A time-resolved fluorescence optical fiber biosensor(TFFBS)for biomedical detection is developed for the first time. By using lanthanide ions

especially europium ions as the fluorescent labels of samples

TFFBS can perform time-resolved fluorescence detection from spectral characteristics of europium ions. This instrument has a novel optical system

composed mainly with fiber couplers and optical fiber

for the collection and guiding of both exciting light and fluorescence of samples. Owing to its flexibility and convenience in adjusting

TFFBS has small size and high detecting sensibility. The unstable property below 2.3% was demonstrated in experiments. The mutual correlation in duplicate measurement is 99.9%. The detection limit is 7.3?10

-10

g/L for Eu 2 maphthoyltrifluoroacetonate

which reaches the levels reported in foreign literature