Processing kodak motion picture films, module 3 analytical procedures

REPRODUCIBILITY
Customer Standard Deviation, 1sc and
95 Percent Confidence Estimate
Reproducibility, or customer standard deviation, (1sc ) 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.
The 95 percent confidence estimate (calculated using the
customer standard deviation) around a single test result will
include the mean value 95 percent of the time.
Three Process ECN-2 “UL” bleach samples were
analyzed by four analysts, on two different days. Duplicate
analyses were performed on each sample, on each of the two
days. These samples were:
1. Three fresh “UL” bleach samples were prepared with
all components at their respective working tank aim
concentrations.
2. A seasoned “UL” bleach sample was analyzed
spectrophotometrically, as received, at 0.078 g/L
iron (II).
3. The same “seasoned” solution, as in number 2, above,
was reanalyzed after, after making an analytically
weighed, standard addition of 0.229 g/L iron (II).
Sample N Mean
“Fresh” at
0.247 g/L
Iron (II)
“Fresh” at
0.492 g/L
Iron (II)
“Fresh” at
1.001 g/L
Iron (II)
“Seasoned”
as
Received
“Seasoned”
with
Standard
Addition
Iron II
Reproducibility
Standard
Deviation, 1s c
g/L Iron (II)
95 Percent
Confidence
Estimate
g/L Iron (II)
16 0.246 g/L 0.005 ± 0.010
16 0.493 g/L 0.007 ± 0.015
16 1.010 0.014 ± 0.029
16 0.078 g/L 0.005 ± 0.010
16 0.271 g/L 0.005 ± 0.011
Bias
Bias is a statistically significant deviation of the mean from
the known iron (II) level at a 95 percent confidence level. It
is determined for fresh samples only. Bias was not
determined for this sample since the component
concentration level was not determined independently of the
test method.
No statistically significant bias was found at all levels for
the Process ECN-2 “fresh” tank “UL” bleach samples
(–0.001 g/L for the 0.25 g/L sample, 0.001 g/L for the
0.492 g/L sample, and 0.009 g/L for the 1.001 g/L sample.
Recovery
Recovery is used instead of bias for seasoned samples, since
the component concentration level was not determined
independently of the test method. It is defined as the
calculated mean for the seasoned sample with a standard
addition of the component minus the mean for the seasoned
sample, divided by the actual amount of the standard
addition. It is expressed as a percentage.
The recovery of the standard addition sample was
84.28 percent and found to be statistically different from
100 percent at the 95 percent confidence level. However, it
was not practically different from 100 percent because the
seasoned solution result was below the calibration range of
the method. When the seasoned sample is in the calibration
range, the recovery of the standard addition is not
statistically different from 100 percent.
2 Processing KODAK Motion Picture Films, Module 3, Analytical Procedures H24.03