Re: Preservation of Milk Samples for Gamma Isotopic Analysis

["David Whitfill" <DWhitfil@kdhe.state.ks.us>]

Many of the milk analysis procedures specify that the sample be preserved
with formalin (37 % formaldehyde solution, reagent grade). The procedures I
have read utilize bisulfite (1 molar sodium bisulfate: 1.04 g per 10 mL
distilled water) during the extraction of iodine. The below example is
taken from an old  EERF Radiochemistry Procedures Manual (EPA 520/5-84-006,
p. I-02-1):

-preserve with formalin containing iodide carrier
-stir milk with anion exchange resin
-iodine eluted from the resin after oxidation to IO_3- with hypochlorate
solution
-After reduction, the iodine is extracted into CCl_4 and reduced with
bisulfite, and back-extracted into water
-Iodine precipitated as PdI_2

We are looking into a substitute for the formalin-anyone have some
suggestions?




jhharner@aep.com@romulus.ehs.uiuc.edu on 02/03/2000 11:12:06 AM

Please respond to radsafe@romulus.ehs.uiuc.edu

Sent by:  radsafe@romulus.ehs.uiuc.edu


To:   Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
cc:

Subject:  Preservation of Milk Samples for Gamma Isotopic Analysis




Does anyone know of a source reference for the use of Sodium Bisulfite as
a simple preservative in Milk samples for Gamma Isotopic Analysis.  I have
called several other facilities.  Many use 40 grams (reagent grade) per
gallon but no one knows where the specification came from.



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