MIL-DTL-3301D
(c) Hydrochloric acid, 37 percent
(d) A stock solution of lead perchlorate is prepared by dissolving (with heating as needed) 50 mgs
of lead in 5 ml. 70 percent perchloric acid in a 500 ml volumetric flask. Cool the resulting
solution thoroughly and dilute, to the mark with distilled water.
(e) A stock solution of manganese is prepared by dissolving 100 mgs of lead metal in 5 ml. 37
percent hydrochloric acid in a 500 ml. volumetric flask. Boil the solution for a few minutes and
then cool the solution thoroughly. Add 5 ml 70 percent perchloric acid and dilute to volume with
distilled water.
4.4.10.1.4 Procedure.
(a) Add 20 ml. of 70 percent nitric acid to the sample contained in the 125 ml flat bottom flask.
(b) Heat the sample on a steam bath under a reflux condenser for about 4-6 hours.
(c) Remove the sample solution to a hot plate and again under a reflux condenser heat until the
solution boils gently. Reflux over night. Note : Do not heat too vigorously in the beginning or
sample solution may foam into the condenser.
(d) After sample solution has refluxed over night, remove the condenser and boil the solution so
that vapors escape. Continue to boil until the sample solution begins to foam.
(e) Remove the sample from the heat and cool slightly. Add 5 ml. of 70 percent perchloric acid.
(f) Return the flask to the heat. Heat slowly and carefully never allowing the reaction to proceed
rapidly enough to remove all the liquid from the bottom of the flask. Note: Do not allow samples
being heated with perchloric acid to go to dryness.
(g) When the reaction has subsided continue heating until white fumes of perchloric acid are seen.
(h) Remove from the hot plate and cool thoroughly. Transfer the solution to a 50 ml volumetric
flask, dilute to the mark with distilled water and mix well.
(i) Prepare working standards by pipetting successively 1, 3, 5 and 8 ml. of the stock lead
perchlorate into a series of four 100 ml. volumetric flasks. In the same order, pipette 1, 3, 5 and 8
ml aliquots of the stock manganese perchlorate solution into the flasks. Add to each flask 8 ml of
70 percent perchloric acid. Dilute to mark with distilled water and mix. These standards give lead
concentrations of 1, 3, 5 and 8 ppm and manganese concentrations of 2, 6, 10, and 16 ppm. Note:
Procedure can also be shortened using "pass or no pass" criteria in the specification. Only one
standard solution then need be prepared.
(j) Prepare a blank solution in 100 ml. volumetric flask. Add 8 ml. 70 percent perchloric acid and
dilute to the mark with distilled water.
(k) The sample (in duplicate), standards and blank are then analyzed by atomic absorption
(following instrument instruction manual and standard safety procedures).For lead use 2833A
analytical wavelength and for manganese the 2795 A wavelength. Use air as the oxidizer and
hydrogen as the fuel. Note: It is recommended that an inert platinum or glass aspiration capillary
be used. If the concentrations of either lead or manganese should prove to be outside the range of
9
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business