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1.
Xiaoyu Yang Pedatsur Neta Stephen E. Stein 《Journal of the American Society for Mass Spectrometry》2017,28(11):2280-2287
Tandem mass spectral library searching is finding increased use as an effective means of determining chemical identity in mass spectrometry-based omics studies. We previously reported on constructing a tandem mass spectral library that includes spectra for multiple precursor ions for each analyte. Here we report our method for expanding this library to include MS2 spectra of fragment ions generated during the ionization process (in-source fragment ions) as well as MS3 and MS4 spectra. These can assist the chemical identification process. A simple density-based clustering algorithm was used to cluster all significant precursor ions from MS1 scans for an analyte acquired during an infusion experiment. The MS2 spectra associated with these precursor ions were grouped into the same precursor clusters. Subsequently, a new top-down hierarchical divisive clustering algorithm was developed for clustering the spectra from fragmentation of ions in each precursor cluster, including the MS2 spectra of the original precursors and of the in-source fragments as well as the MSn spectra. This algorithm starts with all the spectra of one precursor in one cluster and then separates them into sub-clusters of similar spectra based on the fragment patterns. Herein, we describe the algorithms and spectral evaluation methods for extending the library. The new library features were demonstrated by searching the high resolution spectra of E. coli extracts against the extended library, allowing identification of compounds and their in-source fragment ions in a manner that was not possible before. 相似文献
2.
A. A. Stepuk A. G. Veresov V. I. Putlyaev Yu. D. Tret’yakov 《Doklady Physical Chemistry》2007,412(1):11-14
3.
Steven C. Habicht Nelson R. Vinueza Penggao Duan Mingkun Fu Hilkka I. Kenttämaa 《Journal of the American Society for Mass Spectrometry》2010,21(4):559-563
We report here an automated method for the identification of N-oxide functional groups in drug metabolites by using the combination
of liquid chromatography/tandem mass spectrometry (LC/MS
n
) based on ion-molecule reactions and collision-activated dissociation (CAD). Data-dependent acquisition, which has been readily
utilized for metabolite characterization using CAD-based methods, is adapted for use with ion-molecule reaction-based tandem
mass spectrometry by careful choice of select experimental parameters. Two different experiments utilizing ion-molecule reactions
are demonstrated, data-dependent neutral gain MS3 and data-dependent neutral gain pseudo-MS3, both of which generate functional group selective mass spectral data in a single experiment and facilitate increased throughput
in structural elucidation of unknown mixture components. Initial results have been generated by using an LC/MS
n
method based on ion-molecule reactions developed earlier for the identification of the N-oxide functional group in pharmaceutical
samples, a notoriously difficult functional group to identify via CAD alone. Since commercial software and straightforward,
external instrument modification are used, these experiments are readily adaptable to the industrial pharmaceutical laboratory. 相似文献
4.
A. I. Lytkin V. V. Chernikov O. N. Krutova D. K. Smirnova 《Russian Journal of General Chemistry》2018,88(5):954-957
Enthalpy of the complex formation between diglycine (HL±) and Ce3+ or La3+ at 308.15 K and ionic strength of 0.5 mol/L (KNO3) has been determined by means of calorimetry. Thermodynamic parameters of the diglycine complexes formation with Ce3+ and La3+ at different metal to ligand molar ratios have been determined. 相似文献
5.
V. S. Kolosnitsyn E. A. Minnikhanova E. V. Karaseva Yu. K. Dmitriev M. M. Muratov 《Russian Journal of Applied Chemistry》2005,78(5):737-740
The effect of Ca2+, Mg2+, Fe3+, and Al3+ ions on the deposition of electrolytic manganese dioxide from chloride solutions was studied.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 5, 2005, pp. 751–754.Original Russian Text Copyright © 2005 by Kolosnitsyn, Minnikhanova, Karaseva, Dmitriev, Muratov. 相似文献
6.
