Processing kodak motion picture films, module 3 analytical procedures

PROCEDURE
Treatment of the Sample
1. Pipet 50 mL of sample into a 250-mL beaker
containing 75 mL of distilled water and a Teflon
stirring bar.
2. Immerse the pH electrodes into the solution and turn
on the stirrer.
3. Adjust the pH of the solution to 4.5 ± 0.1, dropwise,
with Glacial Acetic Acid.
4. Rinse the electrode assembly with distilled water.
Collect all rinses in the beaker containing the sample.
Titration
1. Place the beaker containing the sample on a magnetic
stirrer. Turn on the stirrer and immerse the Platinum
indicator and double-junction reference electrodes into
the solution.
2. Add 10 drops of 0.001 N Ferrous Ammonium Sulfate
to the solution.
3. Wait 2 minutes for the electrodes to equilibrate.
4. If using a METROHM 536 titrator, adjust the
parameters to the following settings:
5. Titrate the sample with standardized 0.1 N Ferric
Ammonium Sulfate using a 20 mL buret.
6. Determine the equivalence point on the titration curve
using a concentric arcs template. (Refer to Universal
Method ULM-0003-01, Potentiometric Titrations for
Photoprocessing Solutions, or subsequent revisions.)
Calculations
where:
Automatic Titration Stop (stop % U) off
Vertical Chart Span (min/100% vol) 400
Automatic Titration Speed (auto control) off
Maximum Titration Speed (min/100% vol) 15
Titration Mode mV/pH
Horizontal Chart Span (mV) 250
Uncomplexed 1,3-PDTA g/L =
306 = equivalent weight of 1,3-PDTA
(mL titrant) (N titrant) (306)
mL sample
Figure 1 Typical Titration Curve of Free 1,3-PDTA in
ECN-2 ML Bleach
0 2 4 6 8
mL of 0.1000 N FERRIC AMMONIUM SULFATE
405 mv
F002_0942AC
Note: A seasoned solution may exhibit a slightly more
shallow curve shape due to extraneous components.
2 Processing KODAK Motion Picture Films, Module 3, Analytical Procedures H24.03
380 mv
355 mv
330 mv
305 mv
280 mv
255 mv
230 mv
205 mv
180 mv