Hi Sumira,

you could find something interesting in the pubblication (Money, 1989) I'm attaching you. This author elaborated the relationships between the concentration of PEGs with different molecular weight and the osmotic pressure of the solution. You'll find regression equations in order to obtain also the values for PEG 4000. Notice that the reliability of the equations depends on the range of PEG concentration in solution.

You can also find other works (Michel and Kaufmann, 1973; Michel, 1983) concerning PEG 6000 and 8000. The latest is usually more used because of the particles dimension which prevent it from crossing plasma membrane.

All the best

Thanks sir.  I have PEG with MW 400

I have to prepare PEG with -4 bar, -6 bar and -12 bar from PEG 400.   I need chart to sort out the concentration to be utilized for preparation of  PEG 40o so as to bget -4, -6 and -12 bar PEG . 

Hi Sumira,

you may calculate your concentration corresponding to the osmotic pressure you need by a regression equation. You should find it in the Money's article I sent you. Unfortunately I worked only with Peg 8000, for which Michel elaborated a more precise equation so I can't exactly say you how much PEG 4000 you need to reach these pressure values.

Kind regards

Thanks   for assistance.  

Dear Sumira

It will be much better to use PEG of high MW (6000 or 8000) for osmotic stress imposition.

to get required water potential please go through Michel et al. (1983) that has been already sent to you by Romano.

Thanks Abass.