Claudia Landstetter Christian Katzlberger 《Journal of Radioanalytical and Nuclear Chemistry》2009,282(2):467-471
Screening measurements for 3H, 226Ra, 222Rn and 238U in ground water were performed within a ground- and drinking water project in Austria. The aim of this project is to get
an overview of the distribution of natural radionuclide activity concentration levels in ground water bodies. In some cases
this water is used for drinking water abstraction. In this paper methods and results of the screening measurements are presented.
Regions with high activity concentrations were identified and in these regions further investigation for 228Ra, 210Pb and 210Po will be conducted. 相似文献
7.
Zabrouskov V Senko MW Du Y Leduc RD Kelleher NL 《Journal of the American Society for Mass Spectrometry》2005,16(12):2027-2038
An automated top-down approach including data-dependent MS(3) experiment for protein identification/characterization is described. A mixture of wild-type yeast proteins has been separated on-line using reverse-phase liquid chromatography and introduced into a hybrid linear ion trap (LTQ) Fourier transform ion cylclotron resonance (FTICR) mass spectrometer, where the most abundant molecular ions were automatically isolated and fragmented. The MS(2) spectra were interpreted by an automated algorithm and the resulting fragment mass values were uploaded to the ProSight PTM search engine to identify three yeast proteins, two of which were found to be modified. Subsequent MS(3) analyses pinpointed the location of these modifications. In addition, data-dependent MS(3) experiments were performed on standard proteins and wild-type yeast proteins using the stand alone linear trap mass spectrometer. Initially, the most abundant molecular ions underwent collisionally activated dissociation, followed by data-dependent dissociation of only those MS(2) fragment ions for which a charge state could be automatically determined. The resulting spectra were processed to identify amino acid sequence tags in a robust fashion. New hybrid search modes utilized the MS(3) sequence tag and the absolute mass values of the MS(2) fragment ions to collectively provide unambiguous identification of the standard and wild-type yeast proteins from custom databases harboring a large number of post-translational modifications populated in a combinatorial fashion. 相似文献
8.
The performance of recently proposed 5f-in-core pseudopotentials for the trivalent actinides was investigated in calculations
for model complexes An3+L
n− for three selected actinides (An3+ = Ac3+, Cm3+, Lr3+) and eight simple ligands with atoms from the first three periods of the table of elements (L
n− = F−, Cl−, OH−, SH−, CO, NH2−, H2O, H2S, NH3). Results of Hartree-Fock and Coupled Cluster with singles, doubles and perturbative triples calculations using basis sets
of quadruple-zeta quality are compared to corresponding reference data obtained with scalar-relativistic energy-adjusted 5f-in-valence
small-core pseudopotentials. The inclusion of core-polarization potentials in the 5f-in-core pseudopotential calculations
and corrections of the basis set superposition error by the counterpoise correction leads to very good agreement between the
5f-in-valence and 5f-in-core pseudopotential results for bond lengths, bond angles and binding energies. Results from 5f-in-core
pseudopotential calculations using different density functionals also show reasonable agreement with the more rigorous Coupled
Cluster results. It is argued that the An 5f rather than the An f population is a useful criterion for the applicability of
a specific An 5f-in-core pseudopotential. 相似文献
9.
D. Mikolášová K. Rubešová V. Jakeš P. Nekvindová Z. Zlámalová Cílová J. Oswald 《Journal of Sol-Gel Science and Technology》2018,86(2):274-284
Compared to other oxide materials, the sol-gel deposition of an optically transparent LiNbO3 waveguiding film of sufficient thickness (approx. 1?μm) is complicated by the presence of a highly hydrolyzing Nb(V) in the starting solution. Thicker films require more concentrated solutions that are not easily achieved for such ions. This problem may be solved using strong chelating agents such as water-soluble polymers. To prepare a stable Er(III)/Yb(III)/Li(I)/Nb(V)/2-methoxyethanol solution with high metal concentration, we tested three such polymers: polyethylene glycol (PEG), polyacrylic acid (PAA) and polyvinyl alcohol (PVA), and compared them with already used polyvinylpyrrolidone (PVP). The solutions were spin-coated on crystalline sapphire substrates under a multi-step heating-deposition regime. Apart from Er3+/Yb3+ photoluminescence properties, we evaluated the influence of the film microstructure (SEM, AFM) on optical transparency and waveguiding ability in the UV/Vis/NIR region (transmission and m-line spectroscopy). Among the newly tested polymers, only PEG was able to prevent Nb(V) hydrolysis up to a maximum metal concentration of 0.6?mol/L. For PEG and PVP, the crystallization temperature of the deposited films (between 700?°C and 1000?°C) was compared. After further optimization of the heating-deposition process, we were able to prepare a transparent Er3+/Yb3+:LiNbO3 film thick enough to guide an optical signal in the NIR region. Thus, the use of PEG results is one of the very few non-hydrolytic sol-gel methods suitable for the preparation of not only luminescent, but also waveguiding Er3+/Yb3+:LiNbO3 structures. 相似文献
10.
