bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fast‐atom bombardment mass spectrometry of peptide derivatives with diethylpyrocarbonate
Authors: Foti Salvatore , Marletta Donata , Saletti Rosaria , Petrone Goffredo , Daolio S. 
Published: May 2005

AbstractThe reaction products of five peptides with diethylpyrocarbonate, a site‐specific reagent for histidine residues and amino groups, have been synthesized, isolated by high‐performance liquid chromatography (HPLC) and identified by fast‐atom bombardment (FAB) mass spectrometry. Peptides containing histidine, as well as compounds resulting from the N‐carboethoxylation of terminal amino groups and the histidine imidazole ring, provide a derivative produced by cleavage of the histidine heterocyclic ring through a Bamberger reaction. The main masss spectral features of these derivatives are discussed in comparison with structurally related compounds. HPLC along with with FAB MASS spectrometry shows itself to be a suitable technique for the characterization of these structures.
A phenomenological description of a black hole for collisionally induced decomposition products in ion‐trap mass spectrometry
Authors: Guidugli Federico , Traldi Pietro 
Published: May 2005

AbstractThrough extensive studies of collisionally induced decompositions of different precursors by ion‐trap mass spectrometry, the presence of a shadow region was demonstrated. If fragment ions fall into the stability diagram at a qz value of ∼0.78, their absolute intensities drop almost to zero. In order to test this phenomenon, different precursors and different collisionally produced fragment ions have been examined and in every case the fragment at qz = 0.78 disappeared, suggesting that such qz values can be considered as black holes in the microcosmos of the ion‐trap mass spectrometer.
Improved electrospray ionization of synthetic oligodeoxynucleotides
Authors: Stults John T. , Marsters James C. , Carr Steven A. 
Published: May 2005

AbstractA method is described for rapid purification of synthetic oligodeoxynucleotides to remove sodium counter ions prior to electrospray ionization mass spectrometry. The oligomers, following purification by gel electrophoresis, are precipitated from ammonium acetate to replace sodium ions by ammonium ions, and dissolved in water. Negative‐ion electrospray spectra are presented for oligomers with up to 48 residues in which the most intense peaks correspond to the [MnH]n− ion. The spectrum of 77‐mer (Mr24039) shows the predominant peak as due to retention of only a single sodium ion. Changes in the spectra are reported for different instrument orifice voltages and different solution pH. The method should permit rapid, accurate analysis of most typical, synthetic oligodeoxynucleotides.
Behaviour of tetrabutylammonium tribromide under fast‐atom bombardment using protic and aprotic matrices
Authors: Lange C. , Benammar Y. , Berthelot J. 
Published: May 2005

AbstractTetrabutylammonium tribromide in a protic matrix, under FAB desorptiono, does not provide the tribromide anion as it does in the gas phase. In contrast, using an aprotic matrix it gives a complex tribromide anion.
Maximum entropy deconvolution in electrospray mass spectrometry
Authors: Ferrige A. G. , Seddon M. J. , Jarvis S. , Skilling John , Aplin Robert 
Published: May 2005

AbstractThe maximum entropy (MaxEnt) technique has been well established in image processing for the last decade. In more recent times MaxEnt has been applied to spectroscopic techniques and shows considerable promise. As part of a much wider evaluation of the Cambridge software, specifically MemSys3, the MaxEnt technique has been successfully applied to electrospray mass spectra.
Energetics of gramicidin S after UV laser desorption from a ferulic acid matrix
Authors: Huth‐Fehre T. , Becker C. H. , Beavis Ronald C. 
Published: May 2005

AbstractPhotoionization with coherent 118 nm vacuum ultraviolet light is applied to study kinetic energies of gramicidin S and ferulic acid molecules, laser desorbed from a ferulic acid matrix with 266 nm light. Analysis of the matrix photodecomposition products shows decarboxylation as a main photochemical pathway involved with desorption. Entrainment of the polypeptide by the matrix molecules is found under typical conditions. However, the velocity distributions are not particularly narrow, being at most borderline supersonic.
Charge‐remote fragmentation of taurine‐conjugated bile acids
Authors: Griffiths William James , Egestad Börje , Sjövall Jan 
Published: May 2005

