A NEW FLUORESCENCE OPTIC-FIBER SENSOR FOR METRONIDAZOLE

A fluorophore of 1,4-bis(1,3-benzoxazol-2-yl)benzene(BBOB) was selecte d as sensing molecule for constructing a new metronidazole optic-fiber sensor, The sensing performence is based on the fluorescence quenchin g of the plasticized PVC optode membrane trapped with BBOB by metronid azole. The quenching mechanism includes a primary inner filter effect and the formation of a charge-transfer complex between BBOB and metron idazole extracted from aqueous phase into membrane phase. In the range of 4.00 x 10(-6) similar to 1.00 x 10(-4) mol/L, the sensor responds linearly to metronidazole with a detection limit of 1,0 x 10(-6) mol/L metronidazole. A good reversibility and a rapid response within 30 s were obtained. The relative standard deviation of repeating measuremen ts of 1.00 x 10(-4) mol/L metronidazole is 0. 82% (n=10). The sensor s hows good selectivity over the common inorganic ions and pharmaceutica l species and therefore can be used for the direct determination of me tronidazole in commercial preparations, the results were in agreement with those obtained by pharmacopoeia method.