The Applicability of Fluorescence Indicators to Measure Hydrogen Ion Activities by Optimizing Accuracy and Minimizing the Influence of Ionic Strength

  • N. Opitz
  • D. W. Lübbers


pH-sensitive fluorescence indicators can be used for the measurement of hydrogen ion activities [8,10]. To improve the applicability of fluorescence indicators generally, we have developed special fluorescence sensors, optodes, in which the indicator molecules are separated from the medium by a protecting membrane which is permeable for the substance to be measured [2, 3, 5]. Thus, interactions of proteins or colloids of biological fluids with the indicator molecules can be avoided. To eliminate optical interference due to reflection changes, scattering, and non-specific fluorescence, the sensor membrane has to be prepared for optical insulation.


Ionic Strength Tuning Condition Ionic Strength Range Indicator Molecule Ionic Strength Change 
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© Springer-Verlag Berlin Heidelberg 1985

Authors and Affiliations

  • N. Opitz
  • D. W. Lübbers

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