Review on Ion Mobility Spectrometry. Part 1: Current Instrumentation

PubMed Central

Cumeras, R.; Figueras, E.; Davis, C.E.; Baumbach, J.I.; Gràcia, I.

2014-01-01

Ion Mobility Spectrometry (IMS) is a widely used and ‘well-known’ technique of ion separation in gaseous phase based on the differences of ion mobilities under an electric field. All IMS instruments operate with an electric field that provides space separation, but some IMS instruments also operate with a drift gas flow which provides also a temporal separation. In this review we will summarize the current IMS instrumentation. IMS techniques have received an increased interest as new instrumentation has become available to be coupled with mass spectrometry (MS). For each of the eight types of IMS instruments reviewed it is mentioned whether they can be hyphenated with MS and whether they are commercially available. Finally, out of the described devices, the six most-consolidated ones are compared. The current review article is followed by a companion review article which details the IMS hyphenated techniques (mainly gas chromatography and mass spectrometry) and the factors that make the data from an IMS device change as function of device parameters and sampling conditions. These reviews will provide the reader with an insightful view of the main characteristics and aspects of the IMS technique. PMID:25465076

A new instrument of VUV laser desorption/ionization mass spectrometry imaging with micrometer spatial resolution and low level of molecular fragmentation.

PubMed

Wang, Jia; Liu, Feng; Mo, Yuxiang; Wang, Zhaoying; Zhang, Sichun; Zhang, Xinrong

2017-11-01

Mass spectrometry imaging (MSI) has important applications in material research, biology, and medicine. The MSI method based on UV laser desorption/ionization (UVLDI) can obtain images of intact samples, but has a high level of molecular fragmentation. In this work, we report a new MSI instrument that uses a VUV laser (125.3 nm) as a desorption/ionization source to exploit its advantages of high single photon energy and small focus size. The new instrument was tested by the mass spectra of Nile red and FGB (Fibrinogen beta chain) samples and mass spectrometric images of a fly brain section. For the tested samples, the VUVDI method offers lower levels of molecular fragmentations and higher sensitivities than those of the UVLDI method and second ion mass spectrometry imaging method using a Bi 3 + beam. The ablation crater produced by the focused VUV laser on a quartz plate has an area of 10 μm 2 . The VUV laser is prepared based on the four-wave mixing method using three collimated laser beams and a heated Hg cell.

A new instrument of VUV laser desorption/ionization mass spectrometry imaging with micrometer spatial resolution and low level of molecular fragmentation

NASA Astrophysics Data System (ADS)

Wang, Jia; Liu, Feng; Mo, Yuxiang; Wang, Zhaoying; Zhang, Sichun; Zhang, Xinrong

2017-11-01

Mass spectrometry imaging (MSI) has important applications in material research, biology, and medicine. The MSI method based on UV laser desorption/ionization (UVLDI) can obtain images of intact samples, but has a high level of molecular fragmentation. In this work, we report a new MSI instrument that uses a VUV laser (125.3 nm) as a desorption/ionization source to exploit its advantages of high single photon energy and small focus size. The new instrument was tested by the mass spectra of Nile red and FGB (Fibrinogen beta chain) samples and mass spectrometric images of a fly brain section. For the tested samples, the VUVDI method offers lower levels of molecular fragmentations and higher sensitivities than those of the UVLDI method and second ion mass spectrometry imaging method using a Bi3+ beam. The ablation crater produced by the focused VUV laser on a quartz plate has an area of 10 μm2. The VUV laser is prepared based on the four-wave mixing method using three collimated laser beams and a heated Hg cell.

An Integrated Hot-Stage Microscope-Direct Analysis in Real Time-Mass Spectrometry System for Studying the Thermal Behavior of Materials.

PubMed

Ashton, Gage P; Harding, Lindsay P; Parkes, Gareth M B

2017-12-19

This paper describes a new analytical instrument that combines a precisely temperature-controlled hot-stage with digital microscopy and Direct Analysis in Real Time-mass spectrometry (DART-MS) detection. The novelty of the instrument lies in its ability to monitor processes as a function of temperature through the simultaneous recording of images, quantitative color changes, and mass spectra. The capability of the instrument was demonstrated through successful application to four very varied systems including profiling an organic reaction, decomposition of silicone polymers, and the desorption of rhodamine B from an alumina surface. The multidimensional, real-time analytical data provided by this instrument allow for a much greater insight into thermal processes than could be achieved previously.

Advances in imaging secondary ion mass spectrometry for biological samples

DOE PAGES

Boxer, Steven G.; Kraft, Mary L.; Weber, Peter K.

2008-12-16

Imaging mass spectrometry combines the power of mass spectrometry to identify complex molecules based on mass with sample imaging. Recent advances in secondary ion mass spectrometry have improved sensitivity and spatial resolution, so that these methods have the potential to bridge between high-resolution structures obtained by X-ray crystallography and cyro-electron microscopy and ultrastructure visualized by conventional light microscopy. Following background information on the method and instrumentation, we address the key issue of sample preparation. Because mass spectrometry is performed in high vacuum, it is essential to preserve the lateral organization of the sample while removing bulk water, and this hasmore » been a major barrier for applications to biological systems. Furthermore, recent applications of imaging mass spectrometry to cell biology, microbial communities, and biosynthetic pathways are summarized briefly, and studies of biological membrane organization are described in greater depth.« less

75 FR 41505 - Center for Scientific Review; Notice of Closed Meetings

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-16

... for Scientific Review Special Emphasis Panel; Mass Spectrometry Shared Instrumentation Study Section... Instrumentation: Mass Spectrometers. Date: August 5-6, 2010. Time: 8:30 a.m. to 5 p.m. Agenda: To review and...

A Mass Spectrometer in Every Fume Hood

NASA Astrophysics Data System (ADS)

McBride, Ethan M.; Verbeck, Guido F.

2018-06-01

Since their inception, mass spectrometers have played a pivotal role in the direction and application of synthetic chemical research. The ability to develop new instrumentation to solve current analytical challenges in this area has always been at the heart of mass spectrometry, although progress has been slow at times. Herein, we briefly review the history of how mass spectrometry has been used to approach challenges in organic chemistry, how new developments in portable instrumentation and ambient ionization have been used to open novel areas of research, and how current techniques have the ability to expand on our knowledge of synthetic mechanisms and kinetics. Lastly, we discuss the relative paucity of work done in recent years to embrace the concept of improving benchtop synthetic chemistry with mass spectrometry, the disconnect between applications and fundamentals within these studies, and what hurdles still need to be overcome. [Figure not available: see fulltext.

The Effect of Collimating Lens Focusing on Laser Beam Shape in Matrix Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI-MS)

NASA Astrophysics Data System (ADS)

O'Rourke, Matthew B.; Raymond, Benjamin B. A.; Djordjevic, Steven P.; Padula, Matthew P.

2018-03-01

Tissue imaging using matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a well-established technique that, in recent years, has seen wider adoption and novel application. Applications such imaging mass spectrometry (IMS) and biotyping are beginning to gain greater exposure and use; however, with limitations in optimization methods, producing the best result often relies on the ability to customize the physical characteristics of the instrumentation, a task that is challenging for most mass spectrometry laboratories. With this in mind, we have described the effect of making simple adjustments to the laser optics at the final collimating lens area, to adjust the laser beam size and shape in order to allow greater customization of the instrument for improving techniques such as IMS. We have therefore been able to demonstrate that improvements can be made without requiring the help of an electrical engineer or external funding in a way that only costs a small amount of time. [Figure not available: see fulltext.

The Effect of Collimating Lens Focusing on Laser Beam Shape in Matrix Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI-MS).

PubMed

O'Rourke, Matthew B; Raymond, Benjamin B A; Djordjevic, Steven P; Padula, Matthew P

2018-03-01

Tissue imaging using matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a well-established technique that, in recent years, has seen wider adoption and novel application. Applications such imaging mass spectrometry (IMS) and biotyping are beginning to gain greater exposure and use; however, with limitations in optimization methods, producing the best result often relies on the ability to customize the physical characteristics of the instrumentation, a task that is challenging for most mass spectrometry laboratories. With this in mind, we have described the effect of making simple adjustments to the laser optics at the final collimating lens area, to adjust the laser beam size and shape in order to allow greater customization of the instrument for improving techniques such as IMS. We have therefore been able to demonstrate that improvements can be made without requiring the help of an electrical engineer or external funding in a way that only costs a small amount of time. Graphical Abstract ᅟ.

Inductively coupled plasma mass spectrometry and electrospray mass spectrometry for speciation analysis: applications and instrumentation

NASA Astrophysics Data System (ADS)

Rosen, Amy L.; Hieftje, Gary M.

2004-02-01

To gain an understanding of the function, toxicity and distribution of trace elements, it is necessary to determine not only the presence and concentration of the elements of interest, but also their speciation, by identifying and characterizing the compounds within which each is present. For sensitive detection of compounds containing elements of interest, inductively coupled plasma mass spectrometry (ICP-MS) is a popular method, and for identification of compounds via determination of molecular weight, electrospray ionization mass spectrometry (ESI-MS) is gaining increasing use. ICP-MS and ESI-MS, usually coupled to a separation technique such as chromatography or capillary electrophoresis, have already been applied to a large number of research problems in such diverse fields as environmental chemistry, nutritional science, and bioinorganic chemistry, but a great deal of work remains to be completed. Current areas of research to which ICP-MS and ESI-MS have been applied are discussed, and the existing instrumentation used to solve speciation problems is described.

microMS: A Python Platform for Image-Guided Mass Spectrometry Profiling

NASA Astrophysics Data System (ADS)

Comi, Troy J.; Neumann, Elizabeth K.; Do, Thanh D.; Sweedler, Jonathan V.

2017-09-01

Image-guided mass spectrometry (MS) profiling provides a facile framework for analyzing samples ranging from single cells to tissue sections. The fundamental workflow utilizes a whole-slide microscopy image to select targets of interest, determine their spatial locations, and subsequently perform MS analysis at those locations. Improving upon prior reported methodology, a software package was developed for working with microscopy images. microMS, for microscopy-guided mass spectrometry, allows the user to select and profile diverse samples using a variety of target patterns and mass analyzers. Written in Python, the program provides an intuitive graphical user interface to simplify image-guided MS for novice users. The class hierarchy of instrument interactions permits integration of new MS systems while retaining the feature-rich image analysis framework. microMS is a versatile platform for performing targeted profiling experiments using a series of mass spectrometers. The flexibility in mass analyzers greatly simplifies serial analyses of the same targets by different instruments. The current capabilities of microMS are presented, and its application for off-line analysis of single cells on three distinct instruments is demonstrated. The software has been made freely available for research purposes. [Figure not available: see fulltext.

microMS: A Python Platform for Image-Guided Mass Spectrometry Profiling.

PubMed

Comi, Troy J; Neumann, Elizabeth K; Do, Thanh D; Sweedler, Jonathan V

2017-09-01

Image-guided mass spectrometry (MS) profiling provides a facile framework for analyzing samples ranging from single cells to tissue sections. The fundamental workflow utilizes a whole-slide microscopy image to select targets of interest, determine their spatial locations, and subsequently perform MS analysis at those locations. Improving upon prior reported methodology, a software package was developed for working with microscopy images. microMS, for microscopy-guided mass spectrometry, allows the user to select and profile diverse samples using a variety of target patterns and mass analyzers. Written in Python, the program provides an intuitive graphical user interface to simplify image-guided MS for novice users. The class hierarchy of instrument interactions permits integration of new MS systems while retaining the feature-rich image analysis framework. microMS is a versatile platform for performing targeted profiling experiments using a series of mass spectrometers. The flexibility in mass analyzers greatly simplifies serial analyses of the same targets by different instruments. The current capabilities of microMS are presented, and its application for off-line analysis of single cells on three distinct instruments is demonstrated. The software has been made freely available for research purposes. Graphical Abstract ᅟ.

Mass spectrometry for the determination of fission products 135Cs, 137Cs and 90Sr: A review of methodology and applications

NASA Astrophysics Data System (ADS)

Bu, Wenting; Zheng, Jian; Liu, Xuemei; Long, Kaiming; Hu, Sheng; Uchida, Shigeo

2016-05-01

The radioactive fission products 135Cs, 137Cs and 90Sr have been released into the environment by human activities such as nuclear weapon tests, nuclear fuel reprocessing and nuclear power plant accidents. Monitoring of these radionuclides is important for dose assessment. Moreover, the 135Cs/137Cs isotopic ratio can be used as an important long-term fingerprint for radioactive source identification as it varies with weapon, reactor and fuel types. In recent years, mass spectrometry has become a powerful method for the determination of 135Cs, 137Cs and 90Sr in environmental samples. Mass spectrometry is characterized by the high sensitivity and low detection limit and the relatively shorter sample preparation and analysis times compared with radiometric methods. However, the mass spectrometric determination of radiocesium and 90Sr is affected by the peak tailings of the stable nuclides 133Cs and 88Sr, respectively, and the related isobaric and polyatomic interferences. Chemical separation and optimization of the mass spectrometry instrumental setup are strongly needed prior to the mass spectrometry detection. In this paper, we have reviewed the published works about the determination of 135Cs, 137Cs and 90Sr by mass spectrometry. The mass spectrometric techniques we cover are resonance ionization mass spectrometry (RIMS), thermal ionization mass spectrometry (TIMS), accelerator mass spectrometry (AMS) and inductively coupled plasma mass spectrometry (ICP-MS). For each technique, the principles or strategies used for the analysis of these radionuclides are discussed; these included the abundance sensitivity, ways to suppress the interference signals, and the instrumental setup. In particular, the chemical procedures for eliminating the interferences are also summarized. To date, triple quadrupole ICP-MS (ICP-QQQ) showed great ability for the analysis of these radionuclides and the detection limits were as low as 0.01 pg/mL levels. Finally, some investigations on the behaviors of radiocesium and radioactive source identifications are presented with the results of 135Cs/137Cs isotopic ratios measured in various environmental samples.

Steroid Profiling by Gas Chromatography–Mass Spectrometry and High Performance Liquid Chromatography–Mass Spectrometry for Adrenal Diseases

PubMed Central

McDonald, Jeffrey G.; Matthew, Susan

2012-01-01

The ability to measure steroid hormone concentrations in blood and urine specimens is central to the diagnosis and proper treatment of adrenal diseases. The traditional approach has been to assay each steroid hormone, precursor, or metabolite using individual aliquots of serum, each with a separate immunoassay. For complex diseases, such as congenital adrenal hyperplasia and adrenocortical cancer, in which the assay of several steroids is essential for management, this approach is time consuming and costly, in addition to using large amounts of serum. Gas chromatography/mass spectrometry profiling of steroid metabolites in urine has been employed for many years but only in a small number of specialized laboratories and suffers from slow throughput. The advent of commercial high-performance liquid chromatography instruments coupled to tandem mass spectrometers offers the potential for medium- to high-throughput profiling of serum steroids using small quantities of sample. Here, we review the physical principles of mass spectrometry, the instrumentation used for these techniques, the terminology used in this field and applications to steroid analysis. PMID:22170384

Biomark/Organic Analysis with Time-of-Flight Mass Spectrometry

NASA Technical Reports Server (NTRS)

Waite, J. Hunter, Jr.

2004-01-01

The concept of a Comprehensive 2-Dimensional Gas Chromatography coupled with Time-of-Flight Mass Spectrometry (GCxGC-TOWS) for the analysis of organic compounds has been proven with commercially available instrumentation (LECO Corp). The performance of a GCxGC instrument has been characterized in various stages using two independent breadboard systems. The GCxGC separation systems, including the thermal modulator, have been miniaturized to the size of a benchtop configuration. One breadboard system employs a Flame Ionization Detector (FID), whereas the second breadboard system employs a Time-of-Fight mass spectrometer (TOFWS) as a detection system.

Mass Spectrometry Theatre: A Model for Big-Screen Instrumental Analysis

ERIC Educational Resources Information Center

Allison, John

2008-01-01

Teaching lecture or lab courses in instrumental analysis can be a source of frustration since one can only crowd a small number of students around a single instrument, typically leading to round-robin approaches. Round-robin labs can spread students into multiple labs and limit instructor-student interactions. We discuss "Mass Spectrometry…

Clinical review: improving the measurement of serum thyroglobulin with mass spectrometry.

PubMed

Hoofnagle, Andrew N; Roth, Mara Y

2013-04-01

Serum thyroglobulin (Tg) measurements are central to the management of patients treated for differentiated thyroid carcinoma. For decades, Tg measurements have relied on methods that are subject to interference by commonly found substances in human serum and plasma, such as Tg autoantibodies. As a result, many patients need additional imaging studies to rule out cancer persistence or recurrence that could be avoided with more sensitive and specific testing methods. The aims of this review are to: 1) briefly review the interferences common to Tg immunoassays; 2) introduce readers to liquid chromatography-tandem mass spectrometry as a method for quantifying proteins in human serum/plasma; and 3) discuss the potential benefits and limitations of the method in the quantification of serum Tg. Mass spectrometric methods have traditionally lacked the sensitivity, robustness, and throughput to be useful clinical assays. These methods failed to meet the necessary clinical benchmarks due to the nature of the mass spectrometry workflow and instrumentation. Over the past few years, there have been major advances in reagents, automation, and instrumentation for the quantification of proteins using mass spectrometry. More recently, methods using mass spectrometry to detect and quantify Tg have been developed and are of sufficient quality to be used in the management of patients. Novel serum Tg assays that use mass spectrometry may avoid the issue of autoantibody interference and other problems with currently available immunoassays for Tg. Prospective studies are needed to fully understand the potential benefits of novel Tg assays to patients and care providers.

Mass spectrometry in systems biology an introduction.

PubMed

Dunn, Warwick B

2011-01-01

The qualitative detection, quantification, and structural characterization of analytes in biological systems are important requirements for objectives to be fulfilled in systems biology research. One analytical tool applied to a multitude of systems biology studies is mass spectrometry, particularly for the study of proteins and metabolites. Here, the role of mass spectrometry in systems biology will be assessed, the advantages and disadvantages discussed, and the instrument configurations available described. Finally, general applications will be briefly reviewed. Copyright © 2011 Elsevier Inc. All rights reserved.

High Resolution Mass Spectrometry for future space instrumentation : current development within the French Space Orbitrap Consortium

NASA Astrophysics Data System (ADS)

Briois, Christelle; Lebreton, Jean-Pierre; Szopa, Cyril; Thirkell, Laurent; Aradj, Kenzi; Bouabdellah, Abdel; Boukrara, Amirouche; Carrasco, Nathalie; Chalumeau, Gilles; Chapelon, Olivier; Colin, Fabrice; Cottin, Hervé; Engrand, Cécile; Grand, Noel; Kukui, Alexandre; Pennanech, Cyril; Thissen, Roland; Vuitton, Véronique; Zapf, Pascal; Makarov, Alexander

2014-05-01

Mass spectrometry has been used for years in space exploration to characterise the chemical composition of solar system bodies and their environment. Because of the harsh constraints imposed to the space probe instruments, their mass resolution is quite limited compared to laboratory instruments, sometimes leading to significant limitations in the treatment of the data collected with this type of instrumentation. Future in situ solar system exploration missions would significantly benefit from High Resolution Mass Spectrometry (HRMS). For a few years, 5 French laboratories (LPC2E, IPAG, LATMOS, LISA, CSNSM) involved in the chemical investigation of solar system bodies formed a Consortium to develop HRMS for future space exploration, based on the use of the Orbitrap technology (C. Briois et al., 2014, to be submitted). This development is carried out in the frame of a Research and Technology (R&T) development programme partly funded by the French Space Agency (CNES). The work is undertaken in close collaboration with the Thermo Fisher Scientific Company, which commercialises Orbitrap-based laboratory instruments. The R&T activities are currently concentrating on the core elements of the Orbitrap analyser that are required to reach a sufficient maturity level for allowing design studies of future space instruments. We are indeed pursuing, within international collaborations, the definition of several instrument concepts based on the core elements that are subject of our R&T programme. In this talk, we briefly discuss science applications for future orbitrap-based HRMS space instruments. We highlight present results of our R&T programme.

Surface-Induced Dissociation of Protein Complexes in a Hybrid Fourier Transform Ion Cyclotron Resonance Mass Spectrometer.

PubMed

Yan, Jing; Zhou, Mowei; Gilbert, Joshua D; Wolff, Jeremy J; Somogyi, Árpád; Pedder, Randall E; Quintyn, Royston S; Morrison, Lindsay J; Easterling, Michael L; Paša-Tolić, Ljiljana; Wysocki, Vicki H

2017-01-03

Mass spectrometry continues to develop as a valuable tool in the analysis of proteins and protein complexes. In protein complex mass spectrometry studies, surface-induced dissociation (SID) has been successfully applied in quadrupole time-of-flight (Q-TOF) instruments. SID provides structural information on noncovalent protein complexes that is complementary to other techniques. However, the mass resolution of Q-TOF instruments can limit the information that can be obtained for protein complexes by SID. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) provides ultrahigh resolution and ultrahigh mass accuracy measurements. In this study, an SID device was designed and successfully installed in a hybrid FT-ICR instrument in place of the standard gas collision cell. The SID-FT-ICR platform has been tested with several protein complex systems (homooligomers, a heterooligomer, and a protein-ligand complex, ranging from 53 to 85 kDa), and the results are consistent with data previously acquired on Q-TOF platforms, matching predictions from known protein interface information. SID fragments with the same m/z but different charge states are well-resolved based on distinct spacing between adjacent isotope peaks, and the addition of metal cations and ligands can also be isotopically resolved with the ultrahigh mass resolution available in FT-ICR.

A history of mass spectrometry in Australia.

PubMed

Downard, Kevin M; de Laeter, John R

2005-09-01

An interest in mass spectrometry in Australia can be traced back to the 1920s with an early correspondence with Francis Aston who first visited these shores a decade earlier. The region has a rich tradition in both the development of the field and its application, from early measurements of ionization and appearance potentials by Jim Morrison at the Council for Scientific and Industrial Research (CSIR) around 1950 to the design and construction of instrumentation including the first use of a triple quadrupole mass spectrometer for tandem mass spectrometry, the first suite of programs to simulate ion optics (SIMION), the development of early TOF/TOF instruments and orthogonal acceleration and the local design and construction of several generations of a sensitive high-resolution ion microprobe (SHRIMP) instrument. Mass spectrometry has been exploited in the study and characterization of the constituents of this nation's unique flora and fauna from Australian apples, honey, tea plant and eucalyptus oil, snake, spider, fish and frog venoms, coal, oil, sediments and shale, environmental studies of groundwater to geochronological dating of limestone and granite, other terrestrial and meteoritic rocks and coral from the Great Barrier Reef. Peter Jeffery's establishment of geochronological dating techniques in Western Australia in the early 1950s led to the establishment of geochronology research both at the Australian National University and at what is now the Curtin Institute of Technology in the 1960s. This article traces the history of mass spectrometry in its many guises and applications in the island continent of Australia. An article such as this can never be complete. It instead focuses on contributions of scientists who played a major role in the early establishment of mass spectrometry in Australia. In general, those who are presently active in the field, and whose histories are incomplete, have been mentioned at best only briefly despite their important contributions to the field.

Laser Time-of-Flight Mass Spectrometry for Future In Situ Planetary Missions

NASA Technical Reports Server (NTRS)

Getty, S. A.; Brinckerhoff, W. B.; Cornish, T.; Ecelberger, S. A.; Li, X.; Floyd, M. A. Merrill; Chanover, N.; Uckert, K.; Voelz, D.; Xiao, X.;

Estimating rates of denitrification enzyme activity in wetland soils and direct simultaneous quantification of nitrogen and nitrous oxide by membrane inlet mass spectrometry

EPA Science Inventory

Denitrification enzyme activity (DEA) was measured in short-term (4 h) anaerobic assays using Membrane Inlet Mass Spectrometry (MIMS) and electron capture gas chromatography (GC-ECD). Using MIMS, modifications of the instrument and sample handling allowed for the simultaneous me...

Trends in mass spectrometry instrumentation for proteomics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Richard D.

2002-12-01

Mass spectrometry has become a primary tool for proteomics due to its capabilities for rapid and sensitive protein identification and quantitation. It is now possible to identify thousands of proteins from microgram sample quantities in a single day and to quantify relative protein abundances. However, the needs for increased capabilities for proteome measurements are immense and are now driving both new strategies and instrument advances. These developments include those based on integration with multi-dimensional liquid separations and high accuracy mass measurements, and promise more than order of magnitude improvements in sensitivity, dynamic range, and throughput for proteomic analyses in themore » near future.« less

Atmospheric pressure ionization-tandem mass spectrometry of the phenicol drug family.

PubMed

Alechaga, Élida; Moyano, Encarnación; Galceran, M Teresa

2013-11-01

In this work, the mass spectrometry behaviour of the veterinary drug family of phenicols, including chloramphenicol (CAP) and its related compounds thiamphenicol (TAP), florfenicol (FF) and FF amine (FFA), was studied. Several atmospheric pressure ionization sources, electrospray (ESI), atmospheric pressure chemical ionization and atmospheric pressure photoionization were compared. In all atmospheric pressure ionization sources, CAP, TAP and FF were ionized in both positive and negative modes; while for the metabolite FFA, only positive ionization was possible. In general, in positive mode, [M + H](+) dominated the mass spectrum for FFA, while the other compounds, CAP, TAP and FF, with lower proton affinity showed intense adducts with species present in the mobile phase. In negative mode, ESI and atmospheric pressure photoionization showed the deprotonated molecule [M-H](-), while atmospheric pressure chemical ionization provided the radical molecular ion by electron capture. All these ions were characterized by tandem mass spectrometry using the combined information obtained by multistage mass spectrometry and high-resolution mass spectrometry in a quadrupole-Orbitrap instrument. In general, the fragmentation occurred via cyclization and losses or fragmentation of the N-(alkyl)acetamide group, and common fragmentation pathways were established for this family of compounds. A new chemical structure for the product ion at m/z 257 for CAP, on the basis of the MS(3) and MS(4) spectra is proposed. Thermally assisted ESI and selected reaction monitoring are proposed for the determination of these compounds by ultra high-performance liquid chromatography coupled to tandem mass spectrometry, achieving instrumental detection limits down to 0.1 pg. Copyright © 2013 John Wiley & Sons, Ltd.

Mass Spectrometry for Planetary Probes: Past, Present and Future

NASA Technical Reports Server (NTRS)

Niemann, Hasso B.; Harpold, Dan N.; Jamieson, Brian G.; Mahaffy, Paul R.

2005-01-01

Atmospheric entry probes present a unique opportunity for performing quantitative analysis of extra-terrestrial atmospheres in cases where remote sensing alone may not be sufficient and measurements with balloons or aircraft is not practical. An entry probe can provide a complete vertical profile of atmospheric parameters including chemical composition, which cannot be obtained with most other techniques. There are, however, unique challenges associated with building instruments for an entry probe, as compared to orbiters, landers, or rovers. Conditions during atmospheric entry are extreme, there are inherent time constraints due to the short duration of the experiment, and the instrument experiences rapid environmental changes in temperature and pressure as it descends. In addition, there are resource limitations, i.e. mass, power, size and bandwidth. Finally, the demands on the instrument design are determined in large part by conditions (pressure, temperature, composition) unique to the particular body under study, and as a result there is no one-size-fits-all instrument for an atmospheric probe. Many of these requirements can be more easily met by miniaturizing the probe instrument. Our experience building mass spectrometers for atmospheric entry probes leads us to believe that the time is right for a fundamental change in the way spaceflight mass spectrometers are built. The emergence over the past twenty years of Micro-electro- mechanical Systems (MEMS), utilizing lithographic semiconductor fabrication techniques to produce instrument systems in miniature, holds great promise for application to spaceflight mass spectrometry. A highly miniaturized, high performance and low-power mass spectrometer would be an enormous benefit to future entry probe missions, allowing, for example, parallel measurements (e.g., multiple simultaneous gas chromatographic analyses and direct atmospheric leaks.) Such an instrument would also enable mass spectrometry on board small multiple entry probes. In the development of a MEMS Mass Spectrometer, the challenge facing us is to move beyond the proof-of-concept, where research dollars tend to focus, and carry out the detailed work of developing a high performance mass spectrometer system on a chip which meets the unique technical requirements for an atmospheric entry probe described above.

Surface-Induced Dissociation of Protein Complexes in a Hybrid Fourier Transform Ion Cyclotron Resonance Mass Spectrometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Jing; Zhou, Mowei; Gilbert, Joshua D.

Mass spectrometry continues to develop as a valuable tool in the analysis of proteins and protein complexes. In protein complex mass spectrometry studies, surface-induced dissociation (SID) has been successfully applied in quadrupole time-of-flight (Q-TOF) instruments. SID provides structural information on noncovalent protein complexes that is complementary to other techniques. However, the mass resolution of Q-TOF instruments can limit the information that can be obtained for protein complexes by SID. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) provides ultrahigh resolution and ultrahigh mass accuracy measurements. Here in this study, an SID device was designed and successfully installed in amore » hybrid FT-ICR instrument in place of the standard gas collision cell. The SID-FT-ICR platform has been tested with several protein complex systems (homooligomers, a heterooligomer, and a protein-ligand complex, ranging from 53 to 85 kDa), and the results are consistent with data previously acquired on Q-TOF platforms, matching predictions from known protein interface information. Lastly, SID fragments with the same m/z but different charge states are well-resolved based on distinct spacing between adjacent isotope peaks, and the addition of metal cations and ligands can also be isotopically resolved with the ultrahigh mass resolution available in FT-ICR.« less

Surface-Induced Dissociation of Protein Complexes in a Hybrid Fourier Transform Ion Cyclotron Resonance Mass Spectrometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Jing; Zhou, Mowei; Gilbert, Joshua D.

