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Clowers BH Dwivedi P Steiner WE Hill HH Bendiak B 《Journal of the American Society for Mass Spectrometry》2005,16(5):660-669
A series of isobaric disaccharide-alditols, four derived from O-linked glycoproteins, and select trisaccharides were rapidly resolved using tandem high resolution atmospheric pressure ion-mobility time-of-flight mass spectrometry. Electrospray ionization was used to create the gas-phase sodium adducts of each carbohydrate. Using this technique it was possible to separate up to three isobaric disaccharide alditols and three trisaccharides in the gas phase. Reduced mobility values and experimentally determined ion-neutral cross sections are reported for each sodium-carbohydrate complex. These studies demonstrated that ion mobility separations at atmospheric pressure can provide a high-resolution dimension for analysis of carbohydrate ions that is complementary to traditional mass spectral (m/z) ion analysis. Combining these independent principles for separation of ions provides a powerful new bioanalytical tool for the identification of isomeric carbohydrates. 相似文献
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An electrospray ionization (ESI) ambient pressure ion-mobility spectrometer (APIMS) interfaced to an orthogonal reflector time-of-flight mass spectrometer (TOFMS) was evaluated for the first time as a detector for the identification of phenylthiohydantoin (PTH)-derivatized amino acids, the final products in the Edman sequencing process of peptides and proteins. The drift and flight times of the twenty common PTH amino acids were characterized by a well-defined 2-D mobility/mass spectral pattern. The combination of mobility/mass modes of analysis gave rise to a unique trend-line formation for the series of PTH amino acids. In addition, each PTH amino acid had a unique reduced mobility constant K(o), thus enabling the differentiation of all the amino acid derivatives including the PTH-leucine and PTH-isoleucine isomers. More importantly it was shown that it was possible to resolve a complete reference mixture of PTH amino acids in a single experimental run in less than 1 min. Detection limits for the PTH amino acids were found to range from 1.04 to 3.52 ng; indicating that the limits of detection were less than 17.0 pmol for all of the PTH amino acids. 相似文献
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Eric James Davis Brian H. Clowers William F. Siems Herbert H. Hill Jr. 《International Journal for Ion Mobility Spectrometry》2011,14(2-3):117-124
Scientific applications of Ion Mobility Spectrometry require the ability to easily compare data between different laboratories. Reduced mobility values attempt to provide this functionality, but no standard exists for the collection and manipulation of the raw data obtained during an IMS experiment. We have created a comprehensive software suite based on the LabVIEW programming language that can be used to collect and interpret IMS data. The software may be used to collect data from a stand-alone IMS cell, a voltage sweep IMS cell, or a coupled chromatography-IMS system, and this framework may be adapted to incorporate mass spectral data analysis as well. This software is provided under an open source license for the benefit of the IMS community. 相似文献
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Anuj R. Shah Jennifer Davidson Matthew E. Monroe Anoop M. Mayampurath William F. Danielson Yan Shi Aaron C. Robinson Brian H. Clowers Mikhail E. Belov Gordon A. Anderson Richard D. Smith 《Journal of the American Society for Mass Spectrometry》2010,21(10):1784-1788
The diverse range of mass spectrometry (MS) instrumentation along with corresponding proprietary and nonproprietary data formats has generated a proteomics community driven call for a standardized format to facilitate management, processing, storing, visualization, and exchange of both experimental and processed data. To date, significant efforts have been extended towards standardizing XML-based formats for mass spectrometry data representation, despite the recognized inefficiencies associated with storing large numeric datasets in XML. The proteomics community has periodically entertained alternate strategies for data exchange, e.g., using a common application programming interface or a database-derived format. However, these efforts have yet to gain significant attention, mostly because they have not demonstrated significant performance benefits over existing standards, but also due to issues such as extensibility to multidimensional separation systems, robustness of operation, and incomplete or mismatched vocabulary. Here, we describe a format based on standard database principles that offers multiple benefits over existing formats in terms of storage size, ease of processing, data retrieval times, and extensibility to accommodate multidimensional separation systems. 相似文献
