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Electrospray Ionization Time-of-flight Mass Spectrometry (electrospray + ionization_time-of-flight_mass_spectrometry)
Selected AbstractsCharacterization of perfluoroalkyl acrylic oligomers by electrospray ionization time-of-flight mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2008Timothy J. Romack Electrospray ionization time-of-flight mass spectrometry (ESI-ToF-MS) has been successfully employed for the characterization of molecular weight, molecular weight distribution and end groups for bromine-terminated perfluoroalkyl acrylate oligomers prepared using atom transfer radical polymerization. Intact oligomers and smaller quantities of common side products were observed from m/z 1000 to 4000 cationized with a sodium ion, a difluorobenzyl cation or a proton with a minimum of multiply charged species. Number average molecular weight and weight average molecular weight for both the samples that were characterized were in reasonable agreement with independent measurements conducted using GPC-MALS and 1H NMR spectroscopy. Copyright © 2008 John Wiley & Sons, Ltd. [source] High-speed separation and characterization of major constituents in Radix Paeoniae Rubra by fast high-performance liquid chromatography coupled with diode-array detection and time-of-flight mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 1 2009E-Hu Liu A fast high-performance liquid chromatography (HPLC) method coupled with diode-array detection (DAD) and electrospray ionization time-of-flight mass spectrometry (ESI-TOFMS) has been developed for rapid separation and sensitive identification of major constituents in Radix Paeoniae Rubra (RPR). The total analysis time on a short column packed with 1.8-µm porous particles was about 20,min without a loss in resolution, six times faster than the performance of a conventional column analysis (115,min). The MS fragmentation behavior and structural characterization of major compounds in RPR were investigated here for the first time. The targets were rapidly screened from RPR matrix using a narrow mass window of 0.01,Da to restructure extracted ion chromatograms. Accurate mass measurements (less than 5,ppm error) for both the deprotonated molecule and characteristic fragment ions represent reliable identification criteria for these compounds in complex matrices with similar if not even better performance compared with tandem mass spectrometry. A total of 26 components were screened and identified in RPR including 11 monoterpene glycosides, 11 galloyl glucoses and 4 other phenolic compounds. From the point of time savings, resolving power, accurate mass measurement capability and full spectral sensitivity, the established fast HPLC/DAD/TOFMS method turns out to be a highly useful technique to identify constituents in complex herbal medicines. Copyright © 2008 John Wiley & Sons, Ltd. [source] Identification and structural characterization of steroidal glycosides in Hoodia gordonii by ion-trap tandem mass spectrometry and liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 16 2008Bharathi Avula Electrospray ion-trap tandem mass spectrometry (ESI-MS/MS) and high-performance liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometry (LC/ESI-TOFMS) were used to identify and characterize eight C-21 steroidal glycosides in Hoodia gordonii. A generalized fragmentation pathway was proposed by comparing the spectra acquired for eight C-21 steroidal glycosides. The steroidal glycosides in Hoodia gordonii have been classified into two major core groups: hoodigenin A and calogenin. Using the ESI-TOF method, the major core peak ions generated by hoodigenin A glycosides are m/z 313 and 295 and by calogenin glycosides are m/z 479, 461, 299 and 281, respectively. In the MS/MS spectra, fragmentation reactions of the [M+Na]+ ion were recorded to provide structural information about the glycosyl and aglycone moieties. The data illustrates the ability of positive mode ESI for the identification of hoodigenin A and calogenin glycosides, including the nature of the hoodigenin A and calogenin core, the number of sugar residues and the type of saccharide moiety. Copyright © 2008 John Wiley & Sons, Ltd. [source] Characterization of perfluoroalkyl acrylic oligomers by electrospray ionization time-of-flight mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2008Timothy J. Romack Electrospray ionization time-of-flight mass spectrometry (ESI-ToF-MS) has been successfully employed for the