MSn experiments involving low energy collisionally activated dissociation (CAD) in a quadrupole ion trap were used to characterize
the fragmentation of alkali, alkaline earth and transition metal complexes of five cyclic peptides, and the results were compared
with those obtained for protonated cyclic peptides. Complexes with metal ions produced enhanced abundances of the most diagnostic
fragments for elucidating the primary structures. For cyclosporin A, nickel and lithium complexes gave additional sequence
information compared with the protonated peptide. For depsipeptides, sodium and lead complexes were superior to the protonated
peptide or other metal complexes for sequencing residues, and CAD of the lead complexes led to preferential cleavage of two
residues at a time. For cyclic lipopeptides, complexes with silver, nickel and strontium ions provided enhanced abundances
of key fragment ions. 相似文献
11.
Chu-Wei Kuo Shih-Yun Guu Kay-Hooi Khoo 《Journal of the American Society for Mass Spectrometry》2018,29(6):1166-1178
High sensitivity identification of sulfated glycans carried on specific sites of glycoproteins is an important requisite for investigation of molecular recognition events involved in diverse biological processes. However, aiming for resolving site-specific glycosylation of sulfated glycopeptides by direct LC-MS2 sequencing is technically most challenging. Other than the usual limiting factors such as lower abundance and ionization efficiency compared to analysis of non-glycosylated peptides, confident identification of sulfated glycopeptides among the more abundant non-sulfated glycopeptides requires additional considerations in the selective enrichment and detection strategies. Metal oxide has been applied to enrich phosphopeptides and sialylated glycopeptides, but its use to capture sulfated glycopeptides has not been investigated. Likewise, various complementary MS2 fragmentation modes have yet to be tested against sialylated and non-sialylated sulfoglycopeptides due to limited appropriate sample availability. In this study, we have investigated the feasibility of sequencing tryptic sulfated N-glycopeptide and its MS2 fragmentation characteristics by first optimizing the enrichment methods to allow efficient LC-MS detection and MS2 analysis by a combination of CID, HCD, ETD, and EThcD on hybrid and tribrid Orbitrap instruments. Characteristic sulfated glyco-oxonium ions and direct loss of sulfite from precursors were detected as evidences of sulfate modification. It is anticipated that the technical advances demonstrated in this study would allow a feasible extension of our sulfoglycomic analysis to sulfoglycoproteomics. 相似文献
12.
M. Yamamoto A. Sakaguchi J. Tomita T. Imanaka K. Shiraishi 《Journal of Radioanalytical and Nuclear Chemistry》2009,279(1):93-103
To estimate the dietary intakes of 210Pb and 210Po for the Japanese adults and their annual effective doses, 210Pb and 210Po were measured for 240 daily diet samples collected at two locations of Ishikawa Prefecture in Japan over three years by
duplicate portion studies. No appreciable differences in intake rates of 210Pb and 210Po and their 210Po/210Pb ratios were seen among the years in each district, and between the two districts. The intake rates evaluated using 240
diet samples were 0.20 Bq/d/p for 210Pb and 0.61 Bq/d/p for 210Po as a median, respectively. Annual effective doses of 210Pb and 210Po for Japanese adults were estimated to be 0.050 and 0.053 mSv/y, respectively. 相似文献
13.
