Dear isotopists, Prof. C.T.PillingerUs lab have studied a methane isotopic composition in lunar fines and interstellar diamond. This samples are fine powders and have a large surface area. I found a huge terrestrial organic contamination which produce methane during pyrolysis of samples with maximum release at 450-600 C. To remove or reduce this contamination I have tried to heat samples in presence of O2 (without any metal parts). I found that temperatures of methane release is significantly reduced, but the amount of methane is similar. Could anyone give me references about uncompleted vacuum oxidation of organic material, carbon fractionation during that and destroying of organic molecules in presence of oxygen. Thank you for your help! Sergey Assonov ------------------------------------------- Dr S.S. Assonov Planetary Sciences Research Institute The Open University Walton Hall, Milton Keynes, MK7 6AA England Fax: 44 (01908) 655 910 Tel: 44 (01908) 653 558 -------------------------------------------