characterization of molecular weight, molecular weight distribution and end groups for bromine-terminated perfluoroalkyl acrylate oligomers prepared using atom transfer radical polymerization. Intact oligomers and smaller quantities of common side products were observed from m/z 1000 to 4000 cationized with a sodium ion, a difluorobenzyl cation or a proton with a minimum of multiply charged species. Number average molecular weight and weight average molecular weight for both the samples that were characterized were in reasonable agreement with independent measurements conducted using GPC-MALS and 1H NMR spectroscopy. Copyright © 2008 John Wiley & Sons, Ltd. [source] Isotopic pattern and accurate mass determination in urine drug screening by liquid chromatography/time-of-flight mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2006Suvi Ojanperä An efficient method was developed for toxicological drug screening in urine by liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometry. The method relies on a large target database of exact monoisotopic masses representing the elemental formulae of reference drugs and their metabolites. Mass spectral identification is based on matching measured accurate mass and isotopic pattern (SigmaFitÔ) of a sample component with those in the database. Data post-processing software was developed for automated reporting of findings in an easily interpretable form. The mean and median of SigmaFitÔ for true-positive findings were 0.0066 and 0.0051, respectively. The mean and median of mass error absolute values for true-positive findings were 2.51 and 2.17,ppm, respectively, corresponding to 0.65 and 0.60,mTh. For routine screening practice, a SigmaFitÔ tolerance of 0.03 and a mass tolerance of 10,ppm were chosen. Ion abundance differences from urine extracts did not affect the accuracy of the automatically acquired SigmaFitÔ or mass values. The results show that isotopic pattern matching by SigmaFitÔ is a powerful means of identification in addition to accurate mass measurement. Copyright © 2006 John Wiley & Sons, Ltd. [source] Analysis of native and chemically modified oligonucleotides by tandem ion-pair reversed-phase high-performance liquid chromatography/electrospray ionization mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2003Kenneth J. Fountain Ion-pair reversed-phase high-performance liquid chromatography (IP-RP-HPLC) was utilized in tandem with negative-ion electrospray ionization time-of-flight mass spectrometry (ESI-TOFMS) for the analysis of native and chemically modified oligonucleotides. Separation was performed on a 1.0,×,50,mm column packed with porous C18 sorbent with a particle size of 2.5,,m and an average pore diameter of 140 Å. A method was developed which maximizes both chromatographic separation and mass spectrometric sensitivity using an optimized buffer system containing triethylamine and 1,1,1,3,3,3-hexafluoro-2-propanol with a methanol gradient. The ESI-TOFMS tuning parameters were also optimized in order to minimize in-source fragmentation and achieve the best sensitivity. Analyses of native, phosphorothioate, and guanine-rich oligonucleotides were performed by LC/MS. Detection limits were at sub-picomole levels with an average mass accuracy of 125,ppm. The described method allowed for the LC/MS analysis of oligonucleotides up to 110mer in length with little alkali cation adduction. Since sensitive detection of oligonucleotides was achieved with ultraviolet (UV) detection, we utilized a combination of UV-MS for quantitation (UV) and characterization (MS) of oligonucleotides and their failure sequence fragments/metabolites. Copyright © 2003 John Wiley & Sons, Ltd. [source] Determination of diphenylarsinic acid and phenylarsonic acid, the degradation products of organoarsenic chemical warfare agents, in well water by HPLC,ICP-MSAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 2 2005Kenji Kinoshita Abstract Diphenylarsinic acid (DPAA) and phenylarsonic acid (PAA), which were degradation products of organoarsenic chemical warfare agents used as sternutatory gas, were detected in the well water at Kamisu, Ibaraki Prefecture, Japan. The standard material of DPAA was synthesized with aqueous arsenic acid and phenylhydrazine in order to determine organic arsenic compounds in well water. The DPAA showed a protonated ion at m/z 263 [M + H]+ and a loss of H2O ion at m/z 245 [M + H , H2O]+ from protonated ion by the electrospray ionization time-of-flight mass spectrometry. The