User:Sarah Burkhard/Notebook/471 Nano Notebook/2016/09/21

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UV Vis round 3

pH 4 - 12

Fructose concentration : 0.75 mM, 1.25 mM

BSA stock solutions go 4 hours in oven, up to 80 C.

menu > hill icon > menu > choose program 1 > 1 loop

Solutions

0.75 mM Fructose
pH μL of 1 mM HClstock μL of 1 mM NaOHstock μL of 1 M NaOHstock μL of AuCl3stock μL of Fructosestock μL of BSAstock μL of Water
4 500 0 0 335 253 316 3596
5 50 0 0 335 253 316 4046
6 5 0 0 335 253 316 4091
7 0 0 0 335 253 316 4096
8 0 5 0 335 253 316 4091
9 0 50 0 335 253 316 4046
10 0 500 0 335 253 316 3596
11 0 0 5 335 253 316 4091
12 0 0 50 335 253 316 4046


1.25 mM Fructose
pH μL of 1 mM HClstock μL of 1 mM NaOHstock μL of 1 M NaOHstock μL of AuCl3stock μL of Fructosestock μL of BSAstock μL of Water
4 500 0 0 335 422 316 3427
5 50 0 0 335 422 316 3877
6 5 0 0 335 422 316 3922
7 0 0 0 335 422 316 3927
8 0 5 0 335 422 316 3922
9 0 50 0 335 422 316 3877
10 0 500 0 335 422 316 3427
11 0 0 5 335 422 316 3922
12 0 0 50 335 422 316 3877

Objective

Draw conclusions on the concentration of gold nano particles formed, and how the amount formed depends on 1) pH and 2) Fructose concentration. Concentration of nano particles is directly related to absorbance at the relevant wavelength.

Protocol

  1. If Necessary
    1. Turn on the instrument (if not already done)
    2. Turn on the computer (if not already done)
    3. Open the UVProbe software
    4. Get the computer talking to the instrument by clicking the "Connect Button"
  2. Set the measurement "Method"
    1. Click the icon, at the top, that is a yellow circle with a green "M"
    2. Set the wavelength endpoints
      1. Typical for our measurements are: 200 nm to 800 nm
    3. Set the spectrum resolution
      1. Typical for our measurements is 1 nm
    4. Set the acquisition speed/quality
      1. Typical for our measurements is Medium
    5. Set the data collection pathway and the name for the file that will contain every spectrum collected
      1. Change the directory to: C:\Users\Chem Lab\DropBox\CHEM471 2016\UV Vis\Year\Month\Date
      2. Set the filename to something descriptive for all of the samples to be collected
  3. Baseline the detector
    1. Option A
      1. Fill the cuvette you will use for the rest of the measurements with the solvent that suspends your analyte
      2. Place the cuvette in the proper holder in the instrument, making sure that light will pass through 2 clear windows
      3. Click "Baseline"
    2. Option B
      1. Don't place a cuvette in the holder at all
        1. Going this route will require you to take a spectrum of your solvent as a blank. You will have to correct all of your subsequent spectra for your solvent's spectrum. This is the best option when there are multiple users on the same instrument during a single day
      2. Click "Baseline"
  4. Collect data
    1. Place a sample in a properly cleaned cuvette
    2. Place the cuvette in the proper holder making sure that light will pass through two transparent cuvette windows
    3. Click "Start"
  5. Saving data
    1. When the spectrum has been acquired and the instrument has reset itself to its "start" position, you can save your data.
    2. Save data in a format readable by the instrument (.spc files)
      1. From the Menu, select "File > Save As"
      2. Give your file a name that is representative of that particular sample (include descriptors for identity, concentration, or any other important variable)
      3. Click "Save"
    3. Save data in a format readable by analysis software on your computer (.txt files)
      1. From the Menu, select "File > Save As"
      2. Change "Save as type" to "Data Print Table"
      3. Your filename from the previous step will be conserved. Only the file extension will change.
      4. Click Save
    4. Repeat as necessary
  6. Shutting down the instrument
    1. Click the "Disconnect" button at the bottom of the screen
    2. Close out of the software (if at the end of the day)
    3. Shut down the computer (if at the end of the day)
  1. Open the "Q Blue Wireless Temperature Controller" by clicking its icon on the desktop
  2. Set the Temperature
    1. Set the Control Status to "On"
    2. Input your desired temperature
      1. Click "Change" for the Target Temperature and type in the temperature you want for the experiment
      2. For most nanoparticle syntheses, the temperature is 80C
  3. Set the stirring
    1. If you need stirring, and have a stir bar in your cuvette, set the stirrer to "On"


Data Analysis

The chart below shows the absorbance scans across 200-800 nm for pH 4-12 with fructose concentration 0.75 mM.

160921 UVVIS 0.75.PNG

The chart below shows the absorbance scans across 200-800 nm for pH 4-12 with fructose concentration 1.25 mM.

160921 UVVIS 1.25.PNG

The chart below shows the A(530) for pH 4-12 with fructose concentration 0.75 mM.

160921 A530 0.75.PNG

The chart below shows the A(530) for pH 4-12 with fructose concentration 1.25 mM.

160921 A530 1.25.PNG

Notes

pH 11 and 12 seem transparent for both fructose concentrations. This is contradicting our hypothesis from last week, that higher concentrations of fructose facilitate the formation of Au nano particles at higher pH. See last week's observations here.