Processing kodak motion picture films, module 3 analytical procedures

PROCEDURE
Treatment of the Sample
1. Pipette 5.0 mL of the bleach into a 250-mL beaker
containing approximately 100 mL of reagent water.
2. Add 10 mL of glacial acetic acid to the beaker.
Titration
1. 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 silver electrode.) Set the stirrer
speed to stir rapidly without splashing or creating a
vortex.
2. Titrate the sample, through the first break, on an
automatic titrator with standardized 0.05 N silver
nitrate. Use a silver billet as the indicator electrode and
a double junction reference electrode. If using a
METROHM titration system, the following settings
should be used:
Horizontal chart span = 500 mV
Maximum titration speed
(min/100% volume)
= 15
Stop (%U) = OFF
Vertical chart span (mm/100% volume) = 400
Auto control = OFF
Titration mode = mV/pH
Titration “breaks” from = right to left
3. Determine the end point using the concentric arcs
method. (Refer to Universal Method ULM-0003-01,
Potentiometric Titrations for Photoprocessing
Solutions, or any subsequent revisions.) See Figure 1,
Chloride Titration Curve for ECN-2 Persulfate
Bleach, and Figure 2, Chloride Titration Curve for
ECP-2D Persulfate Bleach.
Figure 1 Chloride Titration Curve for ECN-2 Persulfate
Bleach
F002_0966AC
Figure 2 Chloride Titration Curve for ECP-2D
Persulfate Bleach
Processing KODAK Motion Picture Films, Module 3, Analytical Procedures H24.03 3
150 mV
150 mV
0 mV
0 mV
5 10 15 20 25 30 35 40
mL 0.05 N AgNO
3
5 10 15 20 25 30 35 40 45
mL 0.05 N AgNO
3
F002_0965AC