Etude vibrationnelle des associations ioniques dans les solvants aprotiques. 7. Solvatation de (LiNCS)p par les solvants peu polaires

1984 ◽  
Vol 62 (11) ◽  
pp. 2320-2325 ◽  
Author(s):  
Martial Chabanel ◽  
Zhenglie Wang
Keyword(s):  
Ir Spectra ◽  
Ion Pair ◽  
The State ◽  
Infrared Spectrometry ◽  
Solvation Number ◽  
Donor Solvent

Solutions of LiSCN in donor solvent – benzene mixtures have been investigated by solubility measurements and by infrared spectrometry. The state of aggregation of LiSCN has been obtained from the ir spectra in the ν(CN) region 2100–2000 cm−1. The selected solvents (tetrahydrofuran, pyridine, acetone, diethylcarbonate, butylacetate, ethylmethylketone) are more or less associating towards LiSCN. The addition of benzene causes an increase of the associating ability of the solvents. By changing the donor solvent and the amount of benzene it has been possible to obtain the ion pair LiNCS, the dimer (LiNCS)2, and higher aggregates in various proportions. The solvation number of lithium has been measured in solvent vibration regions. Each step of aggregation is accompanied by lithium desolvation. The coordination of lithium in all the species which are formed remains equal to 4, or slightly lower in some cases.

Identification of Bromohydrins in Ozonated Waters

1994 ◽  
Vol 48 (10) ◽  
pp. 1181-1192 ◽  
Author(s):  
Timothy W. Collette ◽  
Susan D. Richardson ◽  
Alfred D. Thruston
Keyword(s):  
Ir Spectra ◽  
Intramolecular Hydrogen Bonding ◽  
Infrared Spectrometry ◽  
Molecular Mechanics Calculations ◽  
Adverse Health Effects ◽  
Resolution Electron ◽  
Electron Impact Mass ◽  
Intramolecular Hydrogen ◽  
Hydrogen Bound ◽  
By Products

Because ozonation is becoming a popular alternative to chlorination for disinfection of drinking water and little is known about the potential adverse health effects of ozonation disinfection by-products (DBPs), we have sought to identify ozone DBPs, particularly brominated organics, which are of principal concern due to their anticipated toxicity. Using gas chromatography coupled (independently) to low-resolution electron-impact mass spectrometry (LR-EI-MS), high-resolution EI-MS, chemical ionization MS (with 2% ammonia in methane), and Fourier transform infrared spectrometry, we have identified a series of bromohydrins and related compounds detected in extracts of an ozonated natural water sample that was artificially enhanced with bromide. The bromohydrins, which constituted the majority of by-products in the samples we studied, were detected but could not be identified by GC/LR-EI-MS, the technique used almost exclusively for environmental monitoring. A key to identifying the bromohydrins was the manifestation of intramolecular hydrogen bonding in the gas-phase IR spectra. Many of the by-products had two chiral centers, and both diastereomers were present and were separated by GC. In most cases, the IR spectra also permitted us to distinguish between diastereomers. We interpreted the IR and EI-MS spectra of several representative compounds in detail, and gave peak assignments for all that were identified. Molecular mechanics calculations and an experimental determination of the enthalpy change for conversion of free and hydrogen-bound conformers for a representative bromohydrin were used to verify the IR interpretations.

scholarly journals Biometric analysis of protein and oil contents of soybean genotypes in different environments

2014 ◽  
Vol 49 (6) ◽  
pp. 475-482 ◽  
Author(s):  
Josiane Isabela da Silva Rodrigues ◽  
Klever Márcio Antunes Arruda ◽  
Cosme Damião Cruz ◽  
Newton Deniz Piovesan ◽  
Everaldo Gonçalves de Barros ◽  
...  
Keyword(s):  
Minas Gerais ◽  
The State ◽  
Infrared Spectrometry ◽  
Environment Interaction ◽  
Soybean Genotype ◽  
Biometric Analysis ◽  
Genotype X Environment ◽  
Soybean Genotypes ◽  
Different Seasons ◽  
Selection For

The objective of this work was to identify by biometric analyses the most stable soybean parents, with higher oil or protein contents, cultivated at different seasons and locations of the state of Minas Gerais, Brazil. Forty-nine genotypes were evaluated in the municipalities of Viçosa, Visconde do Rio Branco, and São Gotardo, in the state of Minas Gerais, from 2009 to 2011. Protein and oil contents were analyzed by infrared spectrometry using a FT-NIR analyzer. The effects of genotype, environment, and genotype x environment interaction were significant. The BARC-8 soybean genotype is the best parent to increase protein contents in the progenies, followed by BR 8014887 and CS 3032PTA276-3-4. Selection for high oil content is more efficient when the crossings involve the Suprema, CD 01RR8384, and A7002 genotypes, which show high mean phenotypic values, wide adaptability, and greater stability to environmental variation.

