Kinetics of the hydrolysis of woody-fibrous mass

The possibility has been shown of obtaining fodder additives by the hydrolysis of woody-fibrous mass with dilute sulfuric acid solutions. The kinetics of hydrolysis have been studied, a calculation has been made of the effective rate constants of hydrolysis of the polysaccharide part of the woody-fibrous mass, and the range of variation of the effective activation energy of the process has been determined.Deceased.Siberian Scientific Research Institute of Cellulose and Board, Bratsk. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 687–690, September–October, 1990.     

Kinetic analysis of cyclic CMP-specific and multifunctional phosphodiesterases by quantitative positive-ion fast-atom bombardment mass spectrometry

Two enzymes, cyclic CMP-specific phosphodiesterase and multifunctional phosphodiesterase, are responsible for the hydrolysis of cytidine 3',5'-cyclic monophosphate in living cells. Quantitation of both enzymes has been carried out by positive-ion fast-atom bombardment mass spectrometric analysis of the enzyme incubates after termination of the reaction. The kinetic data obtained are in close agreement with parallel data obtained by the conventional radiometric assay. The extra facility of the mass spectrometry based assay to monitor several incubation components simultaneously has been exploited to study the concurrent hydrolysis of alternate cyclic nucleotide substrates and provides kinetic parameters of significance in interpreting substrate-enzyme interactions. This is extended by the use of collisionally-induced dissociation of the protonated molecules of the liberated products to identify the mononucleotide isomers resulting from the cyclic nucleotide hydrolysis.     

Characterization of polyphosphoesters by fourier transform ion cyclotron resonance mass spectrometry

FT-ICR mass spectrometry, together with collision-induced dissociation and electron capture dissociation, has been used to characterize the polyphosphoester poly[1,4-bis(hydroxyethyl)terephthalate-alt-ethyloxyphosphate] and its degradation products. Three degradation pathways were elucidated: hydrolysis of the phosphate-[1,4-bis(hydroxyethyl)terephthalate] bonds; hydrolysis of the phosphate-ethoxy bonds; and hydrolysis of the ethyl-terephthalate bonds. The dominant degradation reactions were those that involved the phosphate groups. This work constitutes the first application of mass spectrometry to the characterization of polyphosphoesters and demonstrates the suitability of high mass accuracy FT-ICR mass spectrometry, with CID and ECD, for the structural analysis of polyphosphoesters and their degradation products.     

Electrospray ionization mass spectrometry coupled to liquid chromatography for detection of cisplatin and its hydrated complexes

Electrospray ionization mass spectrometry (ESI-MS) coupled to liquid chromatography (LC) has been applied to investigate cisplatin and its hydrated complexes. Three hydrolysis products were identified following incubation of cisplatin in aqueous solution: monohydrated species, dihydrated species and the hydroxo-bridged dimer, each of which exhibited characteristic mass spectrometric behavior. The technique was employed to investigate the time- and pH-dependent hydrolysis of cisplatin in aqueous solution. The results have demonstrated that LC/ESI-MS is a powerful technique for the analysis of Pt(II) complexes and for monitoring their hydrolysis reactions.     

Quantitation of the enantiomers of rimantadine in human plasma and urine by gas chromatography-mass spectrometry

A gas chromatographic-mass spectrometric procedure has been developed for the quantitation in plasma and urine of the enantiomers of rimantadine, an antiviral drug effective against type A influenza. The assay utilizes derivatization with an optically active reagent, selective ion monitoring, methane negative-ion chemical ionization (NICI) mass spectrometry and stable isotope dilution. The method has been used to measure concentrations of each rimantadine enantiomer over a range of 2.5-250 and 12.5-1250 ng/ml in the plasma and urine, respectively, of four male volunteers administered rimantadine. In plasma and urine, no differences were observed in the disposition of the unconjugated enantiomers. In urine, one enantiomer, but not both, was released following enzymatic hydrolysis.     

