Rapid method for the preparation of a robust optical pH sensor.
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.
Kermis
Haley R
HR
Department of Chemical and Biochemical Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
Kostov
Yordan
Y
Rao
Govind
G
D001709:Biotechnology / Q000379:methods*; D005456:Fluorescent Dyes; D006863:Hydrogen-Ion Concentration; D013050:Spectrometry, Fluorescence / Q000295:instrumentation / Q000379:methods*
D005456:Fluorescent Dyes