The state of anthraquinone in sulfuric acid (UV and IR spectra)

1967 ◽  
Vol 1 (6) ◽  
pp. 565-568
Author(s):  
V. V. Kozlov ◽  
Yu. A. Kolesnik ◽  
L. A. Kazitsyna
Keyword(s):  
Sulfuric Acid ◽  
Ir Spectra ◽  
The State ◽  
Uv And Ir Spectra

Effect of the state of vanadium cations on the IR spectra of adsorbed carbon monoxide

1982 ◽  
Vol 20 (1-2) ◽  
pp. 93-98 ◽  
Author(s):  
A. A. Davydov ◽  
A. A. Budneva ◽  
N. G. Maksimov
Keyword(s):  
Carbon Monoxide ◽  
Ir Spectra ◽  
The State ◽  
Adsorbed Carbon

scholarly journals Feasibility of rapid quantitation of stratum corneum lipid content by Fourier transform infrared spectrometry

2004 ◽  
Vol 18 (3) ◽  
pp. 423-431 ◽  
Author(s):  
Jui-Chen Tsai ◽  
Yu-Li Lo ◽  
Ching-Yu Lin ◽  
Hamm-Ming Sheu ◽  
Jui-Che Lin
Keyword(s):  
Fourier Transform ◽  
Ir Spectra ◽  
Stratum Corneum ◽  
Lipid Content ◽  
High Performance ◽  
Fourier Transform Infrared ◽  
Infrared Spectrometry ◽  
Permeability Barrier ◽  
Fourier Transform Infrared Spectrometry ◽  
Stratum Corneum Lipid

The permeability barrier of skin resides in the stratum corneum, and its properties are mediated by a series of lipid multilayers, enriched in ceramides, cholesterol, and free fatty acids, segregated within the stratum corneum (SC) interstices. SC lipid content is usually determined by gravimetric methods in conjunction with high performance thin layer chromatography, but these methods are time‒consuming and involve hazardous solvents. The objective of the present study was to develop a method of measuring SC lipid content by Fourier transform infrared spectrometry (FTIR) that is fast and requires no solvents. The IR spectra of isolated porcine SC sheets were recorded using a FTIR spectrometer. SC lipid content was determined by gravimetric methods using chloroform–methanol extraction. The peak area of both the CH2symmetric (2850 cm−1) and asymmetric (2920 cm−1) stretching bands in the IR spectra of progressively solvent‒extracted porcine SC sheets decreased with increasing amount of SC lipids removed. When spectral analysis was performed by curve‒fitting using GRAMS/32 software between 3000 to 2800 cm−1, peak area ratios of CH2to CH3asymmetric stretching bands in the IR spectra of 46 isolated porcine SC samples were correlated to SC lipid content (R2=0.90), with the standard error of measurement of 1.91%. The study demonstrated the feasibility of using FTIR technique to rapidly and accurately measure SC lipid content.

scholarly journals Investigation of the catalytic site of actinidin by using benzofuroxan as a reactivity probe with selectivity for the thiolate-imidazolium ion-pair systems of cysteine proteinases. Evidence that the reaction of the ion-pair of actinidin (pKI 3.0, pKII 9.6) is modulated by the state of ionization of a group associated with a molecular pKa of 5.5

1983 ◽  
Vol 213 (3) ◽  
pp. 713-718 ◽  
Author(s):  
E Salih ◽  
K Brocklehurst
Keyword(s):  
Cysteine Proteinase ◽  
Ph Dependence ◽  
Thiol Group ◽  
Order Rate Constant ◽  
Ion Pair ◽  
The State ◽  
Catalytic Site ◽  
Analogous Reaction ◽  
Decreasing Ph ◽  
Electrophilic Reactivity

