Analysis of Tritium in Water: A Collaborative Study

Abstract A liquid scintillation procedure using 1,4-dioxane, naphthalene, PPO, and POPOP as the scintillator was evaluated in a collaborative study of the determination of tritium in water. The tritium counting efficiencies for seven collaborating laboratories using this technique and commercially available liquid scintillation spectrometers ranged from 8.3 to 26.5%. The minimum detectable activity by the method, based on 99% confidence limits, 100 min counting time, and backgrounds from 9 to 67 cpm, ranged from 0.2 to 0.5 pCi/ml. Statistical results showed no evidence for systematic error. The coefficient of variation varies from 3.4 to 7.3% over the concentration range 2.91–115.8 pCi/ml. It is recommended that the method be adopted as official first action.