Processing kodak motion picture films, module 3 analytical procedures

Potentiometric Determination of Kodak Color Developing Agent, CD-3 In Reversal Color
Developers
ECR-125F
Process ECN-2 ECP-2D VNF-1/LC RVNP
Formulas — — DR-150/151 DR-150
INTRODUCTION
The KODAK Developing Agent, CD-3, is extracted into a
butyl acetate solvent layer from a sample of developer. The
CD-3 in the solvent layer is then extracted with dilute
sulfuric acid and titrated with sulfato cerate.
A surfactant (polystyrene sulfonate) is added to minimize
the formation of emulsion layers during the extraction of
developing agent. Occasionally a narrow emulsion layer is
present. If the layer is not transferred to (or with) the sulfuric
acid, no significant error is introduced. Our experience
shows that by using polystrene sulfonate we have slightly
better precision and fewer emulsion problems with seasoned
samples.
An exhaust hood is recommended when using butyl
acetate but is not an absolute necessity. Impervious
Extraction gloves, safety glasses, and observance of local
safety regulations are necessary.
This method requires handling potentially hazardous
chemicals. Consult the Material Safety Data Sheet for each
chemical before use. MSDS's are available from your
chemical supplier.
RELIABILITY
The 95 percent confidence limits for an individual
determination are ± 0.17 g/L for fresh solutions. The limits
are based on 9 data points using standard mixes containing
from 9.00 to 13.00 g/L CD-3.
An empirical calculation is used for the procedure. The
procedure is about 5.O percent low from weighed amounts
of CD-3 in fresh solutions. The empirical calculation was
derived from a 2 variable linear regression of the data. An
empirical calculation was used to compensate for the bias
from weighed amounts of assayed CD-3 when a
stoichiometric calculation is used. When standard additions
of 1 g/L CD-3 were made to seasoned samples, the average
recovery was 96.3 percent.
SPECIAL APPARATUS
pH Meter or Automatic Titrator
Reference Electrode, Double Junction, Orion No. 900200
or equivalent
Indicator Electrode, Platinum Inlay/Disc, Beckman No.
39273 or equivalent
Exhaust Hood
Note: Use pipets and volumetric glassware meeting the
“Class A” definition by the National Institute of Standards
and Technology (NIST).
REAGENTS
Use ACS Reagent Grade reagents unless specified
otherwise.
0.10 M Acidified Ferric Nitrate
0.1% Polystyrene Sulfonate
Butyl Acetate, CH 3 COO(CH 2 ) 3 CH 3 , technical grade
Ferroin Indicator
1.0 N Sulfuric Acid, H 2 SO 4
0.05N Sulfato Cerate, (NH 4 ) 2 Ce(NO 3 ) 6 ,
standardized to 4 decimal places
PROCEDURE
Extraction
1. Pipet (wipe the pipes before leveling) 25.O mL of tank
or replenisher sample into a 250-mL separatory funnel
No. 1.
2. Add 2 mL of 0.1% polystyrene sulfonate from a tip-up
pipes and mix by gently swirling the funnel for 10
seconds.
3. Add, from a tip-up pipes, 25 mL of butyl acetate.
Stopper and shake separatory funnel No. 1 for a few
seconds, then vent through the stopper. Continue to
shake vigorously for 30 seconds, venting occasionally.
4. Allow enough time for complete separation of the
phases.
Note: It may take longer for complete separation of the
phases in highly seasoned samples.
5. Transfer as completely as possible the lower (aqueous)
layer to another 250-mL separatory funnel, No. 2,
without losing any of the top layer containing the
developing agent.
6. Swirl separatory funnel No. 1 and drain any additional
lower (aqueous) layer that separates into separatory
funnel No. 2.
Note: Save the top (butyl acetate) layer in separatory
funnel No. 1.
Processing KODAK Motion Picture Films, Module 3, Analytical Procedures H24.03 1