quantitative analysis of DPAA and PAA was performed by high-performance liquid chromatography inductively coupled plasma mass spectrometry and the system worked well for limpid liquid samples such as well water. Copyright © 2005 John Wiley & Sons, Ltd. [source] Fragmentation study of iridoid glycosides and phenylpropanoid glycosides in Radix Scrophulariae by rapid resolution liquid chromatography with diode-array detection and electrospray ionization time-of-flight mass spectrometryBIOMEDICAL CHROMATOGRAPHY, Issue 8 2010Qian Wu Abstract Rapid resolution liquid chromatography (RRLC) coupled with diode array detection (DAD) and electrospray ionization time-of-flight mass spectrometry (ESI-TOF MS) method was applied to the mass spectral study of a series of naturally occurring iridoid glycosides and phenylpropanoid glycosides in Radix Scrophulariae, which provides higher speed and increased sensitivity without loss of resolution. With dynamic adjustment as the key role of the fragmentor voltage and confirmed with authentic standards, valuable structural information regarding the nature of both the glycoside skeletons was thus obtained. Most compositions were found to possess organic acid moiety such as cinnamoyl, caffeoyl and ferulyol. Besides extensive fragmentation of the carbohydrate moiety, losses of the hydroxyl and glucose residue units showed in the spectra, permitting the exploration of the skeleton and the identity of substituents in the molecule. Ten major iridoid glycosides and 10 phenylpropanoid glycosides were identified or tentatively characterized based on their retention times, UV and TOF MS data. The major fragmentation pathways of PGs in Radix Scrophulariae obtained through the MS data was schemed systematically for the first time, which provides a reference for other PGs derivatives. Copyright © 2009 John Wiley & Sons, Ltd. [source] Rapid analysis of N -linked oligosaccharides in glycoproteins (ovalbumin, ribonuclease B and fetuin) by reversed-phase ultra-performance liquid chromatography with fluorescence detection and electrospray ionization time-of-flight mass spectrometryBIOMEDICAL CHROMATOGRAPHY, Issue 5 2009Takamasa Kurihara Abstract Rapid, selective and sensitive determination of N -linked oligosaccharides in glycoproteins (ovalbumin, ribonuclease B and fetuin) was performed by ultra-performance liquid chromatography (UPLC) with fluorescence (FL) and electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS). The asparaginyl-oligosaccharide moiety was first liberated from each glycoprotein by pronase E (a proteolitic enzyme). The oligosaccharide fractions separated by gel-permeation chromatography were labeled with 1-pyrenesulfonyl chloride (PSC, a fluorescence reagent), separated by UPLC in a short run time, and then detected by FL and TOF-MS. The PSC-labeled oligosaccharides were selectively identified from the FL detection and then sensitively determined by ESI-TOF-MS. As the results, 15, eight and four kinds of N -linked oligosaccharides were detected from ovalbumin, ribonuclease B and fetuin, respectively. Because the present method is rapid (within 9 min), selective and sensitive (approximate 60 fmol, S/N = 5), the determination of N -linked oligosaccharides in various glycoproteins seems to be possible. Copyright © 2008 John Wiley & Sons, Ltd. [source] Application of liquid chromatography,electrospray ionization time-of-flight mass spectrometry for analysis and quality control of compound Danshen preparationsBIOMEDICAL CHROMATOGRAPHY, Issue 4 2009Jun Cao Abstract A liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometry (LC-ESI-TOF-MS) method has been developed to evaluate the quality of three formulas of compound Danshen preparations (CDPs), through a simultaneous determination of 22 marker constituents (nine major phenolic acids, eight major saponins and five major diterpenoids). Optimum separations were obtained with a Zorbax C18 column, using a gradient elution with 0.1% aqueous formic acid and acetonitrile. Limits of detection and quantification were in ranges of 1.58,10.10 and 4.85,28.56 ng/mL. All calibration curves showed good linear regression (r2 >p;0.9900) within the test range, and the recoveries were between 78.4 and 103.1% for all analytes. The assay was successfully utilized to analyze the 22 marker components in 26 samples. The overall results demonstrated that this method is sensitive, accurate and reliable for the quality control of CDPs. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||