Processing kodak motion picture films, module 3 analytical procedures

Potentiometric Determination of Sodium Chloride in EASTMAN Color Films, Persulfate
Bleach
ECN-0009/1
ECP-0009/1
Process ECN-2 ECP-2D VNF-1/LC RVNP
Formulas SR-31 SR-30 — —
INTRODUCTION
The chloride concentration of an Eastman Color Films,
Process ECN-2 or ECP-2D persulfate bleach sample is
determined by potentiometric titration with silver nitrate
solution after acidification with acetic acid. See Figure 1,
Chloride Titration Curve for ECN-2 Persulfate Bleach, and
Figure 2, Chloride Titration Curve for ECP-2D Persulfate
Bleach, for typical titration curves.
This method was developed using a 50-mL burette. If a
20-mL burette is utilized, the burette will refill at 20 mL,
depending on sample chloride concentration. No studies
have been performed to determine the impact of this
substitution.
Use of 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.
PRECISION AND BIAS
Repeatability Standard Deviation, 1sr & 95 Percent
Confidence Estimate (not including bias)
Repeatability standard deviation is an estimate of the
variability one trained analyst should be able to obtain under
favorable conditions (analyzing a sample, with one
instrument, within one day).
The 95 percent confidence estimate (calculated using the
repeatability standard deviation) around a single test will
include the mean value 95 percent of the time.
To obtain the repeatability data, the analyst who
developed this method performed five (5) replicates on each
of the following solutions:
1. A “fresh” persulfate bleach prepared with all
components at their respective aim “working tank”
concentrations:
15.052 g/L NaCl for Process ECN-2
15.016 g/L NaCl for Process ECP-2D
2. A “seasoned” persulfate bleach analyzed, as received at:
17.547 g/L NaCl for Process ECN-2
23.021 g/L NaCl for Process ECP-2D
3. The same “seasoned” solution as in number 2, above,
reanalyzed after making a standard addition of:
5.291 g/L NaCl for Process ECN-2
6.943 g/L NaCl for Process ECP-2D
Samples
(Process
ECN-2)
“Fresh” at
“Aim”
(15.052 g/L
NaCl)
“Seasoned”,
as received
“Seasoned”
with
Standard
Addition
Samples
(Process
ECP-2D)
“Fresh” at
“Aim”
(15.016 g/L
NaCl)
“Seasoned”,
as received
“Seasoned”
with
Standard
Addition
Mean
(g/L NaCl)
Bias
Bias is a statistically significant deviation of the mean from
the known mix level at a 95 percent confidence level. It is
determined for “fresh” samples only. Bias is not determined
for “seasoned” samples, since the component concentration
level was not determined independently of the test method.
A statistically significant positive bias for NaCl of
(0.16 percent) was found for a Process ECN-2 “fresh”
persulfate bleach tank sample. However, this bias was
judged not to be practically significant.
A statistically significant negative bias for NaCl of
(-0.37 percent) was found for a Process ECP-2D “fresh”
persulfate bleach tank sample. However, this was judged not
to be practically significant.
Processing KODAK Motion Picture Films, Module 3, Analytical Procedures H24.03 1
(N)
Repeatability
Standard
Deviation, 1S r
(g/L NaCl)
95 Percent
Confidence
Estimate
(g/L NaCl)
15.076 5 0.018 ± 0.05
17.547 5 0.050 ± 0.14
22.815 5 0.015 ± 0.04
Mean
(g/L NaCl)
(N)
Repeatability
Standard
Deviation, 1S r
(g/L NaCl)
95 Percent
Confidence
Estimate
(g/L NaCl)
14.961 5 0.040 ± 0.11
23.021 5 0.024 ± 0.07
29.855 5 0.022 ± 0.06