Diluting a protease inhibitor cocktail - (Jun/02/2011 )

Hi there

I usually use the compass mini EDTA free cocktail and dilute with 1.5 mL of water to give a 7x Inhibitor solution.
There is only the compass EDTA free cocktail in the lab at the moment (not mini). It says add 2 ml to give a 25x solution. How much more water do I need to make the solution 7x? Would really appreciate the help!

Thank you

Biochem_newbie on Thu Jun 2 15:35:17 2011 said:

Hola 2ml,25x=>1ml50x 50/7=7.15, so diluting to 7ml you will have a 7.15x or diluting to 7.15ml you will have a 7x. so add 5.15 ml to your 2 ml of solution. Buena suerte

I am a little bit confused about product ( Complete, EDTA-free protease inhibitor cocktail tablets, catalog number:11873580001) and the information provided with sheet as I am very new to use this cocktail mixture. It is mentioned that 1 tablet is sufficient for 50 ml extraction. Its all right I understand that. But, my problem is that I am planning to prepare 100X stock of this cocktail, so shall I dissolve 1 tablet in 0.5 ml of solvent or what?? It is suggested in a line in your product description that for 25X, dissolve in 1 ml which really confused me. I think in science basic problems seem to be more buggy.
I think 1 tablet in 0.5 ml will be 100X. Am I right??
then what will be my final concentration during extraction 1X??

I would be happy for any kind of suggestions or informations.

shyamadi on Sat Jun 4 05:12:49 2011 said:

Its confusing what you say.

What does it say? Does it say to dissolve 1 tablet in 50ml so that you have 50ml of solvent to work with (and thus you need to use this entirely for a sample).
(altough: I am not sure what it means 50ml extraction.. )


Anyway, then you say that if you dissolve the tablet (its the same one, I hope?) in 1ml you have a 25X solution?

If dissolving it in 1ml results in 25X , then what happens in you dissolve it in half the volume? It wont be 100X ......

You need to be clear about what you are using.

If the prodcut sheets says: dissolving in 1ml means 25X , then this is the information you need to use!

The information that says you can put one tabled in 50ml is just a hint to use.. it means that 1 tabled it enough to have 50ml of working solution to do a certain test. Is says nothing abou how much X it is... You need to calculate this yourself with the information that 1tabled in 1ml is 25X

pito on Sat Jun 4 10:37:18 2011 said:

yes Sir,
I got your point and I am doing the same as the data sheet suggests.If we dissolve the whole single tablet in 50 ml, it is going to be 1X, but my objective is to make more concentrated (100X) and aliquote for storage and reuses time and again.Therefore, I am planning to dissolve 1 tablet in 2ml so that the final concentration will be 25x as dissolving in very small volume(o.5 ml) for 100X may be problematic.

Many many thanks !!

shyamadi on Tue Jun 7 07:08:01 2011 said:

I think you did not understand the last part of my previous post:

If you dissolve it in 50ml it will NOT be 1X !

The only information about concentration you have it that:

So what you know is that when you dissolve it in 1ml you have 25X !

If you dissolve it in 50ml how much is it then ?
You dilute it 50 times, you its 0,5X !!!

To have 1X you need to dissolve it in 25ml.


Again: check the sheet of instruction manual to make sure you are doing it right!


If the sheet does say that 1 tabled in 1ml is 50X then its ok of course, but make sure its correct , because in your first post you mention that its 25X if you dissolve it in 1ml.

pito on Tue Jun 7 07:51:38 2011 said:

Thank u so much Sir for correcting me. I was going to do a blunder. I went through product description provided in catalog and its 2 ml for 25X. I am really clear about everything now. I appreciate your help and continued responses. Hoping to get more and more !! Cheers