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Making stock solutions


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9 replies to this topic

#1 mary31

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Posted 24 March 2009 - 02:05 AM

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

#2 phage434

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Posted 24 March 2009 - 04:19 AM

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.

#3 lotus

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Posted 24 March 2009 - 09:45 AM

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

#4 mary31

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Posted 24 March 2009 - 11:14 PM

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

#5 moh_eg

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Posted 25 March 2009 - 02:03 AM

try this encyclopedia.

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

#6 hobglobin

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Posted 26 March 2009 - 02:22 AM

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: [attachment=254:lab_faqs__2005.pdf] (about 1MB)

One must presume that long and short arguments contribute to the same end. - Epicurus
...except casandra's that belong to the funniest, most interesting and imaginative (or over-imaginative?) ones, I suppose.

That is....if she posts at all.


#7 mary31

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Posted 28 March 2009 - 08:24 PM

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: [attachment=254:lab_faqs__2005.pdf] (about 1MB)


Thanks a lot for the attachment and advice- hobglobin
:lol:
mary

#8 hobglobin

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Posted 16 April 2009 - 11:59 AM

Have a look here for the download

One must presume that long and short arguments contribute to the same end. - Epicurus
...except casandra's that belong to the funniest, most interesting and imaginative (or over-imaginative?) ones, I suppose.

That is....if she posts at all.


#9 rhombus

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Posted 17 April 2009 - 03:57 AM

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


Dear Mary 31,

Try the MERCK INDEX...it's the bible for chemicals.....gives information on:-
Boiling/melting/freezing points
Solubilty in aqueous/solvents
Maximum concentration that can be achieved
Stability of the compound
Optimium storage temperature
etc etc etc


EVERY LAB SHOULD HAVE ONE!!!!!!!!!


For pH, simple use a pH meter.

Regards

Rhombus

#10 alexades

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Posted 24 April 2009 - 12:56 AM

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.




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