Processing kodak motion picture films, module 3 analytical procedures

Titrimetric Determination Of Benzyl Alcohol In Reversal Color Developers
ECR-1603E
Process ECN-2 ECP-2D VNF-1/LC RVNP
Formulas — — DR-150/151 DR-150
INTRODUCTION
The benzyl alcohol in the alkaline developer is oxidized to
benzoic acid with a solution of permanganate at room
temperature. The excess permanganate is reduced with
hydroxylamine sulfate in an acid solution and nitrogen is
bubbled through the treated sample to provide mixing. The
benzoic acid is extracted into butyl acetate which is then
washed with a saturated sodium chloride solution. Methanol
is added to the butyl acetate extract, and the single phase is
titrated with standardized sodium hydroxide.
Critical steps in the procedure are the bubbling with
nitrogen and the separations. Violent bubbling with foaming
may result in loss of sample. Because of this, a pipet is
preferable to a gas dispersion tube. It is also possible to use
a drawn-out glass tube. If the layers are drawn off too rapidly
and/or too soon after the shaking, they will be contaminated
and high results will occur. Any transfer of the aqueous
phase will also falsely increase the answer.
The butyl acetate should be used in an ignition-free
environment. Locally acceptable practices should be used
when discarding waste butyl acetate.
This method requires handling potentially hazardous
chemicals. Consult the Material Safety Data Sheet for each
chemical before use. MSDS's are available from your
chemical supplier.
RELIABILITY
Four standard mixes, containing 3.50, 4.00, 5.00, and 6.00
mL/L benzyl alcohol, were analyzed in duplicate by four
analysts. The 95 percent confidence limits for an individual
determination, based on these data, are ± 0.20 mL/L benzyl
alcohol.
Crossover data determined on seasoned tank samples,
between the previous version of this procedure (chloroform
as the extractant), and this procedure using butyl acetate,
indicates no significant differences.
SPECIAL APPARATUS
Gas pressure regulator and reducing valve
Note: The flowmeter should measure 0 to 15 L/min. The
regulator must be constructed to withstand a pressure of
3000 pounds per square inch.
Nitrogen cylinder (water-pumped nitrogen)
Note: “High purity” water-pumped nitrogen is not required
but can be used. Oil-pumped nitrogen (left-hand threaded
cylinder) cannot be used with the recommended regulator
valve (right-hand thread) but can be used if a left-hand
threaded regulator valve is available.
Exhaust hood
Note: All pipets and volumetric glassware should be
“Class A” as defined by NIST (National Institute of
Standards and Technology, formerly National Bureau of
Standards).
REAGENTS
All reagents are ACS Reagent Grade unless specified
otherwise.
0.41 M Potassium Permanganate, KMnO 4
2.5 M Hydroxylamine Sulfate, (NH 2 OH) 2 H 2 SO 4
18 N Sulfuric Acid, H 2 SO 4
Butyl Acetate, Reagent Grade
Sodium Chloride NaCl, Saturated solution
Methyl Alcohol containing Thymol blue
0.1 N Sodium Hydroxide, NaOH
(standardized to 4 decimal places)
Processing KODAK Motion Picture Films, Module 3, Analytical Procedures H24.03 1