Analytical Sciences

An Optic Fiber Sensor for Metronidazole Based on the Fluorescence Quenching of a Copolymer Bound Flavone Derivative

Wanhui LIU* , **, Ying WANG*, Jianghong TANG*, Guoli SHEN* and Ruqin YU* ,*

* College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
** Analytical Center, Yantai University, Yantai 264005, China

A new optic-fiber sensor for metronidazole (1-(2-hydroxyethyl)-2-methyl-5-nitromidazole) has been fabricated with a flu-orescent copolymer prepared from 3-hydroxy-4¢­N,N-dimethylaminoflavone methacrylate, methyl methacrylate, and butyl acrylate (PFMB). The sensing is based on the quenching of the fluorescence of a PFMB membrane by metronida-zole. An orthogonal-experimental design was used for the membrane composition optimization. The present sensor responds linearly to metronidazole in the concentration range of 3.00´±0 -5 mol l -1 to 3.00´±0 -3 mol l -1 with a detection limit of 1.00´±0 -5 mol l -1 . The response is on the order of 30 s. The lifetime is enhanced by covalently immobilizing the flavone derivative to the membrane, which hinders leaching of the dye from the membrane. With the described sensor, good reproducibility and reversibility have been realized. The sensor has also shown good selectivity over common inor-ganic anions and cations, and some pharmaceuticals. It can be used for the direct determination of metronidazole in com-mercial pharmaceutical preparations; the obtained results were in agreement with those obtained by a pharmacopoeia method. (Keywords: Optic-fiber sensor, metronidazole, 3-hydroxy-4¢­N,N-dimethylaminoflavone methacrylate)

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