Re: TFP: Radium vs. Sr 90 not distinguished? Error in TFPclaim

["Gerald Nicholls" <GNICHOLL@DEP.STATE.NJ.US>]

There are some details of the analytical procedure used to determine Sr-90 in the children's teeth samples in the appendix to the paper listed in the original posting.  



It is stated that the analyses are performed by Hari D. Sharma, Professor Emeritus of Radiochemistry.  The teeth are dried at 110 degrees C for 12 hours, ground to a powder, weighed and dissolved in nitric acid.  Carriers are added and the Sr and Y precipitated as carbonates and centrifuged.  The precipitate is repeatedly washed with dilute sodium carbonate solution until any coloration is lost.  



The precipitate is then dissolved in hydrochloric acid and samples prepared for liquid scintillation counting using a previsously determined window and counting efficiency derived from an NIST standard solution.  A counting efficiency of 1.67 counts/decay of Sr-90 is given.  Samples are counted 4 times at 100 minutes each.  Background was counted for 5000 minutes.  No information is given regarding blanks, duplicates or cross checks.  Ca is determined by AA spectrometry.



There isn't enough information here to determine whether or not there is interference from naturally occurring radionuclides.  







Gerald P. Nicholls

NJ Dept. of Environmental Protection

609-633-7964

gnicholl@dep.state.nj.us



************************************************************************

You are currently subscribed to the Radsafe mailing list. To unsubscribe,

send an e-mail to Majordomo@list.vanderbilt.edu  Put the text "unsubscribe

radsafe" (no quote marks) in the body of the e-mail, with no subject line.