Fluorescence optical fiber sensor for tetracycline

A new optical fiber sensor for monitoring tetracycline has been described, based on the fluorescence quenching of 1,4-bis(5,5'-dimethylbenzoxazole-1',3'-yl-2')benzene incorporated into a thin plasticized polymer film by tetracycline extracted from aqueous phase into film phase. The sensor is fully reversible and highly reproducible. Furthermore, the sensor exhibits a linear response to tetracycline in the range 6.98x10(-7)-8.73x10(-5) mol l(-1) with a detection limit of 1.06x10(-7) mol l(-1), and with the response time <30 s. The response is also selective to tetracycline, with some common pharmaceutical species, alkali and alkali-earth metal salts being highly discriminated, suggesting that the sensor can be used to monitor tetracycline in three pharmaceutical preparations. The recovery of tetracycline from commercial formulations is 95.3-98.3%.