AbstractTaurine‐conjugated bile acids are an important group of biological metabolites. When investigated by negative‐ion fast‐atom bombardment collision‐induced dissociation mass spectroscopy they show charge‐remote fragmentations of the [MH]− pseudomolecular ion. These fragmentations provide information on the positions of ring substituents remote from the charge site. In the present work we have compared the negative‐ion fast‐atom bombardment collision‐induced dissociation spectra of six different conjugated bile acids.
An ion‐storage time‐of‐flight mass spectrometer for analysis of electrospray ions
Authors: Boyle James G. , Whitehouse Craig M. , Fenn John B. , Cotter Robert J. 
Published: May 2005

AbstractA preliminary design and implementation of a novel approach to electrospray‐mass spectrometry anr described. Based on a time‐of flight mass analysis, the instrument provides several important advantages for on‐line mass analysis: 1, simplicity, ease of use and low manufacturing cost; 2, rapid scan speed, yielding quasi‐instantaneous full mass scans at repetition rates up to several kHz; 3, soft ionization and accurate mass determination of extremely large analyte molecules; 4, high sensitivity.
Dynamic fast‐atom bombardment mass spectrometry of conjugated metabolites of benzo[a]pyrene
Authors: Yang Yang , Egestad Börje , Jernström Bengt , Sjöovall Jan , Gustafsson Jan‐Åke , Rafter Joseph , Bailli T. A. 
Published: May 2005

AbstractThe N‐acetylcysteine, cysteine and gluathione conjugates of r‐7,t‐8‐dihydroxy‐t‐9,10‐oxy‐7,8,9,10‐tetrahydrobenzo[a]pyrene as well as sulphuric and glucuronic acid conjugates of hydroxybenzo[a]pyrenes have been studied by fast‐atom bombardment mass spectrometry (FABMS). Dynamic FABMS has been shown to be advantageous over conventional static FABMS giving more intense spectra with less material in both positive‐and negative‐ion modes. The spectra show quasmolecular ions and fragment ions indicative of the aglycome and/or the conjugating group.
Pyrolysis/mass spectrometry and pyrolysis/gas chromatography/mas spectrometry analysis of polymers
Authors: Blazsó Marianne , Vékey Kàroly 
Published: May 2005

AbstractThe potential of pyrolysis/gas chromatography/mass spectrometry in the study of the chemical composition and structure of polymers and copolymers is demonstrated, and results obtained on polysilane copolymers, phenol‐formaldehyde polycondensates and diol modified epoxy resins are presented. Temperature/time‐resolved pyrolysis mass spectrometry, carried out in the direct inlet of a mass spectrometer, revealed the presence of monomer and oligomer residues and of volatile additives in epoxy resin samples. Basic information was also obtained on the mechanism of thermal decomposition reactions in polysilane copolymers and diol modified epoxy resins.
On some preparation methods in stable‐isotope mass spectrometry and their geochemical applications
Authors: Demény Attila , Fórizs István 
Published: May 2005

AbstractPreparation of samples and their introduction into the mass spectrometer are very important in stable‐isotope mass spectrometry. The authors have found that using the Coleman method for hydrogen gas preparation from water an improved reproducibility can be achieved if the reaction tube containing the zinc and hydrogen gas is kept at >350°C when the hydrogen is collected into the mass spectrometer for measurement. One of the critical conditions for the carbonate preparation is the quality of phosphoric acid. The reproducibility is better if before every preparation series the phosphoric acid is saturated adding phosphoric pentoxide to the acid at 150°C. As an application of stabvle‐isotope mass spectrometry the origin of a certain limestone near Budapest (Hungary) has been determined after a long dispute among geologists.
Mass spectrometry in the study of advanced glycation processes, responsible for long‐term diabetes complications
Authors: Lapolla Annuniziata , Fedele Domenico , Seraglia Roberta , Traldi Pietro , Vékey Kàroly 
Published: May 2005

AbstractMass spectrometry has been usefully employed in the study of the products arising from in vitro and in vivo glycation of proteins. In particular, daughter‐ion spectroscopy has led to an easy detection of 2‐(2‐furoyl)4‐(5)2(furanyl)1‐H‐imidazole in HCI‐hydrolysed glycated albumen and polylysine and the method has allowed us to exclude the presence of the same molecule in in vivo glycated proteins. parent‐ion spectroscopy has been successfully employed in the identification of furoyl‐containing compounds, which are possibly responsible for the results obtained with other analytical approaches.
Calibration and mass measurement in negative‐ion fast‐atom bombardment mass spectrometry
Authors: Sim P. G. , Boyd R. K. , Bertrand M. J. 
Published: May 2005

