Sensors Based on Luminescence Quenching

Suppose that the molecule M absorbs light and is promoted to the excited state M  

The rate at which M is created, d[M ]/dt, is proportional to the concentration of M. The rate constant, ka, depends on the intensity of illumination and the absorptivity of M. The more intense the light and the more efficiently it is absorbed, the faster M will be created. Following absorption, M can emit a photon and return to the ground state  

The rate at which M is lost is proportional to the concentration of M. Alternatively, the excited molecule can lose energy in the form of heat  

---

Xu W., Schmidt R., Whaley M., Demas J.N., DeGraff B.A., Karikari E.K., Famer B.L., Oxygen Sensor Based on Luminescence Quenching Interactions of Pyrene with the Polymer Supports, Anal. Chem. 1995 67 3172-3180. 

Mediated electrochemical sensors aside, there are few sensors involving a reaction at the sensing microzone by which the analyte is not retained to some extent during the time the analytical response is generated. Such is the case with sensors based on luminescence quenching and a few others. Although many of the reactions on which the analytical measurement rests in sensors based on acid—base reactions involve retention of protons, the sensors in question are dealt with in this Section. 

Xu W, Schmidt R, Whaley M, Demas J N, DeGraff B A, Karikari E K and Farmer B L 1995 Oxygen sensors based on luminescence quenching interactions of pyrene with the polymer supports Anal. Chem. 67 3172-80 Peterson J I, Goldstein S R, Fitzgerald R V and Buckhold D K 1980 Fiber optic pH probe for physiological use Anal. Chem. 52 864-9 Peterson J 1 and Vurek G 1984 Fiber-optic sensors for biomedical applications Science 123 123-7... 

Demas, J.N. DeGraff. B.A. Coleman, P.B. Oxygen sensors based on luminescence quenching. Anal. Chem. 1999. 71 (23), 793A-800A. 

We focus on luminescence quenching based sensors, but many of the principles are generic. Quenching-based oxygen detectors are probably the most mature. In homogeneous media with only a single component exponential decay the intensity and lifetime forms of the Stern-Volmer equations are ... 

L. Sacksteder, J. N. Demas, and B. A. DeGraff, Design of oxygen sensors based on quenching of luminescent metal complexes Effect of ligand size and heterogeneity, Anal. Chem. (submitted). 

There are several luminescence flow-through sensors based on both fluorescence quenching phenomena and biolimiinescent reactions. 

Abstract Pressure-sensitive paint (PSP) is applied to the areodynamics measurement. PSP is optical sensor based on the luminescence of dye probe molecules quenching by oxygen gas. Many PSPs are composed of probe dye molecules, such as polycyclic aromatic hydrocarbons (pyrene, pyrene derivative etc.), transition metal complexes (ruthenium(II), osumium(II), iridium(III) etc.), and metalloporphyrins (platinum (II), palladium(II), etc.) immobilized in oxygen permeable polymer (silicone, polystyrene, fluorinated polymer, cellulose derivative, etc.) film. Dye probe molecules adsorbed layer based PSPs such as pyrene derivative and porphyrins directly adsorbed onto anodic oxidised aluminium plat substrate also developed. In this section the properties of various oxygen permeable polymer for matrix and various dye probes for PSP are described. 

Figure 16.1 Main classes of fluorescent molecular sensors of ions and molecules based on (a) quenching of luminescence by collisions with analyte (b) quenching or (c) increase of fluorescence of the complexing fluorophore (d,e) the same processes in fluorophore-receptor assemblies [1]...

A cross-reactive sensor array based on luminescence changes has been reported by Severin and coworkers [74]. In this case no synthetic modifications were operated, but the sensing elements were created by mixing some metal complexes with fluorescent dyes. The complex formation between metal ions, such as Rh, Ru or Pd, quenches the dye fluorescence the peptide competes with the dye for metal ion complexation, removing it from the complex. The fluorescence turn on is the signal of the peptide interaction. The activation of fluorescence is also an indication of the equilibrium reported in Fig. 24 and it is the basis of the peptides discrimination. The sensor array was able to differentiate between several dipeptides at 20-50 X 10 M concentration higher oligopeptides, such as bradykinin and kallidin were also discriminated and the system was also able to differentiate between two dipeptides, carnosine and homocamosine, in a more complex environment such as human serum. 

---