Chemical Forums

Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: javhert on July 09, 2021, 10:46:31 AM

Title: Efficient way to evaporate 1 L water samples for alpha / beta counting.
Post by: javhert on July 09, 2021, 10:46:31 AM

Hi, here in the laboratory we are about to acquire an instrument for gross alpha / beta radiactivity counting in drinking water. Since the acivity values to be measured are rather low (0.1 Bq for alpha and 1 Bq for beta), the analytical methods demand to concentrate a 1 L sample to near dryness before mixing with the scintillation cocktail in the vial.

Since we expect a relatively high sample throughput, evaporating the samples in glass flasks above hot plates sounds like an overly slow and messy process with all the bubbling and splaterring of boiling samples, and at this point there is probably something in the market to do it in a efficient manner. A quick browsing suggested lyophilization or rotary evaporators. Do you have a method in mind to routinely evaporate like 10 samples daily?

Title: Re: Efficient way to evaporate 1 L water samples for alpha / beta counting.
Post by: Babcock_Hall on July 09, 2021, 12:06:37 PM

I don't see an insurmountable difficulty in using rotary evaporation, although I am not sure that it could be fully automated, owing to the problem of bumping (splattering, with a loss of material into the steam duct or beyond).  Your throughput is larger than I have encountered in research labs, and that might be another problem.