Beta spectroscopy

The basic information in the study of sorption processes is the quantity of substances on the interfaces. In order to measure the sorbed quantity accurately, very sensitive analytical methods have to be applied because the typical amount of particles (atoms, ions, and molecules) on the interfaces is about I0-5 mol/m2. In the case of monolayer sorption, the sorbed quantity is within this range. As the sorbed quantity is defined as the difference between quantities of a given substance in the solution and/or in the solid before and after sorption processes (surface excess concentration, Chapter 1, Section 1.3.1), all methods suitable for the analysis of solid and liquid phases can be applied here, too. These methods have been discussed in Sections 4.1 and 4.2. In addition, radioisotopic tracer method can also be applied for the accurate measurement of the sorbed quantities. On the basis of the radiation properties of the available isotopes, gamma and beta spectroscopy can be used as an analytical method. Alpha spectroscopy may also be used, if needed however, it necessitates more complicated techniques and sample preparation due to the significant absorption of alpha radiation. The sensitivity of radioisotopic labeling depends on the half-life of the isotopes. With isotopes having medium half-time (days-years), 10 14-10-10 mol can be measured easily. 

Usually, direct analysis of alpha, beta and some gamma emitters is impossible if the sample is not previously isolated and preconcentrated. There is little use of direct radiometric detection of beta emitters by beta spectroscopy or liquid scintillation because of its low capacity to discriminate between different beta particles. This is because beta particles from a single isotope are emitted with a range... 

Hoskins L C 1984 Resonance Raman-spectroscopy of beta-carotene and lycopene—a physical-chemistry experiment J. Chem. Educ. 61 460-2... 

K. Siegbahn, Beta- and Gamma-ray Spectroscopy, Interscience Publishers, New York, 1955. 

Ermakov IV, Ermakova MR, Gellermann W, and Lademann J (2004b), Non-invasive selective detection of lycopene and beta-carotene in human skin using Raman spectroscopy, J. Biomed. Opt. 9 332-338. 

Kosumi, D., K. Yanagi, R. Fujii, H. Hashimoto, and M. Yoshizawa. 2006. Conjugation length dependence of relaxation kinetics in beta-carotene homologs probed by femtosecond Kerr-gate fluorescence spectroscopy. Chem. Phys. Lett. 425 66-70. 

Young, S. H., Dong, W. J. and Jacobs, R. R. (2000). Observation of a partially opened triple-helix conformation in l->3-beta-glucan by fluorescence resonance energy transfer spectroscopy. J. Biol. Chem. 275, 11874-11879. 

Kobilka, B. K. and Gether, U. (2002). Use of fluorescence spectroscopy to study conformational changes in the beta 2-adrenoceptor. Methods Enzymol. 343, 170-82. 

Microporous nanoparticles with ordered zeolitic structure such as Ti-Beta are used for incorporation into walls or deposition into pores of mesoporous materials to form the micro/mesoporous composite materials [1-3], Microporous particles need to be small enough to be successfully incorporated in the composite structure. This means that the zeolite synthesis has to be stopped as soon as the particles exhibit ordered zeolitic structure. To study the growth of Ti-Beta particles we used 29Si solid-state and liquid-state NMR spectroscopy combined with x-ray powder diffraction (XRPD) and high-resolution transmission electron microscopy (HRTEM). With these techniques we monitored zeolite formation from the initial precursor gel to the final Ti-Beta product. 

Results of 29Si NMR spectroscopy of the Ti-Beta precursor gels are shown in Figure 1. The spectra exhibit peaks that belong to four major types of silica species, Q°, Q1, Q2, and Q3. Here Q" denotes a silicon environment with n Si-O-Si bonds. By comparison of the measured spectra with the 29Si NMR spectra found in the literature [4, 5] we were able to determine that the peak with the chemical shift of -72.9 ppm corresponds to Si monomer Q°, while the peaks at -80.9 ppm and -81.4 ppm are the peaks of Q1 linear trimer and dimer, respectively. The peaks from -83 ppm to -89.8 ppm were contributed to Q2 silicon oligomers, while the peaks at the chemical shifts from -90.3 ppm to -102 ppm were denoted as the part of the Q3 silica species. 

