SEDL / STP / STP863-EB / STP32772S

Metal Ion Sensors Based on Immobilized Fluorogenic Ligands

Seitz, WR
Professor of chemistry, University of New Hampshire, Durham, NH

Saari, LA
Research chemist, Instrumentation Laboratory, Inc., Lexington, MA

Zhujun, Z
Professor of chemistry, Shaansi Normal University, Sian, Shaansi

Pokornicki, S
Chemist, C. R. Bard Corp., North Reading, MA

Hudson, RD
Chemist, Texaco, Inc., Beacon, NY

Sieber, SC
Student, Yale University Medical School, New Haven, CT

Ditzler, MA
Assistant professor, College of the Holy Cross, Worcester, MA

Pages: 15    Published: Jan 1985

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Abstract

A metal ion sensor may be prepared by immobilizing a fluorogenic ligand on the common end of a bifurcated fiber optic. Fluorescence is excited through one arm of the fiber optic and observed through the other. When the immobilized ligand is placed in a solution of metal ion, some of the metal associates with the ligand causing its fluorescence characteristics to change. Equations are derived for the response of a sensor for systems where a 1:1 complex is formed.

We have successfully immobilized several ligands including morin, quercetin, and calcein to cellulose using cyanuric chloride as a coupling reagent. Immobilized morin is only very weakly fluorescent but forms fluorescent complexes with Al⁺³ and Be⁺² and can be used to sense these ions. Immobilized calcein is fluorescent by itself but is quenched by several metal ions. We have also immobilized hydroxy napthol blue and 8-hydroxyquinoline-5-sulfonate on anion exchangers. In addition 2, 2′, 4-trihydroxy-azobenzene and p-tosyl-8-aminoquinoline have been immobilized to silica gel.