Perfluorohexane gas when introduced in the air atmosphere above a film of phospholipid self-supported on an aqueous solution of C2F5-labeled compounds causes the recruitment and immobilization of the latter in the interfacial film. When the phospholipid forms a liquid-condensed Gibbs monolayer, which is the case for dipalmitoylphosphatidylcholine (DPPC), the C2F5-labeled molecule remains trapped in the monolayer after removal of F-hexane. Investigations involve bubble profile analysis tensiometry (Gibbs films), Langmuir monolayers and microbubble experiments. The new phenomenon was utilized to incorporate a hypoxia biomarker, a C2F5-labeled nitrosoimidazole (EF5), in microbubble shells. This finding opens perspectives in the delivery of fluorinated therapeutic molecules and biomarkers.