MIL-PRF-16005F
centrifuge tube again, and record this as the gross weight of the sample. Place the centrifuge tube in a
heavy walled 250 ml beaker to keep it upright, and the beaker in a plastic tub for secondary containment.
Reassemble the apparatus as shown in Figure 1. Using Calpico tape (or equivalent), secure the return
side of the PTFE tubing in the ullage of the centrifuge tube. If this tubing should come out, hydrogen
peroxide would be released into the secondary container. Ensure that the suction side of the tubing is
pushed to the bottom of the centrifuge tube. Fill the ice box with ice then add water to it so that it is a
slush, and ensure that the coil is oriented so that the inlet is at the bottom of the PVC form.
4.4.3.2.3.2 Decomposing the Sample. Turn on the peristaltic pump with a flow of about 0.5 ml
per minute. Observe the system until gas and liquid are seen returning to the centrifuge tube. This
should only be a matter of minutes from when the hydrogen peroxide reaches the coil. Allow the system
to run until no more bubbles are observed in the effluent stream. Typically, this will be accomplished if
the system runs overnight. An 8-hour work shift is not enough time.
4.4.3.2.3.3 Flushing the Apparatus. After the hydrogen peroxide has decomposed, remove the
suction end of the PTFE tubing from the centrifuge tube, and then increase the pump speed to about 10
ml per minute. Lift the coil out of the ice box and invert it so that the outlet of the coil is near the bottom of
the PVC form. Elevate the coil above the top of the centrifuge tube so that gravity assists the draining
process. Once the water has drained out of the coil, check the volume of water left after the reaction,
place 10 to 15 ml (make sure you do not exceed the capacity of the centrifuge tube) of reagent water
(ASTM D 1193 Type 1) in a clean beaker, and allow it to be pumped through the system. Allow the
reagent water to drain into the centrifuge tube. Shut off the peristaltic pump, remove the tubing, and then
apply a gentle gaseous nitrogen purge to the tubing to push out the last of the water. When the water
droplets stop coming out of the tubing, remove the nitrogen flow from the coil. Adjust the volume in the
centrifuge tube to the 50 ml mark with reagent water and label as decomposed solution.
4.4.3.2.3.4 Preparing the Blank Controls. Reconnect the tubing to the peristaltic pump, the coil
may be left inverted, and pump 50 ml of reagent water through the system into a centrifuge tube labeled
as a system blank. Fill a third centrifuge tube with the reagent water and label as a reagent blank.
4.4.3.2.4 Calculation. The concentration of hydrogen peroxide in the decomposed solution shall
be calculated by the following formula:
G -T
=
CH 2O2
V
where
= Concentration of hydrogen peroxide in decomposed solution (g/ml)
C H 2O2
= Gross weight - centrifuge tube with sample (g)
G
= Tare weight of centrifuge tube (g)
T
= Volume of decomposed solution (ml)
V
4.4.4 Anions. This test method covers the determination of trace levels of chloride, nitrate,
phosphate and sulfate in hydrogen peroxide by ion chromatography. The concentration of these anions
is determined by analyzing the decomposed solution prepared in 4.4.3 in accordance with ASTM D 5542.
Calculate the concentration of each anion in the hydrogen peroxide sample using the following formula:
R
A-
=
1000 ⋅ C H 2O2
where
8
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