Making stock solutions - (Mar/24/2009 )

Hi,

I have a number of problems making stock solutions of things I haven''t used before.

1) How do I check which solvent to use?
for eg. when making a solution of PMSF where can I check to find out that I have to make it in isopropanol?

2) How do I check which is the maximun concentrated stock I can make?
1M or 10M

3) How do I check where I have to store this solution and how long this usually lasts?
-20 or shelf or cold room...do I have to wrap Al foil etc?

4) How do I check if I need to ph this solution?
for example 1M imidazole I got to ph it the same ph as the wash buffer when using during protein purification.


I have tried looking at Molecular biology Manuals and I found out that only commonly used solutions are listed, along with the protocols to make them. So if I am trying to make a solution of reagent not in these lists, where do I look for the information.

I ask ppl in my lab but everyone''s busy and sometimes they forget and give me wrong information so I want to know a manual or a handbook or something that I can refer to.

Thanks a lot
mary

This is in general difficult. The Merck Index has solubility information about many chemicals. But, as you point out with PMSF, stability of the compound in solution is another important issue. The sheet that comes with chemicals often contains information on solubility, stability, and storage conditions. pH can often dramatically influence solubility (e.g. EDTA). I don't know of a good, simple place to look for all of this information. Sorry.

hi,
the greatest information resource is the internet. 5 minutes of google searching will usually give you all the information you want to know.

Thanks for the suggestions. I have tried googling and for some things (like making a stock of imidazole) I was not able to find much information.

any more ideas?

Thanks
Mary

try this encyclopedia.

http://en.wikipedia.org/wiki/PMSF

I'd stick to proven and tested recipes and not develop own ones for such general topics. Normally you need time for more severe problems.
This may help: (about 1MB)

hobglobin on Mar 26 2009, 03:22 AM said:

Have a look here for the download

mary31 on Mar 24 2009, 11:05 AM said:

You are required to make 200 cm3 of a 0.1M solution of calcium hydroxide (Ca(OH)2)

Using the same steps as before:

1. Work ot the relative molecular mass of Ca(OH)2 (Ca = 40, H = 1, O = 16). Therefore, 40 + (2 x 1) + (2 x 16) = 74 g.
2. You would need 74 g of Ca(OH)2 if you were making up 1 dm3 of a 1M solution. However, you are required to make up 200 cm3 of a 0.1 M solution. Therefore, you require (74 x 0.1) = 7.4 g in 1 dm3, equivalent to 1.48 g in 200cm3.
3. Dissolve the 1.48 g Ca(OH)2 in distilled water.
4. Make up to 200 cm3 with distilled water.