AbstractThe problem of acceptable accuracy in mass calibration for fast‐atom bombardment (FAB) mass spectrometry has recently received some attention (K. Véekey, Rapid Commun. Mass Spectrom., 2, 213 (1988); Idem., Org. Mass Spectrom., 24, 183 (1989). We describe here a calibration method for negative‐ionFAB, using gold cluster ions, which provides facile mass calibration over the range from can 200u to 10000u. Under suitable conditions, it is possible to use these ions as internal standards for accurate mass measurement.
Mass spectrometry of macrocyclic compounds
Authors: Kiremire Bernard , Seraglia Robert , Traldi Pietro 
Published: May 2005

AbstractThe mass spectrometric behaviour of more than 60 different macrocyclic compounds is reviewed in detail with the aim of depicting general fragmentation pathways, well‐related to the different structural classes. In general, the electron‐ionization‐induced decomposition is characterized by the ejection of single molecules characteristic of the macrocycle. [M + H]+ and [M/2 + H]+ ions are always encountered due to the intrinsic basicity of such molecules.
Direct molecular weight determination of resin‐bound oligopeptides using 252Cf plasma‐desorption mass spectrometry
Authors: Van Veelen P. A. , Tjaden U. R. , Van Greef J. Der 
Published: May 2005

AbstractPlasma‐desorption mass spectrometry is proved to be capable of the direct molecular weight determination of totally protected resin‐bound oligopeptides. The molecular weight measured is the molecualr weight of the fully protected oligopeptide including the molecular weight of the linker, which connects the oligopeptide and the polystyrene resin. This method makes it possible to check the success of (a step in) the synthesis of a peptide before its deprotection or cleaving from the resin. This can made it a strong tool in the analysis of resin‐bound oligopeptides.
Analysis of human pictuitary growth hormone and its charge varriants by fast‐atom bombardment mass spectrometry
Authors: Silberring Jerzy , Brostedt Peter , Ingvast Ander , Nyberg Fred 
Published: May 2005

AbstractThere is evidence that even highly purified preparations of human growth hormone are not homogenous, but contain charge as well as size variants. The charge heterogeneity was suggested to be due to deamidation of the native hormone. To verify this we have applied peptide mapping followed by fast‐atom bombardment mass spectrometry (FAB‐MS), in order to identify fragments containing the altered amino acids. Growth hormone was purfied from human pituitaries and the differently charged forms were separated by column electrophoresis in agarose suspension. The isolated components were treated with trypsin and analysed directly by FAB‐MS without prior separation by reversed‐phase high‐performance liquid chromatography (RP‐HPCL). Using this technique, approximately 80% of the normone structure was recovered and two deamidation sites were found in the fragment T15 (FDTNSHNDDALLK). The results clearly elucidated the potential use of FAB‐MS for the fast secreening of other variants of the growth hormone which are known to exist.
The use of 4‐hydroxybenzenesulfonic acid as a reduction‐inhibiting matrix in liquid secondary‐ion mass spectrometry
Authors: Visentini J. , Nguyen P. M. , Bertrand Michel J. 
Published: May 2005

AbstractThe use 4‐hydroxybenzenesulfonic acid as reduction‐inhibiting and general purpose matrix in fast‐atom bombardment liquid secondary‐ion mass spectrometry (FAB/LSIMS) is discussed. Results obtained in a comparative study using the disulfide‐bridge containing peptide deaminoarginine‐vasopressin and several commonly used matrices indicate that the reduction‐inhibitaing efficiency of 4‐hydroxybenzenesulfonic acid is comparable to that of 3‐nitrobenzyl alcohol while recuction is found to be important in matrices such as thioglycerol and glycerold. Experiments conducted on peptides such as met‐enkephalin and bradykinin, nucleosides and other polar compounds reveal that 4‐hydroxybenzenesulfonic acid is a good solvent and has physical properties which are similar to those of glycerol. This new matrix material is a radical scavenger, surface active, allows persistent secondary‐ion beams and produces a low background signal. The matrix, 4‐hydroxy‐benzenesulfonic acid, generally yields high quality mass spectra which compare well with those obtained in either glycerol or 3‐nitrobenzyl alcohol.
Location of double bonds using the formal addition of CCI2
Authors: Purghart V. , Hocart C. H. , Schlunegger U. P. 
Published: May 2005

