RAPID-DETERMINATION OF RADIUM ISOTOPES BY ALPHA-SPECTROMETRY

An efficient analytical method for the determination of low-levels of Ra-226 and Ra-224 by alpha spectrometry is described. A cation exchang e column was used to separate the analyte from other constituents in t he sample (1-50 mL). After preconcentration and separation, the radium was electrodeposited onto a stainless steel disc from a solution of a mmonium oxalate and hydrochloric acid. The electrodeposition was accom plished by the addition of platinum in microgram amounts. Linear respo nses were greater than two orders of magnitude. Detection limits of th e procedure. taken as three times the standard deviation of several re agent blank analyses, were (1.8 +/- 0.3) x 10(-4) Bq and (2.9 +/- 0.3) x 10(-4) Bq for Ra-226 and Ra-224, respectively. Recoveries of Ra-226 and Ra-224 ranged from 90% to 100% when samples of drinking water, we ll water, and dissolved bones were analyzed. Precision was calculated to be less than 5% for the determination of Ra-226. Matrix effects wer e studied for salts of barium, magnesium, iron, and calcium.