Fluorescence spectroscopy reporter probes

It is of interest to examine the development of the analytical toolbox for rubber deformulation over the last two decades and the role of emerging technologies (Table 2.9). Bayer technology (1981) for the qualitative and quantitative analysis of rubbers and elastomers consisted of a multitechnique approach comprising extraction (Soxhlet, DIN 53 553), wet chemistry (colour reactions, photometry), electrochemistry (polarography, conductometry), various forms of chromatography (PC, GC, off-line PyGC, TLC), spectroscopy (UV, IR, off-line PylR), and microscopy (OM, SEM, TEM, fluorescence) [10]. Reported applications concerned the identification of plasticisers, fatty acids, stabilisers, antioxidants, vulcanisation accelerators, free/total/bound sulfur, minerals and CB. Monsanto (1983) used direct-probe MS for in situ quantitative analysis of additives and rubber and made use of 31P NMR [69]. 

Fluorescence spectroscopy is also particularly well-suited to clarify many aspects of polymer/surfactant interactions on a molecular scale. The technique provides information on the mean aggregation numbers of the complexes formed and measures of the polarity and internal fluidity of these structures. Such interactions may be monitored by fluorescence not only with extrinsic probes or labelled polymers, but also by using fluorescent surfactants. Schild and Tirrell [154] have reported the use of sodium 2-(V-dodecylamino) naphthalene-6-sulfonate (SDN6S) to study the interactions between ionic surfactants and poly(V-isopropylacrylamide). 

A detailed study of the structure of the aggregates of the ionic surfactants in polyelectrolyte networks was presented in Refs. [66,68]. The dynamics of the changes in the microenvironment of the fluorescent probe, pyrene, in slightly crosslinked networks of poly(diallyldimethylammonium bromide) (PDADMAB) during diffusion of sodium dodecyl sulfate (SDS) in the gel phase has been investigated by means of fluorescence spectroscopy. In Ref. [66], an analogous investigation was reported for complexes formal by the sodium salt of PMAA with cetyltrimethylammonium bromide (CTAB). 

The measurements of temperature and species concentrations profiles in premixed, laminar flames play a key role in the development of detailed models of hydrocarbon combustion. Systematic comparisons are given here between a recent laminar methane-air flame model and laser measurements of temperature and species concentrations. These results are obtained by both laser Raman spectroscopy and laser fluorescence. These laser probes provide nonintrusive measurements of combustion species for combustion processes that require high spatial resolution. The measurements reported here demonstrate that the comparison between a model and the measured concentrations of CH, O2,... 

For TIR fluorescence spectroscopy on water/oil interfaces, the choice of a probe molecule is of primary importance. For example, the penetration depth (dp) of an incident evanescent wave at a 1,2-dichloroethane (DCE, refractive index (n) n = 1.44)/water (m2 = 1.33)interface is calculated to be 94nm on the basisofEquation(13),whereX = 580 nm and 0 = 80°. It has been reported that the thickness of a sharp water/oil interface represented by water/DCE is 1 nm [9], so that dp of the incident evanescent wave is thicker than the thickness of the interfacial layer, and the fluorescence characteristics of a probe molecule in the bulk phase are superimposed, more or less, on those at the interface [2]. Therefore, a probe molecule should be highly surface-active and adsorb on the interface, so as to exclude fluorescence of the probe molecule from the bulk phase. In the present experiments, we employed xanthene dyes as fluorescence probes throughout... 

The fluorescent ddA 5 -triphosphate derivative (163) was shown to be an effective substrate for terminal transferase, and various DNA polymerases. The resultant DNA could then be detected by fluorescence spectroscopy. A molecular beacon DNA probe incorporating a donor and a quencher dye has been reported, " which shows high sensitivity and dynamic range. Such molecular beacons are anticipated to have use in DNA/RNA and pro-tein/DNA/RNA interactions. 

Chemical reactions can also take place in GUVs and the synthesis of mRNA inside giant vesicles by T7 RNA polymerase was reported by Oberholzer. Giant vesicles were prepared by the electroformation method and the feasibility of the polymerization was shown after the demonstration that the membrane of some giant vesicles was permeable to nucleotides triphosphates coming from outside the GUV in the presence of ethanol. Typically, the GUVs were loaded by microinjection with the polymerase, and the DNA template necessary for the mRNA synthesis. Finally, the kinetic of the polymerization was probed as a function of time of incubation by fluorescence spectroscopy (Figure 24). 

Various experimental probes on the hydration-shell structure of Cm (aq) reported in literature have yielded a wide range of coordination numbers. To mention a few, EXAFS experiments measured primary hydration numbers of 9 or 7 (based on the truncation of the EXAFS fitting data) in 1M HCIO4 acid [114] and 10 in 0.25 M HCl acid [115]. High energy X-ray scattering (HEXS) experiments yielded a hydration number of 8.8 [114]. Time-resolved laser fluorescence spectroscopy (TREES) found coordination numbers between... 

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