62
Tritium–1
10. When 90 minutes is up, put on the heat-resistant gloves.
Remove the first tube from the block and immediately pull off its
sample tube using a downward, twisting motion as opposed to
a sideways motion. Remove the sample tube within 4 seconds
of removing it from the block or suck-back of the sample will
occur. Dispose of the sample tube and the hot solution left in it
by dropping it into the sink or waste bucket.
11. Invert each collector tube and place it into the collector tube
rack, now with the
D end up. It should take less than two
minutes to pull and separate all 21 tubes.
12. Allow tubes to cool for at least 10 minutes.
13. For each collector tube, hold the tube horizontally and rinse its
walls with the distillate in order to homogenize it. Slowly roll the
distillate around in the tube to gather all droplets clinging to the
tube walls into the bulk of the distillate. Then, slowly return the
collector tube to an upright position so that the
D end is up.
Stubborn drops will often fall into the
M end when the tube is
flicked with a finger.
14. With the
D end still up, break the collector tube in half by pulling
the
D end hard towards the user to break it, then twisting and
tearing off the
D end. Discard the D end.
15. From the
M end distillate, pipet sufficient sample and, if needed,
dilution water into the scintillation vials. Then add scintillation
cocktail and count, following the scintillation counter
manufacturer's instructions. Seal both ends of the tube with
Parafilm if the sample will not be determined immediately.
17.2 Sources
• DOE Method RP580 “Water distillation from soil and aqueous
matrices using a microdistillation system for tritium
determination”, from “DOE Methods for evaluating
environmental and waste management samples”,
DOE/EM–0089T, Rev 2, April 1995, U.S. Dept. of Energy.
• S. Stieg, “A Miniature Membrane Tube for Rapid Parallel
Distillation of Cyanide, Phenolics, Ammonia, Sulfide,
Methylmercury, and Tritium from Waters and Solids”, American
Environmental Laboratory, v9, no. 10, Nov–Dec 1997,
pp10–11.
To Next Page
Loading...
Need help?
General