Mass spectrometry continues to develop as a valuable tool in the analysis of proteins and protein complexes. In protein complex mass spectrometry studies, surface-induced dissociation (SID) has been successfully applied in quadrupole time-of-flight (Q-TOF) instruments. SID provides structural information on non-covalent protein complexes that is complementary to other techniques. However, the mass resolution of Q-TOF instruments can limit the information that can be obtained for protein complexes by SID. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) provides ultrahigh resolution and ultrahigh mass accuracy measurements. In this study, an SID device was designed and successfully installed in a hybridmore » FT-ICR instrument in place of the standard gas collision cell. The SID-FT-ICR platform has been tested with several protein complex systems (homooligomers, a heterooligomer, and a protein-ligand complex, ranging from 53 kDa to 85 kDa), and the results are consistent with data previously acquired on Q-TOF platforms, matching predictions from known protein interface information. SID fragments with the same m/z but different charge states are well-resolved based on distinct spacing between adjacent isotope peaks, and the addition of metal cations and ligands can also be isotopically resolved with the ultrahigh mass resolution available in FT-ICR.« less

Surface-Induced Dissociation of Protein Complexes in a Hybrid Fourier Transform Ion Cyclotron Resonance Mass Spectrometer

DOE PAGES

Yan, Jing; Zhou, Mowei; Gilbert, Joshua D.; ...

2016-12-02

Mass spectrometry continues to develop as a valuable tool in the analysis of proteins and protein complexes. In protein complex mass spectrometry studies, surface-induced dissociation (SID) has been successfully applied in quadrupole time-of-flight (Q-TOF) instruments. SID provides structural information on noncovalent protein complexes that is complementary to other techniques. However, the mass resolution of Q-TOF instruments can limit the information that can be obtained for protein complexes by SID. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) provides ultrahigh resolution and ultrahigh mass accuracy measurements. Here in this study, an SID device was designed and successfully installed in amore » hybrid FT-ICR instrument in place of the standard gas collision cell. The SID-FT-ICR platform has been tested with several protein complex systems (homooligomers, a heterooligomer, and a protein-ligand complex, ranging from 53 to 85 kDa), and the results are consistent with data previously acquired on Q-TOF platforms, matching predictions from known protein interface information. Lastly, SID fragments with the same m/z but different charge states are well-resolved based on distinct spacing between adjacent isotope peaks, and the addition of metal cations and ligands can also be isotopically resolved with the ultrahigh mass resolution available in FT-ICR.« less

Evolution of Instrumentation for the Study of Gas-Phase Ion/Ion Chemistry via Mass Spectrometry

PubMed Central

Xia, Yu; McLuckey, Scott A.

2008-01-01

The scope of gas phase ion/ion chemistry accessible to mass spectrometry is largely defined by the available tools. Due to the development of novel instrumentation, a wide range of reaction phenomenologies have been noted, many of which have been studied extensively and exploited for analytical applications. This perspective presents the development of mass spectrometry-based instrumentation for the study of the gas phase ion/ion chemistry in which at least one of the reactants is multiply-charged. The instrument evolution is presented within the context of three essential elements required for any ion/ion reaction study: the ionization source(s), the reaction vessel or environment, and the mass analyzer. Ionization source arrangements have included source combinations that allow for reactions between multiply charged ions of one polarity and singly charged ions of opposite polarity, arrangements that enable the study of reactions of multiply charged ions of opposite polarity, and most recently, arrangements that allow for ion formation from more than two ion sources. Gas phase ion/ion reaction studies have been performed at near atmospheric pressure in flow reactor designs and within electrodynamic ion traps operated in the mTorr range. With ion trap as a reaction vessel, ionization and reaction processes can be independently optimized and ion/ion reactions can be implemented within the context of MSn experiments. Spatial separation of the reaction vessel from the mass analyzer allows for the use of any form of mass analysis in conjunction with ion/ion reactions. Time-of-flight mass analysis, for example, has provided significant improvements in mass analysis figures of merit relative to mass filters and ion traps. PMID:18083527

Boundaries of mass resolution in native mass spectrometry.

PubMed

Lössl, Philip; Snijder, Joost; Heck, Albert J R

2014-06-01

Over the last two decades, native mass spectrometry (MS) has emerged as a valuable tool to study intact proteins and noncovalent protein complexes. Studied experimental systems range from small-molecule (drug)-protein interactions, to nanomachineries such as the proteasome and ribosome, to even virus assembly. In native MS, ions attain high m/z values, requiring special mass analyzers for their detection. Depending on the particular mass analyzer used, instrumental mass resolution does often decrease at higher m/z but can still be above a couple of thousand at m/z 5000. However, the mass resolving power obtained on charge states of protein complexes in this m/z region is experimentally found to remain well below the inherent instrument resolution of the mass analyzers employed. Here, we inquire into reasons for this discrepancy and ask how native MS would benefit from higher instrumental mass resolution. To answer this question, we discuss advantages and shortcomings of mass analyzers used to study intact biomolecules and biomolecular complexes in their native state, and we review which other factors determine mass resolving power in native MS analyses. Recent examples from the literature are given to illustrate the current status and limitations.

Determination of T-2 and HT-2 toxins from maize by direct analysis in real time mass spectrometry

USDA-ARS?s Scientific Manuscript database

Direct analysis in real time (DART) ionization coupled to mass spectrometry (MS) was used for the rapid quantitative analysis of T-2 toxin, and the related HT-2 toxin, extracted from corn. Sample preparation procedures and instrument parameters were optimized to obtain sensitive and accurate determi...

Ion mobility-mass spectrometry of complex carbohydrates: collision cross sections of sodiated N-linked glycans.

PubMed

Pagel, Kevin; Harvey, David J

2013-05-21

Currently, the vast majority of complex carbohydrates are characterized using mass spectrometry (MS)-based techniques. Measuring the molecular mass of a sugar, however, immediately poses a fundamental problem: entire classes of the constituting monosaccharide building blocks exhibit an identical atomic composition and, consequently, also an identical mass. Therefore, carbohydrate MS data can be highly ambiguous and often it is simply not possible to clearly assign a particular molecular structure. A promising approach to overcome the above-mentioned limitation is to implement an additional gas-phase separation dimension using ion mobility spectrometry (IMS), which is a method in which molecules of identical mass and structure but different structure can be separated according to their shape and collision cross section (CCS). With the emergence of commercially available hybrid ion mobility-mass spectrometry (IM-MS) instruments in 2006, IMS technology became readily available. Because of the nonhomogeneous, traveling wave (TW) field utilized in these instruments, however, CCS values currently cannot be determined directly from the drift times measured. Instead, an external calibration using compounds of known CCS and similar molecular identity is required. Here, we report a calibration protocol for TW IMS instruments using a series of sodiated N-glycans that were released from commercially available glycoproteins using an easy-to-follow protocol. The underlying CCS values were determined using a modified Synapt HDMS instrument with a linear drift tube, which was described in detail previously. Our data indicate that, under in-source fragmentation conditions, only a few glycans are required to obtain a TW IMS calibration of sufficient quality. In this context, however, the type of glycan was shown to be of tremendous importance. Furthermore, our data clearly demonstrate that carbohydrate isomers with identical mass but different conformation can be distinguished based on their CCS when all the associated errors are taken into account.

Extending the frontiers of mass spectrometric instrumentation and methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schieffer, Gregg Martin

2010-01-01

The focus of this dissertation is two-fold: developing novel analysis methods using mass spectrometry and the implementation and characterization of a novel ion mobility mass spectrometry instrumentation. The novel mass spectrometry combines ion trap for ion/ion reactions coupled to an ion mobility cell. The long term goal of this instrumentation is to use ion/ion reactions to probe the structure of gas phase biomolecule ions. The three ion source - ion trap - ion mobility - qTOF mass spectrometer (IT - IM - TOF MS) instrument is described. The analysis of the degradation products in coal (Chapter 2) and the imagingmore » plant metabolites (Appendix III) fall under the methods development category. These projects use existing commercial instrumentation (JEOL AccuTOF MS and Thermo Finnigan LCQ IT, respectively) for the mass analysis of the degraded coal products and the plant metabolites, respectively. The coal degradation paper discusses the use of the DART ion source for fast and easy sample analysis. The sample preparation consisted of a simple 50 fold dilution of the soluble coal products in water and placing the liquid in front of the heated gas stream. This is the first time the DART ion source has been used for analysis of coal. Steven Raders under the guidance of John Verkade came up with the coal degradation projects. Raders performed the coal degradation reactions, worked up the products, and sent them to me. Gregg Schieffer developed the method and wrote the paper demonstrating the use of the DART ion source for the fast and easy sample analysis. The plant metabolite imaging project extends the use of colloidal graphite as a sample coating for atmospheric pressure LDI. DC Perdian and I closely worked together to make this project work. Perdian focused on building the LDI setup whereas Schieffer focused on the MSn analysis of the metabolites. Both Perdian and I took the data featured in the paper. Perdian was the primary writer of the paper and used it as a chapter in his dissertation. Perdian and Schieffer worked together to address the revisions and publish it in Rapid Communications in Mass Spectrometry Journal.« less

Recent advances of liquid chromatography-(tandem) mass spectrometry in clinical and forensic toxicology.

PubMed

Peters, Frank T

2011-01-01

Liquid chromatography (LC) coupled to mass spectrometry (MS) or tandem mass spectrometry (MS/MS) has become increasingly important in clinical and forensic toxicology as well as doping control and is now a robust and reliable technique for routine analysis in these fields. In recent years, methods for LC-MS(/MS)-based systematic toxicological analysis using triple quadrupole or ion trap instruments have been considerably improved and a new screening approach based on high-resolution MS analysis using benchtop time-of-flight MS instruments has been developed. Moreover, many applications for so-called multi-target screening and/or quantification of drugs, poisons, and or their metabolites in various biomatrices have been published. The present paper will provide an overview and discuss these recent developments focusing on the literature published after 2006. Copyright © 2010 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Evolution of Orbitrap Mass Spectrometry Instrumentation

NASA Astrophysics Data System (ADS)

Eliuk, Shannon; Makarov, Alexander

2015-07-01

We discuss the evolution of OrbitrapTM mass spectrometry (MS) from its birth in the late 1990s to its current role as one of the most prominent techniques for MS. The Orbitrap mass analyzer is the first high-performance mass analyzer that employs trapping of ions in electrostatic fields. Tight integration with the ion injection process enables the high-resolution, mass accuracy, and sensitivity that have become essential for addressing analytical needs in numerous areas of research, as well as in routine analysis. We examine three major families of instruments (related to the LTQ Orbitrap, Q Exactive, and Orbitrap Fusion mass spectrometers) in the context of their historical development over the past ten eventful years. We discuss as well future trends and perspectives of Orbitrap MS. We illustrate the compelling potential of Orbitrap-based mass spectrometers as (ultra) high-resolution platforms, not only for high-end proteomic applications, but also for routine targeted analysis.

MALDI mass spectrometry imaging, from its origins up to today: the state of the art.

PubMed

Francese, Simona; Dani, Francesca R; Traldi, Pietro; Mastrobuoni, Guido; Pieraccini, Giuseppe; Moneti, Gloriano

2009-02-01

Mass Spectrometry (MS) has a number of features namely sensitivity, high dynamic range, high resolution, and versatility which make it a very powerful analytical tool for a wide spectrum of applications spanning all the life science fields. Among all the MS techniques, MALDI Imaging mass spectrometry (MALDI MSI) is currently one of the most exciting both for its rapid technological improvements, and for its great potential in high impact bioscience fields. Here, MALDI MSI general principles are described along with technical and instrumental details as well as application examples. Imaging MS instruments and imaging mass spectrometric techniques other than MALDI, are presented along with examples of their use. As well as reporting MSI successes in several bioscience fields, an attempt is made to take stock of what has been achieved so far with this technology and to discuss the analytical and technological advances required for MSI to be applied as a routine technique in clinical diagnostics, clinical monitoring and in drug discovery.

The Lamont--Doherty Geological Observatory Isolab 54 isotope ratio mass spectrometer

NASA Astrophysics Data System (ADS)

England, J. G.; Zindler, A.; Reisberg, L. C.; Rubenstone, J. L.; Salters, V.; Marcantonio, F.; Bourdon, B.; Brueckner, H.; Turner, P. J.; Weaver, S.; Read, P.

1992-12-01

The Lamont--Doherty Geological Observatory (LDGO) Isolab 54 is a double focussing isotope ratio mass spectrometer that allows the measurement of thermal ions produced on a hot filament, (thermal-ionization mass spectrometry (TIMS)), secondary ions produced by sputtering a sample using a primary ion beam, (secondary ion mass spectrometry (SIMS)), and sputtered neutrals resonantly ionized using laser radiation, (sputter-induced resonance ionization mass spectrometry (SIRIMS)). Sputtering is carried out using an Ar primary beam generated in a duoplasmatron and focussed onto the sample using a two-lens column. Resonance ionization is accomplished using a frequency-doubled dye laser pumped by an excimer laser. The Isolab's forward geometry analyzer, consisting of an electrostatic followed by a magnetic sector, allows the simultaneous collection of different isotopes of the same element. This instrument is the first to have a multicollector that contains an ion-counting system based on a microchannel plate as well as traditional Faraday cups. A second electrostatic sector after the multicollector is equipped with an ion-counting Daly detector to allow high abundance sensitivity for measurements of large dynamics range. Selectable source, collector, [alpha] and energy slits on the instrument allow analyses to be made over a range of mass resolving powers and analyzer acceptances. Recent applications of the instrument have included the analyses of U by TIMS, Hf, Th and Re by SIMS and Re and Os by SIRIMS.

Combined distance-of-flight and time-of-flight mass spectrometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Enke, Christie G; Ray, Steven J; Graham, Alexander W

2014-02-11

A combined distance-of-flight mass spectrometry (DOFMS) and time-of-flight mass spectrometry (TOFMS) instrument includes an ion source configured to produce ions having varying mass-to-charge ratios, a first detector configured to determine when each of the ions travels a predetermined distance, a second detector configured to determine how far each of the ions travels in a predetermined time, and a detector extraction region operable to direct portions of the ions either to the first detector or to the second detector.

New Cs sputter ion source with polyatomic ion beams for secondary ion mass spectrometry applications

NASA Astrophysics Data System (ADS)

Belykh, S. F.; Palitsin, V. V.; Veryovkin, I. V.; Kovarsky, A. P.; Chang, R. J. H.; Adriaens, A.; Dowsett, M. G.; Adams, F.

2007-08-01

A simple design for a cesium sputter ion source compatible with vacuum and ion-optical systems as well as with electronics of the commercially available Cameca IMS-4f instrument is reported. This ion source has been tested with the cluster primary ions of Sin- and Cun-. Our experiments with surface characterization and depth profiling conducted to date demonstrate improvements of the analytical capabilities of the secondary ion mass spectrometry instrument due to the nonadditive enhancement of secondary ion emission and shorter ion ranges of polyatomic projectiles compared to atomic ones with the same impact energy.

Chiral Analysis by Tandem Mass Spectrometry Using the Kinetic Method, by Polarimetry, and by [Superscript 1]H NMR Spectroscopy

ERIC Educational Resources Information Center

Fedick, Patrick W.; Bain, Ryan M.; Bain, Kinsey; Cooks, R. Graham

2017-01-01

The goal of this laboratory exercise was for students to understand the concept of chirality and how enantiomeric excess (ee) is experimentally determined using the analysis of ibuprofen as an example. Students determined the enantiomeric excess of the analyte by three different instrumental methods: mass spectrometry, nuclear magnetic resonance…

Structural characterization of product ions by electrospray ionization and quadrupole time-of-flight mass spectrometry to support regulatory analysis of veterinary drug residues in foods Part 2: Benzimidazoles nitromidaz.....

USDA-ARS?s Scientific Manuscript database

RATIONALE: Analysis for identification and quantification of regulated veterinary drug residues in foods are usually achieved by liquid chromatography coupled to tandem mass spectrometry. The instrument method requires the selection of characteristic ions, but structure elucidation is seldom perform...

Analysis of Whiskey by Dispersive Liquid-Liquid Microextraction Coupled with Gas Chromatography/Mass Spectrometry: An Upper Division Analytical Chemistry Experiment Guided by Green Chemistry

ERIC Educational Resources Information Center

Owens, Janel E.; Zimmerman, Laura B.; Gardner, Michael A.; Lowe, Luis E.

2016-01-01

Analysis of whiskey samples prepared by a green microextraction technique, dispersive liquid-liquid microextraction (DLLME), before analysis by a qualitative gas chromatography-mass spectrometry (GC/MS) method, is described as a laboratory experiment for an upper division instrumental methods of analysis laboratory course. Here, aroma compounds in…

Resolving Structural Isomers of Monosaccharide Methyl Glycosides Using Drift Tube and Traveling Wave Ion Mobility Mass Spectrometry

PubMed Central

Li, Hongli; Giles, Kevin; Bendiak, Brad; Kaplan, Kimberly; Siems, William F.; Hill, Herbert H.

2013-01-01

Monosaccharide structural isomers including sixteen methyl-D-glycopyranosides and four methyl-N-acetylhexosamines were subjected to ion mobility measurements by electrospray ion mobility mass spectrometry. Two ion mobility-MS systems were employed: atmospheric pressure drift tube ion mobility time-of-flight mass spectrometry and a Synapt G2 HDMS system which incorporates a low pressure traveling wave ion mobility separator. All the compounds were investigated as [M+Na]+ ions in the positive mode. A majority of the monosaccharide structural isomers exhibited different mobility drift times in either system, depending on differences in their anomeric and stereochemical configurations. In general, drift time patterns (relative drift times of isomers) matched between the two instruments. Higher resolving power was observed using the atmospheric pressure drift tube. Collision cross section values of monosaccharide structural isomers were directly calculated from the atmospheric pressure ion mobility experiments and a collision cross section calibration curve was made for the traveling wave ion mobility instrument. Overall, it was demonstrated that ion mobility-mass spectrometry using either drift tube or traveling wave ion mobility is a valuable technique for resolving subtle variations in stereochemistry among the sodium adducts of monosaccharide methyl glycosides. PMID:22339760

Linear Ion Traps in Space: The Mars Organic Molecule Analyzer (MOMA) Instrument and Beyond

NASA Astrophysics Data System (ADS)

Arevalo, Ricardo; Brinckerhoff, William; Mahaffy, Paul; van Amerom, Friso; Danell, Ryan; Pinnick, Veronica; Li, Xiang; Hovmand, Lars; Getty, Stephanie; Grubisic, Andrej; Goesmann, Fred; Cottin, Hervé

2015-11-01

Historically, quadrupole mass spectrometer (QMS) instruments have been used to explore a wide survey of planetary targets in our solar system, from Venus (Pioneer Venus) to Saturn (Cassini-Huygens). However, linear ion trap (LIT) mass spectrometers have found a niche as smaller, versatile alternatives to traditional quadrupole analyzers.The core astrobiological experiment of ESA’s ExoMars Program is the Mars Organic Molecule Analyzer (MOMA) onboard the ExoMars 2018 rover. The MOMA instrument is centered on a linear (or 2-D) ion trap mass spectrometer. As opposed to 3-D traps, LIT-based instruments accommodate two symmetrical ion injection pathways, enabling two complementary ion sources to be used. In the case of MOMA, these two analytical approaches are laser desorption mass spectrometry (LDMS) at Mars ambient pressures, and traditional gas chromatography mass spectrometry (GCMS). The LIT analyzer employed by MOMA also offers: higher ion capacity compared to a 3-D trap of the same volume; redundant detection subassemblies for extended lifetime; and, a link to heritage QMS designs and assembly logistics. The MOMA engineering test unit (ETU) has demonstrated the detection of organics in the presence of wt.%-levels of perchlorate, effective ion enhancement via stored waveform inverse Fourier transform (SWIFT), and derivation of structural information through tandem mass spectrometry (MS/MS).A more progressive linear ion trap mass spectrometer (LITMS), funded by the NASA ROSES MatISSE Program, is being developed at NASA GSFC and promises to augment the capabilities of the MOMA instrument by way of: an expanded mass range (i.e., 20 - 2000 Da); detection of both positive and negative ions; spatially resolved (<1 mm) characterization of individual rock core layers; and, evolved gas analysis and GCMS with pyrolysis up to 1300° C (enabling breakdown of refractory phases). The Advanced Resolution Organic Molecule Analyzer (AROMA) instrument, being developed through NASA PICASSO and ESA Research and Development Programs, combines a highly capable LIT front end (a la LITMS) with a high-resolution OrbitrapTM (a la CosmOrbitrap) mass analyzer to enable disambiguation of complex molecular signals in organic-rich targets.

Towards monitoring real-time cellular response using an integrated microfluidics-MALDI/nESI-ion mobility-mass spectrometry platform

PubMed Central

Enders, Jeffrey R.; Marasco, Christina C.; Kole, Ayeeshik; Nguyen, Bao; Sundarapandian, Sevugarajan; Seale, Kevin T.; Wikswo, John P.; McLean, John A.

2014-01-01

The combination of microfluidic cell trapping devices with ion mobility-mass spectrometry offers the potential for elucidating in real time the dynamic responses of small populations of cells to paracrine signals, changes in metabolite levels, and delivery of drugs and toxins. Preliminary experiments examining peptides in methanol and recording the interactions of yeast and Jurkat cells with their superfusate have identified instrumental setup and control parameters and on-line desalting procedures. Numerous initial experiments demonstrate and validate this new instrumental platform. Future outlooks and potential applications are addressed, specifically how this instrumentation may be used for fully automated systems biology studies of the significantly interdependent, dynamic internal workings of cellular metabolic and signaling pathways. PMID:21073240

Measuring Thermodynamic Properties of Metals and Alloys With Knudsen Effusion Mass Spectrometry

NASA Technical Reports Server (NTRS)

Copland, Evan H.; Jacobson, Nathan S.

2010-01-01

This report reviews Knudsen effusion mass spectrometry (KEMS) as it relates to thermodynamic measurements of metals and alloys. First, general aspects are reviewed, with emphasis on the Knudsen-cell vapor source and molecular beam formation, and mass spectrometry issues germane to this type of instrument are discussed briefly. The relationship between the vapor pressure inside the effusion cell and the measured ion intensity is the key to KEMS and is derived in detail. Then common methods used to determine thermodynamic quantities with KEMS are discussed. Enthalpies of vaporization, the fundamental measurement, are determined from the variation of relative partial pressure with temperature using the second-law method or by calculating a free energy of formation and subtracting the entropy contribution using the third-law method. For single-cell KEMS instruments, measurements can be used to determine the partial Gibbs free energy if the sensitivity factor remains constant over multiple experiments. The ion-current ratio method and dimer-monomer method are also viable in some systems. For a multiple-cell KEMS instrument, activities are obtained by direct comparison with a suitable component reference state or a secondary standard. Internal checks for correct instrument operation and general procedural guidelines also are discussed. Finally, general comments are made about future directions in measuring alloy thermodynamics with KEMS.

On the isobaric space of 25-hydroxyvitamin D in human serum: potential for interferences in liquid chromatography/tandem mass spectrometry, systematic errors and accuracy issues.

PubMed

Qi, Yulin; Geib, Timon; Schorr, Pascal; Meier, Florian; Volmer, Dietrich A

2015-01-15

Isobaric interferences in human serum can potentially influence the measured concentration levels of 25-hydroxyvitamin D [25(OH)D], when low resolving power liquid chromatography/tandem mass spectrometry (LC/MS/MS) instruments and non-specific MS/MS product ions are employed for analysis. In this study, we provide a detailed characterization of these interferences and a technical solution to reduce the associated systematic errors. Detailed electrospray ionization Fourier transform ion cyclotron resonance (FTICR) high-resolution mass spectrometry (HRMS) experiments were used to characterize co-extracted isobaric components of 25(OH)D from human serum. Differential ion mobility spectrometry (DMS), as a gas-phase ion filter, was implemented on a triple quadrupole mass spectrometer for separation of the isobars. HRMS revealed the presence of multiple isobaric compounds in extracts of human serum for different sample preparation methods. Several of these isobars had the potential to increase the peak areas measured for 25(OH)D on low-resolution MS instruments. A major isobaric component was identified as pentaerythritol oleate, a technical lubricant, which was probably an artifact from the analytical instrumentation. DMS was able to remove several of these isobars prior to MS/MS, when implemented on the low-resolution triple quadrupole mass spectrometer. It was shown in this proof-of-concept study that DMS-MS has the potential to significantly decrease systematic errors, and thus improve accuracy of vitamin D measurements using LC/MS/MS. Copyright © 2014 John Wiley & Sons, Ltd.

imzML: Imaging Mass Spectrometry Markup Language: A common data format for mass spectrometry imaging.

PubMed

Römpp, Andreas; Schramm, Thorsten; Hester, Alfons; Klinkert, Ivo; Both, Jean-Pierre; Heeren, Ron M A; Stöckli, Markus; Spengler, Bernhard

2011-01-01

Imaging mass spectrometry is the method of scanning a sample of interest and generating an "image" of the intensity distribution of a specific analyte. The data sets consist of a large number of mass spectra which are usually acquired with identical settings. Existing data formats are not sufficient to describe an MS imaging experiment completely. The data format imzML was developed to allow the flexible and efficient exchange of MS imaging data between different instruments and data analysis software.For this purpose, the MS imaging data is divided in two separate files. The mass spectral data is stored in a binary file to ensure efficient storage. All metadata (e.g., instrumental parameters, sample details) are stored in an XML file which is based on the standard data format mzML developed by HUPO-PSI. The original mzML controlled vocabulary was extended to include specific parameters of imaging mass spectrometry (such as x/y position and spatial resolution). The two files (XML and binary) are connected by offset values in the XML file and are unambiguously linked by a universally unique identifier. The resulting datasets are comparable in size to the raw data and the separate metadata file allows flexible handling of large datasets.Several imaging MS software tools already support imzML. This allows choosing from a (growing) number of processing tools. One is no longer limited to proprietary software, but is able to use the processing software which is best suited for a specific question or application. On the other hand, measurements from different instruments can be compared within one software application using identical settings for data processing. All necessary information for evaluating and implementing imzML can be found at http://www.imzML.org .

A survey of mass analyzers. [characteristics and features of various instruments and techniques

NASA Technical Reports Server (NTRS)

Moore, W. W., Jr.; Tashbar, P. W.

1973-01-01

With the increasing applications of mass spectrometry technology to diverse services areas, a need has developed for a consolidated survey of the essential characteristics and features of the various instruments and techniques. This report is one approach to satisfying this need. Information has been collected and consolidated into a format which includes for each approach: (1) a general technique description, (2) instrument features information, and (3) a summary of pertinent advantages and disadvantages. With this information, the potential mass spectrometer user should be able to more efficiently select the most appropriate instrument.

Nuclear applications of inorganic mass spectrometry.

PubMed

De Laeter, John

2010-01-01

There are several basic characteristics of mass spectrometry that are not always fully appreciated by the science community. These characteristics include the distinction between relative and absolute isotope abundances, and the influence of isotope fractionation on the accuracy of isotopic measurements. These characteristics can be illustrated in the field of nuclear physics with reference to the measurement of nuclear parameters, which involve the use of enriched isotopes, and to test models of s-, r-, and p-process nucleosynthesis. The power of isotope-dilution mass spectrometry (IDMS) to measure trace elements in primitive meteorites to produce accurate Solar System abundances has been essential to the development of nuclear astrophysics. The variety of mass spectrometric instrumentation used to measure the isotopic composition of elements has sometimes been accompanied by a lack of implementation of basic mass spectrometric protocols which are applicable to all instruments. These metrological protocols are especially important in atomic weight determinations, but must also be carefully observed in cases where the anomalies might be very small, such as in studies of the daughter products of extinct radionuclides to decipher events in the early history of the Solar System. There are occasions in which misleading conclusions have been drawn from isotopic data derived from mass spectrometers where such protocols have been ignored. It is important to choose the mass spectrometer instrument most appropriate to the proposed experiment. The importance of the integrative nature of mass spectrometric measurements has been demonstrated by experiments in which long, double beta decay and geochronological decay half-lives have been measured as an alternative to costly radioactive-counting experiments. This characteristic is also illustrated in the measurement of spontaneous fission yields, which have accumulated over long periods of time. Mass spectrometry is also a valuable tool in the determination of neutron capture cross-section measurements and the application of such determinations in Planetary Science. 2009 Wiley Periodicals, Inc.

The expanding universe of mass analyzer configurations for biological analysis.

PubMed

Calvete, Juan J

2014-01-01

Mass spectrometry (MS) is an analytical technique that measures the mass-to-charge ratio of electrically charged gas-phase particles. All mass spectrometers combine ion formation, mass analysis, and ion detection. Although mass analyzers can be regarded as sophisticated devices that manipulate ions in space and time, the rich diversity of possible ways to combine ion separation, focusing, and detection in dynamic mass spectrometers accounts for the large number of instrument designs. A historical perspective of the progress in mass spectrometry that since 1965 until today have contributed to position this technique as an indispensable tool for biological research has been recently addressed by a privileged witness of this golden age of MS (Gelpí J. Mass Spectrom 43:419-435, 2008; Gelpí J. Mass Spectrom 44:1137-1161, 2008). The aim of this chapter is to highlight the view that the operational principles of mass spectrometry can be understood by a simple mathematical language, and that an understanding of the basic concepts of mass spectrometry is necessary to take the most out of this versatile technique.

Mass Spectrometry as a Powerful Analytical Technique for the Structural Characterization of Synthesized and Natural Products

NASA Astrophysics Data System (ADS)

Es-Safi, Nour-Eddine; Essassi, El Mokhtar; Massoui, Mohamed; Banoub, Joseph

Mass spectrometry is an important tool for the identification and structural elucidation of natural and synthesized compounds. Its high sensitivity and the possibility of coupling liquid chromatography with mass spectrometry detection make it a technique of choice for the investigation of complex mixtures like raw natural extracts. The mass spectrometer is a universal detector that can achieve very high sensitivity and provide information on the molecular mass. More detailed information can be subsequently obtained by resorting to collision-induced dissociation tandem mass spectrometry (CID-MS/MS). In this review, the application of mass spectrometric techniques for the identification of natural and synthetic compounds is presented. The gas-phase fragmentation patterns of a series of four natural flavonoid glycosides, three synthesized benzodiazepines and two synthesized quinoxalinone derivatives were investigated using electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry techniques. Exact accurate masses were measured using a modorate resolution quadrupole orthogonal time-of-flight QqTOF-MS/MS hybrid mass spectrometer instrument. Confirmation of the molecular masses and the chemical structures of the studied compounds were achieved by exploring the gas-phase breakdown routes of the ionized molecules. This was rationalized by conducting low-energy collision CID-MS/MS analyses (product ion- and precursor ion scans) using a conventional quadrupole hexapole-quadrupole (QhQ) tandem mass spectrometer.