AbstractA new method for locating double bonds in olefins and fatty acid is described. The CCI2 moiety, derived form chloroform, was added across the double bonds of a series of compounds using a phase‐transfer reaction. The resulting adducts were then analysed by gas chromatography/positive‐ion electron ionization mass spectrometry. It was found that it is routinely possible to locate a single double bond in a molecule at the microgram level. The method proved, however, to be of no use in locating terminal double bonds or in distinguishing geometrical isomers. It is possible that the method might be extended to di‐olefins.
A matrix‐assisted laser desorption time‐of‐flight mass spectrometer based on a 600ps, 1.2 mJ nitrogen laser
Authors: Chevrier Marc R. , Cotter Robert J. , Roepstorff P. 
Published: May 2005

AbstractThe design and Performance of a short‐pulse UV laser desorption time‐of‐flight mass spectrometer is described. The instrument combines the advantages of a 600 ps, 337 nm Pulsed nitrogen laser with a compact, high‐voltage extraction linear time‐of‐flight analyzer. A number of peptides and proteins have been analyzed to demonstrate senstivity, high mass range, resolution and mixture analysis.
Investigation of products arising from enzymatic digestion of advanced glycated albumin by high‐performance liquid chromatography/mass spectrometry
Authors: Lapolla A. , Gerhardinger C. , Baldo L. , Crepaldi G. , Fedele D. , Porter C. J. , Seraglia R. , Favretto D. , Traldi P. 
Published: May 2005

AbstractThe 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.
Modelling coulomb effects in Fourier‐transform ion cyclotron resonance mass spectrometry by charged disks and charged cylinders
Authors: Chen Shu‐Ping , Comisarow Melvin B. 
Published: May 2005

AbstractA two‐dimensional charged‐disk model is proposed to explain Coulomb‐induced frequencey shifting in Fourier‐transform ion cyclotron resonance (FT‐ICR) mass spectrometry. This model corresponds more closely to the actual FT‐ICR experiment than does the charged‐point model,1 which we recently developed. The model consists of a uniformly charged disk of ions of mass m1, whose excited cyclotron motion is perturbed by a second uniformly charged disk of ions of mass m2, whose cyclotron motion is also excited. By looking in a rotating coordinate frame which rotates at the cyclotron frequency of the first disk, it is seen that the second disk creates an average radial force on the first disk which lowers the cyclotron frequency of the first disk. This radial force is numerically evaluated and found to be a function of the cyclotron radius, the ration of the cyclotron radius to the disk radius, and the charges of the two disks. Unlike the charged‐point model, which was flawed by having an infinite average radial Coulomb force, the average radial Coulomb force for the charged‐disk model is finite. This average Coulomb force allows the use of formulae which permit characterization of a given set of model parameters in terms of an ‘apparent Coulomb distance’, for which a model consisting of point charges with a fixed location in a rotating frame would give the same frequency shift. It is argued that the same ‘apparent Coulomb distance’ would apply for a charged cylinder model, which accounts for Coulomb‐induced line broadening in addition to Coulomb‐induced frequency shifting. It is suggested that the treatment in this paper, together with the use of elongated cells equipped with trapping screens, could permit absolute mass calibrations of T‐ICR spectra.
Ionspray mass spectrometry of marine toxins. III. Analysis of paralytic shellfish poisoning toxins by flow‐injection analysis, liquid chromatography/mass spectrometry and capillary electrophoresis/mass spectrometry
Authors: Pleasance S. , Ayer S. W. , Laycock M. V. , Thibault P. 
Published: May 2005

AbstractIonspray mass spectrometry has been used to monitor the purification of saxitoxin, the parent compound in the family of toxins responsible for paralytic shellfish poisoning (PSP), from a strain of the dinoflagellate Alexandrium excavatum. Quantitative results obtained by flow‐injection analysis are compared to those obtained by high‐performance liquid chromatography with post‐column oxidation and fluorescence detection. The coupling of liquid chromatography and capillary electrophoresis with ionspray mass spectrometry is described for the separation of mixtures of PSP toxins and the highly potent pufferfish toxin tetrodotoxin. Tandem mass spectrometry is used to provide the structural information, and the ability to distinguish isomeric PSP toxins both chromatographically and mass spectrometrically is demonstrated.
Identification of cyclobutane‐type dimers of substituted cinnamic acids by gas chromatography/mass spectrometry
Authors: Stewart D. , Robertson G. W. , Morrison I. M. 
Published: May 2005

