Weidgans, Bernhard M. and Krause, Christian and Klimant, Ingo and Wolfbeis, Otto S. (2004) Fluorescent pH sensors with negligible sensitivity to ionic strength. ANALYST, 129 (7). pp. 645-650. ISSN 0003-2654, 1364-5528
Full text not available from this repository. (Request a copy)Abstract
Optical pH determination has the fundamental disadvantage of measuring a signal that depends on the ionic strength of the sample. The problem originates from the complex relationship between the proton activity and the concentration of the pH-sensitive dye. The effect of ionic strength on the signal depends on the charge of the indicator and its environment, e. g. the immobilisation matrix. We present novel lipophilic fluorescein esters carrying one negative charge. They are embedded in an uncharged, highly proton-permeable hydrogel to give optical pH sensors that show a negligible cross-sensitivity towards ionic strength. The fluorescent dyes differ in their substituents. This variation of substituents results in dissociation constants between 5.5 and 8.5. The indicators were made lipophilic by esterification of the carboxy group with a C-18 alkyl chain. Since their spectral properties are quite similar, two indicators may be used in one sensor. This results in an optical pH sensor with a dynamic range that extends from pH 4.5 to 8.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SELECTIVE OPTODE; RANGE; DERIVATIVES; INDICATORS; YIELDS; SALTS; FILMS; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Analytische Chemie, Chemo- und Biosensorik |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 23 Jul 2021 08:35 |
| Last Modified: | 23 Jul 2021 08:35 |
| URI: | https://pred.uni-regensburg.de/id/eprint/38101 |
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