File formats commonly used in mass spectrometry proteomics.

PubMed

Deutsch, Eric W

2012-12-01

The application of mass spectrometry (MS) to the analysis of proteomes has enabled the high-throughput identification and abundance measurement of hundreds to thousands of proteins per experiment. However, the formidable informatics challenge associated with analyzing MS data has required a wide variety of data file formats to encode the complex data types associated with MS workflows. These formats encompass the encoding of input instruction for instruments, output products of the instruments, and several levels of information and results used by and produced by the informatics analysis tools. A brief overview of the most common file formats in use today is presented here, along with a discussion of related topics.

Application of Laser Mass Spectrometry to Art and Archaeology

NASA Technical Reports Server (NTRS)

Gulian, Lase Lisa E.; Callahan, Michael P.; Muliadi, Sarah; Owens, Shawn; McGovern, Patrick E.; Schmidt, Catherine M.; Trentelman, Karen A.; deVries, Mattanjah S.

2011-01-01

REMPI laser mass spectrometry is a combination of resonance enhanced multiphoton ionization spectroscopy and time of flight mass spectrometry, This technique enables the collection of mass specific optical spectra as well as of optically selected mass spectra. Analytes are jet-cooled by entrainment in a molecular beam, and this low temperature gas phase analysis has the benefit of excellent vibronic resolution. Utilizing this method, mass spectrometric analysis of historically relevant samples can be simplified and improved; Optical selection of targets eliminates the need for chromatography while knowledge of a target's gas phase spectroscopy allows for facile differentiation of molecules that are in the aqueous phase considered spectroscopically indistinguishable. These two factors allow smaller sample sizes than commercial MS instruments, which in turn will require less damage to objects of antiquity. We have explored methods to optimize REMPI laser mass spectrometry as an analytical tool to archaeology using theobromine and caffeine as molecular markers in Mesoamerican pottery, and are expanding this approach to the field of art to examine laccaic acid in shellacs.

Space Applications of Mass Spectrometry. Chapter 31

NASA Technical Reports Server (NTRS)

Hoffman, John H.; Griffin, Timothy P.; Limero, Thomas; Arkin, C. Richard

2010-01-01

Mass spectrometers have been involved in essentially all aspects of space exploration. This chapter outlines some of these many uses. Mass spectrometers have not only helped to expand our knowledge and understanding of the world and solar system around us, they have helped to put man safely in space and expand our frontier. Mass spectrometry continues to prove to be a very reliable, robust, and flexible analytical instrument, ensuring that its use will continue to help aid our investigation of the universe and this small planet that we call home.

Native Mass Spectrometry in Fragment-Based Drug Discovery.

PubMed

Pedro, Liliana; Quinn, Ronald J

2016-07-28

The advent of native mass spectrometry (MS) in 1990 led to the development of new mass spectrometry instrumentation and methodologies for the analysis of noncovalent protein-ligand complexes. Native MS has matured to become a fast, simple, highly sensitive and automatable technique with well-established utility for fragment-based drug discovery (FBDD). Native MS has the capability to directly detect weak ligand binding to proteins, to determine stoichiometry, relative or absolute binding affinities and specificities. Native MS can be used to delineate ligand-binding sites, to elucidate mechanisms of cooperativity and to study the thermodynamics of binding. This review highlights key attributes of native MS for FBDD campaigns.

Imaging Mass Spectrometry on the Nanoscale with Cluster Ion Beams

PubMed Central

2015-01-01

Imaging with cluster secondary ion mass spectrometry (SIMS) is reaching a mature level of development. Using a variety of molecular ion projectiles to stimulate desorption, 3-dimensional imaging with the selectivity of mass spectrometry can now be achieved with submicrometer spatial resolution and <10 nm depth resolution. In this Perspective, stock is taken regarding what it will require to routinely achieve these remarkable properties. Issues include the chemical nature of the projectile, topography formation, differential erosion rates, and perhaps most importantly, ionization efficiency. Shortcomings of existing instrumentation are also noted. Speculation about how to successfully resolve these issues is a key part of the discussion. PMID:25458665

U/Th dating by SHRIMP RG ion-microprobe mass spectrometry using single ion-exchange beads

NASA Astrophysics Data System (ADS)

Bischoff, James L.; Wooden, Joe; Murphy, Fred; Williams, Ross W.

2005-04-01

We present a new analytical method for U-series isotopes using the SHRIMP RG (Sensitive High mass Resolution Ion MicroProbe) mass spectrometer that utilizes the preconcentration of the U-series isotopes from a sample onto a single ion-exchange bead. Ion-microprobe mass spectrometry is capable of producing Th ionization efficiencies in excess of 2%. Analytical precision is typically better than alpha spectroscopy, but not as good as thermal ionization mass spectroscopy (TIMS) and inductively coupled plasma multicollector mass spectrometry (ICP-MS). Like TIMS and ICP-MS the method allows analysis of small samples sizes, but also adds the advantage of rapidity of analysis. A major advantage of ion-microprobe analysis is that U and Th isotopes are analyzed in the same bead, simplifying the process of chemical separation. Analytical time on the instrument is ˜60 min per sample, and a single instrument-loading can accommodate 15-20 samples to be analyzed in a 24-h day. An additional advantage is that the method allows multiple reanalyses of the same bead and that samples can be archived for reanalysis at a later time. Because the ion beam excavates a pit only a few μm deep, the mount can later be repolished and reanalyzed numerous times. The method described of preconcentrating a low concentration sample onto a small conductive substrate to allow ion-microprobe mass spectrometry is potentially applicable to many other systems.

U/Th dating by SHRIMP RG ion-microprobe mass spectrometry using single ion-exchange beads

USGS Publications Warehouse

Bischoff, J.L.; Wooden, J.; Murphy, F.; Williams, Ross W.

2005-01-01

We present a new analytical method for U-series isotopes using the SHRIMP RG (Sensitive High mass Resolution Ion MicroProbe) mass spectrometer that utilizes the preconcentration of the U-series isotopes from a sample onto a single ion-exchange bead. Ion-microprobe mass spectrometry is capable of producing Th ionization efficiencies in excess of 2%. Analytical precision is typically better than alpha spectroscopy, but not as good as thermal ionization mass spectroscopy (TIMS) and inductively coupled plasma multicollector mass spectrometry (ICP-MS). Like TIMS and ICP-MS the method allows analysis of small samples sizes, but also adds the advantage of rapidity of analysis. A major advantage of ion-microprobe analysis is that U and Th isotopes are analyzed in the same bead, simplifying the process of chemical separation. Analytical time on the instrument is ???60 min per sample, and a single instrument-loading can accommodate 15-20 samples to be analyzed in a 24-h day. An additional advantage is that the method allows multiple reanalyses of the same bead and that samples can be archived for reanalysis at a later time. Because the ion beam excavates a pit only a few ??m deep, the mount can later be repolished and reanalyzed numerous times. The method described of preconcentrating a low concentration sample onto a small conductive substrate to allow ion-microprobe mass spectrometry is potentially applicable to many other systems. Copyright ?? 2005 Elsevier Ltd.

Proton-transfer reaction mass spectrometry (PTRMS) in combination with thermal desorption (TD) for sensitive off-line analysis of volatiles.

PubMed

Crespo, Elena; Devasena, Samudrala; Sikkens, Cor; Centeno, Raymund; Cristescu, Simona M; Harren, Frans J M

2012-04-30

When performing trace gas analysis, it is not always possible to bring the source of volatiles and the gas analyzer together. In these cases, volatile storage containers, such as thermal desorption (TD) tubes, can be used for off-line measurement. TD is routinely combined with gas chromatography/mass spectrometry (GC/MS), but so far not with proton-transfer reaction mass spectrometry (PTRMS), which has a faster response. A PTR-quadrupole-MS instrument and a PTR-ion-trap-MS instrument were separately coupled to a TD unit for off-line analysis of trace volatiles in air. Carbograph 1TD/Carbopack X sorbent tubes were filled with different concentrations of a trace gas mixture containing low molecular weight volatiles (32 g/mol up to 136 g/mol) and measured with the above-mentioned combinations. The carrier gas in the TD unit was changed from helium to nitrogen to be able to combine this instrument with the mass spectrometer. Good linearity and reproducibility with the amount of gas stored were obtained. The storage capacity over time (up to 14 days) showed larger variability (<11% for all compounds, except for acetone 27%). Several tubes were filled with breath of different persons, and the breath of a smoker showed increased levels of acetonitrile and benzene. The combination of the PTR ion-trap instrument with the TD unit was also investigated. Due to its higher sampling rate, the ion-trap system showed higher throughput capabilities than the quadrupole system. The combination of TD with PTRMS using both a quadrupole and an ion trap for off-line volatile analysis has been validated. TD tubes can be a robust and compact volatile storage method when the mass spectrometry and the sampling cannot be performed in the same place, for example in large screening studies. In addition, a higher measurement throughput than with GC/MS could be obtained. Copyright © 2012 John Wiley & Sons, Ltd.

In Situ Detection of Organic Molecules on the Martian Surface With the Mars Organic Molecule Analyzer (MOMA) on Exomars 2018

NASA Technical Reports Server (NTRS)

Li, Xiang; Brinckerhoff, William B.; Pinnick, Veronica T; van Amerom, Friso H. W.; Danell, Ryan M.; Arevalo, Ricardo D., Jr.; Getty, Stephanie; Mahaffy, Paul R.

2015-01-01

The Mars Organic Molecule Analyzer (MOMA) investigation on the 2018 ExoMars rover will examine the chemical composition of samples acquired from depths of up to two meters below the martian surface, where organics may be protected from radiative and oxidative degradation. The MOMA instrument is centered around a miniaturized linear ion trap (LIT) that facilitates two modes of operation: i) pyrolysisgas chromatography mass spectrometry (pyrGC-MS); and, ii) laser desorptionionization mass spectrometry (LDI-MS) at ambient Mars pressures. The LIT also enables the structural characterization of complex molecules via complementary analytical capabilities, such as multi-frequency waveforms (i.e., SWIFT) and tandem mass spectrometry (MSMS). When combined with the complement of instruments in the rovers Pasteur Payload, MOMA has the potential to reveal the presence of a wide range of organics preserved in a variety of mineralogical environments, and to begin to understand the structural character and potential origin of those compounds.

Bio-Aerosol Detection Using Mass Spectrometry: Public Health Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ludvigson, Laura D.

2004-01-01

I recently spent a summer as an intern at the Lawrence Livermore National Laboratory. I worked on a project involving the real-time, reagentless, single cell detection of aerosolized pathogens using a novel mass spectrometry approach called Bio-Aerosol Mass Spectrometry (BAMS). Based upon preliminary results showing the differentiation capabilities of BAMS, I would like to explore the development and use of this novel detection system in the context of both environmental and clinical sample pathogen detection. I would also like to explore the broader public health applications that a system such as BAMS might have in terms of infectious disease preventionmore » and control. In order to appreciate the potential of this instrument, I will demonstrate the need for better pathogen detection methods, and outline the instrumentation, data analysis and preliminary results that lead me toward a desire to explore this technology further. I will also discuss potential experiments for the future along with possible problems that may be encountered along the way.« less

Interfacing an aspiration ion mobility spectrometer to a triple quadrupole mass spectrometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adamov, Alexey; Viidanoja, Jyrki; Kaerpaenoja, Esko

2007-04-15

This article presents the combination of an aspiration-type ion mobility spectrometer with a mass spectrometer. The interface between the aspiration ion mobility spectrometer and the mass spectrometer was designed to allow for quick mounting of the aspiration ion mobility spectrometer onto a Sciex API-300 triple quadrupole mass spectrometer. The developed instrumentation is used for gathering fundamental information on aspiration ion mobility spectrometry. Performance of the instrument is demonstrated using 2,6-di-tert-butyl pyridine and dimethyl methylphosphonate.

Analysis of sulfates on low molecular weight heparin using mass spectrometry: structural characterization of enoxaparin.

PubMed

Gupta, Rohitesh; Ponnusamy, Moorthy P

2018-05-31

Structural characterization of low molecular weight heparin (LMWH) is critical to meet biosimilarity standards. In this context, the review focuses on structural analysis of labile sulfates attached to the side-groups of LMWH using mass spectrometry. A comprehensive review of this topic will help readers to identify key strategies for tackling the problem related to sulfate loss. At the same time, various mass spectrometry techniques are presented to facilitate compositional analysis of LMWH, mainly enoxaparin. Areas covered: This review summarizes findings on mass spectrometry application for LMWH, including modulation of sulfates, using enzymology and sample preparation approaches. Furthermore, popular open-source software packages for automated spectral data interpretation are also discussed. Successful use of LC/MS can decipher structural composition for LMWH and help evaluate their sameness or biosimilarity with the innovator molecule. Overall, the literature has been searched using PubMed by typing various search queries such as 'enoxaparin', 'mass spectrometry', 'low molecular weight heparin', 'structural characterization', etc. Expert commentary: This section highlights clinically relevant areas that need improvement to achieve satisfactory commercialization of LMWHs. It also primarily emphasizes the advancements in instrumentation related to mass spectrometry, and discusses building automated software for data interpretation and analysis.

Co-registered Topographical, Band Excitation Nanomechanical, and Mass Spectral Imaging Using a Combined Atomic Force Microscopy/Mass Spectrometry Platform

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ovchinnikova, Olga S.; Tai, Tamin; Bocharova, Vera

The advancement of a hybrid atomic force microscopy/mass spectrometry imaging platform demonstrating for the first time co-registered topographical, band excitation nanomechanical, and mass spectral imaging of a surface using a single instrument is reported. The mass spectrometry-based chemical imaging component of the system utilized nanothermal analysis probes for pyrolytic surface sampling followed by atmospheric pressure chemical ionization of the gas phase species produced with subsequent mass analysis. We discuss the basic instrumental setup and operation and the multimodal imaging capability and utility are demonstrated using a phase separated polystyrene/poly(2-vinylpyridine) polymer blend thin film. The topography and band excitation images showedmore » that the valley and plateau regions of the thin film surface were comprised primarily of one of the two polymers in the blend with the mass spectral chemical image used to definitively identify the polymers at the different locations. Data point pixel size for the topography (390 nm x 390 nm), band excitation (781 nm x 781 nm), mass spectrometry (690 nm x 500 nm) images was comparable and submicrometer in all three cases, but the data voxel size for each of the three images was dramatically different. The topography image was uniquely a surface measurement, whereas the band excitation image included information from an estimated 10 nm deep into the sample and the mass spectral image from 110-140 nm in depth. Moreover, because of this dramatic sampling depth variance, some differences in the band excitation and mass spectrometry chemical images were observed and were interpreted to indicate the presence of a buried interface in the sample. The spatial resolution of the mass spectral image was estimated to be between 1.5 m 2.6 m, based on the ability to distinguish surface features in that image that were also observed in the other images.« less

Co-registered Topographical, Band Excitation Nanomechanical, and Mass Spectral Imaging Using a Combined Atomic Force Microscopy/Mass Spectrometry Platform

DOE PAGES

Ovchinnikova, Olga S.; Tai, Tamin; Bocharova, Vera; ...

2015-03-18

The advancement of a hybrid atomic force microscopy/mass spectrometry imaging platform demonstrating for the first time co-registered topographical, band excitation nanomechanical, and mass spectral imaging of a surface using a single instrument is reported. The mass spectrometry-based chemical imaging component of the system utilized nanothermal analysis probes for pyrolytic surface sampling followed by atmospheric pressure chemical ionization of the gas phase species produced with subsequent mass analysis. We discuss the basic instrumental setup and operation and the multimodal imaging capability and utility are demonstrated using a phase separated polystyrene/poly(2-vinylpyridine) polymer blend thin film. The topography and band excitation images showedmore » that the valley and plateau regions of the thin film surface were comprised primarily of one of the two polymers in the blend with the mass spectral chemical image used to definitively identify the polymers at the different locations. Data point pixel size for the topography (390 nm x 390 nm), band excitation (781 nm x 781 nm), mass spectrometry (690 nm x 500 nm) images was comparable and submicrometer in all three cases, but the data voxel size for each of the three images was dramatically different. The topography image was uniquely a surface measurement, whereas the band excitation image included information from an estimated 10 nm deep into the sample and the mass spectral image from 110-140 nm in depth. Moreover, because of this dramatic sampling depth variance, some differences in the band excitation and mass spectrometry chemical images were observed and were interpreted to indicate the presence of a buried interface in the sample. The spatial resolution of the mass spectral image was estimated to be between 1.5 m 2.6 m, based on the ability to distinguish surface features in that image that were also observed in the other images.« less

Carbohydrate profiling of bacteria by gas chromatography-mass spectrometry and their trace detection in complex matrices by gas chromatography-tandem mass spectrometry.

PubMed

Fox, A

1999-05-28

Bacterial cellular polysaccharides are composed of a variety of sugar monomers. These sugars serve as chemical markers to identify specific species or genera or to determine their physiological status. Some of these markers can also be used for trace detection of bacteria or their constituents in complex clinical or environmental matrices. Analyses are performed, in our hands, employing hydrolysis followed by the alditol acetate derivatization procedure. Substantial improvements have been made to sample preparation including simplification and computer-controlled automation. For characterization of whole cell bacterial hydrolysates, sugars are analyzed by gas chromatography-mass spectrometry (GC-MS). Simple chromatograms are generated using selected ion monitoring (SIM). Using total ion GC-MS, sugars can be readily identified. In more complex clinical and environmental samples, markers for bacteria are present at sufficiently low concentrations that more advanced instrumentation, gas chromatography-tandem mass spectrometry (GC-MS-MS), is preferred for optimal analysis. Using multiple reaction monitoring, MS-MS is used (replacing more conventional SIM) to ignore extraneous chromatographic peaks. Triple quadrupole and ion trap GC-MS-MS instruments have both been used successfully. Absolute chemical identification of sugar markers at trace levels is achieved, using MS-MS, by the product spectrum.

A Developmental History of Polymer Mass Spectrometry

ERIC Educational Resources Information Center

Vergne, Matthew J.; Hercules, David M.; Lattimer, Robert P.

2007-01-01

The history of the development of mass spectroscopic methods used to characterize polymers is discussed. The continued improvements in methods and instrumentation will offer new and better ways for the mass spectral characterization of polymers and mass spectroscopy (MS) should be recognized as a complementary polymer characterization method along…

The emerging process of Top Down mass spectrometry for protein analysis: biomarkers, protein-therapeutics, and achieving high throughput†

PubMed Central

Kellie, John F.; Tran, John C.; Lee, Ji Eun; Ahlf, Dorothy R.; Thomas, Haylee M.; Ntai, Ioanna; Catherman, Adam D.; Durbin, Kenneth R.; Zamdborg, Leonid; Vellaichamy, Adaikkalam; Thomas, Paul M.

2011-01-01

Top Down mass spectrometry (MS) has emerged as an alternative to common Bottom Up strategies for protein analysis. In the Top Down approach, intact proteins are fragmented directly in the mass spectrometer to achieve both protein identification and characterization, even capturing information on combinatorial post-translational modifications. Just in the past two years, Top Down MS has seen incremental advances in instrumentation and dedicated software, and has also experienced a major boost from refined separations of whole proteins in complex mixtures that have both high recovery and reproducibility. Combined with steadily advancing commercial MS instrumentation and data processing, a high-throughput workflow covering intact proteins and polypeptides up to 70 kDa is directly visible in the near future. PMID:20711533

Trends in biochemical and biomedical applications of mass spectrometry

NASA Astrophysics Data System (ADS)

Gelpi, Emilio

1992-09-01

This review attempts an in-depth evaluation of progress and achievements made since the last 11th International Mass Spectrometry Conference in the application of mass spectrometric techniques to biochemistry and biomedicine. For this purpose, scientific contributions in this field at major international meetings have been monitored, together with an extensive appraisal of literature data covering the period from 1988 to 1991. A bibliometric evaluation of the MEDLINE database for this period provides a total of almost 4000 entries for mass spectrometry. This allows a detailed study of literature and geographical sources of the most frequent applications, of disciplines where mass spectrometry is most active and of types of sample and instrumentation most commonly used. In this regard major efforts according to number of publications (over 100 literature reports) are concentrated in countries like Canada, France, Germany, Italy, Japan, Sweden, UK and the USA. Also, most of the work using mass spectrometry in biochemistry and biomedicine is centred on studies on biotransformation, metabolism, pharmacology, pharmacokinetics and toxicology, which have been carried out on samples of blood, urine, plasma and tissue, by order of frequency of use. Human and animal studies appear to be evenly distributed in terms of the number of reports published in the literature in which the authors make use of experimental animals or describe work on human samples. Along these lines, special attention is given to the real usefulness of mass spectrometry (MS) technology in routine medical practice. Thus the review concentrates on evaluating the progress made in disease diagnosis and overall patient care. As regards prevailing techniques, GCMS continues to be the mainstay of the state of the art methods for multicomponent analysis, stable isotope tracer studies and metabolic profiling, while HPLC--MS and tandem MS are becoming increasingly important in biomedical research. However, despite the relatively large number of mass spectrometry reports in the biomedical sciences very few true routine applications are described, and recent technological innovations in instrumentation such as FABMS, electrospray, plasma or laser desorption have contributed relatively much more to structural biology, especially in biopolymer studies of macromolecules rather than to real life biomedical applications on patients and clinical problems.

Development of an Atmospheric Pressure Ionization Mass Spectrometer

NASA Technical Reports Server (NTRS)

1998-01-01

A commercial atmospheric pressure ionization mass spectrometer (APIMS) was purchased from EXTREL Mass Spectrometry, Inc. (Pittsburgh, PA). Our research objectives were to adapt this instrument and develop techniques for real-time determinations of the concentrations of trace species in the atmosphere. The prototype instrument is capable of making high frequency measurements with no sample preconcentrations. Isotopically labeled standards are used as an internal standard to obtain high precision and to compensate for changes in instrument sensitivity and analyte losses in the sampling manifold as described by Bandy and coworkers. The prototype instrument is capable of being deployed on NASA C130, Electra, P3, and DC8 aircraft. After purchasing and taking delivery by June 1994, we assembled the mass spectrometer, data acquisition, and manifold flow control instrumentation in electronic racks and performed tests.

Characterization of extreme ultraviolet laser ablation mass spectrometry for actinide trace analysis and nanoscale isotopic imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Green, Tyler; Kuznetsov, Ilya; Willingham, David

The purpose of this research was to characterize Extreme Ultraviolet Time-of-Flight (EUV TOF) Laser Ablation Mass Spectrometry for high spatial resolution elemental and isotopic analysis. We compare EUV TOF results with Secondary Ionization Mass Spectrometry (SIMS) to orient the EUV TOF method within the overall field of analytical mass spectrometry. Using the well-characterized NIST 61x glasses, we show that the EUV ionization approach produces relatively few molecular ion interferences in comparison to TOF SIMS. We demonstrate that the ratio of element ion to element oxide ion is adjustable with EUV laser pulse energy and that the EUV TOF instrument hasmore » a sample utilization efficiency of 0.014%. The EUV TOF system also achieves a lateral resolution of 80 nm and we demonstrate this lateral resolution with isotopic imaging of closely spaced particles or uranium isotopic standard materials.« less

Airborne mass spectrometers: four decades of atmospheric and space research at the Air Force research laboratory.

PubMed

Viggiano, A A; Hunton, D E

1999-11-01

Mass spectrometry is a versatile research tool that has proved to be extremely useful for exploring the fundamental nature of the earth's atmosphere and ionosphere and in helping to solve operational problems facing the Air Force and the Department of Defense. In the past 40 years, our research group at the Air Force Research Laboratory has flown quadrupole mass spectrometers of many designs on nearly 100 sounding rockets, nine satellites, three Space Shuttles and many missions of high-altitude research aircraft and balloons. We have also used our instruments in ground-based investigations of rocket and jet engine exhaust, combustion chemistry and microwave breakdown chemistry. This paper is a review of the instrumentation and techniques needed for space research, a summary of the results from many of the experiments, and an introduction to the broad field of atmospheric and space mass spectrometry in general. Copyright 1999 John Wiley & Sons, Ltd.

Characterization of polyesters by matrix-assisted laser desorption/ionization and Fourier transform mass spectrometry.

PubMed

Mize, Todd H; Simonsick, William J; Amster, I Jonathan

2003-01-01

Two homopolyesters, poly(neopentyl glycol-alt-isophthalic acid) and poly(hexanediol-alt-azelaic acid), and two copolyesters, poly(dipropoxylated bisphenol-A-alt-(isophthalic acid-co-adipic acid)) and poly(neopentyl glycol-alt-(adipic acid-co-isophthalic acid)) were analyzed by internal source matrix assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS). The high resolution and high mass accuracy provided by FTMS greatly facilitate the characterization of the polyester and copolyester samples. Isobaric resolution allows the ion abundances of overlapping isotopic envelopes to be assessed. Repeat units were confirmed and end functionality assigned. Single shot mass spectra of the entire polymeric distribution demonstrate that the dynamic range of this internal MALDI source instrument and the analyzer cell exceeds performance of those previously reported for higher field instruments. Corrections of space charge mass shift effects are demonstrated for the analytes using an external calibrant and (subsequent to confirmation of structure) via internal calibration which removes ambiguity due to space charge differences in calibrant and analyte spectra. Capillary gel permeation chromatography was used to prepare low polydispersity samples from a high polydispersity polyester, improving the measurement of molecular weight distribution two-fold while retaining the benefits of high resolution mass spectrometry for elucidation of oligomer identity.

Tandem Mass Spectrometry on a Miniaturized Laser Desorption Time-of-Flight Mass Spectrometer

NASA Technical Reports Server (NTRS)

Li, Xiang; Cornish, Timothy; Getty, Stephanie A.; Brinckerhoff, William B.

2016-01-01

Tandem mass spectrometry (MSMS) is a powerful and widely-used technique for identifying the molecular structure of organic constituents of a complex sample. Application of MSMS to the study of unknown planetary samples on a remote space mission would contribute to our understanding of the origin, evolution, and distribution of extraterrestrial organics in our solar system. Here we report on the realization of MSMS on a miniaturized laser desorption time-of-flight mass spectrometer (LD-TOF-MS), which is one of the most promising instrument types for future planetary missions. This achievement relies on two critical components: a curved-field reflectron and a pulsed-pin ion gate. These enable use of the complementary post-source decay (PSD) and laser-assisted collision induced dissociation (L-CID) MSMS methods on diverse measurement targets with only modest investment in instrument resources such as volume and weight. MSMS spectra of selected molecular targets in various organic standards exhibit excellent agreement when compared with results from a commercial, laboratory-scale TOF instrument, demonstrating the potential of this powerful technique in space and planetary environments.

Analysis of antioxidants in insulation cladding of copper wire: a comparison of different mass spectrometric techniques (ESI-IT, MALDI-RTOF and RTOF-SIMS).

PubMed

Schnöller, Johannes; Pittenauer, Ernst; Hutter, Herbert; Allmaier, Günter

2009-12-01

Commercial copper wire and its polymer insulation cladding was investigated for the presence of three synthetic antioxidants (ADK STAB AO412S, Irganox 1010 and Irganox MD 1024) by three different mass spectrometric techniques including electrospray ionization-ion trap-mass spectrometry (ESI-IT-MS), matrix-assisted laser desorption/ionization reflectron time-of-flight (TOF) mass spectrometry (MALDI-RTOF-MS) and reflectron TOF secondary ion mass spectrometry (RTOF-SIMS). The samples were analyzed either directly without any treatment (RTOF-SIMS) or after a simple liquid/liquid extraction step (ESI-IT-MS, MALDI-RTOF-MS and RTOF-SIMS). Direct analysis of the copper wire itself or of the insulation cladding by RTOF-SIMS allowed the detection of at least two of the three antioxidants but at rather low sensitivity as molecular radical cations and with fairly strong fragmentation (due to the highly energetic ion beam of the primary ion gun). ESI-IT- and MALDI-RTOF-MS-generated abundant protonated and/or cationized molecules (ammoniated or sodiated) from the liquid/liquid extract. Only ESI-IT-MS allowed simultaneous detection of all three analytes in the extract of insulation claddings. The latter two so-called 'soft' desorption/ionization techniques exhibited intense fragmentation only by applying low-energy collision-induced dissociation (CID) tandem MS on a multistage ion trap-instrument and high-energy CID on a tandem TOF-instrument (TOF/RTOF), respectively. Strong differences in the fragmentation behavior of the three analytes could be observed between the different CID spectra obtained from either the IT-instrument (collision energy in the very low eV range) or the TOF/RTOF-instrument (collision energy 20 keV), but both delivered important structural information. Copyright 2009 John Wiley & Sons, Ltd.

