Thank you for the answer. I have another one actually. I should dissolve the cholesterol in chloroform then I have to aliquot it. In which tubes can I aliquot it?
I think it is ok to dissolve it in chloroform, but you should always use glass vials with teflon cap that doesn't allow escape of the solvent so that your concentration doesn't change.
Also it is not advised to use plastic pipette or syringe, you should use glass syringes from it to take.