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Proceedings Paper

LED-compatible fluorosensor for ammonium ion and its application to biosensing
Author(s): Otto S. Wolfbeis; Hong Li
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Paper Abstract

We present a fluorescence-based sensing scheme for ammonium ion using nonactin as the receptor/carrier. The ammonium-sensitive material consists of a pvc membrane containing the nonactin, a plasticizer, and a proton carrier (lipophilic nile blue). Sensing is based on the selective extraction of the ammonium ions into the pvc membrane, and a concomitant release of a proton from the dye, contained in the pvc membrane, into the sample solution. Upon deprotonation, the dye undergoes a color change from blue to red which is detected via fluorescence intensity measurements. The sensor fully reversibly responds to ammonium ion, with detection limits varying from 0.03 to 10 mM at near neutral pH. Response times are about 1 min for membrane thicknesses of ca. 2 micrometers . The sensor is fully compatible with solid-state electronics (i.e., LED light sources and photodiode detectors) but suffers from a strong pH dependence of the signal so that the pH of the sample must be kept constant. The sensor is of potential utility in monitoring ammonium ion in wastewater and surface water samples, but may also act as a transducer in all kinds of biochemical reactions during which ammonium ion is released or consumed. Examples of biosensors for urea and creatinine are given.

Paper Details

Date Published: 1 March 1992
PDF: 11 pages
Proc. SPIE 1587, Chemical, Biochemical, and Environmental Fiber Sensors III, (1 March 1992); doi: 10.1117/12.56532
Show Author Affiliations
Otto S. Wolfbeis, Karl-Franzens Univ. (Austria)
Hong Li, Karl-Franzens Univ. (Austria)


Published in SPIE Proceedings Vol. 1587:
Chemical, Biochemical, and Environmental Fiber Sensors III

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