Imaging Mass Spectrometry on the Nanoscale with Cluster Ion Beams

DOE PAGES

Winograd, Nicholas

2014-12-02

Imaging with cluster secondary ion mass spectrometry (SIMS) is reaching a mature level of development. When, using a variety of molecular ion projectiles to stimulate desorption, 3-dimensional imaging with the selectivity of mass spectrometry can now be achieved with submicrometer spatial resolution and <10 nm depth resolution. In this Perspective, stock is taken regarding what it will require to routinely achieve these remarkable properties. Some issues include the chemical nature of the projectile, topography formation, differential erosion rates, and perhaps most importantly, ionization efficiency. Shortcomings of existing instrumentation are also noted. One key part of this discussion involves speculation onmore » how best to resolve these issues.« less

Imaging Mass Spectrometry on the Nanoscale with Cluster Ion Beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Winograd, Nicholas

Imaging with cluster secondary ion mass spectrometry (SIMS) is reaching a mature level of development. When, using a variety of molecular ion projectiles to stimulate desorption, 3-dimensional imaging with the selectivity of mass spectrometry can now be achieved with submicrometer spatial resolution and <10 nm depth resolution. In this Perspective, stock is taken regarding what it will require to routinely achieve these remarkable properties. Some issues include the chemical nature of the projectile, topography formation, differential erosion rates, and perhaps most importantly, ionization efficiency. Shortcomings of existing instrumentation are also noted. One key part of this discussion involves speculation onmore » how best to resolve these issues.« less

Characterization Of Commonly Encountered Explosives Using Highfield Asymmetric Waveform Ion Mobility Spectrometry Coupled With Mass Spectrometry

DTIC Science & Technology

2007-05-01

symptoms depending on the relative concentration, even leading to death.32 2.4. Instrument Settings Both positive and negative ions can be formed...Detection Technology, pp. 619-633, 1992. 7. Osorio, Celia ; Gomez, Lewis M.; Hernandez, Samuel P.; Castro, Miguel E., Time-of- flight Mass Spectroscopy...vol. 15, pp. 1950-1952. 34. Federal Facilities Assessment Branch, Public Health Assessment, US Army Umatilla Depot Activity, Centers for Disease

File Formats Commonly Used in Mass Spectrometry Proteomics*

PubMed Central

Deutsch, Eric W.

2012-01-01

The application of mass spectrometry (MS) to the analysis of proteomes has enabled the high-throughput identification and abundance measurement of hundreds to thousands of proteins per experiment. However, the formidable informatics challenge associated with analyzing MS data has required a wide variety of data file formats to encode the complex data types associated with MS workflows. These formats encompass the encoding of input instruction for instruments, output products of the instruments, and several levels of information and results used by and produced by the informatics analysis tools. A brief overview of the most common file formats in use today is presented here, along with a discussion of related topics. PMID:22956731

Secondary Ion Mass Spectrometry Imaging of Tissues, Cells, and Microbial Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderton, Christopher R.; Gamble, Lara J.

2016-03-01

Mass spectrometry imaging (MSI) techniques are increasingly being utilized within many biological fields, including medicine, pathology, microbial ecology, and more. Of the MSI methods available, secondary ion mass spectrometry (SIMS) offers the highest lateral resolution of any technique. Moreover, SIMS versatility in the number of different operating modes and types of mass spectrometers available has made it an increasing popular method for bio-related measurements. Here, we discuss SIMS ability to image tissues, single cells, and microbes with a particular emphasis on the types chemical and spatial information that can be ascertained by the different types of SIMS instruments and methods.more » The recently developed Fourier transform ion cyclotron resonance (FTICR) SIMS located at PNNL is capable of generating molecular maps of tissues with an unprecedented mass resolving power and mass accuracy, with respect to SIMS measurements. ToF-SIMS can generate chemical maps, where detection of small molecules and fragments can be acquired with an order of magnitude better lateral resolution than the FTICR-SIMS. Furthermore, many of commercially available ToF-SIMS instruments are capable of depth profiling measurements, offering the ability to attain three-dimensional information of one’s sample. The NanoSIMS instrument offers the highest lateral resolution of any MSI method available. In practice, NanoSIMS regularly achieves sub-100 nm resolution of atomic and diatomic secondary ions within biological samples. The strengths of the different SIMS methods are more and more being leveraged in both multimodal-imaging endeavors that use complementary MSI techniques as well with optical, fluorescence, and force microscopy methods.« less

Multi-elemental analysis of aqueous geochemical samples by quadrupole inductively coupled plasma-mass spectrometry (ICP-MS)

USGS Publications Warehouse

Wolf, Ruth E.; Adams, Monique

2015-01-01

Typically, quadrupole inductively coupled plasma-mass spectrometry (ICP-MS) is used to determine as many as 57 major, minor, and trace elements in aqueous geochemical samples, including natural surface water and groundwater, acid mine drainage water, and extracts or leachates from geological samples. The sample solution is aspirated into the inductively coupled plasma (ICP) which is an electrodeless discharge of ionized argon gas at a temperature of approximately 6,000 degrees Celsius. The elements in the sample solution are subsequently volatilized, atomized, and ionized by the ICP. The ions generated are then focused and introduced into a quadrupole mass filter which only allows one mass to reach the detector at a given moment in time. As the settings of the mass analyzer change, subsequent masses are allowed to impact the detector. Although the typical quadrupole ICP-MS system is a sequential scanning instrument (determining each mass separately), the scan speed of modern instruments is on the order of several thousand masses per second. Consequently, typical total sample analysis times of 2–3 minutes are readily achievable for up to 57 elements.

Inorganic trace analysis by mass spectrometry

NASA Astrophysics Data System (ADS)

Becker, Johanna Sabine; Dietze, Hans-Joachim

1998-10-01

Mass spectrometric methods for the trace analysis of inorganic materials with their ability to provide a very sensitive multielemental analysis have been established for the determination of trace and ultratrace elements in high-purity materials (metals, semiconductors and insulators), in different technical samples (e.g. alloys, pure chemicals, ceramics, thin films, ion-implanted semiconductors), in environmental samples (waters, soils, biological and medical materials) and geological samples. Whereas such techniques as spark source mass spectrometry (SSMS), laser ionization mass spectrometry (LIMS), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), glow discharge mass spectrometry (GDMS), secondary ion mass spectrometry (SIMS) and inductively coupled plasma mass spectrometry (ICP-MS) have multielemental capability, other methods such as thermal ionization mass spectrometry (TIMS), accelerator mass spectrometry (AMS) and resonance ionization mass spectrometry (RIMS) have been used for sensitive mono- or oligoelemental ultratrace analysis (and precise determination of isotopic ratios) in solid samples. The limits of detection for chemical elements using these mass spectrometric techniques are in the low ng g -1 concentration range. The quantification of the analytical results of mass spectrometric methods is sometimes difficult due to a lack of matrix-fitted multielement standard reference materials (SRMs) for many solid samples. Therefore, owing to the simple quantification procedure of the aqueous solution, inductively coupled plasma mass spectrometry (ICP-MS) is being increasingly used for the characterization of solid samples after sample dissolution. ICP-MS is often combined with special sample introduction equipment (e.g. flow injection, hydride generation, high performance liquid chromatography (HPLC) or electrothermal vaporization) or an off-line matrix separation and enrichment of trace impurities (especially for characterization of high-purity materials and environmental samples) is used in order to improve the detection limits of trace elements. Furthermore, the determination of chemical elements in the trace and ultratrace concentration range is often difficult and can be disturbed through mass interferences of analyte ions by molecular ions at the same nominal mass. By applying double-focusing sector field mass spectrometry at the required mass resolution—by the mass spectrometric separation of molecular ions from the analyte ions—it is often possible to overcome these interference problems. Commercial instrumental equipment, the capability (detection limits, accuracy, precision) and the analytical application fields of mass spectrometric methods for the determination of trace and ultratrace elements and for surface analysis are discussed.

The allure of mass spectrometry: From an earlyday chemist's perspective.

PubMed

Tőkés, László

2017-07-01

This reminiscing review article is an account of the author's fascination and involvements with mass spectrometry from the perspective of an organic chemist with an interest in natural product chemistry. It covers a period from 1961 through the mid 1990s as mass spectrometry evolved form a novelty technique to become a most widely used analytical technique. Following a brief synopsis of my pathway to mass spectrometry, my research efforts in this field are presented with a focus mainly on evolving principles and technologies which I had personal involvements with. To provide historical perspectives, discussions of these developments are accompanied by brief outlines of the relevant state-of-the-art, shedding light on the technical and conceptual challenges encountered during those early days in mass spectrometry. Examples are presented of my involvements with basic and applied research in mass spectrometry during graduate studies at Stanford University and close to three decade tenure in pharmaceutical research at Syntex Research. My basic research interests focused mainly on principles of electron ionization induced fragmentation mechanisms, with an emphasis on steroids and other model compounds. Extensive deuterium labeling evidence was used to determine the fragmentation mechanisms of the diagnostically significant ions in the spectra of numerous model compounds, uncovering examples of wide-ranging hydrogen transfers, skeletal rearrangements, methyl and phenyl migrations, stereoselective fragmentations and low and high energy fragmentation processes. Depiction of the industrial research phase of my career includes comments on the pivotal role mass spectrometry played on advancing modern pharmaceutical research. Examples are presented of involvements with instrumental developments and a few select cases of applied research, including studies of bile mechanisms in vertebrates, identification of bisphenol-A leaching from sterilized polycarbonate containers, high sensitivity TCDD analyses and other projects. Reflecting on my services for the mass spectrometry society, involvements with the co-founding and 12 year chairing of the Asilomar Conference on Mass Spectrometry and founding of the Bay Area Mass Spectrometry regional MS discussion group, as part of my services for the mass spectrometry community, are presented in some detail. © 2016 Wiley Periodicals, Inc. Mass Spec Rev 36:520-542, 2017. © 2016 The Authors. Mass Spectrometry Reviews Published by Wiley Periodicals, Inc.

Two-step Laser Time-of-Flight Mass Spectrometry to Elucidate Organic Diversity in Planetary Surface Materials.

NASA Technical Reports Server (NTRS)

Getty, Stephanie A.; Brinckerhoff, William B.; Cornish, Timothy; Li, Xiang; Floyd, Melissa; Arevalo, Ricardo Jr.; Cook, Jamie Elsila; Callahan, Michael P.

2013-01-01

Laser desorption/ionization time-of-flight mass spectrometry (LD-TOF-MS) holds promise to be a low-mass, compact in situ analytical capability for future landed missions to planetary surfaces. The ability to analyze a solid sample for both mineralogical and preserved organic content with laser ionization could be compelling as part of a scientific mission pay-load that must be prepared for unanticipated discoveries. Targeted missions for this instrument capability include Mars, Europa, Enceladus, and small icy bodies, such as asteroids and comets.

Instrumentation development for drug detection on the breath

DOT National Transportation Integrated Search

1972-09-01

Based on a survey of candidate analytical methods, mass spectrometry was identified as a promising technique for drug detection on the breath. To demonstrate its capabilities, an existing laboratory mass spectrometer was modified by the addition of a...

A compact permanent magnet cyclotrino for accelerator mass spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, A.T.; Clark, D.J.; Kunkel, W.B.

1995-02-01

The authors describe the development of a new instrument for the detection of trace amounts of rare isotopes, a Cyclotron Mass Spectrometer (CMS). A compact low energy cyclotron optimized for high mass resolution has been designed and has been fabricated. The instrument has high sensitivity and is designed to measure carbon-14 at abundances of < 10{sup {minus}12}. A novel feature of the instrument is the use of permanent magnets to energize the iron poles of the cyclotron. The instrument uses axial injection, employing a spiral inflector. The instrument has been assembled and preliminary measurements of the magnetic field show thatmore » it has a uniformity on the order of 2 parts in 10{sup 4}.« less

MacMS: A Mass Spectrometer Simulator: Abstract of Issue 9906M

NASA Astrophysics Data System (ADS)

Bigger, Stephen W.; Craig, Robert A.

1999-10-01

MacMS is a program for Mac-OS compatible computers that simulates a magnetic sector mass spectrometer (1-4) designed to operate in the mass-to-charge (m/z) ratio range of 1-200 amu. MacMS has two operational modules. The first module (see Figure 1) is called the "Path" module and enables the user to quantitatively examine the trajectory of an ion of given m/z ratio in the electric and magnetic fields of the simulated "instrument". By systematically measuring a series of trajectories of different ions under different electric and magnetic field conditions, the user can determine how the resolution of the "instrument" is affected by these experimentally variable parameters. The user can thus choose suitable instrumental conditions for scanning a given m/z ratio range with good separation between the peaks. The second module (see Figure 2) is called as the "Spectrometer" module and enables the user to record, under any chosen instrumental conditions, the mass spectrum of (i) the instrumental background, (ii) neon, (iii) methane, or (iv) the parent ion of carbon tetrachloride. Both voltage scanning and magnetic scanning are possible (5). A hard copy of any mass spectrum that has been recorded can also be obtained. MacMS can read ASCII data files containing mass spectral information of compounds other than those that are "built-in" to the simulator. The appropriate format for creating such data files is described in the program documentation. There are a number of instructional exercises that can be conducted using the mass spectral information contained within the simulator. These are included in the program documentation. For example, the intensities of the 20Ne+, 21Ne+, and 22Ne+ species can be determined from hard copies of mass spectra of neon that are obtained under different instrumental sensitivities. The relative abundances of the three isotopes of neon can thus be calculated and compared with the literature values (6). The simulator also includes adjustable, fixed-value range and gain settings, which can be used to enhance the resolution and sensitivity of the instrument respectively.

1. Kiser, R. N. Introduction to Mass Spectrometry and its Applications; Prentice-Hall: Englewood Cliffs, N. J., 1965; pp 1-3; pp 32-65.
2. Johnstone, R. A. W.; Rose, M. E. Mass Spectrometry for Chemists and Biochemists, 2nd ed.; Cambridge University Press: Cambridge, 1996.
3. Hill, H. C.; Loudon, A. G. Introduction to Mass Spectrometry; 2nd ed.; Heyden: London, 1972; p 5.
4. Farmer, J. B. In Mass Spectrometry, McDowell, C. A., Ed.; McGraw-Hill: New York, 1963; pp 10-11.
5. Message, G. M. Practical Aspects of Gas Chromatography-Mass Spectrometry, Wiley: New York, 1984; Chapter 3.
6. CRC Handbook of Chemistry and Physics, 55th ed.; CRC: Cleveland, 1974.

Pivotal role of computers and software in mass spectrometry - SEQUEST and 20 years of tandem MS database searching.

PubMed

Yates, John R

2015-11-01

Advances in computer technology and software have driven developments in mass spectrometry over the last 50 years. Computers and software have been impactful in three areas: the automation of difficult calculations to aid interpretation, the collection of data and control of instruments, and data interpretation. As the power of computers has grown, so too has the utility and impact on mass spectrometers and their capabilities. This has been particularly evident in the use of tandem mass spectrometry data to search protein and nucleotide sequence databases to identify peptide and protein sequences. This capability has driven the development of many new approaches to study biological systems, including the use of "bottom-up shotgun proteomics" to directly analyze protein mixtures. Graphical Abstract ᅟ.

A new processing scheme for ultra-high resolution direct infusion mass spectrometry data

NASA Astrophysics Data System (ADS)

Zielinski, Arthur T.; Kourtchev, Ivan; Bortolini, Claudio; Fuller, Stephen J.; Giorio, Chiara; Popoola, Olalekan A. M.; Bogialli, Sara; Tapparo, Andrea; Jones, Roderic L.; Kalberer, Markus

2018-04-01

High resolution, high accuracy mass spectrometry is widely used to characterise environmental or biological samples with highly complex composition enabling the identification of chemical composition of often unknown compounds. Despite instrumental advancements, the accurate molecular assignment of compounds acquired in high resolution mass spectra remains time consuming and requires automated algorithms, especially for samples covering a wide mass range and large numbers of compounds. A new processing scheme is introduced implementing filtering methods based on element assignment, instrumental error, and blank subtraction. Optional post-processing incorporates common ion selection across replicate measurements and shoulder ion removal. The scheme allows both positive and negative direct infusion electrospray ionisation (ESI) and atmospheric pressure photoionisation (APPI) acquisition with the same programs. An example application to atmospheric organic aerosol samples using an Orbitrap mass spectrometer is reported for both ionisation techniques resulting in final spectra with 0.8% and 8.4% of the peaks retained from the raw spectra for APPI positive and ESI negative acquisition, respectively.

Comprehensive analysis of a multidimensional liquid chromatography mass spectrometry dataset acquired on a quadrupole selecting, quadrupole collision cell, time-of-flight mass spectrometer: I. How much of the data is theoretically interpretable by search engines?

PubMed

Chalkley, Robert J; Baker, Peter R; Hansen, Kirk C; Medzihradszky, Katalin F; Allen, Nadia P; Rexach, Michael; Burlingame, Alma L

2005-08-01

An in-depth analysis of a multidimensional chromatography-mass spectrometry dataset acquired on a quadrupole selecting, quadrupole collision cell, time-of-flight (QqTOF) geometry instrument was carried out. A total of 3269 CID spectra were acquired. Through manual verification of database search results and de novo interpretation of spectra 2368 spectra could be confidently determined as predicted tryptic peptides. A detailed analysis of the non-matching spectra was also carried out, highlighting what the non-matching spectra in a database search typically are composed of. The results of this comprehensive dataset study demonstrate that QqTOF instruments produce information-rich data of which a high percentage of the data is readily interpretable.

Introduction of organic/hydro-organic matrices in inductively coupled plasma optical emission spectrometry and mass spectrometry: a tutorial review. Part II. Practical considerations.

PubMed

Leclercq, Amélie; Nonell, Anthony; Todolí Torró, José Luis; Bresson, Carole; Vio, Laurent; Vercouter, Thomas; Chartier, Frédéric

2015-07-23

Inductively coupled plasma optical emission spectrometry (ICP-OES) and mass spectrometry (ICP-MS) are increasingly used to carry out analyses in organic/hydro-organic matrices. The introduction of such matrices into ICP sources is particularly challenging and can be the cause of numerous drawbacks. This tutorial review, divided in two parts, explores the rich literature related to the introduction of organic/hydro-organic matrices in ICP sources. Part I provided theoretical considerations associated with the physico-chemical properties of such matrices, in an attempt to understand the induced phenomena. Part II of this tutorial review is dedicated to more practical considerations on instrumentation, instrumental and operating parameters, as well as analytical strategies for elemental quantification in such matrices. Two important issues are addressed in this part: the first concerns the instrumentation and optimization of instrumental and operating parameters, pointing out (i) the description, benefits and drawbacks of different kinds of nebulization and desolvation devices and the impact of more specific instrumental parameters such as the injector characteristics and the material used for the cone; and, (ii) the optimization of operating parameters, for both ICP-OES and ICP-MS. Even if it is at the margin of this tutorial review, Electrothermal Vaporization and Laser Ablation will also be shortly described. The second issue is devoted to the analytical strategies for elemental quantification in such matrices, with particular insight into the isotope dilution technique, particularly used in speciation analysis by ICP-coupled separation techniques. Copyright © 2015 Elsevier B.V. All rights reserved.

Biological particle analysis by mass spectrometry

NASA Technical Reports Server (NTRS)

Vilker, V. L.; Platz, R. M.

1983-01-01

An instrument that analyzes the chemical composition of biological particles in aerosol or hydrosol form was developed. Efforts were directed toward the acquisition of mass spectra from aerosols of biomolecules and bacteria. The filament ion source was installed on the particle analysis by mass spectrometry system. Modifications of the vacuum system improved the sensitivity of the mass spectrometer. After the modifications were incorporated, detailed mass spectra of simple compounds from the three major classes of biomolecules, proteins, nucleic acids, and carbohydrates were obtained. A method of generating bacterial aerosols was developed. The aerosols generated were collected and examined in the scanning electron microscope to insure that the bacteria delivered to the mass spectrometer were intact and free from debris.

Trace analysis of muramic acid in indoor air using an automated derivatization instrument and GC-MS(2) or GC-MS(3).

PubMed

Harley, William M; Kozar, Michael P; Fox, Alvin

2002-09-01

An automated derivatization instrument has been developed for the preparation of alditol acetates from bacterial hydrolysates for analysis by gas chromatography-mass spectrometry (GC-MS). The current report demonstrates the utility of the automated instrument for the more demanding task of trace analysis of muramic acid (Mur) in airborne dust using gas chromatography-tandem mass spectrometry (GC-MS(2)). Conditions for efficient derivatization of Mur, vital for trace analysis, are rigorous including lactam and imido group formation under anhydrous conditions. Furthermore, as the detection limit is lowered, possible contamination or carry-over of samples becomes an increasingly greater consideration and must not occur. The instrument meets these criteria and was successfully used for assaying the levels of Mur in laboratory air, which were found to be much lower than in the previous studies of heavily occupied schools and agricultural environments. The potential for GC-MS(3) in further lowering the detection limit was also demonstrated.

Science Update: Analytical Chemistry.

ERIC Educational Resources Information Center

Worthy, Ward

1980-01-01

Briefly discusses new instrumentation in the field of analytical chemistry. Advances in liquid chromatography, photoacoustic spectroscopy, the use of lasers, and mass spectrometry are also discussed. (CS)

The allure of mass spectrometry: From an earlyday chemist's perspective

PubMed Central

2016-01-01

1 This reminiscing review article is an account of the author's fascination and involvements with mass spectrometry from the perspective of an organic chemist with an interest in natural product chemistry. It covers a period from 1961 through the mid 1990s as mass spectrometry evolved form a novelty technique to become a most widely used analytical technique. Following a brief synopsis of my pathway to mass spectrometry, my research efforts in this field are presented with a focus mainly on evolving principles and technologies which I had personal involvements with. To provide historical perspectives, discussions of these developments are accompanied by brief outlines of the relevant state‐of‐the‐art, shedding light on the technical and conceptual challenges encountered during those early days in mass spectrometry. Examples are presented of my involvements with basic and applied research in mass spectrometry during graduate studies at Stanford University and close to three decade tenure in pharmaceutical research at Syntex Research. My basic research interests focused mainly on principles of electron ionization induced fragmentation mechanisms, with an emphasis on steroids and other model compounds. Extensive deuterium labeling evidence was used to determine the fragmentation mechanisms of the diagnostically significant ions in the spectra of numerous model compounds, uncovering examples of wide‐ranging hydrogen transfers, skeletal rearrangements, methyl and phenyl migrations, stereoselective fragmentations and low and high energy fragmentation processes. Depiction of the industrial research phase of my career includes comments on the pivotal role mass spectrometry played on advancing modern pharmaceutical research. Examples are presented of involvements with instrumental developments and a few select cases of applied research, including studies of bile mechanisms in vertebrates, identification of bisphenol‐A leaching from sterilized polycarbonate containers, high sensitivity TCDD analyses and other projects. Reflecting on my services for the mass spectrometry society, involvements with the co‐founding and 12 year chairing of the Asilomar Conference on Mass Spectrometry and founding of the Bay Area Mass Spectrometry regional MS discussion group, as part of my services for the mass spectrometry community, are presented in some detail. © 2016 Wiley Periodicals, Inc. Mass Spec Rev 36:520–542, 2017 PMID:26999732

An adaptable multiple power source for mass spectrometry and other scientific instruments.

PubMed

Lin, T-Y; Anderson, G A; Norheim, R V; Prost, S A; LaMarche, B L; Leach, F E; Auberry, K J; Smith, R D; Koppenaal, D W; Robinson, E W; Paša-Tolić, L

2015-09-01

An Adaptable Multiple Power Source (AMPS) system has been designed and constructed. The AMPS system can provide up to 16 direct current (DC) (±400 V; 5 mA), 4 radio frequency (RF) (two 500 VPP sinusoidal signals each, 0.5-5 MHz) channels, 2 high voltage sources (±6 kV), and one ∼40 W, 250 °C temperature-regulated heater. The system is controlled by a microcontroller, capable of communicating with its front panel or a computer. It can assign not only pre-saved fixed DC and RF signals but also profiled DC voltages. The AMPS system is capable of driving many mass spectrometry components and ancillary devices and can be adapted to other instrumentation/engineering projects.

Mass spectrometry of long-lived radionuclides

NASA Astrophysics Data System (ADS)

Becker, Johanna Sabine

2003-10-01

The capability of determining element concentrations at the trace and ultratrace level and isotope ratios is a main feature of inorganic mass spectrometry. The precise and accurate determination of isotope ratios of long-lived natural and artificial radionuclides is required, e.g. for their environmental monitoring and health control, for studying radionuclide migration, for age dating, for determining isotope ratios of radiogenic elements in the nuclear industry, for quality assurance and determination of the burn-up of fuel material in a nuclear power plant, for reprocessing plants, nuclear material accounting and radioactive waste control. Inorganic mass spectrometry, especially inductively coupled plasma mass spectrometry (ICP-MS) as the most important inorganic mass spectrometric technique today, possesses excellent sensitivity, precision and good accuracy for isotope ratio measurements and practically no restriction with respect to the ionization potential of the element investigated—therefore, thermal ionization mass spectrometry (TIMS), which has been used as the dominant analytical technique for precise isotope ratio measurements of long-lived radionuclides for many decades, is being replaced increasingly by ICP-MS. In the last few years instrumental progress in improving figures of merit for the determination of isotope ratio measurements of long-lived radionuclides in ICP-MS has been achieved by the application of a multiple ion collector device (MC-ICP-MS) and the introduction of the collision cell interface in order to dissociate disturbing argon-based molecular ions, to reduce the kinetic energy of ions and neutralize the disturbing noble gas ions (e.g. of 129Xe + for the determination of 129I). The review describes the state of the art and the progress of different inorganic mass spectrometric techniques such as ICP-MS, laser ablation ICP-MS vs. TIMS, glow discharge mass spectrometry, secondary ion mass spectrometry, resonance ionization mass spectrometry and accelerator mass spectrometry for the determination of long-lived radionuclides in quite different materials.

Examining the Heterogeneous Genome Content of Multipartite Viruses BMV and CCMV by Native Mass Spectrometry

NASA Astrophysics Data System (ADS)

van de Waterbeemd, Michiel; Snijder, Joost; Tsvetkova, Irina B.; Dragnea, Bogdan G.; Cornelissen, Jeroen J.; Heck, Albert J. R.

2016-06-01

Since the concept was first introduced by Brian Chait and co-workers in 1991, mass spectrometry of proteins and protein complexes under non-denaturing conditions (native MS) has strongly developed, through parallel advances in instrumentation, sample preparation, and data analysis tools. However, the success rate of native MS analysis, particularly in heterogeneous mega-Dalton (MDa) protein complexes, still strongly depends on careful instrument modification. Here, we further explore these boundaries in native mass spectrometry, analyzing two related endogenous multipartite viruses: the Brome Mosaic Virus (BMV) and the Cowpea Chlorotic Mottle Virus (CCMV). Both CCMV and BMV are approximately 4.6 megadalton (MDa) in mass, of which approximately 1 MDA originates from the genomic content of the virion. Both viruses are produced as mixtures of three particles carrying different segments of the genome, varying by approximately 0.1 MDA in mass (~2%). This mixture of particles poses a challenging analytical problem for high-resolution native MS analysis, given the large mass scales involved. We attempt to unravel the particle heterogeneity using both Q-TOF and Orbitrap mass spectrometers extensively modified for analysis of very large assemblies. We show that manipulation of the charging behavior can provide assistance in assigning the correct charge states. Despite their challenging size and heterogeneity, we obtained native mass spectra with resolved series of charge states for both BMV and CCMV, demonstrating that native MS of endogenous multipartite virions is feasible.

Mass Spectrometry Imaging of Biological Tissue: An Approach for Multicenter Studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rompp, Andreas; Both, Jean-Pierre; Brunelle, Alain

2015-03-01

Mass spectrometry imaging has become a popular tool for probing the chemical complexity of biological surfaces. This led to the development of a wide range of instrumentation and preparation protocols. It is thus desirable to evaluate and compare the data output from different methodologies and mass spectrometers. Here, we present an approach for the comparison of mass spectrometry imaging data from different laboratories (often referred to as multicenter studies). This is exemplified by the analysis of mouse brain sections in five laboratories in Europe and the USA. The instrumentation includes matrix-assisted laser desorption/ionization (MALDI)-time-of-flight (TOF), MALDI-QTOF, MALDIFourier transform ion cyclotronmore » resonance (FTICR), atmospheric-pressure (AP)-MALDI-Orbitrap, and cluster TOF-secondary ion mass spectrometry (SIMS). Experimental parameters such as measurement speed, imaging bin width, and mass spectrometric parameters are discussed. All datasets were converted to the standard data format imzML and displayed in a common open-source software with identical parameters for visualization, which facilitates direct comparison of MS images. The imzML conversion also allowed exchange of fully functional MS imaging datasets between the different laboratories. The experiments ranged from overview measurements of the full mouse brain to detailed analysis of smaller features (depending on spatial resolution settings), but common histological features such as the corpus callosum were visible in all measurements. High spatial resolution measurements of AP-MALDI-Orbitrap and TOF-SIMS showed comparable structures in the low-micrometer range. We discuss general considerations for planning and performing multicenter studies in mass spectrometry imaging. This includes details on the selection, distribution, and preparation of tissue samples as well as on data handling. Such multicenter studies in combination with ongoing activities for reporting guidelines, a common data format (imzML) and a public data repository can contribute to more reliability and transparency of MS imaging studies.« less

Mass Spectrometry in Studies of Protein Thiol Chemistry and Signaling: Opportunities and Caveats

PubMed Central

Devarie Baez, Nelmi O.; Reisz, Julie A.; Furdui, Cristina M.

2014-01-01

Mass spectrometry (MS) has become a powerful and widely utilized tool in the investigation of protein thiol chemistry, biochemistry, and biology. Very early biochemical studies of metabolic enzymes have brought to light the broad spectrum of reactivity profiles that distinguish cysteine thiols with functions in catalysis and protein stability from other cysteine residues in proteins. The development of MS methods for the analysis of proteins using electrospray ionization (ESI) or matrix-assisted laser desorption/ionization (MALDI) coupled with the emergence of high-resolution mass analyzers have been instrumental in advancing studies of thiol modifications, both in single proteins and within the cellular context. This article reviews MS instrumentation and methods of analysis employed in investigations of thiols and their reactivity toward a range of small biomolecules. A selected number of studies are detailed to highlight the advantages brought about by the MS technologies along with the caveats associated with these analyses. PMID:25261734

Chemical Synthesis Coxiella Burnetti Lipopolysaccharides: Structural Studies of Coxiella Burnetti Lipopolysaccharides.

