Verification of combustion rate of recovery and counting efficiency in the analysis of organically bound tritium in biota samples

The analysis procedure of five biota samples’s organically bound tritium (OBT) based on oxidation combustion and liquid scintillation counter (LSC) measurement was established. The combustion experiment under one atmospheric pressure in the presence of Pt-Al2O3 catalyst were carried out. The experiment results shown that the combustion recovery of five samples ranged from 86.4 % to 91.1 %, the combustion recovery of glucose monohydrate is about 93.7 %, which indicate that combustion recovery of biota samples differed from one species to another. Meanwhile, The counting efficiency of quenching agents CH3NO2 and CCl4 decreases from 20.3 % to 0 and from 19.3 % to 0 respectively as the quench agent mass increases from 10 μL to 500 μL. The counting efficiency of quenching agent HNO3 decreases from 22.4 % to 14.6 % as the quench agent mass increases from 10 μL to 500 μL. The SQP (E) value of CH3NO2 and CCl4 decreases as the mass of quenching agents increases, while the SQP (E) value of HNO3 increases as the quench agent mass increases. The SQP(E) of three tested quench agents ranges from 401.8 to 738.4, which covers the SQP(E) range of all the monitored biota samples in recent years. Therefore, the mapped curves and fixed equations are applicable. In addition, comparison experiment of four biota samples between two laboratories shown a relative deviation from 1.2 % to 12.8 %. •Combustion recovery of five biota sample differ form on species to another.•Counting efficiency for all the three quench agents are found to be decreasing.•Quenching curves made by three quench agents cover the SQP(E) value of different biota samples analyzed.