diosgenin and what methods and steps are required? Their is very limited resources I can use so I need someone with a greater knowledge to teach me in what I want to understand, like I've said this is all purely knowledge I wish to gain. I am new to the forum so thankyou for your edit on improving my post and thankyou for your time.