User:Monika Gasiorek/Notebook/CHEM-571 2014F/2014/09/24

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September 24, 2014 Bradford Analysis of Dialysis A Bradford analysis was done on the dialysis samples prepared and dialyzed last week. 600 µL of each soak solution were combined with 200 µL of Bradford reagent and 200 µL of a 50 mM Tris/NaCl buffer The soak solutions included: 50 mM NaCl stock solution with 3500 g/mol MWCO tubing 50 mM Glycine stock solution with 3500 g/mol MWCO tubing Pure water with 3500 g/mol MWCO tubing 50 mM Glycine stock solution with 25k g/mol MWCO tubing 50 mM Glycine stock solution with 3500 g/mol MWCO tubing 100 µL of the contents of each dialysis tubing was combined with 200 µL of Bradford reagent and 700 µL of Tris/NaCl buffer The respective dialysis bag contents were analyzed, all of which initially included 4 mL of 1g/L lysozyme stock solution, except for the very last system, in which 4.0 mL of 36.5 [Au]:[Lys] colloid solution was used in the place of lysozyme against the 50 mM glycine soak with 3500 tubing NOTE: As mentioned previously, the contents of the tube in the fourth system (50 mM glycine solution with 25K g/mol MWCO tubing) were lost during transfer; thus, only four tubing samples are included in the results. Solution Conc of Lysozyme (µg/mL) Abs 3500 NaCl Soak -3.344660194 0.028 3500 H2O Soak -3.975728155 0.015 3500 Gly Soak 2.529126214 0.149 25k Gly Soak -0.09223301 0.095 3500 Gly Colloid 1.703883495 0.132 3500 NaCl/Lys Bag 17.91747573 0.466 3500 H2O/ Lys Bag 18.54854369 0.479 3500 Gly/Lys Bag 20.05339806 0.51 3500 Gly/Coll Bag 2.82038835 0.155 NOTE: Negative concentrations of protein in the soak solutions may be a result of protein precipitation. CaCl2 Conductivity A hard water probe sensitive only to specific polyvalent cations such as Ca2+ was used to measure the conductivity in mV of 5 solutions of CaCl2 of various concentrations. 0.11098 g of CaCl2 was dissolved in 20 mL of water, making a 50 mM CaCl2 solution. 2 mL of this solution was then diluted with 18 mL of water to make the next serial dilution. This step was repeated 3 more times. Concentration Conductivity (mV) 5 µM (-4.1) 50 µM 7.3 0.5 mM 36.1 5 mM 63.6 50 mM 87.8 NOTE: The results were graphed with conductivity as a function of the log of CaCl2 concentration.