Fluorescent optical sensors fiber optic

The second possibility is to make use of the continuous evanescent field that exists at the surface of an optical fiber. The cladding layer is replaced by a layer containing the fluorescent molecular sensor in a short portion of the optical fiber (Figure 10.45). At each reflection at the surface of the fiber core, the eva-... 

K. T. V. Grattan, R. K. Selli, and A. W. Palmer, Ruby fluorescence wavelength division fiber-optic temperature sensor, Rev. Sei. Instrum. 57, 1231-1234 (1987). 

Figure 14.18. Diagrammatic representation of a phenytoin fluorescence energy transfer fiber optic sensor, as described in the text. -< = Antibody-Texas Red P = unlabeled phenytoin P = phenytoin-b-phyco-erythrin. (Adapted from Ref, 119.)...

A reversible, direct fluoroimmunosensor for human serum albumin (HS A) measurement has been described by Bright et al.(m> Antibody Fab fragments are first immobilized on small quartz plates by hinge-region thiols, and then dansylated. The immunosensor is formed by attaching the quartz plates with bound Fab to the distal end of a bifurcated fiber-optic probe, which transmits both the excitation and emission. Binding of ffSA to the immunosensor results in a three- to five-fold enhancement of dansyl fluorescence. The sensor can be reused up to 50 times, with a detection limit of about 1.8 x 10-8 M, and a somewhat limited dynamic range. 

A fluorescence optical sensor for dansyl-L-phenylalanine has been reported [17]. In the optical sensor, the imprinted polymer was held in front of a fiber-optic device by a nylon net. Although the system worked well, there are some inherent problems that need to be addressed the... 

Fiber-Optic Fluorescence Sensors Fiber-optic probes have been used to demonstrate that several fluorescence determinations can be carried out at various locations well awav from a source and a... 

As the potential of optical fiber probes for pH measurements was rapidly recognized, several other articles appeared within a few years75 83. Most were reflectance-based, and Seitz reported the first fluorescent pH sensors84, 78. The article by Janata85 on whether pH optical sensors can really measure pH is another "must" in the early literature since it points to aspects hardly addressed in pH sensor work. 

D. Walt, F. Milanovich, S. Klainer 1986 Polymer modification of a fluorescent fiber optic pH sensor... 

A novel fiber optic sensor concept using antibody-antigen reactions at a glass-liquid interface was reported by Daehne146. The reaction of antibodies immobilized onto the surface of fused silica fiber optic or planar waveguides with antigens in solution was detected by interaction with the evanescent wave. By detecting in-line fluorescence, the measurement of human IgG is described. 

Other medical products based on optical sensor technology include those of Cardiomed (System 4000), Puritan-Bennett, and one of Radiometer (Copenhagen) which has been withdrawn meanwhile. Optical (but non-fiber) sensors for oxygen and for C02 also are widely used for the determination of bacteria in blood. In 1986, Gehrich et al.36 described an optical fluorescence... 

Wolfbeis O.S., Posch H.E., Fiber optic fluorescing sensor for ammonia, Anal. Chim. Acta 1986 185 321. 

Shortreed M., Kopelman R., Kuhn M., Hoyland B., Fluorescent Fiber-Optic Calcium Sensor for Physiological Measurements, Anal. Chem. 1996 68 1414-1418. 

Munkholm C., Walt D.R., Milanovich F.P., Klainer S.M., Polymer modification of fiber optic chemical sensors as a method of enhancing fluorescence signal for pEl measurement, Analytical Chemistry 1986 58 1427-1430. 

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