Chemical Forums
Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: zeshkani_usa on January 20, 2012, 09:07:16 PM
-
Hi there,
I was just going through my old analytical chem book, and i was just flipping through and saw this problem
"Calculate how much of each of the stock reagents listed below should be used to make 100mL of homogenization buffer containing:
10mM Tris pH8.6(dilute 50mM stock)
1mM PMSF (dilute 100mM stock)
1mM EDTA (dilute 20mM stock)
0.2uM pepstatin A (dilute 20uM stock)
1mM 2-mercaptoethanol (dilute 7.1M stock)
okay so this is what i get from this, with these 5 ingredients, all of these need to add up to 100mL
is this problem as simple as using Molarity=Moles/Volume or using C1xV1=C2xV2
I would appriciate it if someone can direct me in the right direction, on how to approach this problem
Thx
-
Both really. The units are Molarity, milli- and micro-, so you will use moles per liter. The thing is, you could never weigh out micro-moles of something with sufficient accuracy, so once you've prepared the suggested stock solutions, you will use C1V=C2V2 to make your solution.
-
okay i think i got it figured out here are my values calculated for each ingredient:
Tris= add 20mL
PMSF= add 1mL
EDTA= add 5mL
2-merca= add 0.014mL (seems low)
this totals to = 27.014mL -100mL(total)= 72.9mL of H2O
does this seem right????
-
all of these need to add up to 100mL
That's assuming your lab doesn't have water to fill it up to the mark. Rather unlikely assumption ;)