MIL-D-70436(AR)
centimeter (cm) and its absorbance determined at a wave length of
410 millimicrons. As reference, a similar cell containing
saturated ammonium acetate solution of the same concentration as
the sample solution shall be used. Since the cell which holds the
basic lead styphnate is not identical with the reference cell the
absorbance obtained as described above shall be corrected for the
difference in the amount of light which the two cells scatter and
absorb. To do this, both cells shall be filled with ammonium
acetate solution and the absorbance of the cell which originally
contained the basic lead styphnate solution shall be measured at a
wave length of 410 millimicrons. The percentage of basic lead
styphnate in the sample shall be calculated on a dry basis as
follows:
Absorbance of basic lead styphnate solution.
A
=
=
Absorbance of ammonium acetate solution.
B
Width of corex cell, cm.
D
=
M
=
Moisture content of sample obtained from 4.5.3 in percent.
Weight of sample.
W
=
Spectrophotometric factor. To determine the spectrophoto-
F
=
metric factor (F) weight a 0.1 gm sample of pure lead
styphnate quantitatively with 50 to 100 ml of diluted water
to a 500 ml volumetric flask, add 30 ml of saturated
ammonium acetate solution to the solution in the flask and
dilute to mark with distilled water. Using aliquots of the
solution, prepare five solutions of lead styphnate ranging
in concentration from .5 to 2.5 mg per 100 ml. Determine
the absorbance of each solution at 410 millimicrons.
Divide concentrations of lead styphnate for each of the
solutions by its corresponding absorbance value. The
average of the five quotients thus obtained shall be used
as the spectrophotometric factor (F) for the lead
styphnate.
4.5.5.2.2 Determination of normal lead styphnate (when
Extract the residue obtained in the barium nitrate
applicable).
determination with sufficient 5 ml portions of ammonium acetate
solution (saturated at about 25°C) until the washings are
calorless. Agitate each portion for about one minute, then allow
each portion to remain in contact with the residue for one
additional minute. Finally, wash the residue with water,
saturated with antimony sulfide, until the washings come through
clear. Reserve the crucible and residue for the tetracene
determination. Transfer the filtrate and washings quantitatively
to a 250 ml calibrated volumetric flask, the beaker washed
thoroughly with distilled water and diluted to the mark. Using a
calibrated pipette, transfer a 2 ml aliquot of this solution to a
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