Processing kodak motion picture films, module 3 analytical procedures

APPENDIX A
Calibration of Spectrophotometer for Sodium
Thiocyanate
This Appendix should be used to establish the initial
calibration equation, whenever the instrument has been
adjusted, or to recheck the calibration (at least every six
months).
Preparation of Standards
A litre of fresh KODAK Reversal First Developer,
Process D-94 should be made containing all the constituents
of the mix at aim tank concentrations, except the sodium
thiocyanate. This solution will be referred to as the Minus
Mix.
1. For the sodium thiocyanate standards in D-94 Reversal
First Developer, weigh out 0.30, 0.60, 0.90, and 1.2 g
portions of assayed (assay procedure appears as
APPENDIX B) sodium thiocyanate to the nearest
0.0001 g.
2. Quantitatively transfer each portion of sodium
thiocyanate to 100-mL volumetric flasks, respectively
labeled with the corresponding weight, washing the
weigh boat with fresh D-94 Reversal First Developer
Minus Mix. Swirl the flasks to dissolve the sodium
thiocyanate.
3. When the sodium thiocyanate has dissolved, fill each
volumetric to the mark with the fresh Minus Mix.
Invert each flask, 6-10 times, to thoroughly mix the
solutions.
Analysis of Standards
1. Run each sample in (at least) duplicate by the method
described in the preceding Procedure.
2. Table of Data gathered from Analysis of Standards:
Standard (g/L NaSCN
as 100% salt)
ABS @ 460 rim
3.018 0.317
3.018 0 319
3.018 0.319
6.046 0.627
6.046 0.627
6.046 0.629
9.036 0.941
9.036 0.944
9.036 0.942
12.032 1.256
12.032 1.243
12.032 1.254
Regression
1. This data was processed by a least squares linear
regression to develop the line represented by equation,
y = mx + b:
Where:
2. The equation generated using the above data was:
3. The calibration equation was done in the following
manner on a (SHIMADZU Model UV 160 U)
spectrophotometer. Four fresh Reversal First
Developer, Process D-94 solutions were prepared (see
step 1 of Preparation of Standards). Each solution was
analyzed in triplicate to create a separate linear
regression, based on 12 data points, for each
spectrophotometer being used. The average standard
deviation (1s) for the linear regression was 0.012 g/L
NaSCN as 100 percent salt, corresponding to a
95 percent confidence estimate of ± 0.026 g/L NaSCN
as 100 percent salt. Each laboratory should calibrate
their spectrophotometer, otherwise an unknown bias
may exist.
APPENDIX B
Assay of Sodium Thiocyanate
This method was obtained from: Reagent Chemicals
American Chemical Society Specifications; Eighth Edition;
American Chemical Society: Washington, DC, 1993.
Reagents
Use ACS Reagent Grade reagents unless otherwise
specified.
0.1 N Silver Nitrate
Caution
Observe safety precautions for handling concentrated
acids. Wear eye protection and impervious gloves. Use
caution and always add acid slowly to water. Corrosive to
skin, metals, and clothing. Avoid contact with liquid and
vapor. Use in an exhaust hood.
Nitric Acid
y = g/L sodium thiocyanate as 100% salt
m = slope of the line or the relation between
absorbance and concentration determined
during calibration [(g/L)/absorbance]
x = net absorbance of the sample at 460 nm
b = the intercept of the calibration line with the
y-axis (in g/L sodium thiocyanate as 100% salt)
NaSCN, g/L as 100% salt = 9.65 (ABS @ 460 nm) – 0.07
Ferric Ammonium Sulfate Indicator Solution
Processing KODAK Motion Picture Films, Module 3, Analytical Procedures H24.03 3