Tritiated leukotriene A(4) and 8-epi-prostaglandin F-2 alpha methyl esters were prepared from the corresponding acetylenic precursors by selective reduction with tritium gas to provide a probe for the metabolite identification of these oxylipins. Partially deactivated Pd-catalysts were prepared from commercial products and their composition was optimized to achieve the better selectivity. A micro-method for the saponification of labelled oxylipins methyl esters was used.