DTIC Science & Technology

1987-11-30

currently evaluating two instrumental techniques which seem highly appropriate to this LPS project, supercritical fluid chromatography (SFC) and...NEW INSTRUMENTAL TECHNIQUES AND METHODS OF APPROACH 1. Supercritical Fluid Chromatography (SFC) ............... 6. 2. SFC and Mass Spectrometry...details are discussed below in the appropriate sections. B. NEW INSTRUMENTAL TECHNIQUES AND METHODS OF APPROACH 1. Supercritical Fluid Chromatography (SFC

Mass spectrometry. [review of techniques

NASA Technical Reports Server (NTRS)

Burlingame, A. L.; Kimble, B. J.; Derrick, P. J.

1976-01-01

Advances in mass spectrometry (MS) and its applications over the past decade are reviewed in depth, with annotated literature references. New instrumentation and techniques surveyed include: modulated-beam MS, chromatographic MS on-line computer techniques, digital computer-compatible quadrupole MS, selected ion monitoring (mass fragmentography), and computer-aided management of MS data and interpretation. Areas of application surveyed include: organic MS and electron impact MS, field ionization kinetics, appearance potentials, translational energy release, studies of metastable species, photoionization, calculations of molecular orbitals, chemical kinetics, field desorption MS, high pressure MS, ion cyclotron resonance, biochemistry, medical/clinical chemistry, pharmacology, and environmental chemistry and pollution studies.

A new technique for high performance tandem time-of- flight mass spectrometry

NASA Astrophysics Data System (ADS)

Katz, Daniel Louis

2001-08-01

The main result of this written dissertation is a mathematical solution to the problem of multiplex recording for high performance tandem time-of-flight mass spectrometry. The prescription is to use a time-lag accelerator in the second stage to match the ion optical properties of the decay fragments to the requirements of the electrostatic ion mirror. With this technique the ion mirror is able to focus the full mass range of fragment ions at a single voltage setting, permitting acquisition of the entire mass spectrum from a single ionization event. This work was performed in support of a joint project carried out by researchers at Oregon State University and The University of Uppsala, Sweden, to design, build and test a tandem instrument featuring precision selection of the precursor species in the first stage of the spectrometer, a means of fragmenting the precursor species, and multiplex recording of the resulting fragment spectrum in the second stage. A patent application has been filed on the complete instrument with the United States Patent Office, a copy of which has been included as an appendix, and a prototype of that instrument has been constructed and awaits testing at Oregon State University.

Design and performance of an instrument for electron impact tandem mass spectrometry and action spectroscopy of mass/charge selected macromolecular ions stored in RF ion trap*

NASA Astrophysics Data System (ADS)

Ranković, Milos Lj.; Giuliani, Alexandre; Milosavljević, Aleksandar R.

2016-06-01

A new apparatus was designed, coupling an electron gun with a linear quadrupole ion trap mass spectrometer, to perform m/ z (mass over charge) selected ion activation by electron impact for tandem mass spectrometry and action spectroscopy. We present in detail electron tracing simulations of a 300 eV electron beam inside the ion trap, design of the mechanical parts, electron optics and electronic circuits used in the experiment. We also report examples of electron impact activation tandem mass spectra for Ubiquitin protein, Substance P and Melittin peptides, at incident electron energies in the range from 280 eV to 300 eV.

A new hybrid electrospray Fourier transform mass spectrometer: design and performance characteristics.

PubMed

O'connor, Peter B; Pittman, Jason L; Thomson, Bruce A; Budnik, Bogdan A; Cournoyer, Jason C; Jebanathirajah, Judith; Lin, Cheng; Moyer, Susanne; Zhao, Cheng

2006-01-01

A new hybrid electrospray quadrupole Fourier transform mass spectrometry (FTMS) instrument design is shown and characterized. This instrument involves coupling an electrospray source and mass-resolving quadrupole, ion accumulation, and collision cell linear ion trap system developed by MDS Sciex with a home-built ion guide and ion cyclotron resonance (ICR) cell. The iterative progression of this design is shown. The final design involves a set of hexapole ion guides to transfer the ions from the accumulation/collision trap through the magnetic field gradient and into the cell. These hexapole ion guides are separated by a thin gate valve and two conduction limits to maintain the required <10(-9) mbar vacuum for FTICR. Low-attomole detection limits for a pure peptide are shown, 220 000 resolving power in broadband mode and 820 000 resolving power in narrow-band mode are demonstrated, and mass accuracy in the <2 ppm range is routinely available provided the signal is abundant, cleanly resolved, and internally calibrated. This instrument design provides high experimental flexibility, allowing Q2 CAD, SORI-CAD, IRMPD, and ECD experiments with selected ion accumulation as well as experiments such as nozzle skimmer dissociation. Initial top-down mass spectrometry experiments on a protein is shown using ECD.

Accelerator mass spectrometry of strontium-90 for homeland security, environmental monitoring and human health

NASA Astrophysics Data System (ADS)

Tumey, Scott J.; Brown, Thomas A.; Hamilton, Terry E.; Hillegonds, Darren J.

2008-05-01

Strontium-90 is one of the most hazardous materials managed by agencies charged with protecting the public from radiation. Traditional radiometric methods have been limited by low sample throughput and slow turnaround times. Mass spectrometry offers the advantage of shorter analysis times and the ability to measure samples immediately after processing, however conventional mass spectrometric techniques are susceptible to molecular isobaric interferences that limit their overall sensitivity. In contrast, accelerator mass spectrometry is insensitive to molecular interferences and we have therefore begun developing a method for determination of 90Sr by accelerator mass spectrometry. Despite a pervasive interference from 90Zr, our initial development has yielded an instrumental background of ∼108 atoms (75 mBq) per sample. Further refinement of our system (e.g. redesign of our detector, use of alternative target materials) is expected to push the background below 106 atoms, close to the theoretical limit for AMS. Once we have refined our system and developed suitable sample preparation protocols, we will utilize our capability in applications to homeland security, environmental monitoring and human health.

Characterization of aerosol particles from grass mowing by joint deployment of ToF-AMS and ATOFMS instruments

NASA Astrophysics Data System (ADS)

Drewnick, Frank; Dall'Osto, Manuel; Harrison, Roy

During a measurement campaign at a semi-urban/industrial site a grass-cutting event was observed, when the lawn in the immediate surrounding of the measurement site was mowed. Using a wide variety of state-of-the-art aerosol measurement technology allowed a broad characterization of the aerosol generated by the lawn mowing. The instrumentation included two on-line aerosol mass spectrometers: an Aerodyne Time-of-Flight Aerosol Mass Spectrometer (ToF-AMS) and a TSI Aerosol Time-of-Flight Mass Spectrometer (ATOFMS); in addition, a selection of on-line aerosol concentration and size distribution instruments (OPC, APS, SMPS, CPC, FDMS-TEOM, MAAP) was deployed. From comparison of background aerosol measurements during most of the day with the aerosol measured during the lawn mowing, the grass cutting was found to generate mainly two different types of aerosol particles: an intense ultrafine particle mode (1 h average: 4 μg m -3) of almost pure hydrocarbon-like organics and a distinct particle mode in the upper sub-micrometer size range containing particles with potassium and nitrogen-organic compounds. The ultrafine particles are probably lubricating oil particles from the lawn mower exhaust; the larger particles are swirled-up plant debris particles from the mowing process. While these particle types were identified in the data from the two mass spectrometers, the on-line aerosol concentration and size distribution data support these findings. The results presented here show that the combination of quantitative aerosol particle ensemble mass spectrometry (ToF-AMS) and single particle mass spectrometry (ATOFMS) provides much deeper insights into the nature of the aerosol properties than each of the instruments could do alone. Therefore a combined deployment of both types of instruments is strongly recommended.

Challenges ahead for mass spectrometry and proteomics applications in epigenetics.

PubMed

Kessler, Benedikt M

2010-02-01

Inheritance of biological information to future generations depends on the replication of DNA and the Mendelian principle of distribution of genes. In addition, external and environmental factors can influence traits that can be propagated to offspring, but the molecular details of this are only beginning to be understood. The discoveries of DNA methylation and post-translational modifications on chromatin and histones provided entry points for regulating gene expression, an area now defined as epigenetics and epigenomics. Mass spectrometry turned out to be instrumental in uncovering molecular details involved in these processes. The central role of histone post-translational modifications in epigenetics related biological processes has revitalized mass spectrometry based investigations. In this special report, current approaches and future challenges that lay ahead due to the enormous complexity are discussed.

Novel product ions of 2-aminoanilide and benzimidazole Ag(I) complexes using electrospray ionization with multi-stage tandem mass spectrometry.

PubMed

Johnson, Byron S; Burinsky, David J; Burova, Svetlana A; Davis, Roman; Fitzgerald, Russ N; Matsuoka, Richard T

2012-05-15

The 2-aminoaniline scaffold is of significant value to the pharmaceutical industry and is embedded in a number of pharmacophores including 2-aminoanilides and benzimidazoles. A novel application of coordination ion spray mass spectrometry (CIS-MS) for interrogating the silver ion (Ag(+)) complexes of a homologous series of these compounds using multi-stage tandem mass spectrometry is described. Unlike the ubiquitous alkali metal ion complexes, Ag(+) complexes of 2-aminoanilides and benzimidazoles were found to yield [M - H](+) ions in significant abundance via gas-phase elimination of the metal hydride (AgH) resulting in unique product ion cascades. Sample introduction was by liquid chromatography with mass spectrometry analysis performed on a hybrid linear ion trap/orbitrap instrument capable of high-resolution measurements. Rigorous structural characterization by multi-stage tandem mass spectrometry using [M +  H](+), [M - H](-) and [M - H](+) precursor ions derived from ESI and CIS experiments was performed for the homologous series of 2-aminoanilide and benzimidazole compounds. A full tabular comparison of structural information resulting from these product ion cascades was produced. Multi-stage tandem mass spectrometry of [M - H](+) ions resulting from Ag(+) complexes of 2-aminoanilides and benzimidazoles in CIS-MS experiments produced unique product ion cascades that exhibited complementary structural information to that obtained from tandem mass spectrometry of [M  +  H](+) and [M - H](-) ions by electrospray ionization (ESI). These observations may be broadly applicable to other compounds that are observed to form Ag(+) complexes and eliminate AgH. Copyright © 2012 John Wiley & Sons, Ltd.

An expert system/ion trap mass spectrometry approach for life support systems monitoring

NASA Technical Reports Server (NTRS)

Palmer, Peter T.; Wong, Carla M.; Yost, Richard A.; Johnson, Jodie V.; Yates, Nathan A.; Story, Michael

1992-01-01

Efforts to develop sensor and control system technology to monitor air quality for life support have resulted in the development and preliminary testing of a concept based on expert systems and ion trap mass spectrometry (ITMS). An ITMS instrument provides the capability to identify and quantitate a large number of suspected contaminants at trace levels through the use of a variety of multidimensional experiments. An expert system provides specialized knowledge for control, analysis, and decision making. The system is intended for real-time, on-line, autonomous monitoring of air quality. The key characteristics of the system, performance data and analytical capabilities of the ITMS instrument, the design and operation of the expert system, and results from preliminary testing of the system for trace contaminant monitoring are described.

Recent advances in secondary ion mass spectrometry of solid acid catalysts: large zeolite crystals under bombardment.

PubMed

Hofmann, Jan P; Rohnke, Marcus; Weckhuysen, Bert M

2014-03-28

This Perspective aims to inform the heterogeneous catalysis and materials science community about the recent advances in Time-of-Flight-Secondary Ion Mass Spectrometry (ToF-SIMS) to characterize catalytic solids by taking large model H-ZSM-5 zeolite crystals as a showcase system. SIMS-based techniques have been explored in the 1980-1990's to study porous catalyst materials but, due to their limited spectral and spatiotemporal resolution, there was no real major breakthrough at that time. The technical advancements in SIMS instruments, namely improved ion gun design and new mass analyser concepts, nowadays allow for a much more detailed analysis of surface species relevant to catalytic action. Imaging with high mass and lateral resolution, determination of fragment ion patterns, novel sputter ion concepts as well as new mass analysers (e.g. ToF, FTICR) are just a few novelties, which will lead to new fundamental insight from SIMS analysis of heterogeneous catalysts. The Perspective article ends with an outlook on instrumental innovations and their potential use for catalytic systems other than zeolite crystals.

Oil-in-water monitoring using membrane inlet mass spectrometry.

PubMed

Brkić, Boris; France, Neil; Taylor, Stephen

2011-08-15

A membrane inlet mass spectrometry (MIMS) system has been used for detection and analysis of two types of North Sea crude oil. The system was installed on-field on the Flotta Oil Terminal (Orkney, UK). It consisted of a quadrupole mass spectrometer (QMS) connected to the capillary probe with a silicone-based membrane. The produced mass spectra and calibration plots from the MIMS instrument showed the capability to measure levels of individual hydrocarbons within crude oil in seawater. The generated mass spectra from the field tests also showed the ability to distinguish between different types of oil and to determine concentrations of toxic hydrocarbons in oil (e.g., benzene, toluene, and xylene (BTX)). The performance of the instrument at different temperatures of seawater and oil droplet sizes was also investigated. The results showed that the QMS-based MIMS system has a potential to complement existing oil-in-water (OiW) monitors by being able to detect different oil types and specific hydrocarbon concentrations with high accuracy, which are currently not supported in commercially available OiW monitors.

Critical comparison of mass analyzers for forensic hair analysis by ambient ionization mass spectrometry.

PubMed

Duvivier, Wilco F; van Beek, Teris A; Nielen, Michel W F

2016-11-15

Recently, several direct and/or ambient mass spectrometry (MS) approaches have been suggested for drugs of abuse imaging in hair. The use of mass spectrometers with insufficient selectivity could result in false-positive measurements due to isobaric interferences. Different mass analyzers have been evaluated regarding their selectivity and sensitivity for the detection of Δ9-tetrahydrocannabinol (THC) from intact hair samples using direct analysis in real time (DART) ionization. Four different mass analyzers, namely (1) an orbitrap, (2) a quadrupole orbitrap, (3) a triple quadrupole, and (4) a quadrupole time-of-flight (QTOF), were evaluated. Selectivity and sensitivity were assessed by analyzing secondary THC standard dilutions on stainless steel mesh screens and blank hair samples, and by the analysis of authentic cannabis user hair samples. Additionally, separation of isobaric ions by use of travelling wave ion mobility (TWIM) was investigated. The use of a triple quadrupole instrument resulted in the highest sensitivity; however, transitions used for multiple reaction monitoring were only found to be specific when using high mass resolution product ion measurements. A mass resolution of at least 30,000 FWHM at m/z 315 was necessary to avoid overlap of THC with isobaric ions originating from the hair matrix. Even though selectivity was enhanced by use of TWIM, the QTOF instrument in resolution mode could not indisputably differentiate THC from endogenous isobaric ions in drug user hair samples. Only the high resolution of the (quadrupole) orbitrap instruments and the QTOF instrument in high-resolution mode distinguished THC in hair samples from endogenous isobaric interferences. As expected, enhanced selectivity compromises sensitivity and THC was only detectable in hair from heavy users. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Detection systems for mass spectrometry imaging: a perspective on novel developments with a focus on active pixel detectors.

PubMed

Jungmann, Julia H; Heeren, Ron M A

2013-01-15

Instrumental developments for imaging and individual particle detection for biomolecular mass spectrometry (imaging) and fundamental atomic and molecular physics studies are reviewed. Ion-counting detectors, array detection systems and high mass detectors for mass spectrometry (imaging) are treated. State-of-the-art detection systems for multi-dimensional ion, electron and photon detection are highlighted. Their application and performance in three different imaging modes--integrated, selected and spectral image detection--are described. Electro-optical and microchannel-plate-based systems are contrasted. The analytical capabilities of solid-state pixel detectors--both charge coupled device (CCD) and complementary metal oxide semiconductor (CMOS) chips--are introduced. The Medipix/Timepix detector family is described as an example of a CMOS hybrid active pixel sensor. Alternative imaging methods for particle detection and their potential for future applications are investigated. Copyright © 2012 John Wiley & Sons, Ltd.

Miniaturized GC/MS instrumentation for in situ measurements: micro gas chromatography coupled with miniature quadrupole array and paul ion trap mass spectrometers

NASA Technical Reports Server (NTRS)

Holland, P.; Chutjian, A.; Darrach, M.; Orient, O.

2002-01-01

Miniaturized chemical instrumentation is needed for in situ measurements in planetary exploration and other spaceflight applications where factors such as reduction in payload requirements and enhanced robustness are important. In response to this need, we are 'continuing to develop miniaturized GC/MS instrumentation which combines chemical separations by gas chromatography (GC) with mass spectrometry (MS) to provide positive identification of chemical compounds in complex mixtures of gases, such as those found in the International Space Station's cabin atmosphere. Our design approach utilizes micro gas chromatography components coupled with either a miniature quadrupole mass spectrometer array (QMSA) or compact, high-resolution Paul ion trap.

ICP-MS and Planetary Geosciences

NASA Astrophysics Data System (ADS)

Davenport, J. D.

2014-01-01

This article, describing inductively coupled plasma mass spectrometry, is one in a series of articles, "Instruments of Cosmochemistry," highlighting the essential tools and amazing technology used by talented scientists seeking to unravel how the Solar System formed. You will find information on how the instrument works as well as how it is helping new discoveries come to light.

Mass Spectrometry Parameters Optimization for the 46 Multiclass Pesticides Determination in Strawberries with Gas Chromatography Ion-Trap Tandem Mass Spectrometry

NASA Astrophysics Data System (ADS)

Fernandes, Virgínia C.; Vera, Jose L.; Domingues, Valentina F.; Silva, Luís M. S.; Mateus, Nuno; Delerue-Matos, Cristina

2012-12-01

Multiclass analysis method was optimized in order to analyze pesticides traces by gas chromatography with ion-trap and tandem mass spectrometry (GC-MS/MS). The influence of some analytical parameters on pesticide signal response was explored. Five ion trap mass spectrometry (IT-MS) operating parameters, including isolation time (IT), excitation voltage (EV), excitation time (ET), maximum excitation energy or " q" value (q), and isolation mass window (IMW) were numerically tested in order to maximize the instrument analytical signal response. For this, multiple linear regression was used in data analysis to evaluate the influence of the five parameters on the analytical response in the ion trap mass spectrometer and to predict its response. The assessment of the five parameters based on the regression equations substantially increased the sensitivity of IT-MS/MS in the MS/MS mode. The results obtained show that for most of the pesticides, these parameters have a strong influence on both signal response and detection limit. Using the optimized method, a multiclass pesticide analysis was performed for 46 pesticides in a strawberry matrix. Levels higher than the limit established for strawberries by the European Union were found in some samples.

A New Mass Spectrometer for Upper Atmospheric Measurements in the Auroral Region

NASA Astrophysics Data System (ADS)

Everett, E. A.; Dyer, J. S.; Watson, M.; Sanderson, W.; Schicker, S.; Work, D.; Mertens, C. J.; Bailey, S. M.; Syrstad, E. A.

2011-12-01

We have previously presented a new rocket-borne time-of-flight mass spectrometer (TOF-MS) for measurements in the mesosphere / lower thermosphere (MLT). Traditionally, mass spectrometry in the MLT has been difficult, mainly due to the elevated ambient pressures of the MLT and high speeds of a sounding rocket flight, which affect the direct sampling of the ambient atmosphere and spatial resolution. The TOF-MS is a versatile, inherently adaptable, axial-sampling instrument, capable of operating in a traditional TOF mode or in a multiplexing Hadamard-transform mode where high spatial resolution is desired. To minimize bow shock effects at low altitudes (~70-110km), the ram surface of the TOF-MS can be cryogenically cooled using liquid He to adsorb impinging gas particles. The vacuum pumping system for the TOF-MS is tailored to the specific mission and instrument configuration. Depending on the instrument gas load and operating altitude, cryo, miniature turbo pump or getter-based pumping systems may be employed. Terrestrial TOF-MS instruments often employ a reflectron, essentially an ion-mirror, to improve mass resolving power and compensate for the thermal velocity distribution of particles being measured. The TOF-MS can be arranged in either a simple linear or reflectron configuration. Simulations and modeling are used to compare instrument mass resolution for linear and reflectron configurations for several variable conditions including vehicle velocity and ambient temperature, ultimately demonstrating the potential to make rocket-borne mass spectrometry measurements with unit-mass resolution up to at least 48 amu. Preliminary analyses suggest that many species of interest (including He, CO2, O2, O2+ , N2, N2+, and NO+) can be measured with an uncertainty below 10% relative standard deviation on a sounding rocket flight. We also present experimental data for a laboratory prototype linear TOF-MS. Experimental data is compared to simulation and modeling efforts to validate and confirm instrument performance and capability. Two proposed rocket campaigns for investigations of the auroral region include the TOF-MS. By making accurate composition measurements of the neutral atmosphere from 70 to 120km, Mass Spectrometry of the Turbopause Region (MSTR) aims to improve the accuracy of temperature measurements in the turbopause region, improve the MSIS model atmosphere and examine the transition from the turbulently mixed lower atmosphere to the diffusive equilibrium of the upper atmosphere. The ROCKet-borne STorm Energetics of Auroral Dosing in the E-region (ROCK-STEADE) mission will study energy transfer in the E-region during an aurora by examining auroral emissions and measuring concentrations of neutrals and ions. The instrument suite for ROCK-STEADE includes two mass spectrometers, one each to measure neutrals and ions in the altitude range of 70 - 170km. The ability of the TOF-MS instrument to make accurate measurements will greatly aid in better understanding the MLT.

Strategies to avoid false negative findings in residue analysis using liquid chromatography coupled to time-of-flight mass spectrometry.

PubMed

Kaufmann, Anton; Butcher, Patrick

2006-01-01

Liquid chromatography coupled to orthogonal acceleration time-of-flight mass spectrometry (LC/TOF) provides an attractive alternative to liquid chromatography coupled to triple quadrupole mass spectrometry (LC/MS/MS) in the field of multiresidue analysis. The sensitivity and selectivity of LC/TOF approach those of LC/MS/MS. TOF provides accurate mass information and a significantly higher mass resolution than quadrupole analyzers. The available mass resolution of commercial TOF instruments ranging from 10 000 to 18 000 full width at half maximum (FWHM) is not, however, sufficient to completely exclude the problem of isobaric interferences (co-elution of analyte ions with matrix compounds of very similar mass). Due to the required data storage capacity, TOF raw data is commonly centroided before being electronically stored. However, centroiding can lead to a loss of data quality. The co-elution of a low intensity analyte peak with an isobaric, high intensity matrix compound can cause problems. Some centroiding algorithms might not be capable of deconvoluting such partially merged signals, leading to incorrect centroids.Co-elution of isobaric compounds has been deliberately simulated by injecting diluted binary mixtures of isobaric model substances at various relative intensities. Depending on the mass differences between the two isobaric compounds and the resolution provided by the TOF instrument, significant deviations in exact mass measurements and signal intensities were observed. The extraction of a reconstructed ion chromatogram based on very narrow mass windows can even result in the complete loss of the analyte signal. Guidelines have been proposed to avoid such problems. The use of sub-2 microm HPLC packing materials is recommended to improve chromatographic resolution and to reduce the risk of co-elution. The width of the extraction mass windows for reconstructed ion chromatograms should be defined according to the resolution of the TOF instrument. Alternative approaches include the spiking of the sample with appropriate analyte concentrations. Furthermore, enhanced software, capable of deconvoluting partially merged mass peaks, may become available. Copyright (c) 2006 John Wiley & Sons, Ltd.

Fundamentals of Biomolecule Analysis by Electrospray Ionization Mass Spectrometry

ERIC Educational Resources Information Center

Weinecke, Andrea; Ryzhov, Victor

2005-01-01

Electrospray ionization (ESI) is a soft ionization technique that allows transfer of fragile biomolecules directly from solution into the gas phase. An instrumental analysis laboratory experiment is designed that would introduce the students to the ESI technique, major parameters of the ion trap mass spectrometers and some caveats in…

Cleaning up the masses: exclusion lists to reduce contamination with HPLC-MS/MS.

PubMed

Hodge, Kelly; Have, Sara Ten; Hutton, Luke; Lamond, Angus I

2013-08-02

Mass spectrometry, in the past five years, has increased in speed, accuracy and use. With the ability of the mass spectrometers to identify increasing numbers of proteins the identification of undesirable peptides (those not from the protein sample) has also increased. Most undesirable contaminants originate in the laboratory and come from either the user (e.g. keratin from hair and skin), or from reagents (e.g. trypsin), that are required to prepare samples for analysis. We found that a significant amount of MS instrument time was spent sequencing peptides from abundant contaminant proteins. While completely eliminating non-specific protein contamination is not feasible, it is possible to reduce the sequencing of these contaminants. For example, exclusion lists can provide a list of masses that can be used to instruct the mass spectrometer to 'ignore' the undesired contaminant peptides in the list. We empirically generated be-spoke exclusion lists for several model organisms (Homo sapiens, Caenorhabditis elegans, Saccharomyces cerevisiae and Xenopus laevis), utilising information from over 500 mass spectrometry runs and cumulative analysis of these data. Here we show that by employing these empirically generated lists, it was possible to reduce the time spent analysing contaminating peptides in a given sample thereby facilitating more efficient data acquisition and analysis. Given the current efficacy of the Mass Spectrometry instrumentation, the utilisation of data from ~500 mass spec runs to generate be-spoke exclusion lists and optimise data acquisition is the significance of this manuscript. Copyright © 2013 Elsevier B.V. All rights reserved.

A Compact Tandem Two-Step Laser Time-of-Flight Mass Spectrometer for In Situ Analysis of Non-Volatile Organics on Planetary Surfaces

NASA Technical Reports Server (NTRS)

Getty, Stephanie A.; Brinckerhoff, William B.; Li, Xiang; Elsila, Jamie; Cornish, Timothy; Ecelberger, Scott; Wu, Qinghao; Zare, Richard

2014-01-01

Two-step laser desorption mass spectrometry is a well suited technique to the analysis of high priority classes of organics, such as polycyclic aromatic hydrocarbons, present in complex samples. The use of decoupled desorption and ionization laser pulses allows for sensitive and selective detection of structurally intact organic species. We have recently demonstrated the implementation of this advancement in laser mass spectrometry in a compact, flight-compatible instrument that could feasibly be the centerpiece of an analytical science payload as part of a future spaceflight mission to a small body or icy moon.

Flying Cages in Traveling Wave Ion Mobility: Influence of the Instrumental Parameters on the Topology of the Host-Guest Complexes

NASA Astrophysics Data System (ADS)

Carroy, Glenn; Lemaur, Vincent; Henoumont, Céline; Laurent, Sophie; De Winter, Julien; De Pauw, Edwin; Cornil, Jérôme; Gerbaux, Pascal

2018-01-01

Supramolecular mass spectrometry has emerged in the last decade as an orthogonal method to access, at the molecular level, the structures of noncovalent complexes extracted from the condensed phase to the rarefied gas phase using electrospray ionization. It is often considered that the soft nature of the ESI source confers to the method the capability to generate structural data comparable to those in the condensed phase. In the present paper, using the ammonium ion/cucurbituril combination as a model system, we investigate using ion mobility and computational chemistry the influence of the instrumental parameters on the topology, i.e., internal versus external association, of gaseous host/guest complex ions. MS and theoretical data are confronted to condensed phase data derived from nuclear magnetic resonance spectroscopy to assess whether the instrumental parameters can play an insidious role when trying to derive condensed phase data from mass spectrometry results. [Figure not available: see fulltext.

Determination of the rare-earth elements in geological materials by inductively coupled plasma mass spectrometry

USGS Publications Warehouse

Lichte, F.E.; Meier, A.L.; Crock, J.G.

1987-01-01

A method of analysis of geological materials for the determination of the rare-earth elements using the Inductively coupled plasma mass spectrometric technique (ICP-MS) has been developed. Instrumental parameters and factors affecting analytical results have been first studied and then optimized. Samples are analyzed directly following an acid digestion, without the need for separation or preconcentration with limits of detection of 2-11 ng/g, precision of ?? 2.5% relative standard deviation, and accuracy comparable to inductively coupled plasma emission spectrometry and instrumental neutron activation analysis. A commercially available ICP-MS instrument is used with modifications to the sample introduction system, torch, and sampler orifice to reduce the effects of high salt content of sample solutions prepared from geologic materials. Corrections for isobaric interferences from oxide ions and other diatomic and triatomic ions are made mathematically. Special internal standard procedures are used to compensate for drift in metahmetal oxide ratios and sensitivity. Reference standard values are used to verify the accuracy and utility of the method.

Comparison of Different Ion Mobility Setups Using Poly (Ethylene Oxide) PEO Polymers: Drift Tube, TIMS, and T-Wave

NASA Astrophysics Data System (ADS)

Haler, Jean R. N.; Massonnet, Philippe; Chirot, Fabien; Kune, Christopher; Comby-Zerbino, Clothilde; Jordens, Jan; Honing, Maarten; Mengerink, Ynze; Far, Johann; Dugourd, Philippe; De Pauw, Edwin

2018-01-01

Over the years, polymer analyses using ion mobility-mass spectrometry (IM-MS) measurements have been performed on different ion mobility spectrometry (IMS) setups. In order to be able to compare literature data taken on different IM(-MS) instruments, ion heating and ion temperature evaluations have already been explored. Nevertheless, extrapolations to other analytes are difficult and thus straightforward same-sample instrument comparisons seem to be the only reliable way to make sure that the different IM(-MS) setups do not greatly change the gas-phase behavior. We used a large range of degrees of polymerization (DP) of poly(ethylene oxide) PEO homopolymers to measure IMS drift times on three different IM-MS setups: a homemade drift tube (DT), a trapped (TIMS), and a traveling wave (T-Wave) IMS setup. The drift time evolutions were followed for increasing polymer DPs (masses) and charge states, and they are found to be comparable and reproducible on the three instruments. [Figure not available: see fulltext.

