Week 15 (Iron Content) Flashcards
Beer’s Law
-relates light absorbance to concentration
-A=εbc
-A= absorbance (au) (increases when c increases)
-ε= molar absorptivity (1/Mcm)
-b= path length (usually 1 cm)
-c= concentration (M)
Standard curve
-takes known x values (concentration) and plots relevant measurements on y-axis
-can be used to predict measurements that have not been made experimentally
-y=mx+b -> A=εbc, where A=y, c=x, m=εb
Selected Event Mode (SpectroVis)
-measures absorbance at a specified wavelength without scanning other wavelengths
-typically between 0-1
Ferritin
-human ferritin is a hollow protein sphere containing 24 identical peptide units
-ferritin= apoferritin + iron core
-a single ferritin can hold up to 4,500 iron atoms in iron core
Apoferritin
-an empty ferritin shell (without iron core) with molar mass of 474,000 g/mol
iron core (ferrihydrite)
-FeO(OH) or [FeO(OH)]₈[FeO(H₂PO₄)]
-molar mass= 879.7 g/mol
-insoluble salt
peptide bond
-covalent bond between amino acids formed by dehydration synthesis
-can be destroyed by strong acids or strong bases
Ferrozine
-bidentate ligand, connects at 2 places
-binds with Fe(II) to form intense purple complex (allows it to be detected at very low concentrations)
-only forms complex with Fe(II), not Fe(III)
Fe(III) vs Fe(II)
-Iron is readily oxidized to Fe(III) by exposure to atmosphere
-Fe(III) is not usually soluble at pH of 7 (pH of human body/water), instead precipitates as iron hydroxide
-iron is stored as Fe(III) oxo-hydroxide structure in soluble ferritin protein
-ferrozine does not form complex ion with Fe(III), only Fe(II), so in order to measure iron content, Fe(III) must be reduced to Fe(II) by DHF
Blank vs Regular solution
-blank will contain everything except thing being measured/creates color (ferritin)
M₁V₁ = M₂V₂
-Dilution Calculator
-M= molarity (mol/L)
-V= volumes
