Solutions Containing More
Than One Solute
•
SM Buffer
•
TE Buffer
NOTE: To successfully accomplish this
section you must be familiar and
comfortable with all information,
manipulation and definition from
previous lectures. This section will allow
you to use every thing you have learned
in this unit. Congratulations!!
SOLUTION WITH KNOWN ELEMENTS
 When given a solution with multiple known solute weights and final
solution volume the procedure is like a recipe. This is the easiest way to
make a solution with multiple solutes.
Ex) You are asked to make 2 liters of syrup water by weighing out 2
grams of sugar, 1 gram of salt and dissolving it in water.
You simply weigh out 2 grams of sugar, 1 gram of salt and dissolve it in water then
bring it to volume to 2 liters.
Much like sugar, some solutes require that they are heated on a heating plate to be able
to dissolve. Always check your reagent information sheet (MSDS)
INDIVIDUAL SOLUTION PREPARATION
PRIOR TO THE FINAL SOLUTION
 Final solutions maybe composed of a specific combination of small amounts
of other solutions that you must also prepare.
Ex) You are asked to make a media for a cell line by adding
100mL of IMDM
50mL of FBS
10µL Penicillin
You would make each of the three solutions according to their
recipes and then add 100mL of IMDM, 50mL of FBS and 10µL of penicillin in a
sterile bottle.You would not bring it to volume since specific amounts of each
one are required and this maybe due to a desired percent concentration.
SOLUTION PREPARED FROM ONLY FINAL
CONCENTRATIONS
 There is no final volume or weight of each solute given in this type of
solution.The only information provided is the concentration of each
one solute. This is so one can make this solution at any volume desired.
To do this you would have to calculate the amounts of each solute
needed to produce the desired concentration in your preferred final
volume.
 There are two very popular solutions used in laboratories: SM Buffer
and TE Buffer
SM BUFFER
 SM Buffer is made by combining:
0.2M Tris, pH 7.5
1 mM MgSO4
0.1 M NaCl
0.01 % gelatin
Neither the amounts of each nor the final volume is given, thus there are no stock solutions.
Follow these steps:
1.
Decide a final volume to prepare. This volume depends on how often and how much will be used.
2.
Weigh out the Tris. Solve using equations in Topic 8 “One Solute Solutions” Bring the Tris to
desired pH
3.
Weigh out the NaCl. Add into the Tris
4.
Weigh out MgSO4, add to buffer
5.
Weigh out and add gelatin after calculating how much gelatin is required to make 1% in 1 liter.
TE BUFFER
 TE Buffer is made by combining:
10 mM Tris, pH 7.6
1 mM Na2-EDTA
1.
Decide how much you would like to prepare . We will prepare 100mL in this example
2.
Determine how much Tris and Na2-EDTA is required to properly dissolve by referring to
the product label and the proper stock solution of each one. In this case Na2-EDTA is
dissolved at 0.5M stock solution; tris 0.1M stock solution.
3.
Calculate how much Tris is required using C1V1=C2V2
(0.1M)(x)=(0.010M)(100mL); x= 10mL
Calculate how much Na2-EDTA is required using C1V1=C2V2
(0.5 M)(x)=(0.001M)(100mL); x=0.2mL= 200µL
4.
Combine 10mL trist stock, 200uL Na2-EDTA stock and bring to final volume 100mL with
water.
5.
Check pH