Project Summary
Original Protocol
- Prepare at least 5 mL of 15 mg/mL BSA in deionized water.
- Prepare at least 5 mL of 5 mM Mercury (II) nitrate in deionized water.
- Pour 5 mL of the BSA solution into a 25 mL round bottom flask; stir this solution in the hood.
- Vortex the mercury solution (to help the compound dissolve) and add 5 mL of the solution to the round bottom (while stirring).
- Add a few drops of 1 M NaOH to the stirring mixture to achieve ~pH 9. (I most commonly ended up with a pH of 10).
- Allow 8-12 hours to pass.
- Prepare 5 mL of 20 mM sodium sulfide.
- Add 4 mL of 20 mM sodium sulfide to the round bottom (while stirring).
- Allow 15 minutes to pass
- Transfer to a larger round bottom flask and rotovap the solution with a water bath set to ~40°C.
- Once completely dry (a thin film will develop along the sides of the flask), remove from the rotovap.
- Slowly add a few mL of DI water while gently swirling the round bottom flask. First, a hydrogel network should form along the sides of the glass as the film rehydrates.
- Slowly add more DI water until the hydrogel detaches from the glass and collapses into sol-gel structures suspended in solution.
"Quick" Protocol (15 min Synthesis)
- Prepare at least 5 mL of 15 mg/mL BSA in deionized water.
- Prepare at least 5 mL of 5 mM Mercury (II) nitrate in deionized water.
- Prepare 5 mL of 20 mM sodium sulfide.
- Pour 5 mL of the BSA solution into a 25 mL round bottom flask; stir this solution in the hood.
- Vortex the mercury solution (to help the compound dissolve) and add 5 mL of the solution to the round bottom (while stirring).
- Add a few drops of 1 M NaOH to the stirring mixture to achieve ~pH 9. (I most commonly ended up with a pH of 10).
- Immediately add 4 mL of 20 mM sodium sulfide to the round bottom (while stirring).
- Allow 15 minutes to pass
- Transfer to a larger round bottom flask and rotovap the solution with a water bath set to ~40°C.
- Once completely dry (a thin film will develop along the sides of the flask), remove from the rotovap.
- Slowly add a few mL of DI water while gently swirling the round bottom flask. First, a hydrogel network should form along the sides of the glass as the film rehydrates.
- Slowly add more DI water until the hydrogel detaches from the glass and collapses into sol-gel structures suspended in solution.
Note: These solutions have a tendency to bump on the rotovap. Watch carefully and be ready to break vacuum temporarily in the beginning!
Filtration Protocol
I conducted vacuum filtration once using a membrane filter (Supor-450, 47mm, 0.45μm). This worked to separate the gels from the solution, however do not leave the product on the membrane to dry--it will get stuck the membrane.
Summary of Syntheses Attempted
Date
|
Batch
|
Reaction Temp (C)
|
Reaction Time (hrs)
|
Notes
|
Gel Formation?
|
9/9/2014 |
JCS 1 |
23 |
11.58 |
no heating |
Not Attempted
|
9/16/2014 |
JCS 2 |
41 |
|
mantle setting 11 |
Not Attempted
|
9/23/2014 |
JCS 3 |
37 |
13.5 |
mantle setting 10 |
Not Attempted
|
9/30/2014 |
JCS 4 |
23 |
11.5 |
no heating |
Yes (first discovery)
|
9/30/2014 |
JCS 5 |
50 |
11.5 |
mantle setting 14.5 |
Yes
|
10/7/2014 |
JCS 6 |
23 |
11 |
no heating |
Not Attempted
|
11/4/2014 |
JCS 7 |
23 |
|
no heating, BSA Control |
No (Structures did form but were noticeably different)
|
11/11/2014 |
JCS 8 |
23 |
7.5 |
Hg into BSA |
Not Attempted
|
11/11/2014 |
JCS 9 |
23 |
7.5 |
BSA into Hg |
Not Attempted
|
11/11/2014 |
JCS 10 |
Cold Room |
7.5 |
cold room synthesis- no change |
Not Attempted
|
11/18/2014 |
JCS 11 |
23 |
48 |
attempting gel formation again |
Yes
|
11/18/2014 |
JCS 12 |
23 |
48 |
attempting gel formation again |
Yes
|
1/22/2015 |
JCS 13 |
23 |
24 |
No Mercury |
No
|
1/29/2015 |
JCS 14 |
23 |
Over Weekend |
No Sodium Sulfide |
No (similar to BSA-only)
|
2/4/2015 |
JCS 15 |
23 |
24 |
No BSA |
No (black precipitate)
|
2/5/2015 |
JCS 16 |
23 |
15 minutes |
original protocol with changed timeline |
Yes
|
2/20/2015 |
JCS 17 |
23 |
15 minutes |
Decreased BSA conc (x10) |
No
|
Determining Sol-Gel formation factors
Sample
|
BSA
|
Mercury
|
NaOH
|
Sulfide
|
Overnight
|
Temp
|
Formed?
|
JCS13 |
X |
|
X |
X |
X |
Room |
No
|
JCS14 |
X |
X |
X |
|
X (over weekend) |
Room |
No
|
JCS15 |
|
X |
X |
X |
X |
Room |
No
|
JCS16 |
X |
X |
X |
X |
|
Room |
Yes
|
JCS17 |
X (decreased factor of 10) |
X |
X |
X |
|
Room |
No
|
|