Analytical procedures of selected nuclides

After 20-30 min, the resistance increases the power supply switches automatically to voltage limitation at 6 V. When the current has dropped to 0.2 A (after about 50-60 min do not proceed to lower currents or longer plating time) the plating should be stopped in one quick procedure add 1-2 mL of concentrated ammonia solution (25 %), immediately disconnect the plugs and add distilled water to the rim (while still in the fume hood CI2 evolution) and rinse the cell with ample distilled water. 

Take the cell apart. Remove the silver plate, rinse with distilled water and dry. Flame the plate gently in a gas flame to fix the Th to the silver. Heat until the colour changes in reflected light, but avoid overheating which would melt the silver. Mark the sample name and plating date on the back of the plate. 

This is the standard procedure for the determination of Th in an Fe(OH)3 precipitate from 20 L of seawater Fleer, 1991 Buesseler et aL, 1994). High activities of Th can also be 

Precipitate Fe(OH)3, using 1 mL of Th spike (16dpm/mL) as the yield tracer (Section 13.7.3). Take up the precipitate in 9mol/L HO. Add some concentrated HO to make up for reaction with 5 nunol of Fe(OH)3. The solution should be 9 mol/L in HO and have a volume of approximately 30 mL. Allow some time for complete dissolution. 

Run a chloride column (Section 13.7.5), using a wide (IS mm 0) column because a large amount of Fe has to be retained on the resin. 

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Analytical procedures of selected nuclides Delayed Coincidence Circuit... 

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