MIL-DTL-398D
4.7.7.3 Analysis of RDX samples and standards. Prior to the
analysis of either RDX samples or standards, the pumping of
mobile phase through the system shall be initiated at a flow rate
of 1.5 milliliters per minute. The HPLC system shall be allowed
to equilibrate at ambient conditions for approximately 10 minutes
or until the flow of mobile phase and the output reading on the
UV detector are stable. After the HPLC system has stabilized,
the sample loop on the HPLC injector system shall be filled with
an aliquot of the RDX sample or standard. Using either manual or
automated injection techniques, the aliquot of sample in the 20
microliter sample loop on the injector should be transferred to
the HPLC column. The peak area data from the HPLC chromatogram
for the HMX component in the samples and standards should be
calculated and retained using the data collection system (i.e.
computer, computing integrator, etc.).
4.7.7.4 Preparation and analysis of RDX calibration
standards. Calibration standards having the approximate
concentrations provided in Table IV shall be prepared. The RDX
and HMX used in the calibration standards shall have a minimum
purity of 99.9%. Prepare the calibration standards by weighing
the RDX and HMX components to the nearest 0.0001 gram in tared
250-ml glass volumetric flasks with ground glass stoppers. Add
approximately 100 milliliters of HPLC grade acetone to the
flasks. Cap the flasks and place the standards in an ultrasonic
bath for 10 minutes or until the RDX and HMX are completely
dissolved and uniformly mixed. Allow the standard mixtures to
cool to ambient temperature, and then fill to the mark of the
volumetric flasks using HPLC grade acetone.
TABLE IV.
Composition of the RDX/HMX Standards
RDX
HMX
Percent
Weight (grams)
Percent
Weight (grams)
96.0
0.4800
4.0
0.0200
89.5
0.4475
10.5
0.0525
83.0
0.4150
17.0
0.0850
Each calibration standard which is prepared shall be tested using
the conditions and methodology outlined in 4.7.7.1 and 4.7.7.3.
4.7.7.5 Preparation and analysis of RDX samples. Dry
approxio ately 1 gram of the RDX sample to be tested in an oven at
m
100 + 5 C for a minimum of one hour. Using an analytical
balance, weigh approximately 0.05 gram of the dried RDX to the
nearest 0.0001 gram in a clean, glass 30-ml bottle with a Teflon
lined lid. Add 25.0 milliliters of HPLC grade acetone to the
bottle using an automatic repipette. Cap the bottle and place
the samples in an ultrasonic bath for 10 minutes or until the RDX
is completely dissolved and the solution is uniformly mixed.
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