CASTDan:Abstract18
Kostov, Y., Kermis H.R.,Rao G. (2003) Rapid method for the preparation of a robust optical pH sensor. The Analysis. 128 1181–1186
Abstract:
A simple and rapid method for the preparation of a fluorescence-based optical pH sensor is described. The sensor
is based on excitation ratiometric detection of a methacryloyl-modified analog of the well-known fluorescent pH
indicator dye, 8-hydroxy-1,3,6-pyrene trisulfonic acid (HPTS). The modified dye,
6-methacryloyl-8-hydroxy-1,3-pyrene disulfonic acid (MA-HPDS), is similar in structure and function to HPTS.
However, unlike HPTS, the presence of the methacrylate moiety allows MA-HPDS to participate as a comonomer
in a free radical polymerization reaction. Covalent immobilization by this method is simple, as the preparation of
the modified dye is accomplished in a single reaction step and its subsequent reaction with a comonomer results in
simultaneous immobilization and purification. Sensors were prepared by copolymerization of the MA-HPDS with
poly(ethylene glycol) diacrylate. Minimal leaching of the immobilized dye was observed from the HPDS–PEG
matrix. The copolymer of HPDS and PEG-DA is fully autoclavable. The sensor is useful over the pH range of
6–9, with excellent reproducibility. Ionic strength effects on the apparent pKa of the immobilized dye are small
and predictable.