Si NMR spectroscopy reveals that the silicon monomers and dimers start to bind into higher silicon oligomers at the very beginning of the Ti-Beta synthesis procedure. After... 

With the combined methods of 29Si NMR spectroscopy, X-ray diffraction, HRTEM and SAED we were able to characterize the Ti-Beta particle growth. 29Si NMR spectroscopy gave us an opportunity to see the formation of nanoparticles even before they were detectable with other techniques such as XRD. The above mentioned techniques enabled us to obtain sufficient knowledge to prepare Ti-Beta nanoparticles which were than successfully incorporated in novel micro/mesoporous materials [1],... 

The NH4-Beta-300 (Zeolyst International, number denote Si02/Al203 molar ratio) was transformed to corresponding proton form using a step calcination procedure at 500 °C. H-Beta-300 was partially modified with Fe by repeated ion-exchange method (Fe(III)nitrate). The surface areas as well as acidities (Bronsted and Lewis acid sites) of Fe-Beta (iron content - 0.1 wt %) were determined by nitrogen adsorption and pyridine desorption at 250, 350 and 450 °C using FTIR spectroscopy [6]. 

Fleischmann M., Graves P.R., Robinson J., The Raman-spectroscopy of the ferricyanide ferrocyanide system at gold, beta-palladium hydride and platinum-electrodes, J. Electroanal. Chem. 1985 182 87-98. 

Stintzing FC, Schieber A and Carle R. 2002. Identification of betalains from yellowbeet (beta vulgaris L.) and cactus pear (Opuntiaficus-indica L. Mill.) by high performance liquid chromatography-electrospray ionization mass spectroscopy. J Agric Food Chem 50 2302—2307. 

Saaby S, Knudsen KR, Ladlow M, Ley SV (2005) The Use of a Continuous Flow-Reactor Employing a Mixed Flydrogen-Liquid Flow Stream for the Efficient Reduction of Imines to Amines. Chem Commun 23 2909-2911 Seebach D, Overhand M, Kilhnle FNM, Martinoni D, Oberer L, Hommel U, Widmer H (1996) Beta-Peptides Synthesis by Arndt-Eistert Homologation with Concomitant Peptide Coupling. Structure Determination by NMR and CD Spectroscopy and by X-ray Crystallography. Helical Secondary Structure of a Beta-Hexapeptide in Solution and its Stability Towards Pepsin. Helv Chim Acta 79 913-941... 

The various spectroscopic techniques had revealed that Ti4+ ions in TS-1, Ti-beta and, Ti-MCM-41 are 4-coordinate in the dehydrated state. Tetrapodal Ti(OSi)4 and tripodal Ti(OH)(OSi)3 are the main Ti species. Upon exposure to H20, NH3, H202, or TBHP, they increase their coordination number to 5 or 6. On samples in which the Ti4+ has been grafted onto the silica (referred to as Ti f MCM-41), a dipodal Ti species (Ti(OH)2(OSi)2) may also be present. As a result of interaction with the oxidant ROOH (R = H, alkyl), the formation of 7)1- and p2-peroxo (Ti-O-O-), hydroperoxo (Ti-OOH), and superoxo (Ti02 ) species has been observed experimentally (Section III). A linear correlation between the concentration of the p2-hydroperoxo species and the catalytic activity for propene epoxidation has also been noted from vibration spectroscopy (133). 

J. Nishikawa, K. Tori, 3-Substituent Effect and 3-Methylene Substituent Effect on the Structure-Reactivity Relationship of 7 beta-(Acylamino)-3-cephem-4-carboxylic Acid Derivatives Studied by Carbon-13 and IR Spectroscopies , J. Med. Chem. 1984, 27, 1657-1663. 

