MIL-PRF-87930B
APPENDIX B
CHLORIDE
B.1 SCOPE
B.1.1 Scope. This Appendix describes two methods for the determination of chloride content of
the propellant. This Appendix is a mandatory part of the specification. The information contained herein
is intended for compliance.
B.2 METHODS
B.2.1 Specific ion electrode method.
B.2.1.1 Procedure. Rinse the propellant residue container in one vessel from 4.3.7 with a 5 mL
aliquot of 1N sulfuric acid (H2SO4). Briefly stir and heat the liquid to boiling and cover with an inverted
watch glass to prevent the condensate from escaping. Transfer the solution to a 25 mL volumetric flask.
Rinse vessel with a second 5 mL aliquot of acid followed by one 5 mL aliquot of purified water. Combine
the aliquots in the 25 mL volumetric flask and add two to three drops of bromocresol green indicator.
Dropwise titrate the contents of the flask to a green endpoint with 1N sodium hydroxide (NaOH) and dilute
to the mark with purified water. Mix the solution and transfer approximately 10 mL to a 25 mL beaker.
Immerse the electrodes in the sample solution and record the millivolt reading. Compare the millivolt
reading from the sample to a calibration curve prepared from chloride standards and record the
concentration (ppmv) of the sample.
B.2.1.2 Calibration. Add 50 mL of purified water plus one drop of 0.1 N H2SO4 to each of five
100 mL volumetric flasks. Then add 0.5, 1.0, 2.5 and 5.0 mL of a 1000 ppm chloride standard
sequentially to four of the five flasks. Add 2-3 drops of bromocresol green indicator to each of the five
flasks and if necessary adjust with 0.1 N H2SO4 or 0.1N NaOH to obtain a green endpoint. Dilute each to
the mark with purified water and mix the solutions thoroughly. The calibration standards are equivalent to
-
a blank, 5, 10, 25 and 50 ppm Cl respectively. Pour enough of the standards into a small beaker to cover
-
the electrode tips and record the resulting millivolt reading. Prepare a calibration curve of Cl
-
concentration to mV and use this to determine Cl concentration in the sample.
B.2.1.3 Calculation. Calculate the percent chloride in the sample using the following formula:
(���� ��-)(�� )
%�� =
-
�� �(�)(1 × 104)
�
�� = Final dilution volume taken from NVR residue in mL.
where,
� = Volume of propellant used in NVR analysis in mL.
�
� = Density of H-70 (1.03 g/mL).
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