Optimization of a method, based on thermal oxidation using a tube furnace system (Pyrolyser), for the separation of organically bound tritium (OBT) from environmental matrices is discussed. Results show that a maximum of ~ 4 g of the vegetation sample, typical wild plant leaves of tropical regions, and ~ 8 g of sediment sample can be combusted efficiently in the pyrolyser system. The recovery of OBT from wheat sample was observed to be ~ 92% and that for sediment sample was ~ 88%. The minimum detectable activity (MDA) at 95% confidence level was 3.4 Bq kg−1 for a sample weight = 4 g, counting time = 30,000 s, and detection efficiency = 23%.