Caldwell, G.W., Easlick, S.M., Gunnet, J., Masucci, J.A., and Demarest, K., In vitro permeability of eight beta-blockers through Caco-2 monolayers utilizing liquid chromatography/electrospray ionization mass spectroscopy, /. Mass Spectrom., 33, 607,1998. 

TTie TOCSY 2D NMR experiment correlates all protons of a spin system, not just those directly connected via three chemical bonds. For the protein example, the alpha proton, Ft , and all the other protons are able to transfer magnetization to the beta, gamma, delta, and epsilon protons if they are connected by a continuous chain—that is, the continuous chain of protons in the side chains of the individual amino acids making up the protein. The COSY and TOCSY experiments are used to build so-called spin systems—that is, a list of resonances of the chemical shift of the peptide main chain proton, the alpha proton(s), and all other protons from each aa side chain. Which chemical shifts correspond to which nuclei in the spin system is determined by the conventional correlation spectroscopy connectivities and the fact that different types of protons have characteristic chemical shifts. To connect the different spin systems in a sequential order, the nuclear Overhauser effect spectroscopy... 

Infrared spectroscopy has been used to help solve or determine the structure of zeolites. The technique is particularly useful for identifying the presence of double four- and six-rings as well as five-membered pentasil rings. In the structural characterization of beta zeolite, Newsam and coworkers used a variety of techniques including IR, electron microscopy (TEM), X-ray diffraction (XRD) and sorption data to solve the stacked, faulted structure [57]. The presence of IR absorption bands at 1232 and 560cm indicated that the structure contained five-member pentasil building units. 

A series of Beta zeolites have been synthesized in the presence of tetraethylammonium hydroxide (TEA). Samples with Si/Al ratio in the 7-100 range have been characterized by X-ray powder diffraction, I.R. spectroscopy, and pyridine adsorption. The fraction of TEA which is compensating the charge of the framework aluminum is removed at temperatures higher than those required to remove "occluded" TEA. Three hydroxyl bands are observed at 3740 cm l (silanol groups), 3680 cm" (extraframework Al) and 3615 cm 1 (acid hydroxyl groups interacting with pyridine). 

The tetraethylammonium-Beta (TEA-3) zeolites used in this work have been synthesized following the procedure described in the literature (5). Samples with Si/Al ratios between 7 and 106 (as measured by chemical analysis) and crystallite sizes in the range of 0.2-0.9 ym (as measured by scanning microscopy) were obtained. The H-form of these zeolites was prepared in the following way the TEA-3 samples were heated at 550 C for 3 hours by slowly increasing the calcination temperature (5°C min l), with one-hour intermediate steps at 350 and 450 C. After this treatment all TEA molecules had been removed from the zeolite (as monitored by IR spectroscopy). In a second step, the zeolite was exchanged with 1 M ammonium acetate solution and then heated at 550°C for 3 hours as described. 

Handhook of Experimental Stress Analysis , J. Wiley, NY (1950), p 982 (Fairly comprehensive description of y-ravs technique is given) 11) K. Siegbahm, "Beta and Gamma Ray Spectroscopy , Interscience, NY (1955) 12)W.J. Price, "Nuclear Radiation Detection ,... 

The wavelengths of IR absorption bands are characteristic of specific types of chemical bonds. In the past infrared had little application in protein analysis due to instrumentation and interpretation limitations. The development of Fourier transform infrared spectroscopy (FUR) makes it possible to characterize proteins using IR techniques (Surewicz et al. 1993). Several IR absorption regions are important for protein analysis. The amide I groups in proteins have a vibration absorption frequency of 1630-1670 cm. Secondary structures of proteins such as alpha(a)-helix and beta(P)-sheet have amide absorptions of 1645-1660 cm-1 and 1665-1680 cm, respectively. Random coil has absorptions in the range of 1660-1670 cm These characterization criteria come from studies of model polypeptides with known secondary structures. Thus, FTIR is useful in conformational analysis of peptides and proteins (Arrondo et al. 1993). 

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