Identification des colles protéiques présentesdans les œuvres d’art par couplage CG/SMà trappe d’ions

In order to restore artworks, the identification of the organic binders used by the artists for their works is sometimes necessary. A method leading to a fast and effective identification of a very weak quantity of proteins has been carried out by using gas chromatography/mass spectrometry ions trap after hydrolysis and derivatisation by ethyl chloroformate of the binder. It is possible with this method to point out the presence of sturgeon glue in artworks.     

In Process Citation

The products of hydrolysis of tetrahydrozoline [2-(1,2,3,4-tetrahydro-1-naphthyl)-2-imidazoline] have been isolated by thin-layer chromatography and identified by ultraviolet and infrared spectroscopic analysis. Their structure has been well established by use of mass spectrometry and a degradation scheme advanced. Alkaline hydrolysis opens the imidazoline ring to give an amide compound which undergoes further hydrolysis, in acid solution, to 1,2,3,4-tetrahydronaphthoic acid and ethyl-enediamine.     

Radiochemical study of hydrolysable carbides

A simple radiochemical method has been developed for the phase analysis of hydrolysable carbides. The method is based on the radio gas chromatography of gaseous products of carbide hydrolysis with simultaneous mass and activity detection. The tritium-labelled hydrocarbons evolved (tritium oxide used for hydrolysis) are characteristic of the individual carbide phases. An application for Group III b carbide phase analysis is demonstrated.     

A Useful Disulfide Linker for Single‐Bead Analysis of Peptide Libraries

A disulfide‐linker for conventional peptide synthesis, attached to a PEGA‐resin, has been developed. Reductive hydrolysis cleaves the linker within minutes, liberating the synthesized peptide for rapid sequencing by tandem mass spectrometry. The method has been tested for ten peptides in a single‐bead fashion.     

Refinement of the structure of asperumine

Summary 1. Asperumine has been isolated from the combined alkaloids ofSymphytum caucasicum.2. The hydrolysis and hydrogenolysis of asperumine has given heliotridine, acetone, and angelic and asperuminic acids.3. The structure of asperumine has been refined on the basis of the products of hydrolysis and hydrogenolysis and also of features of the mass and NMR spectra.4. It has been established that asperumine is an isomer of heliosupine in the 2,3,4-trihydroxy-2-methylpentane-3-carboxylic acid moiety.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 478–480, July–August, 1974.     

单丁基磷酸酯的合成与表征

本文报道用三氯氧磷酯化、水解方法制备单丁基磷酸酯，用红外、核磁共振，质谱等方法对其结构进行了分析与表征。     

Oxygenated triacylglycerols of the lipids ofOnopordum acanthium seeds

The results on the structure and composition of the epoxyacyl-, hydroxyacyl-, and epoxyacylhydroxyacylacylglycerols ofOnopordum acanthium L. seeds obtained by enzymatic hydrolysis have been supplemented with the aid of mass spectrometry. The desirability of using a combination of the two methods for these purposes has been shown.     

Characterization of Ti(6)O(4)(O(2)C(4)H(5))(8)(OCH(2)CH(3))(8) by electrospray time of flight mass spectrometry

A titanium oxide molecular cluster prepared by hydrolysis of titanium tetraethoxide in the presence of methacrylic acid, can be characterized by electrospray time of flight mass spectrometry (ESMS-TOF). The chemistry of such systems is not well known and ESMS is a powerful technique for studying the reactions of clusters in solution. The fingerprint of the cluster fragmentation suggests formation of Ti(x)O(y) core fragments that represent commonly observed structural constructs in bulk titanium oxide metallates. The fragmentation steps provide insight into the hydrolytic conversion of this molecular sol gel intermediate into bulk TiO(2). While MS has been applied to the study of metal alkoxide hydrolysis mechanisms, mass spectra of isolated individual titanium oxide clusters have not previously been reported.     

Structure of synaptogenin B — An artefactual aglycone of glycosides from the holothurianSynapta maculata

The structure of the previously unknown synaptogenin B, the main product of the acid hydrolysis of the triterpene oligosides synaptosides S-2 and S-3 from the holothurianSynapta maculata has been established. To prove the structure, diketones were obtained from synaptogenin B and the known stichopogenin, and their identity was shown on the basis of¹H NMR and mass spectra. Synaptogenin B is a 3β-hydroxyholost-9(11)-en-23-one. It has been shown that holost-9(11)-en-3β-o1 is formed as minor component in the acid hydrolysis of the synaptosides.     

