Processing kodak motion picture films, module 3 analytical procedures

APPARATUS
Spectrophotometer with a tungsten lamp
1-cm Silica Cell
All volumetric glassware should meet all Class A
specifications, as defined by American Society for Testing
and Materials (ASTM) Standards E 287, E 288, and E 969,
unless otherwise stated.
REAGENTS
All reagents should be ACS Reagent Grade unless otherwise
specified.
KODAK Anti-Calcium, No. 4
Molybdenum Reagent
1.0 N Sulfuric Acid, H 2 SO 4
PROCEDURE
A. Treatment of Sample
1. Add, from a tip-up Pipet, 5 mL of KODAK Anti-
Calcium No. 4 to a 100 mL volumetric flask
containing a magnetic stir bar. (Allow 15 seconds for
the tip-up pipet to drain.)
2. Start stirring moderately. Pipet (wipe the pipet before
leveling) 3.00 mL of Color Developer solution into
the flask.
3. Set, but do not start, a timer for five minutes.
4. Add, from a tip-up pipet, 10 mL of molybdenum
reagent to the flask. Immediately start the timer.
5. To the flask, add, from a graduated cylinder, 80 mL of
1.0 N sulfuric acid that is at room temperature
(20.0°C-24.0°C).
6. Remove the stirring bar and dilute the solution to its
final 100.0 mL volume with 1.0 N sulfuric acid.
7. Stopper the flask and invert it five times to complete
mixing.
B Absorbance Measurement
1. Zero the spectrophotometer vs. air.
2. After four minutes have elapsed, rinse and fill a 1-cm
silica cell with the molybdenum blue solution
(Step A.7, above).
3. Place the cell in the sample compartment of the
spectrophotometer and measure the solution
absorbance at 725-nm (AR) at exactly five minutes
after the addition of the molybdenum reagent in
Step A.4, above. Record the absorbance.
Note: Do not place the cell in the spectrophotometer for
longer than one minute.
CALCULATIONS
y=mx+b
Definition of the equation is found in the Regression section
of Appendix A.
Where:
mg/L RA-1 = m (A 725 )+b
Each laboratory should establish its own regression equation
based on a set of calibration standards. Appendix A explains
this calibration procedure. The regression equation may be
different for each spectrophotometer. A typical regression
equation line for the effluent is described by the following
equation:
Example:
m = slope of the calibration line
[(mg/L) RA-1 / ABU @725 ]
A 725 = Absorbance of sample at 725 nm
b = the intercept of the calibration line
with the y-axis (mg/L RA-1)
mg/L RA-1 = 143.3 (A 725 ) – 4.355
A 725 = 0.847
mg/L RA-1 = 143.3 (0.847) - 4.355
= 117.0
Processing KODAK Motion Picture Films, Module 3, Analytical Procedures H24.03 3