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CRER-1068
APPENDIX 2
Preparation of Standards
1.
Make up standard solutions by dissolving Specpure*
strontium or barium carbonate in a solution containing a
minimum quantity of nitric acid (1.011 gm strontium
carbonate or 0.862 gm barium carbonate per 100 ml gives
6 mg/ml of. strontium or barium).
gravity.
Using a micro-balance weigh
Determine the specific
10 wl of standardized solution
(60 peg of strontium or barium) into a tared three mm I.D.
thin-walled silica tube.
Ref (6).
Introduce the solution
into the capillary in the following manner.
Heat the
capillary slightly to expel part of the air and place the
tip in the liquid.
On cooling, the liquid draws partially
into the tube.
Transfer the liquid to the closed end of
the tube by centrifuging and flame-seal the open end.
Place in oven at 110°C for one hour.
Discard if the solution
has evaporated,
'
Irradiate as outlined in Annex 1, section 2(b) and 3.
Allow a one hour period of decay after removal from the
reactor.
Immerse the silica tube in boiling aqua regia for one to
two minutes to remove contamination from the outside.
Wash
with water.
Crush the tube in a 10 ml Erlenmeyer flask containing 2 ml
of carrier solution (20 mg strontium per ml).
Mix and
transfer the solution to a 5 ml volumetric flask.
f
:
Wash the Erlenmeyer flask three times with 0.5 ml of water,
transferring the washings to the volumetric flask.
up to volume.
Make
Transfer 500 wl of the solution’ (6 pe of activated strontium
or barium) to a counting tray.
Dry under infra-red lamp.
10.
Count.
* Trademark of Johnson Matthey & Company