عنوان
Fabrication of an optical pH sol-gel sensor based on Thionine dye
نویسنده (گان)
Vafi,Mahboubeh;Rounaghi,Gholam hossein ;ٍeshaghi,Zarrin
چکیده مقاله
In the present work, an optical chemical sensor was constructed by incorporating the thionine (TN) dye molecules (Figure 1) into a sol-gel silica matrix and it was used for determination the pH of the aqueous solutions. Entrapment of TN dye into the silica matrix was made via an acid-catalyzed sol-gel reaction of tetraethyl orthosilicate (TEOS) and the thionine molecules. The thionine molecules in the immobilized form, showed a different spectral behavior than its solution form. After optimizing the experimental conditions, the fabricated optical sensor showed a fast response to pH changes in the range of 11-13 with a response time about one minute. Also, the obtained results indicate that the proposed pH sensor, has a good reproducibility, reversibility, stability and low leaching and a long lifetime of over 7 months.

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