Tritium isotope effect in high-performance liquid chromatography of eicosanoids

A significant difference in retention time between unlabeled and the corresponding multi-tritium-labeled eicosanoid has been observed in the high performance liquid chromatography (HPLC) analysis of 11 eicosanoids. Variations in retention time range from 3-7%, depending on the separation conditions as well as the number and position of the tritium substitution. Multi-tritium-labeled eicosanoids were eluted earlier than the corresponding unlabeled eicosanoid in reversed phase HPLC, whereas no isotope effect was seen with 14C- and 3H2-eicosanoids. Considerations must be given to this tritium isotope effect whenever both multi-tritium-labeled and unlabeled eicosanoids are used for HPLC cochromatography or recovery studies.