AbstractSubstituted cinnamic acids were dimerized, under fluorescent or UV light, as a glassy coating on a vial then subsequently analysed by GC/MS. Mass Spectrometric analysis of the dimers formed by each acid allowed the assignment of the dimer as a truxillic or truxinic structure since these structures had distinctive fragmentation patterns; the breakdown of the truxillic acids involves a McLafferty rearrangment before fragmentation occurs, whereas the truxinic acids, which have both carboxy groups on one side and both aromatic groups on the other, fragment asymmetrically to give characteristic stilbene and dicarboxylate fragments. It is apparent from the results of the dimerization of the lcinnamic acids that, under the conditions used here, if the monomeric acid had the capacity for hydrogen bonding using the ring substituent as well as the carboxy group, the dimerization products would be overshelmingly truxillic in structure. However, if only the carboxy group could hydrogen bond, the products would be almost exclusively traxinic in structure.
Molecular weight determination of ferrocenyl‐aryl‐plumbanes by 252Cf plasma‐desorption combined with a linear and reflecting time‐of‐flight mass spectrometer
Authors: Allmaier G. , Roepstorff P. , Schwarzhans K. E. , Utri G. 
Published: May 2005

AbstractA study of the analytical potential of 252Cf plasma‐desorption mass spectrometry for the melecular weight determination of metallocene complexes isreported. Two ferrocenyl‐phenyl‐plumbanes were successfully analysed in the positive‐ as well as the negative‐ion mode using this method. The positive‐ion mass spectra in particular provided molecular weight information and gave structurally informative fragment ions of this organometallic material. Salinples were deposited by the classical electrospray technique on aluminized targets. The molecular‐ion regions were recorded both on a liner and a reflecting time‐of‐flight instrument. The isotopic pattern of the molecular ions obtained by the reflecting mass spectrometer was compared with the theoretically calculated values and showed excellent agreement.
Structure interconversion in isomeric guanine derivatives at elevated sample temperature
Authors: Kralj B. , Kramer V. , Žigon D. , Kobe J. , Plavec J. 
Published: May 2005

AbstractGuanine derivatives were examined using the tandem mass spectrometry (MS/MS) method. Isomeric structure differences were explored by means of the unimolecular decomposition spectra of the common ion m/z 151 having the empirical formula of the guanine molecular ion. An interconversion of the isomeric structures as the sample temperature is gradually raised, was observed.
Peptide sequencing by matrix‐assisted laser‐desorption mass spectrometry
Authors: Spengler Bernhard , Kirsch Dieter , Kaufmann Raimund , Jaeger Ernst 
Published: May 2005

AbstractA novel method of peptide sequencing by mass spectrometry is described. Metastable decay of laser‐desorbedions, taking place in the first field‐free drift region of a reflectron time‐of‐flight mass spectrometer, has been monitored to get structural information from larger peptides. Fragment ions from metastable decay are mass analysed by adjusting the potentiaals of the ion reflectron according to the kinetic energies of the ions. The features of the technique and its significance for future applications are outlined.
Determination of the acyl moieties of the antibiotic complex A40926 and their relation with the membrane lipids of the producer strain
Authors: Zerilli Luigi F. , Edwards Duncan M. F. , Borghi Angelo , Gallo Gian G. , Selva Enrico , Denaro Maurizio , Lancini Gian C. 
Published: May 2005

AbstractStructures of the fatty acid characterizing the various components of A40926 were determined by gas chromatography/mass spectrometry on the methyl esters obtained by methanolysis of the complex. The results confirm the residues previously assigned to Factor A (n‐Undecanoic acid) and B (10‐methyl‐undecanoic acid) and establish the residues of Factor A1(9‐methyl‐decanoic acid), B1 (n‐dodecanoic acid), RS1 (8‐methyl‐nonanoic acid), RS2 (n‐decanoic acid), and RS3 (n‐tridecanoic acid). As the actinomadura species contain in their mycelia large quantities of C15‐C17 fatty acid residues as membrane phospholipids, these mycelia were saponified and the fatty acids obtained were analyzed as above. There is a close correlation beterrn the fatty acid content of A40923 complex and that of longer homologues in the producer mycelia.