A Method for the Elimination of Ashing in Strontium90 Determination of Milk

Abstract
After the addition of a known amount of Sr carrier, the milk is treated with an equal volume of 24% trichloroacetic acid. The solution is filtered and the alkaline earths are precipitated from the filtrate by adjusting the pH to 8.5 - 9.0 with NaOH after which Na2CO3 is added to insure complete precipitation. The alkaline earths are separated and analyzed as described elsewhere for milk ash. Results of 22 milk samples showed that the Sr90 values obtained by analysis of alkaline earth precipitates are not significantly different from those obtained by analysis of milk ash.