Sensors based on luminescence suffer from the fact that during the operating time of the instrument changes in source intensity, light throughput, detector sensitivity, indicator quantum yield, and indicator concentration are inevitable and have to be overcome by extensive referencing and recalibration procedures. Sensors based on luminescence decay time should not suffer from these drawbacks. Decay-time sensing has relied so far on dynamic quenching, which is not well suited for pH measurements. Several other mechanisms are described in this contribution. The conditions necessary for an indicator to be useful in a decay time based pH sensing scheme are clarified and the suitability of this scheme is demonstrated.

Date Published: 30 April 1993
PDF: 8 pages
Proc. SPIE 1796, Chemical, Biochemical, and Environmental Fiber Sensors IV, (30 April 1993); doi: 10.1117/12.143521

Published in SPIE Proceedings Vol. 1796:
Chemical, Biochemical, and Environmental Fiber Sensors IV
Robert A. Lieberman, Editor(s)