Xiaoju Liu Guoyu Ren Xiangrong Ma Yulin Xiang Liguo Gao Xiaoyan Ma 《Russian Journal of Applied Chemistry》2017,90(12):2016-2018
An efficient highly diluted synthetic approach to the synthesis of 1,9-dicarbonyl-2,8-dioxo-butyne ester ferrocenophane (L) has been developed. The title compound was characterized by IR, UV, FL, 1H NMR, spectroscopies, elemental analysis and so on. Further complex L shows fluorescence responses to Co2+ and Cu2+ in CH3OH, The results indicate that the complex could be applied in multianayte detection. The binding ability of receptor L CH3OH was tested for various cations (Co2+, Cu2+, Zn2+, and Ni2+ in water) and the binding constants for Co2+ and Cu2+ were the computed, having a distinct absorbance shift. The receptor is a very attractive array because its distinct absorbance shift profile in a semi-aqueous phase, making it applicable in the area of biology, environmental sciences and material chemistry. 相似文献
14.
A. D. Sajeniouk 《Journal of Radioanalytical and Nuclear Chemistry》2005,264(2):337-342
15.
Chang Heon Lee Moo Yul Suh Kwang Yong Jee Won Ho Kim 《Journal of Radioanalytical and Nuclear Chemistry》2007,272(1):187-194
A sequential separation procedure has been developed for the determination of 99Tc, 94Nb, 55Fe, 90Sr and 59/63Ni in various radioactive wastes generated from nuclear power plants. Ion exchange and extraction chromatography were adopted
for individual separation of the radionuclides. Precipitation was supplementarily utilized for both purification of the individual
radionuclides and preparation of the radionuclide sources for use in a radioactivity measurement. The chromatographic separation
behavior of the radionuclides both from the sample matrix metals and from one another was investigated using stable metals,
Re (as a surrogate of 99Tc), Nb, Fe, Sr and Ni. The validity of the procedure for reliability and applicability was evaluated by measuring the recovery
of the metal carriers added to synthetic radioactive waste solutions. The recoveries by the chromatographic separation were
in the range of 84.8 to 102.2% with 2s of less than 8.6%, the recoveries by the precipitation being in the range of 84.3 to 97.3% with 2s of less than 10.9%. 相似文献
16.
Cho R Huang Y Schwartz JC Chen Y Carlson TJ Ma J 《Journal of the American Society for Mass Spectrometry》2012,23(5):880-888
Identification of drug metabolites can often yield important information regarding clearance mechanism, pharmacologic activity,
or toxicity for drug candidate molecules. Additionally, the identification of metabolites can provide beneficial structure-activity
insight to help guide lead optimization efforts towards molecules with optimal metabolic profiles. There are challenges associated
with detecting and identifying metabolites in the presence of complex biological matrices, and new LC-MS technologies have
been developed to meet these challenges. In this report, we describe the development of an experimental approach that applies
unique features of the hybrid linear ion trap Orbitrap mass spectrometer to streamline in vitro and in vivo metabolite identification
experiments. The approach, referred to as MSM, utilizes multiple collision cells, dissociation methods, mass analyzers, and detectors. With multiple scan types and different
dissociation modes built into one experimental method, along with flexible post-acquisition analysis options, the MSM workflow offers an attractive option to fast and reliable identification of metabolites in different kinds of in vitro and
in vivo samples. The MSM workflow was successfully applied to metabolite identification analysis of verapamil in both in vitro rat hepatocyte incubations
and in vivo rat bile samples. 相似文献
17.
