User:Karlena L. Brown/Notebook/PVOH Research/2012/10/24

OBJECTIVES

• Make porphyrin solutions with varied SO₄^2- salts
• Take UV-Vis of porphyrin solutions with varied SO₄^2- salts

Porphyrin Salt Selection and Preparations

SO₄^2- salts used:Fe₂(SO₄)₃, Al₃(SO₄)₃, FeSO₄,& Na₂SO₄

Preparing 100mM Stock Solutions For Each Salt :

1. Obtain four clean 100mL volumetric flasks with stoppers
2. Measure out calculated amounts of each salt to establish 100mM concentration
3. Add varied salt amounts to each volumetric flask (one salt per flask)
4. Fill each volumetric flask ½ full with HPLC grade H₂O
5. Swirl each flask thoroughly for ~ 5 minutes to begin the dissolving process
6. Finish adding HPLC grade H₂O to each volumetric flask to line

(Ensure that the volumetric calibration line is not surpassed or solution must be remade.)

100mM Salt Solution Calculations

• 100mM Fe₂(SO₄)₃ Solution

  MW Fe2(SO4)3: 278.91 g/mol
  100mM Fe2(SO4)3 × (100mL H2O / 1000mL H2O) × (278.91g Fe2(SO4)3 / 1 mol Fe2(SO4)3) = 2.8791g Fe2(SO4)3
 

• 100mM Al₃(SO₄)₃ Solution

  MW Al3(SO4)3: 356.37 g/mol
  100mM Al3(SO4)3 × (100mL H2O / 1000mL H2O) × (656.37g Al3(SO4)3 / 1 mol Al3(SO4)3) = 6.5637g Al3(SO4)3
 

• 100mM FeSO₄ Solution

  MW FeSO4: 278.01 g/mol
  100mM FeSO4 × (50mL H2O / 1000mL H2O) × (278.01g FeSO4 / 1 mol FeSO4) = 1.3901g FeSO4
 

• 100mM Na₂SO₄ Solution

  MW Na2SO4: 142.04 g/mol
  100mM Na2SO4 × (100mL H2O / 1000mL H2O) × (142.04g Na2SO4 / 1 mol Na2SO4Na2SO4) = 1.4204g Na2SO4
 

UV-Vis Spectrum of Porphyrin with Salts

A specific porphyrin solution (944.5nM) was selected for exemplary UV - Vis analysis pertaining to each salt. Furthermore, 0.1mL each salt was combined with this particular porphyrin solution.

Notes

• Originally Al₃(SO₄)₃ was prepared at a 100mM concentration; however, this solution proved to be too concentrated for UV-Vis Analysis. The salt never fully dissolved into solution within the volumetric flask even with persistent heating. The solution remained very opaque and cloudy with precipitate falling out of solution.
• The FeSO₄ 100mM solution was actually prepared at a later date which is why it was not previously recorded on the UV-Vis spectrum presented regarding the 944.5nM porphyrin sample. Also for the FeSO₄ salt solution, it was prepared in a 50mL volumetric flask instead of a 100mL volumetric flask.