Processing kodak motion picture films, module 3 analytical procedures

Colorimetric Determination of Thiocyanate in KODAK Reversal First Developer,
Process D-94
D94-0003/1
Process ECN-2 ECP-2D VNF-1/LC RVNP B/W Reversal
Formulas — — — — D94/D95R
INTRODUCTION
This method describes the spectrophotometric determination
of thiocyanate contained in a KODAK Reversal First
Developer, D-94 between 3.0 and 12.0 g/L NaSCN
calculated as 100 percent salt. An aliquot of the sample is
reacted with acidified ferric nitrate reagent to produce a
red-colored ferri-thiocyanate complex. The absorbance of
this solution is measured at 460 nm on a spectrophotometer.
This absorbance value follows Beer's Law to yield a linear
relationship with thiocyanate concentration which can be
represented by the linear regression equation displayed in the
Calculation section.
Use of this method requires handling of potentially
hazardous chemicals. Material Safety Data Sheets should be
consulted for each chemical before use. These can be
obtained from each chemical supplier.
PRECISION AND BIAS
Repeatability
One fresh KODAK Reversal First Developer, Process D-94
tank sample was analyzed by one analyst on one day using
one spectrophotometer. The sample was analyzed three
times. The fresh sample was prepared at aim level (6.046 g/
L NaSCN as 100 percent salt). A seasoned tank sample was
analyzed in the same manner as the fresh sample. A standard
addition of 2.309 g/L, NaSCN was made to this seasoned
tank sample and the sample was analyzed in the same
manner as the fresh and seasoned samples. This sample was
analyzed five times.
Repeatability Standard Deviation, 1s r
This is an estimate of the variability one trained analyst
should be able to obtain under favorable conditions
(analyzing a sample with one instrument within a day).
Sample (N)
Fresh Tank
(prepared at 6.046 g/L
NaSCN)
Seasoned sample
(mean = 9.223 g/L NaSCN
as 100% salt)
Seasoned sample + addition
(mean = 11.568 g/L NaSCN
as 100% salt)
3
3
5
Repeatability Standard
Deviation, 1S r
0.011 g/L NaSCN
as 100% salt
0.15 g/L NaSCN
as 100% salt
0.033 g/L NaBr
as 100% salt
Bias
Bias is a statistically significant deviation of the mean from
the known analyte level at a 95 percent confidence level.
Bias is reported for fresh samples only, because the analyte
level in the seasoned samples was not determined by an
independent test method. Bias is based on the information
obtained in the repeatability study above.
A statistically significant low bias was found at the fresh
tank aim level. However, this bias was not practically
significant.
Recovery
Recovery is defined as a measure of the method's ability to
predict the amount of analyte in a seasoned sample,
containing a standard addition of the analyte. The percent
recovery is based on the information obtained in the
repeatability study described the Repeatability Standard
Deviation, 1s r section above.
Recovery =
[X(seas + know addition) – X(season)] 100
known addition
The recovery of the standard addition was not statistically
different from 100 percent.
Reproducibility
One fresh tank sample of KODAK Reversal First Developer,
Process D-94 was analyzed by four analysts on two separate
days using one spectrophotometer. The sample was analyzed
four times each day. The fresh sample was prepared at aim
level (6.003 g/L NaSCN as 100 percent salt). A seasoned
sample of KODAK Reversal First Developer, Process D-94
analyzed to be 5.972 g/L NaSCN as 100 percent salt, was
tested in the same manner as the fresh tank sample above.
One set of data was not used to calculate the statistics. The
data was rejected due to a possible dilution error.
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.
Sample (N)
Fresh tank
(prepared at 6.003 g/L NaSCN
as 100% salt)
Seasoned
(mean = 5.972 g/L NaSCN
as 100% salt)
Customer Standard
Deviation, 1S c
Processing KODAK Motion Picture Films, Module 3, Analytical Procedures H24.03 1
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0.060 g/L NaSCN
as 100% salt
0.048 g/L NaSCN
as 100% salt