Marin Ayranov Dorothea Schumann 《Journal of Radioanalytical and Nuclear Chemistry》2010,286(3):649-654
The station for pions cancer therapy was operated at PSI from 1980 to 1992. After a cooling time of 12 years it’s made of
copper beam dump was cut and samples were taken for analytical purposes. The sampling collected about 500 g of high active
copper chips that can be used for separation of exotic radionuclides. The analyses by gamma spectrometry, LSC and AMS showed
main nuclides present to be 60Co, 54Mn, 22Na, 65Zn, 26Al, 53Mn, 59Ni, 63Ni, 55Fe and 60Fe and 44Ti with a daughter nuclide 44Sc. In the frame of ERAWAST project a procedure combining selective precipitation and ion exchange for the separation of the
rare radionuclides from the copper beam dump was developed. The proposed separation procedure is easy for remote controlled
implementation in a hot cell. The ion exchange separation of Ni, Al, Mg, Ti and Fe was complete and high decontamination factors
for copper and cobalt were achieved. Based on the developed procedure a remotely controlled system for separation of exotic
radionuclides from the copper chips was set up. The full scale system was installed in a hot cell where high activity levels
can be handled. In order to evaluate the reliability and functionality of the system extensive tests have been done. During
the test period 13.86 g in total of the proton irradiated copper beam dump were processed for separation of 26Al, 59Ni, 53Mn, 44Ti and 60Fe. The results showed that the system was operational and the radionuclide separation was selective with high chemical yield.
The procedure manages as well the generated liquid wastes containing high level of 60Co activity. 相似文献
18.
Dimitrios C. Xarchoulakos Konstantina Kehagia Nikolaos Kallithrakas-Kontos Constantinos Potiriadis 《Journal of Radioanalytical and Nuclear Chemistry》2017,312(2):285-292
For the first time, a radiological study for the dissolved 238U, 234U, 210Pb and 210Po was held in major Greek rivers across the country. 234U/238U activity ratios are above one in all samples and 210Po/210Pb activity ratios are respectively below the unit indicating the disequilibrium in the samples. Quite satisfactory correlations were observed among 234U and 238U as well as among 210Po and 210Pb values. Uranium isotopes were separated by ion exchange and electroplated on stainless steel plates. 210Po was spontaneously deposited on nickel plates, while 210Pb was indirectly determined through the ingrowth of 210Po. The sources were measured by a-spectrometry. 相似文献
19.
The hydrolytic species of lanthanide ions, La3+ and Sm3+, in water at I = 0.1 mol·dm?3 KCl ionic strength and temperatures of 298.15, 310.15 and 318.15 K were investigated by potentiometry. The hydrolytic species were modeled by the HySS simulation program. From the results, the hydrolytic species of each metal ion at different temperatures were calculated using the program HYPERQUAD2013. The hydrolysis constants (log10 β) of [La(OH)]2+ and La(OH)3 were calculated as ?8.52 ± 0.46, ?26.84 ± 0.48, and log10 β values of [Sm(OH)]2+, [Sm(OH)2]+, Sm(OH)3 were calculated as ?7.11 ± 0.21, ?15.84 ± 0.25 and ?23.44 ± 0.52 in aqueous media at 298.15 K, respectively. The dependence of the hydrolysis constants on the temperature allowed us to calculate the enthalpy, entropy, and Gibbs energy of hydrolysis values of each species. 相似文献
20.
Non-aggregated spherical polystyrene (PS) particles were coated with GdPO4:Tb3+/Ce3+ phosphor layers by a conventional hydrothermal synthesis using poly(vinylpyrrolidone) (PVP) as an additive without further
annealing treatment. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy
(TEM), photoluminescence (PL), as well as luminescence decay experiments were used to characterise the resulting core-shell
structured PS@GdPO4:Tb3+/Ce3+ samples. The results of XRD indicated that the PS particles were successfully coated with the GdPO4:Tb3+/Ce3+ phosphor layers, which could be further verified by the images of FESEM. Under ultraviolet excitation, the PS@GdPO4:Tb3+/Ce3+ phosphors show Tb3+ characteristic emission, i.e. 5D4-7FJ (J = {6, 5, 4, 3}) emission lines with green emission 5D4-7F5 (543 nm) as the most prominent group. The core-shell phosphors so obtained have potential applications in field emission
display (FED) and plasma display panels (PDP). 相似文献