Rapid determination of Sr-90 by electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS)

A two-step temperature program has been developed to determine Sr-90 in highly active samples in the presence of Zr. In a first step, Sr is volatilized at 2400 degrees C using argon as a carrier gas, while Zr is completely retained in the graphite tube. It is removed in a second step by adding 0.1% CHF3 to the argon carrier gas and increasing the temperature to 2650 degrees C. Even a 100fold excess of Zr has no detrimental effects on the determination of Sr-90. The detection limit is 2 pg/ml (10 Bq/ml) without using a modifier.