User:Matt Hartings/Notebook/AU Biomaterials Design Lab/2014/02/06: Difference between revisions
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==Objective== | ==Objective== | ||
To | # To prepare for the synthesis BSA-Zn<sub>m</sub>Mn<sub>n-m</sub>S<sub>n</sub> quantum dots using the protocol described [http://onlinelibrary.wiley.com/doi/10.1002/chem.201204035/abstract here]. We do not have a subscription to this journal. So ask me for a copy of the paper if you want one. | ||
# Today I'm also synthesizing cysteine-Zn<sub>m</sub>Mn<sub>n-m</sub>S<sub>n</sub> quantum dots using the procedure described [[User:Matt_Hartings/Notebook/AU_Biomaterials_Design_Lab/2014/02/03 | here]]. | |||
==Description== | ==Description== | ||
# Add | <b>1. BSA-Zn<sub>m</sub>Mn<sub>n-m</sub>S<sub>n</sub> quantum dot prep</b> | ||
<u>Solutions to be made</u> | |||
# BSA/NaBH<sub>4</sub> | |||
## Dissolve 4.14g of BSA in 60mL of water (That's 69 mg/mL BSA) | |||
## Add 0.4g NaBH<sub>4</sub> (That's 6.7 mg/mL NaBH<sub>4</sub>) | |||
## Stir until no more bubbles (H<sub>2</sub>) are generated. | |||
### Note NaBH<sub>4</sub> can be dangerous to work with see [http://en.wikipedia.org/wiki/Sodium_borohydride#Safety here] and [http://www.sciencelab.com/msds.php?msdsId=9924969 here]. | |||
### I will be doing all of the handling of this material until researchers add it to their reactions. | |||
#100mM Zn(CH<sub>3</sub>COO)<sub>2</sub> | |||
## FW = 219.49 g/mol | |||
## V = 50mL | |||
## mass to be measured = 1.0975g | |||
## actual mass = 1.0970g | |||
## actual concentration = 100 mM | |||
#10mM Mn(CH<sub>3</sub>COO)<sub>2</sub> | |||
## FW = 173.02 g/mol | |||
## V = 50mL | |||
## mass to be measured = 0.0865g | |||
## actual mass = 0.0870 | |||
## actual concentration = 10.1mM | |||
#100mM Na<sub>2</sub>S (Note: paper uses 0.25M) | |||
## FW = 240.18 g/mol | |||
## V = 50mL | |||
## mass to be measured = 1.201g | |||
## actual mass = 1.2060g | |||
## actual concentration = 100mM | |||
<u>Protocol</u> | |||
# Start preparing a 70C water bath | |||
# Add a stir bar to a 100mL round bottom flask | |||
# Add 1 mL of BSA/NaBH<sub>4</sub> to the flask | |||
# Add 2.25mL of Zn stock solution | |||
## Note: Solution will form a white precipitate upon addition of Zn<sup>2+</sup> | |||
# Add 2.5mL of Mn stock solution | |||
# Adjust the volume to 19mL using 13.25mL of water | |||
# Stir mixture | |||
# Adjust pH of solution to 9 with 1M NaOH | |||
## Note how much NaOH you ultimately use | |||
## Adding NaOH will help dispel the precipitate | |||
# Seal container with a rubber septum | |||
# Bubble N<sub>2</sub> through the sample for 20 minutes | |||
## Use the protocol we previously [[User:Matt_Hartings/Notebook/AU_Biomaterials_Design_Lab/2014/01/24 | developed]] | |||
# Add 2.5mL of Na<sub>2</sub>S solution | |||
# Put the reaction vessel in the water bath and stir for three hours | |||
# Store reaction mixture at 4C until later use. | |||
<b>2. cysteine-Zn<sub>m</sub>Mn<sub>n-m</sub>S<sub>n</sub> quantum dot synthesis</b> | |||
Note: [[User:Eleni_N._Kalivas/Notebook/CHEM-571/2014/02/05 | Eleni]], [[User:James_C._Schwabacher/Notebook/CHEM-571/2014/02/05 | James]], and Andrew ran this procedure yesterday. It took more than 60uL to bring the pH up to 11. While they were changing the pH, a clear precipitate formed in solution. Upon addition of 2 more mL of 1M NaOH, the precipitate dissolved back into solution, and the solution turned an orange'ish color. I also observed the presence of a black precipitate suspended in solution. When I run this today, I'm going to add NaOH drop wise until the original ppt goes away and then check the pH. | |||
# To a 250mL round bottom is added a stir bar and | |||
## 50mL of 20mM L-cysteine | |||
## 5mL of 100mM ZnSO<sub>4</sub> (0.5 mmol) | |||
## 5.437mL of 10.3mM MnCl<sub>2</sub> (0.056 mmol) | |||
### This is where the white ppt is observed | |||
## The pH of this mixture is adjusted to 11 with ~1M NaOH | |||
### The solution was added drop wise, and I used between 1.5 and 2.0mL before the ppt disappeared | |||
### After the ppt went back into solution, the pH was close to 11 and I stopped adding NaOH | |||
# This mixture is stirred N<sub>2</sub> for 30 minutes (started at 8:46am) | |||
# 5.505mL of 101mM Na<sub>2</sub>S is quickly added. (started at 9:20) | |||
# The solution is stirred for 20 minutes | |||
# The solution is then aged at 50C under air for 2 hours. (Started at 9:47) | |||
# The nano particles are purified through precipitation by ethanol and centrifuging at 5000rpm for 5 minutes | |||
## That's all they really say about this. I'm assuming it means: | |||
### The reaction mixture is cooled in an ice bath. | |||
#### I performed this step for 1 hour as I was busy with other things in lab/office | |||
### At least 200mL of chilled ethanol is added to the reaction mixture to precipitate the solid | |||
#### I began chilling this in the freezer as soon as I put the reaction in the 50C water bath. | |||
### I stopped at this point because my QDs did not precipitate out of solution. Will need to contact author. I tried ethanol as well as acetone (as I had seen in other reports) | |||
### I placed the tubes in the freezer | |||
### After about 10 minutes I did notice some precipitate. I'm going to let them ppt longer (overnight and collect them tomorrow). | |||
### The solid is collected by centrifugation (5 minutes at 5000 rpm) | |||
### The solid is re-dissolved in a minimum amount of cold water | |||
### The nanoparticles are precipitated through the addition of cold ethanol | |||
### Steps 4 and 5 are repeated once | |||
### The product is dried under vacuum and the product is stored in an inert environment. | |||
==Data== | ==Data== |
Revision as of 11:35, 6 February 2014
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Objective
Description1. BSA-ZnmMnn-mSn quantum dot prep Solutions to be made
Protocol
2. cysteine-ZnmMnn-mSn quantum dot synthesis Note: Eleni, James, and Andrew ran this procedure yesterday. It took more than 60uL to bring the pH up to 11. While they were changing the pH, a clear precipitate formed in solution. Upon addition of 2 more mL of 1M NaOH, the precipitate dissolved back into solution, and the solution turned an orange'ish color. I also observed the presence of a black precipitate suspended in solution. When I run this today, I'm going to add NaOH drop wise until the original ppt goes away and then check the pH.
Data
NotesThis area is for any observations or conclusions that you would like to note.
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