Determination of 227Ac in water by alpha spectrometry after purification with titanium phosphate and DGA resin

A new routine method to measure 227 Ac in water samples was developed. Actinium-227 was separated from potential radioactive and matrix interferences using a DGA resin (Eichrom) at optimal extraction and elution conditions (2 M and 15.7 M HNO 3 , respectively). This was possible because Ac was pre-concentrated and separated from Ca using titanium phosphate co-precipitation at pH 3.5. Finally, 227 Ac was counted by alpha spectrometry for 48 h after a cerium fluoride micro-precipitation. A minimal detection limit of 0.03 ± 0.01 Bq l −1 was obtained. The method was validated using spiked water samples.