Processing kodak motion picture films, module 3 analytical procedures

APPARATUS
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.
1.0-cm silica cell
2.0- and 3.0-mL pipettes
100- and 250-mL volumetric flasks
Double-beam spectrophotometer, equipped with a
tungsten light source (i.e., Shimadzu Model UV160U)
REAGENTS
Use ACS Reagent Grade reagents unless otherwise
specified.
Nitric Acid, HNO 3 (5.0 N)
Potassium Persulfate, K 2 S 2 O 8 (40 g/L)
Ammonium Thiocyanate, NH 4 SCN (200 g/L)
Water, Type I Reagent-This method was developed, and
the resulting statistical data were obtained using reagent
water equivalent to or purer than Type I Grade, as defined
in ASTM Standard D 1193. Other grades of water, e.g.,
reverse osmosis (RO), demineralized, or distilled water,
may give equivalent results, but the effects of water
quality on method performance have not been studied.
PROCEDURE
1. Zero the Spectrophotometer
a. Adjust the wavelength on the spectrophotometer
to 477 nm.
b. Zero the spectrophotometer vs air.
2. Blank
a. Prepare a blank solution by adding 10 mL of 5 N
nitric acid, 1 mL of 40 g/L potassium persulfate,
and 25 mL of 200 g/L ammonium thiocyanate to
a 100-mL volumetric flask.
b. Swirl to mix reagents, dilute to the mark with
reagent water & invert 6 to 10 times to mix.
c. Rinse a clean, 1-cm silica cell 3-5 times with
blank solution from step b and fill the silica cell
with the blank. Rinse the outer surfaces of the
cell with reagent water and wipe dry with a
tissue. Place the cell into the sample beam cell
holder of the spectrophotometer.
d. Read the absorbance of the blank within
2 minutes at 477 nm vs. air as (ABSblk). e. Remove the silica cell and rinse 3 to 5 times with
reagent water.
3. Sample
a. Add approximately 200 mL of reagent water to
a 250-mL volumetric flask.
b. Pipette 2.0 mL of the sample into the 250-mL
flask. Fill to volume with reagent water. Invert
the flask 6 to 10 times to mix.
c. To a 100-mL volumetric flask, add 10 mL of 5 N
nitric and 1 mL of 40 g/L potassium persulfate.
Swirl to mix.
d. Pipette 3.0 mL of the diluted sample from step
3b, into the 100-mL flask.
e. Add 25 mL of 200 g/L ammonium thiocyanate
solution to the 100-mL flask, while swirling the
flask. Fill to volume with reagent water. Invert
the flask 6 to 10 times to mix.
f. Rinse the 1-cm silica cell 3-5 times with the
sample from step 3e, and then fill the silica cell
with the sample. Rinse the outer surfaces of the
cell with reagent water and wipe dry with a
tissue. Place the cell into the
spectrophotometer’s sample beam cell holder.
g. Record the absorbance of sample at 477 nm vs.
air as (ABSspl ). Absorbance should be recorded
within 2 minutes of sample preparation.
Note: When using a single-beam spectrophotometer, as
opposed to a double-beam spectrophotometer, the procedure
is the same. However, a new blank should be prepared for
each sample due to the instability of the blank.
Processing KODAK Motion Picture Films, Module 3, Analytical Procedures H24.03 3