Determination of non-exchangeable organically bound tritium concentration in reference material of pine needles (NIST 1575a)

Non-Exchangeable Organically Bound Tritium (Nx-OBT) in a biological reference material: NIST 1575a Pine Needles was determined by radiometry and noble gas mass spectrometry. Nx-OBT concentration ranged from 1.08 to 1.45 Bq L −1 -combustion water (CW) (n = 4) with mean value (± S.D.) of 1.25 ± 0.15 Bq L −1 -CW in radiometry and ranged from 1.12 to 1.35 Bq L −1 -CW (n = 3) with mean value of 1.22 ± 0.25 Bq L −1 -CW in mass spectrometry. For the Pine Needles reference material, there is no proposed value about Nx-OBT, but our results showed a good agreement with the data determined by different methods. Thus, it is useful material for the quality control of Nx-OBT measurements.