Processing kodak motion picture films, module 3 analytical procedures
Processing kodak motion picture films, module 3 analytical procedures
Processing kodak motion picture films, module 3 analytical procedures
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Titrimetric Determination of EASTMAN Color Developing Agent, CD-2, in Process ECP-2<br />
Developer with Sulfato Cerate<br />
ECP-0003/1<br />
Process ECN-2 ECP-2D VNF-1/LC RVNP<br />
Formulas — SD-50/51 — —<br />
INTRODUCTION<br />
This method describes an <strong>analytical</strong> procedure for measuring<br />
EASTMAN Color Developing Agent, CD-2, in Process<br />
ECP-2 Developer. CD-2 in the aqueous developer sample is<br />
extracted with an organic solvent (butyl acetate). An<br />
inorganic salt (NaCI) and a surfactant (polystyrene<br />
sulfonate) are added to minimize the formation of emulsion<br />
layers during the extraction of CD-2. In seasoned samples,<br />
an emulsion layer is usually present. If the layer does not<br />
transfer to the sulfuric acid, no significant error is<br />
introduced. The CD-2 in the solvent layer is then backextracted<br />
with sulfuric acid. This acid layer can then be<br />
titrated with sulfato cerate, using either an automatic titrator<br />
to record a potentiometric end point or manually titrated<br />
using ferroin indicator, to detect the end point visually.<br />
The potentiometric titration is recommended over the<br />
visual end point titration. However, for those unable to use<br />
instrumentation, the manual titrimetric technique, using the<br />
visual ferroin indicator, is included. Judging end points with<br />
a visual color change, especially if the samples are highly<br />
seasoned and highly colored, can differ from person to<br />
person. The potentiometric method overcomes this problem<br />
because the end point is detected potentiometrically and<br />
displayed graphically by the titrator.<br />
For the potentiometric measurement, a METROHM<br />
Potentiograph, Model E536 or equivalent should be used.<br />
The potentiometric titration requires a platinum indicator<br />
electrode and a double-junction reference electrode.<br />
This method requires handling potentially hazardous<br />
chemicals. Consult the Material Safety Data Sheet for each<br />
chemical before use. MSDS's are available from your<br />
chemical supplier.<br />
PRECISION AND BIAS<br />
Repeatability<br />
To obtain the repeatability data, a single skilled analyst<br />
performed five (5) replicates on each of the following<br />
solutions during methods development (this procedure was<br />
performed by both potentiometric and visual end point<br />
detection):<br />
a. A “fresh” EASTMAN Color Films, Process ECP-2<br />
developer prepared with all components at their<br />
respective working tank aim concentrations<br />
(2.9590 g/L CD-2).<br />
b. A “seasoned” EASTMAN Color Films, Process ECP-2<br />
developer analyzed as received at 1.0537 g/L CD-2<br />
(potentiometrically) and 1.1041 g/L CD-2 (visually).<br />
c. The same “seasoned” solution as in number b, above,<br />
reanalyzed after making an <strong>analytical</strong>ly weighed,<br />
standard addition of 1.0216 g/L CD-2 for the<br />
potentiometric study and 1.0108 g/L CD-2 for the visual<br />
study.<br />
Reproducibility<br />
Three EASTMAN Color Films, Process ECP-2 developer<br />
samples were analyzed by four analysts, each using different<br />
titration stations, on two different days. Each analyst<br />
analyzed each sample by both the potentiometric and the<br />
visual end point technique. Duplicate analyses were<br />
performed on each sample, on each of the two days. These<br />
samples were:<br />
a. A “fresh” tank solution prepared at 2.9620 g/L CD-2.<br />
b. An EASTMAN Color Films, Process ECP-2 “seasoned”<br />
tank developer sample analyzed, as received, in the<br />
same manner as the “fresh” developer. The “seasoned”<br />
sample of EASTMAN Color Films, Process ECP-2<br />
developer, analyzed to be 2.5321 g/L CD-2<br />
potentiometrically and 2.568 g/L CD-2 visually.<br />
c. The same (as in #2, above) EASTMAN Color Films,<br />
Process ECP-2 “seasoned” tank developer sample<br />
reanalyzed in the same manner as the “fresh” developer,<br />
after a standard addition of CD-2 was made. A standard<br />
addition of 0.8406 g/L CD-2 was made to that<br />
“seasoned” sample for the potentiometric and visual<br />
calibration study.<br />
<strong>Processing</strong> KODAK Motion Picture Films, Module 3, Analytical Procedures H24.03 1