Processing kodak motion picture films, module 3 analytical procedures

Calculations
a. Range: 0.5–2.5 g/L Iron (II) (100 µL)
Iron (III)
Calculation:
Iron (II), g/L = 5.40 (A 510 ) – 0.27
b. Range: 2.5–12.5 g/L Iron (II) (50 µL)
Calculation:
Iron (II), g/L = 25.66 (A 510) – 0.69
Iron(III), g/L - Total Iron, g/L - Iron(II), g/L
APPENDIX 1
Determination of the Absorptivity of the
Iron-Thiocyanate Complex
Reagents
Distilled water
Ammonium Thiocyanate, 200 g/L
Potassium Persulfate, 40 g/L
Ferric Nitrate, 9-hydrate, ACS reagent grade
Potassium Iodide
Hydrochloric Acid, concentrate
Starch indicator
Sodium Thiosulfate, 0.1 N standardized to
4 decimal places
Nitric Acid, 0.1 N
Procedure
1. Weigh 9.0 g of Ferric Nitrate, 9-hydrate, ± 0.001 g,
and transfer to a 250-mL volumetric flask. Dissolve
and dilute to volume with distilled water. Invert
several times to mix. This solution is labeled as
5g/LFe.
2. Prepare a blank by adding 25 mL 2.5 N Sulfuric Acid,
10 mL 40 g/L Potassium Persulfate, and 25 mL 200 g/
L Ammonium Thiocyanate to a 100-mL volumetric
flask. Swirl to mix. Dilute to volume with distilled
water. Invert several times to mix.
3. Rinse a clean 1-cm silica cell several times with the
blank solution and then fill the cell with the blank
solution. Clean (with distilled water) and dry (with a
tissue) the outer faces of the cell.
4. Zero the spectrophotometer at 474 nm vs air.
5. Place the cell containing the blank in the sample cell
compartment. Read the absorbance at 474 nm. This is
Ablk .
6. Pipet 5.0 mL of the 5 g/L Fe solution prepared in step 1
into a 500-mL volumetric flask. Dilute to volume with
0.1 N Nitric Acid. Invert several times to mix.
7. To a 100-mL volumetric flask, add 25 mL 2.5 N
Sulfuric Acid and 10 mL of 40 g/L Potassium
Persulfate. Swirl to mix.
8. Pipet 3.0 mL of the solution from step 6 into the
volumetric flask from step 7. Swirl to mix.
9. Add 25 mL of 200 g/L Ammonium Thiocyanate to the
100-mL volumetric flask. Swirl to mix. Dilute to
volume with distilled water. Invert several times to
mix.
10. Remove the sample cell containing the blank from the
spectrophotometer. Rinse the cell several times and fill
with the solution from step 9. Clean the outer faces of
the cell with distilled water and dry with a tissue.
11. Determine the absorbance of the solution in step 10 at
474 nm vs air. This is AStd #1 .
Processing KODAK Motion Picture Films, Module 3, Analytical Procedures H24.03 3