Hydrolytic stability of polybenzobisoxazole and polyterephthalamide body armor

Previous work conducted at the National Institute of Standards and Technology (NIST) to investigate the field failures of soft body armor containing the material poly(p -phenylene-2,6-benzobisoxazole), or PBO, revealed that this material was susceptible to hydrolysis, and a mechanism of this hydrolysis was proposed. In this work, viscometric estimations of the molar mass of environmentally conditioned PBO are used to support a previously proposed mechanism of PBO hydrolysis. Results with PBO were compared with poly(p-phenylene terephthalamide), or PPTA, which has been used in body armor applications for more than 30 years. Losses in tensile strength were found to correspond to a reduction in molar mass for PBO. This indicates that chain scission due to complete hydrolysis is occurring in this material. Similar trends were observed for PPTA, but the relationship between molar mass reduction and losses in tensile strength was not as evident for this material. Confocal microscopy, mechanical properties measurements, and molecular spectroscopy are used to further investigate the degradation of both PBO and PPTA.     

Inhibiting properties of lignin

Inhibitory efficacy has been determined by the method of the weight losses of steel in acid with native lignin, hydrolysis lignin, ammoniated native lignin, chlorinated hydrolysis lignin, and ammoniated hydrolysis lignin, and without these additives. It has been established that the efficacy of lignin and its modifications as inhibitors of acid corrosion increases with a rise in the number of carboxy groups in the macromolecule, and therefore the ammoniated hydrolysis lignin is the most effective.Central Scientific-Research and Planning Technological Institute for the Mechanization and Electrification of Animal Husbandry of the Southern Zone of the USSR. Zaporozh'e Astrakhan Technical Institute of the Fisheries Industry and Economy, Astrakhan'. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 378–380, May–June, 1983.     

Investigation of products arising from enzymatic digestion of advanced glycated albumin by high-performance liquid chromatography/mass spectrometry.

The structural investigation of the products arising from 28 days incubation of albumin with high glucose concentration and further enzymatic hydrolysis has been carried out by means of high-performance liquid chromatography/mass spectrometry (HPLC/MS) under plasmaspray conditions. By this approach many different compounds have been detected, and for most of them, possible structures have been proposed on the basis of literature data and molecular weight assignments.     

New evidence supporting the formation of a diaziridinium cation in the hydrolytic fission of diaziridines

The isolation and characterization of the bisulfate salt of the 3,3-dimethyldiaziridinium monocation is described. Elemental analysis, infrared, mass spectral, and conductivity data are presented along with results of chemical investigations to support the proposed structure. The only diaziridinium salts isolated previously were formulated as dications, hence the scope of diaziridine salt formation has been greatly expanded and new evidence has been provided which supports the formation of diaziridinium cations in acid hydrolysis and reductive fission.     

Problems associated with the surface characterization of polystyrene latices

It has been shown that polystyrene latices prepared by the surfactant free emulsion polymerization process often contain sufficient residual monomer and possibly low-molecular-weight material and reaction by-products, such as benzaldehyde, which are not efficiently removed by dialysis, to affect their bulk and surface characteristics. These materials have been identified by gel permeation chromatography (GPC) and infrared (IR) spectroscopy studies and their effective removal by steam stripping has been investigated. Steam stripping has proved to be efficient in this process but it led to rapid hydrolysis of the surface sulfate groups and a consequent change in the surface characteristics. The problem of hydrolysis of sulfate groups under various environments has been studied. The problems associated with the identification of weak acid end groups are discussed and several alternative explanations for their occurrence are advanced.     

The hydrolysis of clofentezine and related tetrazines as the basis of determination of residues in bovine tissues

Summary A method has been developed for the determination of total clofentezine-derived residues in bovine tissues. It comprises hydrolysis with conc. hydrobromic acid to effect liberation of the free metabolite residue and determination by gas chromatography with mass selective detection in the selected ion mode. The limit of determination is 0.05 mg/kg equivalent clofentezine.