Studying the Formation, Evolution, and Habitability of the Galilean Satellites

NASA Technical Reports Server (NTRS)

McGrath, M.; Waite, J. H. Jr.; Brockwell, T.; McKinnon, W.; Wyrick, D.; Mousis, O.; Magee, B.

2013-01-01

Highly sensitive, high-mass resolution mass spectrometry is an important in situ tool for the study of solar system bodies. In this talk we detail the science objectives, develop the rationale for the measurement requirements, and describe potential instrument/mission methodologies for studying the formation, evolution, and habitability of the Galilean satellites. We emphasize our studies of Ganymede and Europa as described in our instrument proposals for the recently selected JUICE mission and the proposed Europa Clipper mission.

Tandem Mass Spectrometry Imaging and in Situ Characterization of Bioactive Wood Metabolites in Amazonian Tree Species Sextonia rubra.

PubMed

Fu, Tingting; Touboul, David; Della-Negra, Serge; Houël, Emeline; Amusant, Nadine; Duplais, Christophe; Fisher, Gregory L; Brunelle, Alain

2018-06-19

Driven by a necessity for confident molecular identification at high spatial resolution, a new time-of-flight secondary ion mass spectrometry (TOF-SIMS) tandem mass spectrometry (tandem MS) imaging instrument has been recently developed. In this paper, the superior MS/MS spectrometry and imaging capability of this new tool is shown for natural product study. For the first time, via in situ analysis of the bioactive metabolites rubrynolide and rubrenolide in Amazonian tree species Sextonia rubra (Lauraceae), we were able both to analyze and to image by tandem MS the molecular products of natural biosynthesis. Despite the low abundance of the metabolites in the wood sample(s), efficient MS/MS analysis of these γ-lactone compounds was achieved, providing high confidence in the identification and localization. In addition, tandem MS imaging minimized the mass interferences and revealed specific localization of these metabolites primarily in the ray parenchyma cells but also in certain oil cells and, further, revealed the presence of previously unidentified γ-lactone, paving the way for future studies in biosynthesis.

Development of a plug-type IMS-MS instrument and its applications in resolving problems existing in in-situ detection of illicit drugs and explosives by IMS.

PubMed

Du, Zhenxia; Sun, Tangqiang; Zhao, Jianan; Wang, Di; Zhang, Zhongxia; Yu, Wenlian

2018-07-01

Ion mobility spectrometry (IMS) which acts as a rapid analysis technique is widely used in the field detection of illicit drugs and explosives. Due to limited separation abilities of the pint-sized IMS challenges and problems still exist regarding high false positive and false negative responses due to the interference of the matrix. In addition, the gas-phase ion chemistry and special phenomena in the IMS spectra, such one substance showing two peaks, were not identified unambiguously. In order to explain or resolve these questions, in this paper, an ion mobility spectrometry was coupled to a mass spectrometry (IMS-MS). A commercial IMS is embedded in a custom-built ion chamber shell was attached to the mass spectrometer. The faraday plate of IMS was fabricated with a hole for the ions to passing through to the mass spectrometer. The ion transmission efficiency of IMS-MS was optimized by optimizing the various parameters, especially the distance between the faraday plate and the cone of mass spectrum. This design keeps the integrity of the two original instruments and the mass spectrometry still works with multimode ionization source (i.e., IMS-MS, ESI-MS, APCI-MS modes). The illicit drugs and explosive samples were analyzed by the IMS-MS with 63 Ni source. The results showed that the IMS-MS is of high sensitivity. The ionization mechanism of the illicit drug and explosive samples with 63 Ni source were systematically studied. In addition, the interferent which interfered the detection of cocaine was identified as dibutyl phthalate (DBP) by this platform. The reason why the acetone solution of amphetamine showed two peaks was explained. Copyright © 2018 Elsevier B.V. All rights reserved.

Concomitant Ion Effects on Isotope Ratio Measurements with Liquid Sampling – Atmospheric Pressure Glow Discharge Ion Source Orbitrap Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoegg, Edward D.; Marcus, R. Kenneth; Hager, Georg

2018-02-28

In an effort to understand and improve the accuracy and precision of the liquid sampling- atmospheric pressure glow discharge (LS-APGD)/Orbitrap system, effects of concomitant ions on the acquired mass spectra are examined and presented. The LS-APGD/ Orbitrap instrument system is capable of high quality isotope ratio measurements, which are of high analytical interest for nuclear non-proliferation detection applications. The presence of background and concomitant ions (water clusters, matrix, and other analytes) has presented limitations in earlier studies. In order to mitigate these effects, an alternative quadrupole-Orbitrap hybrid mass spectrometer was employed in this study. This instrument configuration has a quadrupolemore » mass filter preceding the Orbitrap to filter-out undesired non-analyte ions. Results are presented for the analysis of U in the presence of Rb, Ag, Ba, and Pb as concomitants, each present at 5 µg/mL concentration. Progressive filtering of each concomitant ion shows steadily improved U isotope ratio performance. Ultimately, a 235U/238U ratio of 0.007133, with a relative accuracy of -2.1% and a relative standard deviation of 0.087% was achieved using this system, along with improved calibration linearity and lowered limits of detection. The resultant performance compares very favorably with other commonly accepted isotope ratio measurement platforms - surprisingly so for an ion trap type mass spectrometry instrument.« less

Qualitative Amino Acid Analysis of Small Peptides by GC/MS.

ERIC Educational Resources Information Center

Mabbott, Gary A.

1990-01-01

Experiments designed to help undergraduate students gain experience operating instruments and interpreting gas chromatography and mass spectrometry data are presented. Experimental reagents, procedures, analysis, and probable results are discussed. (CW)

Accurate mass measurement: terminology and treatment of data.

PubMed

Brenton, A Gareth; Godfrey, A Ruth

2010-11-01

High-resolution mass spectrometry has become ever more accessible with improvements in instrumentation, such as modern FT-ICR and Orbitrap mass spectrometers. This has resulted in an increase in the number of articles submitted for publication quoting accurate mass data. There is a plethora of terms related to accurate mass analysis that are in current usage, many employed incorrectly or inconsistently. This article is based on a set of notes prepared by the authors for research students and staff in our laboratories as a guide to the correct terminology and basic statistical procedures to apply in relation to mass measurement, particularly for accurate mass measurement. It elaborates on the editorial by Gross in 1994 regarding the use of accurate masses for structure confirmation. We have presented and defined the main terms in use with reference to the International Union of Pure and Applied Chemistry (IUPAC) recommendations for nomenclature and symbolism for mass spectrometry. The correct use of statistics and treatment of data is illustrated as a guide to new and existing mass spectrometry users with a series of examples as well as statistical methods to compare different experimental methods and datasets. Copyright © 2010. Published by Elsevier Inc.

Selective-Reagent-Ionization Mass Spectrometry: New Prospects for Atmospheric Research

NASA Astrophysics Data System (ADS)

Sulzer, Philipp; Jordan, Alfons; Hartungen, Eugen; Hanel, Gernot; Jürschik, Simone; Herbig, Jens; Märk, Lukas; Märk, Tilmann D.

2014-05-01

Proton-Transfer-Reaction Mass Spectrometry (PTR-MS), which was introduced to the scientific community in the 1990's, has quickly evolved into a well-established technology for atmospheric research and environmental chemistry [1]. Advantages of PTR-MS are i) high sensitivities of several hundred cps/ppbv, ii) detection limits at or below the pptv level, iii) direct injection sampling (i.e. no sample preparation), iv) response times in the 100 ms regime and v) online quantification. However, one drawback is a somehow limited selectivity, as in case of quadrupole mass filter based instruments only information about nominal m/z are available. In Time-Of-Flight (TOF) mass analyzer based instruments selectivity is drastically increased by a high mass resolution of up to 8000 m/Δm, but e.g. isomers still cannot be separated. In 2009 we introduced an advanced version of PTR-MS, which permits switching the reagent ions from H3O+ to NO+ and O2+, respectively [2]. This novel type of instrumentation was called Selective-Reagent-Ionization Mass Spectrometry (SRI-MS) and has been successfully used to separate isomers, e.g. the biogenic compounds isoprene and 2-methyl-3-buten-2-ol as shown by Karl et al. [3]. Switching the reagent ions dramatically increases selectivity and thus applicability of SRI-MS in atmospheric research. Here we report on the latest results utilizing an even more advanced embodiment of SRI-MS enabling the use of the additional reagent ions Kr+ and Xe+ [4]. With this technology important atmospheric compounds, such as CO2, CO, CH4, O2, etc. can be quantified and selectivity is increased even further. We present comparison data between diesel and gasoline car exhaust gases and quantitative data on indoor air for these compounds, which are not detectable with classical PTR-MS. Additionally, we show very recent examples of isomers which cannot be separated with PTR-MS but can clearly be distinguished with SRI-MS. Finally, we give an overview of ongoing SRI-MS developments, which include TOF based instruments with increased sensitivity of one order of magnitude (i.e. in the 103 cps/ppbv regime) by means of using a quadrupole ion guide between the drift tube and the TOF analyzer. It is expected that these developments will have a serious impact in atmospheric research, because increased sensitivity implies reduced measurement times and thus, e.g. even more accurate flux measurements. References [1] J. de Gouw, C. Warneke, T. Karl, G. Eerdekens, C. van der Veen, R. Fall, Mass Spectrometry Reviews, 26 (2007), 223-257. [2] A. Jordan, S. Haidacher, G. Hanel, E. Hartungen, J. Herbig, L. Märk, R. Schottkowsky, H. Seehauser, P. Sulzer, T.D. Märk, International Journal of Mass Spectrometry, 286 (2009), 32 - 38. [3] T. Karl, A. Hansel, L. Cappellin, L. Kaser, I. Herdlinger-Blatt, W. Jud, Atmospheric Chemistry and Physics, 12/24 (2012), 11877-11884. [4] P. Sulzer, A. Edtbauer, E. Hartungen, S. Juerschik, A. Jordan, G. Hanel, S. Feil, S. Jaksch, L. Märk, T.D. Märk, International Journal of Mass Spectrometry, 321 (2012), 66-70. Acknowledgement We acknowledge financial support by the Austrian Research Promotion Agency (FFG), Wien.

Separation of Caffeine from Beverages and Analysis Using Thin-Layer Chromatography and Gas Chromatography-Mass Spectrometry

ERIC Educational Resources Information Center

Torres y Torres, Janelle L.; Hiley, Shauna L.; Lorimor, Steven P.; Rhoad, Jonathan S.; Caldwell, Benjamin D.; Zweerink, Gerald L.; Ducey, Michael

2015-01-01

The Characterization and Analysis of a Product (CAP) project is used to introduce first-semester general chemistry students to chemical instrumentation through the analysis of caffeine-containing beverage products. Some examples of these products have included coffee, tea, and energy drinks. Students perform at least three instrumental experiments…

Investigation of an enhanced resolution triple quadrupole mass spectrometer for high-throughput liquid chromatography/tandem mass spectrometry assays.

PubMed

Yang, Liyu; Amad, Ma'an; Winnik, Witold M; Schoen, Alan E; Schweingruber, Hans; Mylchreest, Iain; Rudewicz, Patrick J

2002-01-01

Triple quadrupole mass spectrometers, when operated in multiple reaction monitoring (MRM) mode, offer a unique combination of sensitivity, specificity, and dynamic range. Consequently, the triple quadrupole is the workhorse for high-throughput quantitation within the pharmaceutical industry. However, in the past, the unit mass resolution of quadrupole instruments has been a limitation when interference from matrix or metabolites cannot be eliminated. With recent advances in instrument design, triple quadrupole instruments now afford mass resolution of less than 0.1 Dalton (Da) full width at half maximum (FWHM). This paper describes the evaluation of an enhanced resolution triple quadrupole mass spectrometer for high-throughput bioanalysis with emphasis on comparison of selectivity, sensitivity, dynamic range, precision, accuracy, and stability under both unit mass (1 Da FWHM) and enhanced (

Accelerator mass spectrometry of Strontium-90 for homeland security, environmental monitoring, and human health

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tumey, S J; Brown, T A; Hamilton, T F

2008-03-03

Strontium-90 is one of the most hazardous materials managed by agencies charged with protecting the public from radiation. Traditional radiometric methods have been limited by low sample throughput and slow turnaround times. Mass spectrometry offers the advantage of shorter analysis times and the ability to measure samples immediately after processing, however conventional mass spectrometric techniques are susceptible to molecular isobaric interferences that limit their overall sensitivity. In contrast, accelerator mass spectrometry is insensitive to molecular interferences and we have therefore begun developing a method for determination of {sup 90}Sr by accelerator mass spectrometry. Despite a pervasive interference from {sup 90}Zr,more » our initial development has yielded an instrumental background of {approx} 10{sup 8} atoms (75 mBq) per sample. Further refinement of our system (e.g., redesign of our detector, use of alternative target materials) is expected to push the background below 10{sup 6} atoms, close to the theoretical limit for AMS. Once we have refined our system and developed suitable sample preparation protocols, we will utilize our capability in applications to homeland security, environmental monitoring, and human health.« less

Analysis of the aflatoxin AFB1 from corn by direct analysis in real time - mass spectrometry (DART-MS)

USDA-ARS?s Scientific Manuscript database

Direct analysis in real time (DART) ionization coupled to a high resolution mass spectrometer (MS) was used for screening of aflatoxins from a variety of surfaces and the rapid quantitative analysis of aflatoxins extracted from corn. Sample preparation procedure and instrument parameter settings wer...

Critical factors determining the quantification capability of matrix-assisted laser desorption/ionization– time-of-flight mass spectrometry

PubMed Central

Wang, Chia-Chen; Lai, Yin-Hung; Ou, Yu-Meng; Chang, Huan-Tsung; Wang, Yi-Sheng

2016-01-01

Quantitative analysis with mass spectrometry (MS) is important but challenging. Matrix-assisted laser desorption/ionization (MALDI) coupled with time-of-flight (TOF) MS offers superior sensitivity, resolution and speed, but such techniques have numerous disadvantages that hinder quantitative analyses. This review summarizes essential obstacles to analyte quantification with MALDI-TOF MS, including the complex ionization mechanism of MALDI, sensitive characteristics of the applied electric fields and the mass-dependent detection efficiency of ion detectors. General quantitative ionization and desorption interpretations of ion production are described. Important instrument parameters and available methods of MALDI-TOF MS used for quantitative analysis are also reviewed. This article is part of the themed issue ‘Quantitative mass spectrometry’. PMID:27644968

Improving the Sensitivity of Mass Spectrometry by Using a New Sheath Flow Electrospray Emitter Array at Subambient Pressures

DOE PAGES

Cox, Jonathan T.; Marginean, Ioan; Kelly, Ryan T.; ...

2014-03-28

Arrays of chemically etched emitters with individualized sheath gas capillaries have been developed to enhance electrospray ionization (ESI) at subambient pressures. By including an emitter array in a subambient pressure ionization with nanoelectrospray (SPIN) source, ionization and transmission efficiency can be maximized allowing for increased sensitivity in mass spectrometric analyses. The SPIN source eliminates the major ion losses at conventional ESI-mass spectrometry (MS) interface by placing the emitter in the first vacuum region of the instrument. To facilitate stable electrospray currents in such conditions we have developed an improved emitter array with individualized sheath gas around each emitter. The utilitymore » of the new emitter arrays for generating stable multi-electrosprays at subambient pressures was probed by coupling the emitter array/SPIN source with a time of flight (TOF) mass spectrometer. The instrument sensitivity was compared between single emitter/SPIN-MS and multi-emitter/SPIN-MS configurations using an equimolar solution of 9 peptides. An increase in sensitivity correlative to the number of emitters in the array was observed.« less

Improving the Sensitivity of Mass Spectrometry by Using a New Sheath Flow Electrospray Emitter Array at Subambient Pressures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cox, Jonathan T.; Marginean, Ioan; Kelly, Ryan T.

Arrays of chemically etched emitters with individualized sheath gas capillaries have been developed to enhance electrospray ionization (ESI) at subambient pressures. By including an emitter array in a subambient pressure ionization with nanoelectrospray (SPIN) source, ionization and transmission efficiency can be maximized allowing for increased sensitivity in mass spectrometric analyses. The SPIN source eliminates the major ion losses at conventional ESI-mass spectrometry (MS) interface by placing the emitter in the first vacuum region of the instrument. To facilitate stable electrospray currents in such conditions we have developed an improved emitter array with individualized sheath gas around each emitter. The utilitymore » of the new emitter arrays for generating stable multi-electrosprays at subambient pressures was probed by coupling the emitter array/SPIN source with a time of flight (TOF) mass spectrometer. The instrument sensitivity was compared between single emitter/SPIN-MS and multi-emitter/SPIN-MS configurations using an equimolar solution of 9 peptides. An increase in sensitivity correlative to the number of emitters in the array was observed.« less

Intact cell mass spectrometry (ICMS) used to type methicillin-resistant Staphylococcus aureus: media effects and inter-laboratory reproducibility.

PubMed

Walker, J; Fox, A J; Edwards-Jones, V; Gordon, D B

2002-02-01

Intact cell mass spectrometry (ICMS) rapidly analyses the surface composition of microorganisms providing rapid, discriminatory fingerprints for identification and subtyping of important nosocomial pathogens such as methicillin resistant Staphylocccus aureus (MRSA). In this study, ICMS using matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI TOF/MS) was assessed for the identification and subtyping of MRSA. An intra- and inter-laboratory reproducibility study was carried out and the effects of culture media (an important source of variation for ICMS) were also studied. Several media used for the cultural identification of MRSA were examined using a panel of well-characterised staphylococcal isolates (n=26). Six MRSA isolates were analysed over a 1-month period for intra-laboratory reproducibility on the same instrument and three different culture media. Spectra were consistent for each isolate between the four experiments on the same culture medium. Individual isolates produced different spectral profiles on different culture media. Spectra from organisms grown on Columbia blood agar contained more peaks (approximately 120) compared to Columbia agar (approximately 50) and methicillin mannitol salt agar (approximately 25). All 26 staphylococcal isolates were subjected to an inter-laboratory study on two MALDI instruments. For each isolate, the overall spectral profile was the same for each of the two instruments but the baseline threshold values was adjusted due to instrument differences in detector sensitivities. Differences between certain regions of the spectra reproducibly identified isolates belonging to the two major MRSA strains (EMRSA phage group 15 and 16). These results demonstrate ICMS with appropriate media selection is a rapid and reproducible technique for identification and discrimination of MRSA.

Next generation offline approaches to trace organic compound speciation: Approaching comprehensive speciation with soft ionization and very high resolution tandem mass spectrometry

NASA Astrophysics Data System (ADS)

Khare, P.; Marcotte, A.; Sheu, R.; Ditto, J.; Gentner, D. R.

2017-12-01

Intermediate- and semi-volatile organic compounds (IVOCs and SVOCs) have high secondary organic aerosol (SOA) yields, as well as significant ozone formation potentials. Yet, their emission sources and oxidation pathways remain largely understudied due to limitations in current analytical capabilities. Online mass spectrometers are able to collect real time data but their limited mass resolving power renders molecular level characterization of IVOCs and SVOCs from the unresolved complex mixture unfeasible. With proper sampling techniques and powerful analytical instrumentation, our offline tandem mass spectrometry (i.e. MS×MS) techniques provide molecular-level and structural identification over wide polarity and volatility ranges. We have designed a novel analytical system for offline analysis of gas-phase SOA precursors collected on custom-made multi-bed adsorbent tubes. Samples are desorbed into helium via a gradual temperature ramp and sample flow is split equally for direct-MS×MS analysis and separation via gas chromatography (GC). The effluent from GC separation is split again for analysis via atmospheric pressure chemical ionization quadrupole time-of-flight mass spectrometry (APCI-Q×TOF) and traditional electron ionization mass spectrometry (EI-MS). The compounds for direct-MS×MS analysis are delivered via a transfer line maintained at 70ºC directly to APCI-Q×TOF, thus preserving the molecular integrity of thermally-labile, or other highly-reactive, organic compounds. Both our GC-MS×MS and direct-MS×MS analyses report high accuracy parent ion masses as well as information on molecular structure via MS×MS, which together increase the resolution of unidentified complex mixtures. We demonstrate instrument performance and present preliminary results from urban atmospheric samples collected from New York City with a wide range of compounds including highly-functionalized organic compounds previously understudied in outdoor air. Our work offers new insights into emerging emission sources in urban environments that can have a major impact on public health and also improves understanding of anthropogenic SOA precursor emissions.

Analytical techniques for steroid estrogens in water samples - A review.

PubMed

Fang, Ting Yien; Praveena, Sarva Mangala; deBurbure, Claire; Aris, Ahmad Zaharin; Ismail, Sharifah Norkhadijah Syed; Rasdi, Irniza

2016-12-01

In recent years, environmental concerns over ultra-trace levels of steroid estrogens concentrations in water samples have increased because of their adverse effects on human and animal life. Special attention to the analytical techniques used to quantify steroid estrogens in water samples is therefore increasingly important. The objective of this review was to present an overview of both instrumental and non-instrumental analytical techniques available for the determination of steroid estrogens in water samples, evidencing their respective potential advantages and limitations using the Need, Approach, Benefit, and Competition (NABC) approach. The analytical techniques highlighted in this review were instrumental and non-instrumental analytical techniques namely gas chromatography mass spectrometry (GC-MS), liquid chromatography mass spectrometry (LC-MS), enzyme-linked immuno sorbent assay (ELISA), radio immuno assay (RIA), yeast estrogen screen (YES) assay, and human breast cancer cell line proliferation (E-screen) assay. The complexity of water samples and their low estrogenic concentrations necessitates the use of highly sensitive instrumental analytical techniques (GC-MS and LC-MS) and non-instrumental analytical techniques (ELISA, RIA, YES assay and E-screen assay) to quantify steroid estrogens. Both instrumental and non-instrumental analytical techniques have their own advantages and limitations. However, the non-instrumental ELISA analytical techniques, thanks to its lower detection limit and simplicity, its rapidity and cost-effectiveness, currently appears to be the most reliable for determining steroid estrogens in water samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

In vivo Real-Time Mass Spectrometry for Guided Surgery Application

NASA Astrophysics Data System (ADS)

Fatou, Benoit; Saudemont, Philippe; Leblanc, Eric; Vinatier, Denis; Mesdag, Violette; Wisztorski, Maxence; Focsa, Cristian; Salzet, Michel; Ziskind, Michael; Fournier, Isabelle

2016-05-01

Here we describe a new instrument (SpiderMass) designed for in vivo and real-time analysis. In this instrument ion production is performed remotely from the MS instrument and the generated ions are transported in real-time to the MS analyzer. Ion production is promoted by Resonant Infrared Laser Ablation (RIR-LA) based on the highly effective excitation of O-H bonds in water molecules naturally present in most biological samples. The retrieved molecular patterns are specific to the cell phenotypes and benign versus cancer regions of patient biopsies can be easily differentiated. We also demonstrate by analysis of human skin that SpiderMass can be used under in vivo conditions with minimal damage and pain. Furthermore SpiderMass can also be used for real-time drug metabolism and pharmacokinetic (DMPK) analysis or food safety topics. SpiderMass is thus the first MS based system designed for in vivo real-time analysis under minimally invasive conditions.

BioAerosol Mass Spectrometry: Reagentless Detection of Individual Airborne Spores and Other Bioagent Particles Based on Laser Desorption/Ionization Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steele, Paul Thomas

2004-09-01

Better devices are needed for the detection of aerosolized biological warfare agents. Advances in the ongoing development of one such device, the BioAerosol Mass Spectrometry (BAMS) system, are described here in detail. The system samples individual, micrometer-sized particles directly from the air and analyzes them in real-time without sample preparation or use of reagents. At the core of the BAMS system is a dual-polarity, single-particle mass spectrometer with a laser based desorption and ionization (DI) system. The mass spectra produced by early proof-of-concept instruments were highly variable and contained limited information to differentiate certain types of similar biological particles. Themore » investigation of this variability and subsequent changes to the DI laser system are described. The modifications have reduced the observed variability and thereby increased the usable information content in the spectra. These improvements would have little value without software to analyze and identify the mass spectra. Important improvements have been made to the algorithms that initially processed and analyzed the data. Single particles can be identified with an impressive level of accuracy, but to obtain significant reductions in the overall false alarm rate of the BAMS instrument, alarm decisions must be made dynamically on the basis of multiple analyzed particles. A statistical model has been developed to make these decisions and the resulting performance of a hypothetical BAMS system is quantitatively predicted. The predictions indicate that a BAMS system, with reasonably attainable characteristics, can operate with a very low false alarm rate (orders of magnitude lower than some currently fielded biodetectors) while still being sensitive to small concentrations of biological particles in a large range of environments. Proof-of-concept instruments, incorporating some of the modifications described here, have already performed well in independent testing.« less

An introduction to hybrid ion trap/time-of-flight mass spectrometry coupled with liquid chromatography applied to drug metabolism studies.

PubMed

Liu, Zhao-Ying

2012-12-01

Metabolism studies play an important role at various stages of drug discovery and development. Liquid chromatography combined with mass spectrometry (LC/MS) has become a most powerful and widely used analytical tool for identifying drug metabolites. The suitability of different types of mass spectrometers for metabolite profiling differs widely, and therefore, the data quality and reliability of the results also depend on which instrumentation is used. As one of the latest LC/MS instrumentation designs, hybrid ion trap/time-of-flight MS coupled with LC (LC-IT-TOF-MS) has successfully integrated ease of operation, compatibility with LC flow rates and data-dependent MS(n) with high mass accuracy and mass resolving power. The MS(n) and accurate mass capabilities are routinely utilized to rapidly confirm the identification of expected metabolites or to elucidate the structures of uncommon or unexpected metabolites. These features make the LC-IT-TOF-MS a very powerful analytical tool for metabolite identification. This paper begins with a brief introduction to some basic principles and main properties of a hybrid IT-TOF instrument. Then, a general workflow for metabolite profiling using LC-IT-TOF-MS, starting from sample collection and preparation to final identification of the metabolite structures, is discussed in detail. The data extraction and mining techniques to find and confirm metabolites are discussed and illustrated with some examples. This paper is directed to readers with no prior experience with LC-IT-TOF-MS and will provide a broad understanding of the development and utility of this instrument for drug metabolism studies. Copyright © 2012 John Wiley & Sons, Ltd.

Effects of drift gas on collision cross sections of a protein standard in linear drift tube and traveling wave ion mobility mass spectrometry.

PubMed

Jurneczko, Ewa; Kalapothakis, Jason; Campuzano, Iain D G; Morris, Michael; Barran, Perdita E

2012-10-16

There has been a significant increase in the use of ion mobility mass spectrometry (IM-MS) to investigate conformations of proteins and protein complexes following electrospray ionization. Investigations which employ traveling wave ion mobility mass spectrometry (TW IM-MS) instrumentation rely on the use of calibrants to convert the arrival times of ions to collision cross sections (CCS) providing "hard numbers" of use to structural biology. It is common to use nitrogen as the buffer gas in TW IM-MS instruments and to calibrate by extrapolating from CCS measured in helium via drift tube (DT) IM-MS. In this work, both DT and TW IM-MS instruments are used to investigate the effects of different drift gases (helium, neon, nitrogen, and argon) on the transport of multiply charged ions of the protein myoglobin, frequently used as a standard in TW IM-MS studies. Irrespective of the drift gas used, recorded mass spectra are found to be highly similar. In contrast, the recorded arrival time distributions and the derived CCS differ greatly. At low charge states (7 ≤ z ≤ 11) where the protein is compact, the CCS scale with the polarizability of the gas; this is also the case for higher charge states (12 ≤ z ≤ 22) where the protein is more unfolded for the heavy gases (neon, argon, and nitrogen) but not the case for helium. This is here interpreted as a different conformational landscape being sampled by the lighter gas and potentially attributable to increased field heating by helium. Under nanoelectrospray ionization (nESI) conditions, where myoglobin is sprayed from an aqueous solution buffered to pH 6.8 with 20 mM ammonium acetate, in the DT IM-MS instrument, each buffer gas can yield a different arrival time distribution (ATD) for any given charge state.

Investigations of chemical warfare agents and toxic industrial compounds with proton-transfer-reaction mass spectrometry for a real-time threat monitoring scenario.

PubMed

Kassebacher, Thomas; Sulzer, Philipp; Jürschik, Simone; Hartungen, Eugen; Jordan, Alfons; Edtbauer, Achim; Feil, Stefan; Hanel, Gernot; Jaksch, Stefan; Märk, Lukas; Mayhew, Chris A; Märk, Tilmann D

2013-01-30

Security and protection against terrorist attacks are major issues in modern society. One especially challenging task is the monitoring and protection of air conditioning and heating systems of buildings against terrorist attacks with toxic chemicals. As existing technologies have low selectivity, long response times or insufficient sensitivity, there is a need for a novel approach such as we present here. We have analyzed various chemical warfare agents (CWAs) and/or toxic industrial compounds (TICs) and related compounds, namely phosgene, diphosgene, chloroacetone, chloroacetophenone, diisopropylaminoethanol, and triethyl phosphate, utilizing a high-resolution proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOFMS) instrument with the objective of finding key product ions and their intensities, which will allow a low-resolution quadrupole mass spectrometry based PTR-MS system to be used with high confidence in the assignment of threat agents in the atmosphere. We obtained high accuracy PTR-TOFMS mass spectra of the six compounds under study at two different values for the reduced electric field in the drift tube (E/N). From these data we have compiled a table containing product ions, and isotopic and E/N ratios for highly selective threat compound detection with a compact and cost-effective quadrupole-based PTR-MS instrument. Furthermore, using chloroacetophenone (tear gas), we demonstrated that this instrument's response is highly linear in the concentration range of typical Acute Exposure Guideline Levels (AEGLs). On the basis of the presented results it is possible to develop a compact and cost-effective PTR-QMS instrument that monitors air supply systems and triggers an alarm as soon as the presence of a threat agent is detected. We hope that this real-time surveillance device will help to seriously improve safety and security in environments vulnerable to terrorist attacks with toxic chemicals. Copyright © 2012 John Wiley & Sons, Ltd.

