Substrate Fiber-optic probe

The biberty (Fig. 10), a monomode microwave reactor for automated SPPS, was recently introduced by the CEM Corporation [153]. Although this instrument was originally developed for SPPS, it also allows for a broader scale of solid-phase applications. The solid-phase vial is equipped with a polypropylene frit and cap at one end (the entire assembly fitting into the standard 10 mb CEM reaction vessel) to allow the processing of 0.1 to 1.0 mmol quantities of resin attached substrates. An integrated fiber optic probe provides... 

Volkan M., Stokes D.L., Vo-Dihn T., Surface-enhanced Raman of dopamine and neurotransmitters using sol-gel substrates and polymer-coated fiber-optic probes, Appl. Spectrosc. 2000 54 1842-1848. 

All plasma exposures were carried out in an IPC (International Plasma Corporation) 2005 capacitance-coupled barrel reactor at 13.56MHz. The reactor was equipped with an aluminum etch tunnel and a temperature controlled sample stage. Pressure was monitored with an MKS capacitance manometer RF power was monitored with a Bird R.F. power meter and substrate temperature was measured with a Fluoroptic thermometer utilizing a fiber optic probe which was immune to R.F. noise. 

One of the most important sensors needed is one that reliably monitors cell density. An IR fiber-optic cell density probe has been used for this because it can directly monitor cell growth (without dilution) in high-cell-density bacterial fermentations. The ability to do an online sample filtration through the use of hollow fibers or rotating filters has made possible continuous, online measurement of glucose, lactate, and other metabolites. However, glucose, nitrogen substrate, and phosphate sensors that can withstand repeated system sterilization are still needed. 

Optodes provided with non-fluorescent esters of fluorophores have been used for the determination of external enzyme activities. The fluorophores are liberated by the enzymes and then seen by the optical Ober [214], As ecamples of p(02)-modulated optical biosensors, a glucose probe [213] and an ethanol probe [216] can be mentioned sensors based on glucose, alcohol, and other oxidases were reviewed by Opitz and Lttbbers [217]. The advantages of these 02-dependent optical biosensors are that, unlike corresponding amperometric sensors, they do not consume O2 and that they are strictly diffusion limited in their response. Fiber-optical devices are also available for the determination of substrates of dehydrogenases the NADH fluorescence produced by the immobilized enzyme is measured as a function of time [218, 219]. 

In the case of oversized samples (e.g., works of art), substrates with unusual shapes or difficult to get at samples such as board components or recessed sample areas, coatings can be remotely probed using a fiber-optic interface that directs the light from the source into a sampling probe head and thereafter collects the transmitted light into the detector of an IR spectrometer. The probe head (a mini-turized ATR element or a reflectance probe with actual sample interface areas as... 

FIGURE 17.40 Working principle of SPECM. A combined optical fiber/microelectrode probe excites photoreactions on a substrate (here oxidation of Br") and also detects photoproducts amperometrically (hereby reducing the photogenerated Br2). (Adapted from Casillas, N. et al., J. Electrochem. Soc., 142, L16,1995. With permission. Copyright 1995 Electrochemical Society.)... 

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