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W E Steiner B H Clowers K Fuhrer M Gonin L M Matz W F Siems A J Schultz H H Hill 《Rapid communications in mass spectrometry : RCM》2001,15(23):2221-2226
Rapid screening and identification of drug and other mixtures are possible using a novel ambient pressure high-resolution ion mobility (APIMS) orthogonal reflector time-of-flight mass spectrometer (TOFMS). Departing ions from the APIMS drift tube traversed a pressure interface between the APIMS and TOFMS where they were subjected to numerous gas collisions that could produce selective fragmentation. By increasing the accelerating field in the pressure interface region, the ions generated using water-cooled electrospray ionization (ESI) underwent collision-induced dissociation (CID). Mixtures of ESI ions were separated by APIMS based on their respective size-to-charge (s/z) ratios while CID and analysis of mass-to-charge (m/z) ratios occurred in the pressure interface and TOFMS. Product ions that were formed in this pressure interface region could be readily assigned to precursor ions by matching the mobility drift times. This process was demonstrated by the examination of a mixture of amphetamines and the resulting fragmentation patterns of the mobility-separated precursor ion species [M + H](+). 相似文献
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Luke Garcia Carolyn Saba Gabriela Manocchio Gordon A. Anderson Eric Davis Brian H. Clowers 《International Journal for Ion Mobility Spectrometry》2017,20(3-4):87-93
Excluding the ion source, an ion mobility spectrometer is fundamentally comprised of drift chamber, ion gate, pulsing electronics, and a mechanism for amplifying and recording ion signals. Historically, the solutions to each of these challenges have been custom and rarely replicated exactly. For the IMS research community few detailed resources exist that explicitly detail the construction and operation of ion mobility systems. In an effort to address this knowledge gap we outline a solution to one of the key aspects of a drift tube ion mobility system, the ion gate pulser. Bradbury-Nielsen or Tyndall ion gates are found in nearly every research-grade and commercial IMS system. While conceptually simple, these gate structures often require custom, high-voltage, floating electronics. In this report we detail the operation and performance characteristics of a wifi-enabled, MOSFET-based pulser design that uses a lithium-polymer battery and does not require high voltage isolation transformers. Currently, each output of this circuit follows a TTL signal with ~20 ns rise and fall times, pulses up to +/? 200 V, and is entirely isolated using fiber optics. Detailed schematics and source code are provided to enable continued use of robust pulsing electronics that ease experimental efforts for future comparison. 相似文献
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Summary A sensitive method for the absorptiometric determination of hafnium has been developed. It is based on the reaction of hafnium with molybdophosphoric acid at pH 4.0. The method follows Beer's law in the range 0–14 parts per million hafnium. Data on interfering substances are presented.
Zusammenfassung Ein empfindliches Verfahren zur Hafniumbestimmung durch Absorptionsmessung wurde ausgearbeitet. Es beruht auf der Reaktion des Hafniums mit Molybdänphosphorsäure bei pH 4,0. Bis 14 ppm Hf ist das Beersche Gesetz erfüllt. Störende Ionen werden angegeben.相似文献
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An electrospray ionization-dual gate-ion mobility-quadrupole ion trap mass spectrometer was used to evaluate the separation characteristics of isomeric flavonoid diglycosides adducted with sodium, potassium, and silver. This instrumental configuration allows ions to be selectively accumulated within the ion trap on the basis of their gas phase conformation prior to mass analysis. For the metal cations examined, silver produced the most compact adducts with flavonoid diglycosides. Listed in order of increasing size, the trend of flavonoid diglycoside ion-neutral cross sections adducted with Na+, K+, and Ag+ was narirutin < naringin < hesperidin < neohesperidin < rutin. To examine the separation contribution of the carbohydrate group, hesperetin, the aglycone of hesperidin, and neohesperin were compared to quercetin, the aglycone of rutin. Separation of the flavonoid diglycosides indicated that quercetin-derived diglycosides drifted longer than their hesperetin-derived isomers. Combined with the observed collision assisted dissociation (CAD) data, these findings suggest that carbohydrate moiety plays a significant role in both the separation and metal chelating characteristics of flavonoid diglycosides. 相似文献