Processing kodak motion picture films, module 3 analytical procedures

Back-Extraction of the Developing Agent
1. Add 100 mL of 1.0 N sulfuric acid to separatory funnel
No. 2 and swirl, rinsing the inside walls of the funnel.
Save the funnel contents for step 3.
2. Gently swirl separatory funnel No. 1 and discard, as
completely as possible, any lower (aqueous) layer that
separates, taking care not to lose any of the butyl
acetate layer.
3. Transfer the contents of separatory funnel No. 2 into
funnel No. 1.
4. Swirl the funnel for 30 seconds. Stopper the funnel;
invert and vent through the stopcock. Shake the
separatory funnel horizontally for a few seconds;
invert and vent through the stopcock. Continue to
shake vigorously for 30 seconds, venting 2 times.
5. Allow enough time for complete separation of the
phases.
Note: It may take longer for complete separation of the
phases in highly seasoned samples.
6. Transfer the lower (acid) layer from separatory funnel
No. 1 to a 250-mL beaker without losing any of the top
layer.
7. Swirl separatory funnel No. 1 and transfer any
additional lower (acid) layer that separates, as
completely as possible, into the beaker.
Titration of the Developing Agent with Sulfato
Cerate
Note: The end-point of the titration step can be determined
either potentiometrically (Step 1 below) or visually (Step 2
below).
1. Potentiometric Titration
a. Add 5 drops of ferroin indicator and a magnetic
stir bar to the 250-mL beaker (from steps 6 & 7
of the Back-Extraction of the Developing Agent
procedure).
Note: Do not omit the ferroin, it aids the definition of
the end point.
b. Set the following parameters, if using a
METROHM 536 titrator:
Titration mode mV/pH
Horizontal chart span 750 mV
Autocontrol OFF
Maximum titration speed 15 min/100% volume
Vertical chart span 400 mm/100% volume
Automatic titration stop
(U%)
c. Place the 250-mL beaker on the METROHM
titrator stand and add a magnetic stir bar. Place
the electrodes in the beaker. (NOTE: The titrant
delivery tip should be placed so that the titrant
flows past the reference electrode before the
platinum electrode.) Set the stirrer speed to stir
rapidly without splashing or creating a vortex.
Titrate the solution with standardized 0.05 N
sulfato cerate through the inflection.
d. Determine the end point using concentric arcs.
(Refer to Universal Method ULM-0003-01,
Potentiometric Titrations for Photoprocessing
Solutions, or any subsequent revisions.) Record
the end point as mL A.
e. Add 100 mL of 1.0 N sulfuric acid to a second
250-mL beaker containing a magnetic stir bar.
Add 5 drops of ferroin indicator.
f. Place the second beaker on the METROHM
titrator stand and titrate through the inflection
point with standardized 0.05 N sulfate cerate.
Record any measurable end point as mL B.
(This is the blank. This determination needs to
be performed only once, if a series of analyses
will be performed.)
Processing KODAK Motion Picture Films, Module 3, Analytical Procedures H24.03 5
OFF
Indicator electrode Platinum, BECKMAN,
Model 39373 or
equivalent
Reference electrode Double-junction
ORION, Model
900200 or equivalent