Making a cell culture medium

[87er]

Hey I have a problem (and still an undergrad so don't hate).

I'm about to make a 10x RPMI 1640 (GIBCO) medium. I have this powder: http://products.invitrogen.com/ivgn/product/23400062 It says 10L and 104,3g on the box (meaning and 104,3g/10L right?) I need 10ml of (as said above) a 10x solution. Does that mean I have to take 0,1403g in 10ml? And in what do I need to dissolve the powder? PBS buffer or sterile water?

Regards.

[JackBean]

where did you find, you should add 104g to 10l?

[87er]

Hi,

I think you misunderstood me, I mean there's 10L and 104,3g printed on the thing. So I thought that there are 104,3g in that thing when you purchase it and that's enough for 10L when you would dissolve it. So I just calculated how much I need for 10ml of a 10x solution. Or am I getting this wrong?

[JackBean]

I meant something else, but as I'm thinking about it now, you're probably right.
So, if it is for 10l of 1× medium, you should use 100-times less, thus 1.04g, right?

[canalon]

As far as I can see you are supposed to add the pouch to 10L of sterile double- distilled/milliQ water, aliquote in convenient form, store at recommended temperature (I assume 4ºC) and enjoy.

I would certainly not recommend to prepare 10ml from such a pouch as you would very likely not get the right formulation. I don't know how fine the powder is but when I see that some of the products are less than a mg/L, there is a high probablility that it will not end up in your pouch when you mix you 100mg of powder.
This is the kind of thing that should be fully prepared at once.

[87er]

canalon, you're right with adding all of this to 10L. But the pouch has been used before which would mean that I would have to weigh what's left and then calculate how much water I still need (still doable though). But if I would dissolve everything in MilliQ, I would have 1x. I need 10x though. So here's my calculation:

104,3 g for 10L of 1x
10,43g for 1000ml of 1x
0,1043g for 10ml of 1x
1,043g for 10ml of 10x (made a calculation error in my first post btw, JackBean's calc is correct of course)

I know that it probably won't be 10x exactly due to what canalon pointed out but it does not need to be that extremely accurate.

edit: powder is very fine