Benzofuroxan reacts with the catalytic-site thiol group of actinidin (EC 3.4.22.14, the cysteine proteinase from Actinidia chinensis) to produce stoicheiometric amounts of the chromophoric reduction product, o-benzoquinone dioxime, and of a catalytically inactive derivative of actinidin that is devoid of thiol and that is assumed to contain, initially at least, the sulphenic acid of cysteine-25. A similar result applies also to papain (EC 3.4.22.2). The rate of o-benzoquinone dioxime formation is neither increased by inclusion of 2-mercaptoethanol or hydroxylamine in the reaction mixture nor decreased by changing the solvent from H2O to 2H2O. The change of solvent was shown to be without effect also on the rate of reaction of benzofuroxan with papain. These results suggest that the reactions of benzofuroxan with both actinidin and papain involve rate-determining attack of the catalytic-site thiol group to produce an intermediate adduct that then reacts rapidly with water to form enzyme sulphenic acid and o-benzoquinone dioxime. The pH-dependence of the second-order rate constant for the reaction of benzofuroxan with actinidin was determined in the pH range 4.3-10.2. In marked contrast with the analogous reaction of papain (reported by Shipton & Brocklehurst [(1977) Biochem. J. 167, 799-810]) the pH-k profile for the actinidin reaction clearly contains a sigmoidal component with pKa 5.5, in which k increases with decreasing pH. These data together with the molecular pKa values for S-/ImH+ ion-pair formation and decomposition (3.0 and 9.6) suggest that the combined nucleophilic-electrophilic reactivity of the ion-pair of actinidin might be controlled by the state of ionization of another ionizing group, associated with the molecular pKa of 5.5. The pH-dependence of k for the reaction of actinidin with benzofuroxan at 25 degrees C at I 0.1 in aqueous buffers containing 6.7% (v/v) ethanol is probably adequately described by: k = k1/(1 + [H+]/KI + KII/[H+]) + k2/(1 + [H+]/KII + KIII/ [H+] + k3/(1 + [H+]/KIII) in which kI = 2.55 M -1 X s -1, k2 = 1.35 M -1, k3 = 0.93 M -1 X s -1, pKI = 3.0, pKII = 5.5 and pKIII = 9.6. By contrast, the analogous reaction of papain may be described by the same equation but with kI = 0, k2 = 2.2 M -1 X s -1, k3 = 1.3 M -1 X s -1, pKII = 3.6 and pKIII = 9.0.

scholarly journals Plasma Protein Contents Determined by Fourier-Transform Infrared Spectrometry

2001 ◽  
Vol 47 (4) ◽  
pp. 730-738 ◽  
Author(s):  
Cyril Petibois ◽  
Georges Cazorla ◽  
André Cassaigne ◽  
Gérard Déléris
Keyword(s):  
Fourier Transform ◽  
Ir Spectra ◽  
Spectral Range ◽  
Plasma Proteins ◽  
Fourier Transform Infrared ◽  
Infrared Spectrometry ◽  
Ir Absorption ◽  
Apo B ◽  
Ir Spectrometry ◽  
Ft Ir

Abstract Background: Fourier-transform infrared (FT-IR) spectrometry has been used to measure small molecules in plasma. We wished to extend this use to measurement of plasma proteins. Methods: We analyzed plasma proteins, glucose, lactate, and urea in 49 blood samples from 35 healthy subjects and 14 patients. For determining the concentration of each biomolecule, the method used the following steps: (a) The biomolecule was sought for which the correlation between spectral range areas of plasma FT-IR spectra and concentrations determined by comparison method was greatest. (b) The IR absorption of the biomolecule at the most characteristic spectral range was calculated by analyzing pure samples of known concentrations. (c) The plasma concentration of the biomolecule was determined using the FT-IR absorption of the pure compound and the integration value obtained for the plasma FT-IR spectra. (d) The spectral contribution of the biomolecule was subtracted from the plasma FT-IR spectra, and the resulting spectra were saved for further analyses. (e) The same method was then applied to determining the concentrations of other biomolecules by sequentially comparing the resulting FT-IR spectra. Results: Results agreed with those obtained by clinical methods for the following biomolecules when analyzed in the following order: albumin, glucose, fibrinogen, IgG2, lactate, IgG1, α1-antitrypsin, α2-macroglobulin, transferrin, apolipoprotein (Apo)-A1, urea, Apo-B, IgM, Apo-C3, IgA, IgG4, IgG3, IgD, haptoglobin, and α1-acid glycoprotein. Conclusion: FT-IR spectrometry is a useful tool for determining concentrations of several plasma biomolecules.

Carbon Dioxide Clathrates: An IR Spectroscopic Marker for Arthritis?

1993 ◽  
Vol 47 (9) ◽  
pp. 1519-1521 ◽  
Author(s):  
Hans H. Eysel ◽  
Michael Jackson ◽  
Henry H. Mantsch ◽  
Glen T. D. Thomson
Keyword(s):  
Carbon Dioxide ◽  
Synovial Fluid ◽  
Ir Spectra ◽  
Clinical Diagnosis ◽  
The State ◽  
Clathrate Hydrates ◽  
State Of Health ◽  
Biological Media ◽  
Ir Spectroscopic ◽  
Arthritic Joints

The IR spectra of dry films of synovial fluid from normal and arthritic joints are presented. The spectra suggest the existence of CO2 clathrates in these fluids which are of remarkable stability in comparison to well-known CO2 clathrate hydrates. To our knowledge, this is the first demonstration of the formation of CO2 clathrates in biological media. The proportion of CO2 clathrates found in synovial fluid appears to vary with the state of health of joints and thus may be of use in the clinical diagnosis of arthritis.

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