Processing kodak motion picture films, module 3 analytical procedures

Cerimetric Determination of KODAK Color Developing Agent, CD-2, in Stop Bath
ECP-2-2010A
Process ECN-2 ECP-2D VNF-1/LC RVNP
Formulas — SB-14 — —
INTRODUCTION
Using this analytical procedure you can measure the amount
of KODAK Color Developing Agent, CD-2, carried into a
Process ECP-2D Stop Bath. The pH of the stop bath sample
is adjusted to the approximate pH of an ECP-2D developer,
using 6 N sodium hydroxide. The CD-2 is then extracted
with water-saturated ethyl acetate. The CD-2 in the solvent
layer is then extracted with sulfuric acid and titrated with
sulfato cerate, using an automatic titrator.
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
Three fresh and two seasoned samples of Process ECP-2
Stop Bath were analyzed by four analysts on two separate
days using multiple titrators. The samples were run in
duplicate on each day. The fresh samples were prepared at 1,
3, and 5 g/L CD-2.
The seasoned samples consisted of Process ECP-2 Stop
Bath from a processor, analyzed as received (at 2.22 g/L
CD-2) and with a standard addition of 0.428 g/L CD-2.
Customer Standard Deviation, 1s c
The customer standard deviation (1s c ) is an estimate of the
variability * a customer could expect when submitting a
sample to any Photoprocessing Quality Services laboratory,
where any trained analyst could test the sample using any
instrument on any day.
Samples (N)
Customer Standard
Deviation, 1Sc Fresh 1 g/L CD-2 16 0.052 g/L
Fresh 3 g/L CD-2 14 0.040 g/L
Fresh 5 g/L CD-2 15 0.091 g/L
Seasoned (mean = 2.22 g/L CD-2) 16 0.073 g/L
Seasoned (mean = 2.60 g/L CD-2) 16 0.048 g/L
* This assumes the customer laboratory meets the same certification
requirements as the Kodak laboratory that developed this method.
95 Percent Confidence Estimate
(not including bias)
The 95 percent Confidence Estimate (calculated using the
repeatability standard deviation) around a single test will
include the mean CD level 95 percent of the time.
Samples 95 Percent Confidence Estimate
Fresh 3 g/L CD-2 ± 0.086 g/L
Seasoned ± 0.156 g/L
Bias
Bias is a statistically significant deviation of the mean from
the known CD-2 level at the 95 percent confidence level. It
is determined for fresh samples only Bias is not determined
for seasoned samples, since the component concentration
level cannot be determined independently of the test method.
A statistically significant bias was found at all levels. A
low bias of 19 percent was found at the 1 g/L level. A low 10
percent bias was also found at both the 3 and 5 g/L level.
These biases are felt to be caused by air oxidation during pH
adjustment and less than complete extraction of the samples.
Recovery
Recovery is used instead of bias for seasoned samples, since
the component level cannot be determined independently of
the test method. It is defined as the calculated mean for the
seasoned sample with a standard addition of the component,
divided by the calculated mean for the seasoned sample plus
the actual amount of the standard addition. It is expressed as
a percentage.
The recovery of the standard addition sample was
statistically different from 100 percent, but was not
practically significant.
Processing KODAK Motion Picture Films, Module 3, Analytical Procedures H24.03 1