Iodine fluorescence

Complexes of ruthenium(ll) and methyl-substituted derivatives of 1,10-phenanthroline have been suggested as iodine fluorescent indicators under conditions where a starch does not function, such as highly acid, dilute, or colored solutions. 

Fig. 5 ES cells, eluted as shown in Fig. 4, are characterized according to functional parameters described in the text Bidimensional cytometric map of FS and fluorescence (Ki67). Right Monodimensional propidium iodine fluorescence. Up center Clonogenicity activities of the three collected fractions of Fig. 4. Down center Microscopic image of ES cell clone.

Figure 34. Normalized iodine fluorescence intensity vs. applied potential and reflectivity profile for a Pt/C LSM immersed in an aqueous solution containing SOpM NaI/0.1 M NajS02-(From Abruna, H. D., White, J. H., et al., J. Phys. Chem. 92, 7045 (1988), with permission.)...

Munkner T. 1974. Iodine fluorescent scintigraphy. In XVI Collogue de Mddecine Nucleaire de Langue Franfaise, Clermont Ferrand. 

The sample is pyrolyzed in an 80/20 mixture of oxygen and nitrogen at from 1050 to 1100°C the combustion gases are analyzed by iodine titration or by UV fluorescence. Up to 20% of the sulfur can escape analysis, however. 

Most of the thiazoles studied absorb in the ultraviolet above 254 nm, and the best detection for these compounds is an ultraviolet lamp (with plates containing a fluorescent indicator). Other indicator systems also exist, among which 5% phosphomolybdic acid in ethanol, diazotized sulfanilic acid or Pauly s reagent (Dragendorff s reagent for arylthiazoles), sulfuric anisaldehyde, and vanillin sulfuric acid followed by Dragendorff s reagent develop alkylthiazoles. Iodine vapor is also a useful wide-spectrum indicator. 

Unlike the situation regarding the crossing between the Vq and Fj potentials for Nal (see Figure 9.41), that for NaBr results in very efficient and rapid dissociation to give Na + Br when it is excited to Fj. Flow would you expect the fluorescence intensity from the neutral bromine atoms to vary with time compared with that for iodine atoms from Nal in Figure 9.42 ... 

Thin-Layer Chromatography. Chiral stationary phases have been used less extensively in tic as in high performance Hquid chromatography (hplc). This may, in large part, be due to lack of avakabiHty. The cost of many chiral selectors, as well as the accessibiHty and success of chiral additives, may have inhibited widespread commerciali2ation. Usually, nondestmctive visuali2ation of the sample spots in tic is accompHshed using iodine vapor, uv or fluorescence. However, the presence of the chiral selector in the stationary phase can mask the analyte and interfere with detection (43). 

Iodine vapor is characterized by the familiar violet color and by its unusually high specific gravity, approximately nine times that of air. The vapor is made up of diatomic molecules at low temperatures at moderately elevated temperatures, dissociation becomes appreciable. The concentration of monoatomic molecules, for example, is 1.4% at 600°C and 101.3 kPa (1 atm) total pressure. Iodine is fluorescent at low pressures and rotates the plane of polarized light when placed in a magnetic field. It is also thermoluminescent, emitting visible light when heated at 500°C or higher. 

Emetine andcephaeline, the two major alkaloids of ipecacuanha, begin to fluoresce after treatment with iodine vapor [254], The molecular iodine, which acts as a quencher, must be removed by heating in the drying cupboard or on a hotplate... 

Exposure of rhodamine 6G-impregnated silica gel layers to iodine vapor for two to five minutes followed by irradiation with UV light leads to the sensitive blue coloration of the chromatogram zones on a greenish fluorescent background [8, 10]. 

Emetine, cephaeline Silica gel 60 After iodine treatment emetine fluoresces yellow and cephaeline blue [17]... 

Brown-violet chromatogram zones are generally formed on a yellow background and, in some cases, these fluoresce when viewed under UV light (X = 254 or 365 nm) after the evaporation of the excess iodine. Sometimes colorless chromatogram zones are formed on a brown background, for example, if the iodine reacts chemically with the substances that are chromatographed. 

Nitrous fiunes reagent 225, 226 Nondestructive detection 42 ff -with fluorescent reagents 44 -with iodine 46 -with pH-indicator 45 Noradrenaline 76, 240, 393 — 396 Norephedrine 76 Norfenefnne 76 Norfenfluramine derivatives 45 1 l-Nor-d -THC-9-carboxy lie acid 289,292 Novonal 339 Nucleosides 364... 

Figure 5.16. Plot of data for the external heavy-atom quenching of pyrene fluorescence in benzene at 20°C. Polaro-graphic half-wave reduction potentials Ein are used as a measure of the electron affinity of the quencher containing chlorine (O), bromine ( ), or iodine (3). From Thomaz and Stevens<148) with permission of W. A. Benjamin, New York.

The iodine-catalyzed photoisomerization of all-trans- a- and (3-carotenes in hexane solutions produced by illumination with 20 W fluorescence light (2000 lux) and monitored by HPLC with diode-array detection yielded a different isomer distribution (Chen et al. 1994). Four cis isomers of [3-carotene (9-cis, 13-cis, 15-cis, and 13,15-cli-r/.v) and three cis isomers of a-carotene (9-cis, 13-cis, and 15-ri.v) were separated and detected. The kinetic data fit into a reversible first-order model. The major isomers formed during the photosensitized reaction of each carotenoid were 13,15-di-d.v- 3-carotene and 13-ds-a-carotene (Chen et al. 1994). 

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