Time-Resolved Molecular Characterization of Limonene/Ozone Aerosol using High-Resolution Electrospray Ionization Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bateman, Adam P.; Nizkorodov, Serguei; Laskin, Julia

2009-09-09

Molecular composition of limonene/O3 secondary organic aerosol (SOA) was investigated using high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) as a function of reaction time. SOA was generated by ozonation of D-limonene in a reaction chamber and sampled at different time intervals using a cascade impactor. The SOA samples were extracted into acetonitrile and analyzed using a HR-ESI-MS instrument with a resolving power of 100,000 (m/Δm). The resulting mass spectra provided detailed information about the extent of oxidation inferred from the O:C ratios, double bond equivalency (DBE) factors, and aromaticity indexes (AI) in hundreds of identified individual SOA species.

Detection of Radiation-Exposure Biomarkers by Differential Mobility Prefiltered Mass Spectrometry (DMS-MS)

PubMed Central

Coy, Stephen L.; Krylov, Evgeny V.; Schneider, Bradley B.; Covey, Thomas R.; Brenner, David J.; Tyburski, John B.; Patterson, Andrew D.; Krausz, Kris W.; Fornace, Albert J.; Nazarov, Erkinjon G.

2010-01-01

Technology to enable rapid screening for radiation exposure has been identified as an important need, and, as a part of a NIH / NIAD effort in this direction, metabolomic biomarkers for radiation exposure have been identified in a recent series of papers. To reduce the time necessary to detect and measure these biomarkers, differential mobility spectrometry – mass spectrometry (DMS-MS) systems have been developed and tested. Differential mobility ion filters preselect specific ions and also suppress chemical noise created in typical atmospheric-pressure ionization sources (ESI, MALDI, and others). Differential-mobility-based ion selection is based on the field dependence of ion mobility, which, in turn, depends on ion characteristics that include conformation, charge distribution, molecular polarizability, and other properties, and on the transport gas composition which can be modified to enhance resolution. DMS-MS is able to resolve small-molecule biomarkers from nearly-isobaric interferences, and suppresses chemical noise generated in the ion source and in the mass spectrometer, improving selectivity and quantitative accuracy. Our planar DMS design is rapid, operating in a few milliseconds, and analyzes ions before fragmentation. Depending on MS inlet conditions, DMS-selected ions can be dissociated in the MS inlet expansion, before mass analysis, providing a capability similar to MS/MS with simpler instrumentation. This report presents selected DMS-MS experimental results, including resolution of complex test mixtures of isobaric compounds, separation of charge states, separation of isobaric biomarkers (citrate and isocitrate), and separation of nearly-isobaric biomarker anions in direct analysis of a bio-fluid sample from the radiation-treated group of a mouse-model study. These uses of DMS combined with moderate resolution MS instrumentation indicate the feasibility of field-deployable instrumentation for biomarker evaluation. PMID:20305793

Analysis of non-steroidal anti-inflammatory drugs in milk using QuEChERS and liquid chromatography coupled to mass spectrometry: triple quadrupole versus Q-Orbitrap mass analyzers.

PubMed

Rúbies, Antoni; Guo, Lili; Centrich, Francesc; Granados, Mercè

2016-08-01

We developed a Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method for the high throughput determination of 10 non-steroidal anti-inflammatory drugs (NSAIDs) in milk samples using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) with a triple quadrupole (QqQ) instrument and an electrospray ionization (ESI) source. The new extraction procedure is highly efficient, and we obtained absolute recoveries in the range 78.1-97.1 % for the extraction and clean-up steps. Chromatographic separation is performed in the gradient mode with a biphenyl column and acidic mobile phases consisting of water and acetonitrile containing formic acid. The chromatographic run time was about 12 min, and NSAID peaks showed a good symmetry factor. For MS/MS detection, we used multiple reaction monitoring (MRM) mode, using ESI in both positive and negative modes. Our method has been validated in compliance with the European Commission Decision 657/2002/EC, and we obtained very satisfactory results in inter-laboratory testing. Furthermore, we explored the use of a hybrid high resolution mass spectrometer, combining a quadrupole and an Orbitrap mass analyzer, for high resolution (HR) MS/MS detection of NSAIDs. We achieved lower NSAID quantification limits with Q-Orbitrap high resolution mass spectrometry (HRMS/MS) detection than those achieved with the QqQ instrument; however, its main feature is its very high selectivity, which makes HRMS/MS particularly suitable for confirmatory analysis.

An automated gas chromatography time-of-flight mass spectrometry instrument for the quantitative analysis of halocarbons in air

NASA Astrophysics Data System (ADS)

Obersteiner, F.; Bönisch, H.; Engel, A.

2016-01-01

We present the characterization and application of a new gas chromatography time-of-flight mass spectrometry instrument (GC-TOFMS) for the quantitative analysis of halocarbons in air samples. The setup comprises three fundamental enhancements compared to our earlier work (Hoker et al., 2015): (1) full automation, (2) a mass resolving power R = m/Δm of the TOFMS (Tofwerk AG, Switzerland) increased up to 4000 and (3) a fully accessible data format of the mass spectrometric data. Automation in combination with the accessible data allowed an in-depth characterization of the instrument. Mass accuracy was found to be approximately 5 ppm in mean after automatic recalibration of the mass axis in each measurement. A TOFMS configuration giving R = 3500 was chosen to provide an R-to-sensitivity ratio suitable for our purpose. Calculated detection limits are as low as a few femtograms by means of the accurate mass information. The precision for substance quantification was 0.15 % at the best for an individual measurement and in general mainly determined by the signal-to-noise ratio of the chromatographic peak. Detector non-linearity was found to be insignificant up to a mixing ratio of roughly 150 ppt at 0.5 L sampled volume. At higher concentrations, non-linearities of a few percent were observed (precision level: 0.2 %) but could be attributed to a potential source within the detection system. A straightforward correction for those non-linearities was applied in data processing, again by exploiting the accurate mass information. Based on the overall characterization results, the GC-TOFMS instrument was found to be very well suited for the task of quantitative halocarbon trace gas observation and a big step forward compared to scanning, quadrupole MS with low mass resolving power and a TOFMS technique reported to be non-linear and restricted by a small dynamical range.

Mass Spectrometry Imaging Can Distinguish on a Proteomic Level Between Proliferative Nodules Within a Benign Congenital Nevus and Malignant Melanoma.

PubMed

Lazova, Rossitza; Yang, Zhe; El Habr, Constantin; Lim, Young; Choate, Keith Adam; Seeley, Erin H; Caprioli, Richard M; Yangqun, Li

2017-09-01

Histopathological interpretation of proliferative nodules occurring in association with congenital melanocytic nevi can be very challenging due to their similarities with congenital malignant melanoma and malignant melanoma arising in association with congenital nevi. We hereby report a diagnostically challenging case of congenital melanocytic nevus with proliferative nodules and ulcerations, which was originally misdiagnosed as congenital malignant melanoma. Subsequent histopathological examination in consultation by one of the authors (R.L.) and mass spectrometry imaging analysis rendered a diagnosis of congenital melanocytic nevus with proliferative nodules. In this case, mass spectrometry imaging, a novel method capable of distinguishing benign from malignant melanocytic lesions on a proteomic level, was instrumental in making the diagnosis of a benign nevus. We emphasize the importance of this method as an ancillary tool in the diagnosis of difficult melanocytic lesions.

Mass Spectrometry on Future Mars Landers

NASA Technical Reports Server (NTRS)

Brinckerhoff, W. B.; Mahaffy, P. R.

2011-01-01

Mass spectrometry investigations on the 2011 Mars Science Laboratory (MSL) and the 2018 ExoMars missions will address core science objectives related to the potential habitability of their landing site environments and more generally the near-surface organic inventory of Mars. The analysis of complex solid samples by mass spectrometry is a well-known approach that can provide a broad and sensitive survey of organic and inorganic compounds as well as supportive data for mineralogical analysis. The science value of such compositional information is maximized when one appreciates the particular opportunities and limitations of in situ analysis with resource-constrained instrumentation in the context of a complete science payload and applied to materials found in a particular environment. The Sample Analysis at Mars (SAM) investigation on MSL and the Mars Organic Molecule Analyzer (MOMA) investigation on ExoMars will thus benefit from and inform broad-based analog field site work linked to the Mars environments where such analysis will occur.

Investigating quantitation of phosphorylation using MALDI-TOF mass spectrometry.

PubMed

Parker, Laurie; Engel-Hall, Aaron; Drew, Kevin; Steinhardt, George; Helseth, Donald L; Jabon, David; McMurry, Timothy; Angulo, David S; Kron, Stephen J

2008-04-01

Despite advances in methods and instrumentation for analysis of phosphopeptides using mass spectrometry, it is still difficult to quantify the extent of phosphorylation of a substrate because of physiochemical differences between unphosphorylated and phosphorylated peptides. Here we report experiments to investigate those differences using MALDI-TOF mass spectrometry for a set of synthetic peptides by creating calibration curves of known input ratios of peptides/phosphopeptides and analyzing their resulting signal intensity ratios. These calibration curves reveal subtleties in sequence-dependent differences for relative desorption/ionization efficiencies that cannot be seen from single-point calibrations. We found that the behaviors were reproducible with a variability of 5-10% for observed phosphopeptide signal. Although these data allow us to begin addressing the issues related to modeling these properties and predicting relative signal strengths for other peptide sequences, it is clear that this behavior is highly complex and needs to be further explored. John Wiley & Sons, Ltd

Investigating quantitation of phosphorylation using MALDI-TOF mass spectrometry

PubMed Central

Parker, Laurie; Engel-Hall, Aaron; Drew, Kevin; Steinhardt, George; Helseth, Donald L.; Jabon, David; McMurry, Timothy; Angulo, David S.; Kron, Stephen J.

2010-01-01

Despite advances in methods and instrumentation for analysis of phosphopeptides using mass spectrometry, it is still difficult to quantify the extent of phosphorylation of a substrate due to physiochemical differences between unphosphorylated and phosphorylated peptides. Here we report experiments to investigate those differences using MALDI-TOF mass spectrometry for a set of synthetic peptides by creating calibration curves of known input ratios of peptides/phosphopeptides and analyzing their resulting signal intensity ratios. These calibration curves reveal subtleties in sequence-dependent differences for relative desorption/ionization efficiencies that cannot be seen from single-point calibrations. We found that the behaviors were reproducible with a variability of 5–10% for observed phosphopeptide signal. Although these data allow us to begin addressing the issues related to modeling these properties and predicting relative signal strengths for other peptide sequences, it is clear this behavior is highly complex and needs to be further explored. PMID:18064576

Technical aspects of neonatal screening using tandem mass spectrometry. Report from the 4th meeting of the International Society for Neonatal Screening.

PubMed

Simonsen, H; Jensen, U G

1999-12-01

Quantitative analysis of amino acids (AA) and acylcarnitines using tandem mass spectrometry is an emerging technology used to screen neonatal dried blood spot samples for disorders in the metabolism of AA, organic acids and fatty acids. This paper provides a brief review of some of the technically oriented issues which emerged at the 4th meeting of the International Society for Neonatal Screening in Stockholm, 1999. The information covers sample preparation, instrumentation, data acquistion modes, internal standards, interpretation, confounding factors and practical screening experience.

Analysis of Rare Earth Elements in Geologic Samples using Inductively Coupled Plasma Mass Spectrometry; US DOE Topical Report - DOE/NETL-2016/1794

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bank, Tracy L.; Roth, Elliot A.; Tinker, Phillip

2016-04-17

Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is used to measure the concentrations of rare earth elements (REE) in certified standard reference materials including shale and coal. The instrument used in this study is a Perkin Elmer Nexion 300D ICP-MS. The goal of the study is to identify sample preparation and operating conditions that optimized recovery of each element of concern. Additionally, the precision and accuracy of the technique are summarized and the drawbacks and limitations of the method are outlined.

Estimation of the quantification uncertainty from flow injection and liquid chromatography transient signals in inductively coupled plasma mass spectrometry

NASA Astrophysics Data System (ADS)

Laborda, Francisco; Medrano, Jesús; Castillo, Juan R.

2004-06-01

The quality of the quantitative results obtained from transient signals in high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICPMS) and flow injection-inductively coupled plasma mass spectrometry (FI-ICPMS) was investigated under multielement conditions. Quantification methods were based on multiple-point calibration by simple and weighted linear regression, and double-point calibration (measurement of the baseline and one standard). An uncertainty model, which includes the main sources of uncertainty from FI-ICPMS and HPLC-ICPMS (signal measurement, sample flow rate and injection volume), was developed to estimate peak area uncertainties and statistical weights used in weighted linear regression. The behaviour of the ICPMS instrument was characterized in order to be considered in the model, concluding that the instrument works as a concentration detector when it is used to monitorize transient signals from flow injection or chromatographic separations. Proper quantification by the three calibration methods was achieved when compared to reference materials, although the double-point calibration allowed to obtain results of the same quality as the multiple-point calibration, shortening the calibration time. Relative expanded uncertainties ranged from 10-20% for concentrations around the LOQ to 5% for concentrations higher than 100 times the LOQ.

POTAMOS mass spectrometry calculator: computer aided mass spectrometry to the post-translational modifications of proteins. A focus on histones.

PubMed

Vlachopanos, A; Soupsana, E; Politou, A S; Papamokos, G V

2014-12-01

Mass spectrometry is a widely used technique for protein identification and it has also become the method of choice in order to detect and characterize the post-translational modifications (PTMs) of proteins. Many software tools have been developed to deal with this complication. In this paper we introduce a new, free and user friendly online software tool, named POTAMOS Mass Spectrometry Calculator, which was developed in the open source application framework Ruby on Rails. It can provide calculated mass spectrometry data in a time saving manner, independently of instrumentation. In this web application we have focused on a well known protein family of histones whose PTMs are believed to play a crucial role in gene regulation, as suggested by the so called "histone code" hypothesis. The PTMs implemented in this software are: methylations of arginines and lysines, acetylations of lysines and phosphorylations of serines and threonines. The application is able to calculate the kind, the number and the combinations of the possible PTMs corresponding to a given peptide sequence and a given mass along with the full set of the unique primary structures produced by the possible distributions along the amino acid sequence. It can also calculate the masses and charges of a fragmented histone variant, which carries predefined modifications already implemented. Additional functionality is provided by the calculation of the masses of fragments produced upon protein cleavage by the proteolytic enzymes that are most widely used in proteomics studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

Advanced capabilities for in situ planetary mass spectrometry

NASA Astrophysics Data System (ADS)

Arevalo, R. D., Jr.; Mahaffy, P. R.; Brinckerhoff, W. B.; Getty, S.; Benna, M.; van Amerom, F. H. W.; Danell, R.; Pinnick, V. T.; Li, X.; Grubisic, A.; Cornish, T.; Hovmand, L.

2015-12-01

NASA GSFC has delivered highly capable quadrupole mass spectrometers (QMS) for missions to Venus (Pioneer Venus), Jupiter (Galileo), Saturn/Titan (Cassini-Huygens), Mars (MSL and MAVEN), and the Moon (LADEE). Our understanding of the Solar System has been expanded significantly by these exceedingly versatile yet low risk and cost efficient instruments. GSFC has developed more recently a suite of advanced instrument technologies promising enhanced science return while selectively leveraging heritage designs. Relying on a traditional precision QMS, the Analysis of Gas Evolved from Samples (AGES) instrument measures organic inventory, determines exposure age and establishes the absolute timing of deposition/petrogenesis of interrogated samples. The Mars Organic Molecule Analyzer (MOMA) aboard the ExoMars 2018 rover employs a two-dimensional ion trap, built analogously to heritage QMS rod assemblies, which can support dual ionization sources, selective ion enrichment and tandem mass spectrometry (MS/MS). The same miniaturized analyzer serves as the core of the Linear Ion Trap Mass Spectrometer (LITMS) instrument, which offers negative ion detection (switchable polarity) and an extended mass range (>2000 Da). Time-of-flight mass spectrometers (TOF-MS) have been interfaced to a range of laser sources to progress high-sensitivity laser ablation and desorption methods for analysis of inorganic and non-volatile organic compounds, respectively. The L2MS (two-step laser mass spectrometer) enables the desorption of neutrals and/or prompt ionization at IR (1.0 up to 3.1 µm, with an option for tunability) or UV wavelengths (commonly 266 or 355 nm). For the selective ionization of specific classes of organics, such as aromatic hydrocarbons, a second UV laser may be employed to decouple the desorption and ionization steps and limit molecular fragmentation. Mass analyzers with substantially higher resolving powers (up to m/Δm > 100,000), such as the Advanced Resolution Organic Molecule Analyzer (AROMA) and multipass QMS instruments now under development, offer the potential to disambiguate key chemical signatures in complex mass spectra. Other innovative technologies being pursued include: ion inlet systems; tunable lasers; high-temp pyrolysis ovens; and, sample capture/enrichment techniques.

Determination of the aflatoxin AFB1 from corn by direct analysis in real time-mass spectrometry (DART-MS)

USDA-ARS?s Scientific Manuscript database

Direct analysis in real time (DART) ionization coupled to a high resolution mass spectrometer (MS) was used for screening of aflatoxins from a variety of surfaces and the rapid quantitative analysis of a common form of aflatoxin, AFB1, extracted from corn. Sample preparation procedure and instrument...

Mass spectrometry methods for the analysis of biodegradable hybrid materials

NASA Astrophysics Data System (ADS)

Alalwiat, Ahlam

This dissertation focuses on the characterization of hybrid materials and surfactant blends by using mass spectrometry (MS), tandem mass spectrometry (MS/MS), liquid chromatography (LC), and ion mobility (IM) spectrometry combined with measurement and simulation of molecular collision cross sections. Chapter II describes the principles and the history of mass spectrometry (MS) and liquid chromatography (LC). Chapter III introduces the materials and instrumentation used to complete this dissertation. In chapter IV, two hybrid materials containing poly(t-butyl acrylate) (PtBA) or poly(acrylic acid) (PAA) blocks attached to a hydrophobic peptide rich in valine and glycine (VG2), as well as the poly(acrylic acid) (PAA) and VG2 peptide precursor materials, are characterized by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), electrospray ionization mass spectrometry (ESI-MS) and ion mobility mass spectrometry (IM-MS). Collision cross-sections and molecular modeling have been used to determine the final architecture of both hybrid materials. Chapter V investigates a different hybrid material, [BMP-2(HA)2 ], comprised of a dendron with two polyethylene glycol (PEG) branches terminated by a hydroxyapatite binding peptide (HA), and a focal point substituted with a bone morphogenic protein mimicking peptide (BMP-2). MALDI-MS, ESI-MS and IM-MS have been used to characterize the HA and BMP-2 peptides. Collisionally activated dissociation (CAD) and electron transfer dissociation (ETD) have been employed in double stage (i.e. tandem) mass spectrometry (MS/MS) experiments to confirm the sequences of the two peptides HA and BMP-2. The MALDI-MS, ESI-MS and IM-MS methods were also applied to characterize the [BMP-2(HA)2] hybrid material. Collision cross-section measurements and molecular modeling indicated that [BMP-2(HA)2] can attain folded or extended conformation, depending on its degree of protonation (charge state). Chapter VI focuses on the analysis of alkyl polyglycoside (APG) surfactants by MALDI-MS and ESI-MS, MS/MS, and by combining MS and with ion mobility (IM) and/or ultra-performance liquid chromatography (UPLC) separation in LC-IM and LC-IM-MS experiments. Chapter VII summaries this dissertation's findings.

Characterization of a Hybrid Optical Microscopy/Laser Ablation Liquid Vortex Capture/Electrospray Ionization System for Mass Spectrometry Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cahill, John F.; Kertesz, Vilmos; Van Berkel, Gary J.

Herein, a commercial optical microscope, laser microdissection instrument was coupled with an electrospray ionization mass spectrometer via a low profile liquid vortex capture probe to yield a hybrid optical microscopy/mass spectrometry imaging system. The instrument has bright-field and fluorescence microscopy capabilities in addition to a highly focused UV laser beam that is utilized for laser ablation of samples. With this system, material laser ablated from a sample using the microscope was caught by a liquid vortex capture probe and transported in solution for analysis by electrospray ionization mass spectrometry. Both lane scanning and spot sampling mass spectral imaging modes weremore » used. The smallest area the system was able to ablate was ~0.544 μm × ~0.544 μm, achieved by oversampling of the smallest laser ablation spot size that could be obtained (~1.9 μm). With use of a model photoresist surface, known features as small as ~1.5 μm were resolved. The capabilities of the system with real world samples were demonstrated first with a blended polymer thin film containing poly(2-vinylpyridine) and poly(N-vinylcarbazole). Using spot sampling imaging, sub-micrometer sized features (0.62, 0.86, and 0.98 μm) visible by optical microscopy were clearly distinguished in the mass spectral images. A second real world example showed the imaging of trace amounts of cocaine in mouse brain thin tissue sections. Lastly, with use of a lane scanning mode with ~6 μm × ~6 μm data pixels, features in the tissue as small as 15 μm in size could be distinguished in both the mass spectral and optical images.« less

Characterization of a Hybrid Optical Microscopy/Laser Ablation Liquid Vortex Capture/Electrospray Ionization System for Mass Spectrometry Imaging

DOE PAGES

Cahill, John F.; Kertesz, Vilmos; Van Berkel, Gary J.

2015-10-22

Herein, a commercial optical microscope, laser microdissection instrument was coupled with an electrospray ionization mass spectrometer via a low profile liquid vortex capture probe to yield a hybrid optical microscopy/mass spectrometry imaging system. The instrument has bright-field and fluorescence microscopy capabilities in addition to a highly focused UV laser beam that is utilized for laser ablation of samples. With this system, material laser ablated from a sample using the microscope was caught by a liquid vortex capture probe and transported in solution for analysis by electrospray ionization mass spectrometry. Both lane scanning and spot sampling mass spectral imaging modes weremore » used. The smallest area the system was able to ablate was ~0.544 μm × ~0.544 μm, achieved by oversampling of the smallest laser ablation spot size that could be obtained (~1.9 μm). With use of a model photoresist surface, known features as small as ~1.5 μm were resolved. The capabilities of the system with real world samples were demonstrated first with a blended polymer thin film containing poly(2-vinylpyridine) and poly(N-vinylcarbazole). Using spot sampling imaging, sub-micrometer sized features (0.62, 0.86, and 0.98 μm) visible by optical microscopy were clearly distinguished in the mass spectral images. A second real world example showed the imaging of trace amounts of cocaine in mouse brain thin tissue sections. Lastly, with use of a lane scanning mode with ~6 μm × ~6 μm data pixels, features in the tissue as small as 15 μm in size could be distinguished in both the mass spectral and optical images.« less

Gas-phase ion chemistry and organic chemistry-the story of a hybrid six sector mass spectrometer--the "AutoSpec 6F".

PubMed

Gerbaux, Pascal; Lamote, Luc; Van Haverbeke, Yves; Flammang, Robert; Brown, Jeffrey M

2012-01-01

The AutoSpec 6F mass spectrometer is a large, floor standing instrument comprising a pair of commercial EBE geometry (AutoSpec) mass spectrometers coupled in series to provide an hybrid EBE-EBE configuration, (E and B being respectively electrostatic and magnetic sectors.) It was designed in close collaboration between Professor R. Flammang and VG Analytical in Manchester, UK. It was equipped with five collision cells and allowed the recording of high energy CID (collision induced dissociation), MIKES (mass analyzed ion kinetic energy spectrometry) and NRMS (neutralization re-ionization mass spectrometry) data as well as consecutive MSn analyses. The field-free regions between sectors allowed the study of unimolecular decomposition products from long-lived metastable ions. The mass spectrometer became even more versatile when an RF-only quadrupole collision cell was installed between the second and the third electric sector. This allowed the study of associative ion/molecule reactions in the low kinetic energy regime. Bimolecular chemical reactions were performed inside the quadrupole cell when a neutral reagent was introduced and the reaction products were analyzed by high energy CID in the downstream sectors. This paper tells the history and summarizes the capabilities of this versatile instrument.

Diagnostics aid for mass spectrometer trouble-shooting

NASA Astrophysics Data System (ADS)

Filby, E. E.; Rankin, R. A.; Webb, G. W.

The MS Expert system provides problem diagnostics for instruments used in the Mass Spectrometry Laboratory (MSL). The most critical results generated on these mass spectrometers are the uranium concentration and isotopic content data used for process control and materials accountability at the Idaho Chemical Processing Plant. The two purposes of the system are: (1) to minimize instrument downtime and thereby provide the best possible support to the Plant, and (2) to improve long-term data quality. This system combines the knowledge of several experts on mass spectrometry to provide a diagnostic tool, and can make these skills available on a more timely basis. It integrates code written in the Pascal language with a knowledge base entered into a commercial expert system shell. The user performs some preliminary status checks, and then selects from among several broad diagnostic categories. These initial steps provide input to the rule base. The overall analysis provides the user with a set of possible solutions to the observed problems, graded as to their probabilities. Besides the trouble-shooting benefits expected from this system, it will also provide structures diagnostic training for lab personnel. In addition, development of the system knowledge base has already produced a better understanding of instrument behavior. Two key findings are that a good user interface is necessary for full acceptance of the tool, and a development system should include standard programming capabilities as well as the expert system shell.

The Laser Ablation Ion Funnel: Sampling for in situ Mass Spectrometry on Mars

NASA Technical Reports Server (NTRS)

Johnson, Paul V.; Hodyss, Robert; Tang, Keqi; Brinckerhoff, William B.; Smith, Richard D.

2011-01-01

A considerable investment has been made by NASA and other space agencies to develop instrumentation suitable for in situ analytical investigation of extra terrestrial bodies including various mass spectrometers (time-of-flight, quadrupole ion trap, quadrupole mass filters, etc.). However, the front-end sample handling that is needed to collect and prepare samples for interrogation by such instrumentation remains underdeveloped. Here we describe a novel approach tailored to the exploration of Mars where ions are created in the ambient atmosphere via laser ablation and then efficiently transported into a mass spectrometer for in situ analysis using an electrodynamic ion funnel. This concept would enable elemental and isotopic analysis of geological samples with the analysis of desorbed organic material a possibility as well. Such an instrument would be suitable for inclusion on all potential missions currently being considered such as the Mid-Range Rover, the Astrobiology Field Laboratory, and Mars Sample Return (i.e., as a sample pre-selection triage instrument), among others.

Comparison of mineral dust and droplet residuals measured with two single particle aerosol mass spectrometers

NASA Astrophysics Data System (ADS)

Wonaschütz, Anna; Ludwig, Wolfgang; Zawadowicz, Maria; Hiranuma, Naruki; Hitzenberger, Regina; Cziczo, Daniel; DeMott, Paul; Möhler, Ottmar

2017-04-01

Single Particle mass spectrometers are used to gain information on the chemical composition of individual aerosol particles, aerosol mixing state, and other valuable aerosol characteristics. During the Mass Spectrometry Intercomparison at the Fifth Ice Nucleation (FIN-01) Workshop, the new LAAPTOF single particle aerosol mass spectrometer (AeroMegt GmbH) was conducting simultaneous measurements together with the PALMS (Particle Analysis by Laser Mass Spectrometry) instrument. The aerosol particles were sampled from the AIDA chamber during ice cloud expansion experiments. Samples of mineral dust and ice droplet residuals were measured simultaneously. In this work, three expansion experiments are chosen for a comparison between the two mass spectrometers. A fuzzy clustering routine is used to group the spectra. Cluster centers describing the ensemble of particles are compared. First results show that while differences in the peak heights are likely due to the use of an amplifier in PALMS, cluster centers are comparable.

An improved pseudotargeted metabolomics approach using multiple ion monitoring with time-staggered ion lists based on ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry.

PubMed

Wang, Yang; Liu, Fang; Li, Peng; He, Chengwei; Wang, Ruibing; Su, Huanxing; Wan, Jian-Bo

2016-07-13

Pseudotargeted metabolomics is a novel strategy integrating the advantages of both untargeted and targeted methods. The conventional pseudotargeted metabolomics required two MS instruments, i.e., ultra-high performance liquid chromatography/quadrupole-time- of-flight mass spectrometry (UHPLC/Q-TOF MS) and UHPLC/triple quadrupole mass spectrometry (UHPLC/QQQ-MS), which makes method transformation inevitable. Furthermore, the picking of ion pairs from thousands of candidates and the swapping of the data between two instruments are the most labor-intensive steps, which greatly limit its application in metabolomic analysis. In the present study, we proposed an improved pseudotargeted metabolomics method that could be achieved on an UHPLC/Q-TOF/MS instrument operated in the multiple ion monitoring (MIM) mode with time-staggered ion lists (tsMIM). Full scan-based untargeted analysis was applied to extract the target ions. After peak alignment and ion fusion, a stepwise ion picking procedure was used to generate the ion lists for subsequent single MIM and tsMIM. The UHPLC/Q-TOF tsMIM MS-based pseudotargeted approach exhibited better repeatability and a wider linear range than the UHPLC/Q-TOF MS-based untargeted metabolomics method. Compared to the single MIM mode, the tsMIM significantly increased the coverage of the metabolites detected. The newly developed method was successfully applied to discover plasma biomarkers for alcohol-induced liver injury in mice, which indicated its practicability and great potential in future metabolomics studies. Copyright © 2016 Elsevier B.V. All rights reserved.

Determination of selected non-authorized insecticides in peppers by liquid chromatography time-of-flight mass spectrometry and tandem mass spectrometry.

