Evanescent-wave spectroscopy

In these sensors, the intrinsic absorption of the analyte is measured directly. No indicator chemistry is involved. Thus, it is more a kind of remote spectroscopy, except that the instrument comes to the sample (rather than the sample to the instrument or cuvette). Numerous geometries have been designed for plain fiber chemical sensors, all kinds of spectroscopies (from IR to mid-IR and visible to the UV from Raman to light scatter, and from fluorescence and phosphorescence intensity to the respective decay times) have been exploited, and more sophisticated methods including evanescent wave spectroscopy and surface plasmon resonance have been applied. 

Hocde S., Pledel-Boussard C., Fonteneau G., Lucas J., TeAsSe glass fibers for evanescent wave spectroscopy, Proc. SPIE 3849 (1999), Boston. 

Krioukov E., Klunder D.J.W., Driessen A., Greve J., Otto C., Integrated optical microcavities for enhanced evanescent-wave spectroscopy, Optics Letters 2002 27 1504-1506. 

Krioukov, E. Klunder, D. J. W. Driessen, A. Greve, J. Otto, C., Integrated optical micro cavities for enhanced evanescent wave spectroscopy, Opt. Lett. 2002, 27, 1504 1506... 

Jakusch, M. Janotta, M. Mizaikoff, B. Mosbach, K. Haupt, K., Molecularly imprinted polymers and infrared evanescent wave spectroscopy. A chemical sensors approach, Anal. Chem. 1999, 71, 4786 1791... 

ECD = electron capture detector EPA = Environmental Protection Agency FEWS = fiber evanescent wave spectroscopy FID = flame ionization detection FT-IR = Fourier transform infrared GC = gas chromatography HECD = Hall electrolytic conductivity detector HRGC = high resolution gas chromatography HSD = halide-sensitive detector H2SO4 = sulfuric acid LDPE = low-density polyethylene MS = mass spectrometry NIOSH = National Institute for Occupational Safety and Health NR = not reported PI = photoionization UV = ultraviolet detection... 

An in situ method for tetrachloroethylene analysis using fiber evanescent wave spectroscopy (FEWS) has been described by Krska et al. (1993). In this method, the water flows through a glass chamber containing a silver halide fiber coated with low-density polyethylene in an amorphous phase. The coating serves to concentrate the tetrachloroethylene, and the compound is detected using infrared spectrophotometry. The detection limit of this method, which was validated using headspace GC, was 1 ppm. 

Evanescent Wave Spectroscopy Surface Plasmon Resonance... 

D using the same monomer and TRIM as the cross-linker [28,29]. In this case, tobacco peroxidase was used as the enzyme and the chemiluminescent reaction with luminol was used for the detection. Infrared evanescent wave spectroscopy was also used to study 2,4-D imprinted polymers prepared using 4-VPy and MMA as the... 

Raichlin Y. Katzir A. (2008). Fiber-Optic Evanescent Wave Spectroscopy in the Middle Infrared. Applied Spectroscopy, Vol.62, No.2, p>p. 55A-72A, ISSN 1943-3530 Rappoport, Z. Marek, I. (2004). The chemistry of organolithium compounds, Wiley, ISBN 0-470-84339-X, Chichester... 

The curing of an epoxy resin adj acent to an embedded silica optical fibre was monitored in situ by evanescent wave spectroscopy. The epoxy resin was partially fluorinated and had a lower refractive index than the silica fibre. The lower refractive index of the epoxy resin allowed the silica optical fibre to be used as a waveguide for the internal reflection of the near-IR light. The epoxy resin curing was determined as a function of time and temp, by analysis of the near-IR spectmm from the epoxy adj acent to the fibre obtained by the interaction of the evanescent wave that occurred at each internal reflection with the low refractive index epoxy resin. The results obtained showed that epoxy ring-opening and... 

D. S. Blair, L. W. Burgess and A. M. Brodsky, Study of analyte diffusion into a silicone-clad fiber-optic chemical sensor by evanescent wave spectroscopy, Appl. Spectr., 49 [11], 1636-1645 (1995). 

ATR has been found as an easy to use, non-destmctive and surface-sensitive IR sampling technique for the in situ investigation of CMP processes (Hind et al., 2001). It was initially pushed by Harrick (1967) and comprehensively treated in his early book and following editions together with Mirabella (1985). Numerous alternative and partially deceptive names are used instead of ATR spectroscopy internal reflection spectroscopy, evanescent wave spectroscopy, frustrated total internal reflection (FTIR, which should not to be confused with Fourier-transform infrared spectroscopy) and multiple internal reflection (MIR, which should not to be confused with mid-infrared )- Therefore, in the following the term ATR as defined in Section 14.4.1 and illustrated with Figure 14.8 is used exclusively. 

Measurements with evanescent wave spectroscopy have been made, using both glass slides as a waveguide and optical fibres such as polymer-clad silica (PCS) fibre without the cladding. 

A large number of different biochemical systems have been studied by optical measurement on continuous surfaces, using ellipsometry, attenuated total refiection, interference techniques and total internal reflection fluorescence (reference 6 lists 45 different experiments). It is therefore likely that evanescent wave spectroscopy will become a widely applied technique in the future. 

Wise and co-workers used an infrared (IR) evanescent wave spectroscopy technique to follow the disappearance of a tracer of deuterated 1,4-polybutadiene (PBDE) displaced in a channel by unlabeled PBDE of the same molecular weight. Linear PBDE is a convenient polymer for experimental research because it flows at room temperature and has a viscosity that is relatively insensitive to shear rate. One face of the channel was fabricated from a ZnSe IR crystal, and the deuterated polymer was placed on the surface. The deuterated polymer was then allowed to equilibrate with hydrogenated polymer of the same molecular weight, and flow was initiated. The concentration of deuterated polymer in the wall region after the... 

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