User:Beatriz Gimenez De C./Notebook/571/2014/09/02

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Tasklist Prepare Stock Solutions 0.15 M NaOH prepared (3.00g of NaOH in 500 mL with DI water) + (NaOH is hygroscopic and the final concentration will not be able to be measured accurately/ it cannot be used as a primary standard) 200 μM isoleucine, aspartic acid, histidine, tyrosine and alanine stock solutions. 100 mL solutions were prepared. 200 μmol/L × 131.17 g/mol × 0.1 L = 0.00262 g of isoleucine (calculation for all solutions: 0.00266 g of aspartic acid, 0.00310 g of histidine, 0.00362 g of tyrosine, 0.00178 g of alanine) Standardize titrant Potassium Hydrogen Phthalate (KHPhth) standard for NaOH. (0.501 g of KHPhth +17 mL of water + titrated with NaOH stock solution + 5 drops of Phenolphthalein/indicator) Titration repeated two times + yielded same result Final concentration of NaOH = average of results from the three trials = 0.1485 M. Trial KHPhth in solution (g) NaOH titrated (mL) 1 0.501 16.70 2 0.518 17.10 3 0.519 17.10 Titrate Amino Acids Isoleucine (Hydrophobic) 0.3896 g of Isoleucine + 10 mL of DI water + 10 mL of 21 mM HCl -> initial pH 3.351. 0.1485 M NaOH stock solution titrated 2 mL intervals until pH reached around 10 + pH recorded every 2 mL (titration curve). Histidine It was suggested that amino acid solutions be made that would require 20 mL of NaOH to be titrated. 0.4608 g of Histidine + 10 mL of DI water + 10 mL of 21 mM HCl -> initial pH 2.538. 0.1485 M NaOH stock solution titrated 2 mL intervals until pH reached around 10 + pH recorded every 2 mL (titration curve). UV/VIS Spectra Fluorescence Spectra Collect data/sample from DSC