PubMed

Mezcua, Milagros; Ferrer, Carmen; García-Reyes, Juan F; Martínez-Bueno, María Jesús; Albarracín, Micaela; Claret, María; Fernández-Alba, Amadeo R

2008-05-01

In this work, two analytical methods based on liquid chromatography coupled to electrospray time-of-flight mass spectrometry (LC/ESI-TOFMS) and tandem mass spectrometry (LC/ESI-MS/MS) are described for the identification, confirmation and quantitation of three insecticides non-authorized in the European Union (nitenpyram, isocarbophos and isofenphos-methyl) but detected in recent monitoring programmes in pepper samples. The proposed methodologies involved a sample extraction procedure using liquid-liquid partition with acetonitrile followed by a cleanup step based on dispersive solid-phase extraction. Recovery studies performed on peppers spiked at different fortification levels (10 and 50 microg kg(-1)) yielded average recoveries in the range 76-100% with relative standard deviation (RSD) (%) values below 10%. Identification, confirmation and quantitation were carried out by LC/TOFMS and LC/MS/MS using a hybrid triple quadrupole linear ion trap (QqLIT) instrument in multiple-reaction monitoring (MRM) mode. The obtained limits of quantitation (LOQs) were in the range 0.1-5 microg kg(-1), depending on each individual technique. Finally, the proposed methods were successfully applied to the analysis of suspected pepper samples. Copyright (c) 2008 John Wiley & Sons, Ltd.

Parallel Exploration of Interaction Space by BioID and Affinity Purification Coupled to Mass Spectrometry.

PubMed

Hesketh, Geoffrey G; Youn, Ji-Young; Samavarchi-Tehrani, Payman; Raught, Brian; Gingras, Anne-Claude

2017-01-01

Complete understanding of cellular function requires knowledge of the composition and dynamics of protein interaction networks, the importance of which spans all molecular cell biology fields. Mass spectrometry-based proteomics approaches are instrumental in this process, with affinity purification coupled to mass spectrometry (AP-MS) now widely used for defining interaction landscapes. Traditional AP-MS methods are well suited to providing information regarding the temporal aspects of soluble protein-protein interactions, but the requirement to maintain protein-protein interactions during cell lysis and AP means that both weak-affinity interactions and spatial information is lost. A more recently developed method called BioID employs the expression of bait proteins fused to a nonspecific biotin ligase, BirA*, that induces in vivo biotinylation of proximal proteins. Coupling this method to biotin affinity enrichment and mass spectrometry negates many of the solubility and interaction strength issues inherent in traditional AP-MS methods, and provides unparalleled spatial context for protein interactions. Here we describe the parallel implementation of both BioID and FLAG AP-MS allowing simultaneous exploration of both spatial and temporal aspects of protein interaction networks.

Quantification of steroid hormones in human serum by liquid chromatography-high resolution tandem mass spectrometry.

PubMed

Matysik, Silke; Liebisch, Gerhard

2017-12-01

A limited specificity is inherent to immunoassays for steroid hormone analysis. To improve selectivity mass spectrometric analysis of steroid hormones by liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been introduced in the clinical laboratory over the past years usually with low mass resolution triple-quadrupole instruments or more recently by high resolution mass spectrometry (HR-MS). Here we introduce liquid chromatography-high resolution tandem mass spectrometry (LC-MS/HR-MS) to further increase selectivity of steroid hormone quantification. Application of HR-MS demonstrates an enhanced selectivity compared to low mass resolution. Separation of isobaric interferences reduces background noise and avoids overestimation. Samples were prepared by automated liquid-liquid extraction with MTBE. The LC-MS/HR-MS method using a quadrupole-Orbitrap analyzer includes eight steroid hormones i.e. androstenedione, corticosterone, cortisol, cortisone, 11-deoxycortisol, 17-hydroxyprogesterone, progesterone, and testosterone. It has a run-time of 5.3min and was validated according to the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) guidelines. For most of the analytes coefficient of variation were 10% or lower and LOQs were determined significantly below 1ng/ml. Full product ion spectra including accurate masses substantiate compound identification by matching their masses and ratios with authentic standards. In summary, quantification of steroid hormones by LC-MS/HR-MS is applicable for clinical diagnostics and holds also promise for highly selective quantification of other small molecules. Copyright © 2017 Elsevier B.V. All rights reserved.

The Assessment of Selectivity in Different Quadrupole-Orbitrap Mass Spectrometry Acquisition Modes

NASA Astrophysics Data System (ADS)

Berendsen, Bjorn J. A.; Wegh, Robin S.; Meijer, Thijs; Nielen, Michel W. F.

2015-02-01

Selectivity of the confirmation of identity in liquid chromatography (tandem) mass spectrometry using Q-Orbitrap instrumentation was assessed using different acquisition modes based on a representative experimental data set constructed from 108 samples, including six different matrix extracts and containing over 100 analytes each. Single stage full scan, all ion fragmentation, and product ion scanning were applied. By generating reconstructed ion chromatograms using unit mass window in targeted MS2, selected reaction monitoring (SRM), regularly applied using triple-quadrupole instruments, was mimicked. This facilitated the comparison of single stage full scan, all ion fragmentation, (mimicked) SRM, and product ion scanning applying a mass window down to 1 ppm. Single factor Analysis of Variance was carried out on the variance (s2) of the mass error to determine which factors and interactions are significant parameters with respect to selectivity. We conclude that selectivity is related to the target compound (mainly the mass defect), the matrix, sample clean-up, concentration, and mass resolution. Selectivity of the different instrumental configurations was quantified by counting the number of interfering peaks observed in the chromatograms. We conclude that precursor ion selection significantly contributes to selectivity: monitoring of a single product ion at high mass accuracy with a 1 Da precursor ion window proved to be equally selective or better to monitoring two transition products in mimicked SRM. In contrast, monitoring a single fragment in all ion fragmentation mode results in significantly lower selectivity versus mimicked SRM. After a thorough inter-laboratory evaluation study, the results of this study can be used for a critical reassessment of the current identification points system and contribute to the next generation of evidence-based and robust performance criteria in residue analysis and sports doping.

Advances in 193 nm excimer lasers for mass spectrometry applications

NASA Astrophysics Data System (ADS)

Delmdahl, Ralph; Esser, Hans-Gerd; Bonati, Guido

2016-03-01

Ongoing progress in mass analysis applications such as laser ablation inductively coupled mass spectrometry of solid samples and ultraviolet photoionization mediated sequencing of peptides and proteins is to a large extent driven by ultrashort wavelength excimer lasers at 193 nm. This paper will introduce the latest improvements achieved in the development of compact high repetition rate excimer lasers and elaborate on the impact on mass spectrometry instrumentation. Various performance and lifetime measurements obtained in a long-term endurance test over the course of 18 months will be shown and discussed in view of the laser source requirements of different mass spectrometry tasks. These sampling type applications are served by excimer lasers delivering pulsed 193 nm output of several mJ as well as fast repetition rates which are already approaching one Kilohertz. In order to open up the pathway from the laboratory to broader market industrial use, sufficient component lifetimes and long-term stable performance behavior have to be ensured. The obtained long-term results which will be presented are based on diverse 193 nm excimer laser tube improvements aiming at e.g. optimizing the gas flow dynamics and have extended the operational life the laser tube for the first time over several billion pulses even under high duty-cycle conditions.

Molecular Analyzer for Complex Refractory Organic-Rich Surfaces (MACROS)

NASA Technical Reports Server (NTRS)

Getty, Stephanie A.; Cook, Jamie E.; Balvin, Manuel; Brinckerhoff, William B.; Li, Xiang; Grubisic, Andrej; Cornish, Timothy; Ferrance, Jerome; Southard, Adrian

2017-01-01

The Molecular Analyzer for Complex Refractory Organic-rich Surfaces, MACROS, is a novel instrument package being developed at NASA Goddard Space Flight Center. MACROS enables the in situ characterization of a sample's composition by coupling two powerful techniques into one compact instrument package: (1) laser desorption/ionization time-of-flight mass spectrometry (LDMS) for broad detection of inorganic mineral composition and non-volatile organics, and (2) liquid-phase extraction methods to gently isolate the soluble organic and inorganic fraction of a planetary powder for enrichment and detailed analysis by liquid chromatographic separation coupled to LDMS. The LDMS is capable of positive and negative ion detection, precision mass selection, and fragment analysis. Two modes are included for LDMS: single laser LDMS as the broad survey mode and two step laser mass spectrometry (L2MS). The liquid-phase extraction will be done in a newly designed extraction module (EM) prototype, providing selectivity in the analysis of a complex sample. For the sample collection, a diamond drill front end will be used to collect rock/icy powder. With all these components and capabilities together, MACROS offers a versatile analytical instrument for a mission targeting an icy moon, carbonaceous asteroid, or comet, to fully characterize the surface composition and advance our understanding of the chemical inventory present on that body.

Recent developments in qualitative and quantitative analysis of phytochemical constituents and their metabolites using liquid chromatography-mass spectrometry.

PubMed

Wu, Haifeng; Guo, Jian; Chen, Shilin; Liu, Xin; Zhou, Yan; Zhang, Xiaopo; Xu, Xudong

2013-01-01

Over the past few years, the applications of liquid chromatography coupled with mass spectrometry (LC-MS) in natural product analysis have been dramatically growing because of the increasingly improved separation and detection capabilities of LC-MS instruments. In particular, novel high-resolution hybrid instruments linked to ultra-high-performance LC and the hyphenations of LC-MS with other separation or analytical techniques greatly aid unequivocal identification and highly sensitive quantification of natural products at trace concentrations in complex matrices. With the aim of providing an up-to-date overview of LC-MS applications on the analysis of plant-derived compounds, papers published within the latest years (2007-2012) involving qualitative and quantitative analysis of phytochemical constituents and their metabolites are summarized in the present review. After briefly describing the general characteristics of natural products analysis, the most remarkable features of LC-MS and sample preparation techniques, the present paper mainly focuses on screening and characterization of phenols (including flavonoids), alkaloids, terpenoids, steroids, coumarins, lignans, and miscellaneous compounds in respective herbs and biological samples, as well as traditional Chinese medicine (TCM) prescriptions using tandem mass spectrometer. Chemical fingerprinting analysis using LC-MS is also described. Meanwhile, instrumental peculiarities and methodological details are accentuated. Copyright © 2012 Elsevier B.V. All rights reserved.

Mass spectrometry. [in organic ion and biorganic chemistry and medicine

NASA Technical Reports Server (NTRS)

Burlingame, A. L.; Cox, R. E.; Derrick, P. J.

1974-01-01

Review of the present status of mass spectrometry in the light of pertinent recent publications spanning the period from December 1971 to January 1974. Following an initial survey of techniques, instruments, and computer applications, a sharp distinction is made between the chemistry of organic (radical-)ions and analytical applications in biorganic chemistry and medicine. The emphasis is on the chemistry of organic (radical-)ions at the expense of inorganic, organometallic, and surface ion chemistry. Biochemistry and medicine are chosen because of their contemporary importance and because of the stupendous contributions of mass spectroscopy to these fields in the past two years. In the review of gas-phase organic ion chemistry, special attention is given to studies making significant contributions to the understanding of ion chemistry.

Gas-phase structural characterization of neuropeptides Y Y1 receptor antagonists using mass spectrometry: Orbitrap vs triple quadrupole.

PubMed

Silva, Eduarda M P; Varandas, Pedro A M M; Melo, Tânia; Barros, Cristina; Alencastre, Inês S; Barreiros, Luísa; Domingues, Pedro; Lamghari, Meriem; Domingues, M Rosário M; Segundo, Marcela A

2018-03-20

Collision induced dissociation of triple quadrupole mass spectrometer (CID-QqQ) and high-energy collision dissociation (HCD) of Orbitrap were compared for four neuropeptides Y Y1 (NPY Y1) receptor antagonists and showed similar qualitative fragmentation and structural information. Orbitrap high resolution and high mass accuracy HCD fragmentation spectra allowed unambiguous identification of product ions in the range 0.04-4.25 ppm. Orbitrap mass spectrometry showed abundant analyte-specific product ions also observed on CID-QqQ. These results show the suitability of these product ions for use in quantitative analysis by MRM mode. In addition, it was found that all compounds could be determined at levels >1 μg L -1 using the QqQ instrument and that the detection limits for this analyzer ranged from 0.02 to 0.6 μg L -1 . Overall, the results obtained from experiments acquired in QqQ show a good agreement with those acquired from the Orbitrap instrument allowing the use of this relatively inexpensive technique (QqQ) for accurate quantification of these compounds in clinical and academic applications. Copyright © 2018 Elsevier B.V. All rights reserved.

High-energy and low-energy collision-induced dissociation of protonated flavonoids generated by MALDI and by electrospray ionization

NASA Astrophysics Data System (ADS)

March, Raymond E.; Li, Hongxia; Belgacem, Omar; Papanastasiou, Dimitris

2007-04-01

Product ion mass spectra of a series of nine protonated flavonoids have been observed by electrospray ionization combined with quadrupole/time-of-flight (ESI QTOF), and matrix-assisted laser desorption ionization combined either with quadrupole ion trap (MALDI QIT) tandem mass spectrometry or time-of-flight tandem mass spectrometry (MALDI TOF ReTOF). The compounds examined are 3,6-, 3,2'-, and 3,3'-dihydoxyflavone, apigenin (5,7,4'-trihydroxyflavone), luteolin (5,7,3',4'-tetrahydroxyflavone), apigenin-7-O-glucoside, hesperidin (5,7,3'-trihydroxy-4'-methoxyflavanone), daidzen (7,4'-dihydroxyisoflavone), and rutin (quercitin-3-O-rutinoside) where quercitin is 3,5,7,3',4'-pentahydroxyflavone; sodiated rutin was examined also. The center-of-mass energies in ESI QTOF and MALDI QIT are similar (1-4 eV) and their product ion mass spectra are virtually identical. In the MALDI TOF ReTOF instrument, center-of-mass energies range from 126-309 eV for sodiated rutin to protonated dihydroxyflavones, respectively. Due to the high center-of-mass energies available with the MALDI TOF ReTOF instrument, some useful structural information may be obtained; however, with increasing precursor mass/charge ratio, product ion mass spectra become simplified so as to be of limited structural value. Electronic excitation of the protonated (and sodiated) species examined here offers an explanation for the very simple product ion mass spectra observed particularly for glycosylated flavonoids.

Determination of phenylalanine isotope ratio enrichment by liquid chromatography/time- of-flight mass spectrometry.

PubMed

Wu, Zhanpin; Zhang, Xiao-Jun; Cody, Robert B; Wolfe, Robert R

2004-01-01

The application of time-of-flight mass spectrometry to isotope ratio measurements has been limited by the relatively low dynamic range of the time-to-digital converter detectors available on commercial LC/ToF-MS systems. Here we report the measurement of phenylalanine isotope ratio enrichment by using a new LC/ToF-MS system with wide dynamic range. Underivatized phenylalanine was injected onto a C18 column directly with 0.1% formic acid/acetonitrile as the mobile phase. The optimal instrument parameters for the time-of-flight mass spectrometer were determined by tuning the instrument with a phenylalanine standard. The accuracy of the isotope enrichment measurement was determined by the injection of standard solutions with known isotope ratios ranging from 0.02% to 9.2%. A plot of the results against the theoretical values gave a linear curve with R2 of 0.9999. The coefficient of variation for the isotope ratio measurement was below 2%. The method is simple, rapid, and accurate and presents an attractive alternative to traditional GC/MS applications.

A critical review of inductively coupled plasma-mass spectrometry for geoanalysis, geochemistry and hydrology, Part 1. Analytical performance

USGS Publications Warehouse

Brenner, I.B.; Taylor, Howard E.

1992-01-01

Present-day inductively coupled plasma-mass spectrometry (ICP-MS) instrumentation is described briefly. Emphasis is placed on performance characteristics for geoanalysis, geochemistry, and hydrology. Applications where ICP-MS would be indispensable are indicated. Determination of geochemically diagnostic trace elements (such as the rare earth elements [REE], U and Th), of isotope ratios for fingerprinting, tracer and other geo-isotope applications, and benchmark isotope dilution determinations are considered to be typical priority applications for ICP-MS. It is concluded that ICP-MS furnishes unique geoanalytical and environmental data that are not readily provided by conventional spectroscopic (emission and absorption) techniques.

Elimination of boron memory effect in inductively coupled plasma-mass spectrometry by ammonia gas injection into the spray chamber during analysis

NASA Astrophysics Data System (ADS)

Al-Ammar, Assad S.; Gupta, Rajesh K.; Barnes, Ramon M.

2000-06-01

Injection of 10-20 ml/min of ammonia gas into an inductively coupled plasma-mass spectrometry (ICP-MS) spray chamber during boron determination eliminates the memory effect of a 1 μg/ml B solution within a 2-min washing time. Ammonia gas injection also reduces the boron blank by a factor of four and enhances the sensitivity by 33-90%. Boron detection limits are improved from 12 and 14 to 3 and 4 ng/ml, respectively, for two ICP-MS instruments. Trace boron concentrations in certified reference materials agree well using ammonia gas injection.

A Retrospective Evaluation of the Use of Mass Spectrometry in FDA Biologics License Applications

NASA Astrophysics Data System (ADS)

Rogstad, Sarah; Faustino, Anneliese; Ruth, Ashley; Keire, David; Boyne, Michael; Park, Jun

2017-05-01

The characterization sections of biologics license applications (BLAs) approved by the United States Food and Drug Administration (FDA) between 2000 and 2015 were investigated to examine the extent of the use of mass spectrometry. Mass spectrometry was found to be integral to the characterization of these biotherapeutics. Of the 80 electronically submitted monoclonal antibody and protein biotherapeutic BLAs included in this study, 79 were found to use mass spectrometric workflows for protein or impurity characterization. To further examine how MS is being used in successful BLAs, the applications were filtered based on the type and number of quality attributes characterized, the mass spectrometric workflows used (peptide mapping, intact mass analysis, and cleaved glycan analysis), the methods used to introduce the proteins into the gas phase (ESI, MALDI, or LC-ESI), and the specific types of instrumentation used. Analyses were conducted over a time course based on the FDA BLA approval to determine if any trends in utilization could be observed over time. Additionally, the different classes of protein-based biotherapeutics among the approved BLAs were clustered to determine if any trends could be attributed to the specific type of biotherapeutic.

Reagent for Evaluating Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) Performance in Bottom-Up Proteomic Experiments.

PubMed

Beri, Joshua; Rosenblatt, Michael M; Strauss, Ethan; Urh, Marjeta; Bereman, Michael S

2015-12-01

We present a novel proteomic standard for assessing liquid chromatography-tandem mass spectrometry (LC-MS/MS) instrument performance, in terms of chromatographic reproducibility and dynamic range within a single LC-MS/MS injection. The peptide mixture standard consists of six peptides that were specifically synthesized to cover a wide range of hydrophobicities (grand average hydropathy (GRAVY) scores of -0.6 to 1.9). A combination of stable isotope labeled amino acids ((13)C and (15)N) were inserted to create five isotopologues. By combining these isotopologues at different ratios, they span four orders of magnitude within each distinct peptide sequence. Each peptide, from lightest to heaviest, increases in abundance by a factor of 10. We evaluate several metrics on our quadrupole orbitrap instrument using the 6 × 5 LC-MS/MS reference mixture spiked into a complex lysate background as a function of dynamic range, including mass measurement accuracy (MMA) and the linear range of quantitation of MS1 and parallel reaction monitoring experiments. Detection and linearity of the instrument routinely spanned three orders of magnitude across the gradient (500 fmol to 0.5 fmol on column) and no systematic trend was observed for MMA of targeted peptides as a function of abundance by analysis of variance analysis (p = 0.17). Detection and linearity of the fifth isotopologue (i.e., 0.05 fmol on column) was dependent on the peptide and instrument scan type (MS1 vs PRM). We foresee that this standard will serve as a powerful method to conduct both intra-instrument performance monitoring/evaluation, technology development, and inter-instrument comparisons.

Parallel Reaction Monitoring: A Targeted Experiment Performed Using High Resolution and High Mass Accuracy Mass Spectrometry

PubMed Central

Rauniyar, Navin

2015-01-01

The parallel reaction monitoring (PRM) assay has emerged as an alternative method of targeted quantification. The PRM assay is performed in a high resolution and high mass accuracy mode on a mass spectrometer. This review presents the features that make PRM a highly specific and selective method for targeted quantification using quadrupole-Orbitrap hybrid instruments. In addition, this review discusses the label-based and label-free methods of quantification that can be performed with the targeted approach. PMID:26633379

Direct chemical-analysis of uv laser-ablation products of organic polymers by using selective ion monitoring mode in gas-chromatography mass-spectrometry

USGS Publications Warehouse

Cho, Yirang; Lee, H.W.; Fountain, S.T.; Lubman, D.M.

1994-01-01

Trace quantities of laser ablated organic polymers were analyzed by using commercial capillary column gas chromatography/mass spectrometry; the instrument was modified so that the laser ablation products could be introduced into the capillary column directly and the constituents of each peak in the chromatogram were identified by using a mass spectrometer. The present study takes advantage of the selective ion monitoring mode for significantly improving the sensitivity of the mass spectrometer as a detector, which is critical in analyzing the trace quantities and confirming the presence or absence of the species of interest in laser ablated polymers. The initial composition of the laser ablated polymers was obtained by using an electron impact reflectron time-of-flight mass spectrometer and the possible structure of the fragments observed in the spectra was proposed based on the structure of the polymers.

Real-time quantitative analysis of H2, He, O2, and Ar by quadrupole ion trap mass spectrometry.

PubMed

Ottens, Andrew K; Harrison, W W; Griffin, Timothy P; Helms, William R

2002-09-01

The use of a quadrupole ion trap mass spectrometer (QITMS) for quantitative analysis of hydrogen and helium as well as of other permanent gases is demonstrated. Like commercial instruments, the customized QITMS uses mass selective instability; however, this instrument operates at a greater trapping frequency and without a buffer gas. Thus, a useable mass range from 2 to over 50 daltons (Da) is achieved. The performance of the ion trap is evaluated using part-per-million (ppm) concentrations of hydrogen, helium, oxygen, and argon mixed into a nitrogen gas stream, as outlined by the National Aeronautics and Space Administration (NASA), which is interested in monitoring for cryogenic fuel leaks within the Space Shuttle during launch preparations. When quantitating the four analytes, relative accuracy and precision were better than the NASA-required minimum of 10% error and 5% deviation, respectively. Limits of detection were below the NASA requirement of 25-ppm hydrogen and 100-ppm helium; those for oxygen and argon were within the same order of magnitude as the requirements. These results were achieved at a fast data recording rate, and demonstrate the utility of the QITMS as a real-time quantitative monitoring device for permanent gas analysis. c. 2002 American Society for Mass Spectrometry.

Time-of-flight mass spectrometry: Introduction to the basics.

PubMed

Boesl, Ulrich

2017-01-01

The intention of this tutorial is to introduce into the basic concepts of time-of-flight mass spectrometry, beginning with the most simple single-stage ion source with linear field-free drift region and continuing with two-stage ion sources combined with field-free drift regions and ion reflectors-the so-called reflectrons. Basic formulas are presented and discussed with the focus on understanding the physical relations of geometric and electric parameters, initial distribution of ionic parameters, ion flight times, and ion flight time incertitude. This tutorial is aimed to help the applicant to identify sources of flight time broadening which limit good mass resolution and sources of ion losses which limit sensitivity; it is aimed to stimulate creativity for new experimental approaches by discussing a choice of instrumental options and to encourage those who toy with the idea to build an own time-of-flight mass spectrometer. Large parts of mathematics are shifted into a separate chapter in order not to overburden the text with too many mathematical deviations. Rather, thumb-rule formulas are supplied for first estimations of geometry and potentials when designing a home-built instrument, planning experiments, or searching for sources of flight time broadening. © 2016 Wiley Periodicals, Inc. Mass Spec Rev 36:86-109, 2017. © 2016 Wiley Periodicals, Inc.

Metabolomics by Gas Chromatography-Mass Spectrometry: the combination of targeted and untargeted profiling

PubMed Central

Fiehn, Oliver

2016-01-01

Gas chromatography-mass spectrometry (GC-MS)-based metabolomics is ideal for identifying and quantitating small molecular metabolites (<650 daltons), including small acids, alcohols, hydroxyl acids, amino acids, sugars, fatty acids, sterols, catecholamines, drugs, and toxins, often using chemical derivatization to make these compounds volatile enough for gas chromatography. This unit shows that on GC-MS- based metabolomics easily allows integrating targeted assays for absolute quantification of specific metabolites with untargeted metabolomics to discover novel compounds. Complemented by database annotations using large spectral libraries and validated, standardized standard operating procedures, GC-MS can identify and semi-quantify over 200 compounds per study in human body fluids (e.g., plasma, urine or stool) samples. Deconvolution software enables detection of more than 300 additional unidentified signals that can be annotated through accurate mass instruments with appropriate data processing workflows, similar to liquid chromatography-MS untargeted profiling (LC-MS). Hence, GC-MS is a mature technology that not only uses classic detectors (‘quadrupole’) but also target mass spectrometers (‘triple quadrupole’) and accurate mass instruments (‘quadrupole-time of flight’). This unit covers the following aspects of GC-MS-based metabolomics: (i) sample preparation from mammalian samples, (ii) acquisition of data, (iii) quality control, and (iv) data processing. PMID:27038389

Translational value of liquid chromatography coupled with tandem mass spectrometry-based quantitative proteomics for in vitro-in vivo extrapolation of drug metabolism and transport and considerations in selecting appropriate techniques.

PubMed

Al Feteisi, Hajar; Achour, Brahim; Rostami-Hodjegan, Amin; Barber, Jill

2015-01-01

Drug-metabolizing enzymes and transporters play an important role in drug absorption, distribution, metabolism and excretion and, consequently, they influence drug efficacy and toxicity. Quantification of drug-metabolizing enzymes and transporters in various tissues is therefore essential for comprehensive elucidation of drug absorption, distribution, metabolism and excretion. Recent advances in liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) have improved the quantification of pharmacologically relevant proteins. This report presents an overview of mass spectrometry-based methods currently used for the quantification of drug-metabolizing enzymes and drug transporters, mainly focusing on applications and cost associated with various quantitative strategies based on stable isotope-labeled standards (absolute quantification peptide standards, quantification concatemers, protein standards for absolute quantification) and label-free analysis. In mass spectrometry, there is no simple relationship between signal intensity and analyte concentration. Proteomic strategies are therefore complex and several factors need to be considered when selecting the most appropriate method for an intended application, including the number of proteins and samples. Quantitative strategies require appropriate mass spectrometry platforms, yet choice is often limited by the availability of appropriate instrumentation. Quantitative proteomics research requires specialist practical skills and there is a pressing need to dedicate more effort and investment to training personnel in this area. Large-scale multicenter collaborations are also needed to standardize quantitative strategies in order to improve physiologically based pharmacokinetic models.

Use of ICP/MS with ultrasonic nebulizer for routine determination of uranium activity ratios in natural water

USGS Publications Warehouse

Kraemer, T.F.; Doughten, M.W.; Bullen, T.D.

2002-01-01

A method is described that allows precise determination of 234U/238U activity ratios (UAR) in most natural waters using commonly available inductively coupled plasma/mass spectrometry (ICP/MS) instrumentation and accessories. The precision achieved by this technique (??0.5% RSD, 1 sigma) is intermediate between thermal ionization mass spectrometry (??0.25% RSID, 1 sigma) and alpha particle spectrometry (??5% RSD, 1 sigma). It is precise and rapid enough to allow analysis of a large number of samples in a short period of time at low cost using standard, commercially available quadrupole instrumentation with ultrasonic nebulizer and desolvator accessories. UARs have been analyzed successfully in fresh to moderately saline waters with U concentrations of from less than 1 ??g/L to nearly 100 ??g/L. An example of the uses of these data is shown for a study of surface-water mixing in the North Platte River in western Nebraska. This rapid and easy technique should encourage the wider use of uranium isotopes in surface-water and groundwater investigations, both for qualitative (e.g. identifying sources of water) and quantitative (e.g. determining end-member mixing ratios purposes.

How MOMA will search for Life bio-indicators at Mars in 2018 ?

NASA Astrophysics Data System (ADS)

Coll, Patrice; Goesmann, Fred; Raulin, Francois; Becker, Luann; Szopa, Cyril; Buch, Arnaud; Pinnick, Veronika; Steininger, Harald; Sternberg, Robert; Freissinet, Caroline; Roders, O.; Grand, N.; Reynolds, E.; Coscia, D.; Correia, J. J.; Granier, P.; Lustrement, B.; Jerome, M.; Philippon, C.; Steinmetz, E.; Krause, I.; Bierwirth, M.; Jaskulek, S.; Adams, E.; Antoine, M.; Cornish, T.; Ellers, G.; Hogue, P.; Strohbehn, K.

The MOMA experiment is part of the scientific payload of the 2018 ExoMars mission. MOMA is a joint European and US instrument that combines gas chromatography and laser desorption to an ion trap mass spectrometer. Its purpose is to answer questions pertaining to the fields of astro-and exobiology; the study of the origin, evolution, and distribution of life in the universe. The primary goal of MOMA is the detection of organics, including refractory organics, on Mars. In case of success, the question of biotic or abiotic source is addressed by molecular identification in terms of chirality and isotopic composition. Together with the other analytical instruments of the Pasteur payload we are confident that we will address the question of life on Mars with MOMA and its two basic operational modes laser desorption mass-spectrometry (LD-MS) and gas-chromatography mass-spectrometry (GC-MS) and will further gain valuable, new scientific data which will further our understanding of the Martian system. The MOMA instrument provides the opportunity to analyse Martian soil and rock samples in two different ways. As a first option the milled sample can be filled into one of the MOMA ovens which are located on a rotatable sample carousel. After the filling process the oven will be moved to the tapping station which seals the oven. Heating of the oven up to 900C evaporates all volatile sample components. These volatiles will be purged by a Helium flow to the GC. After doing the gas chromatography analysis the GC exhaust gas will be guided to the mass spectrometer for a further mass spectrographic analysis. This is the GC-MS mode of the instrument. As a second option a refillable container (sample tray) which is also mounted on the carousel can be filled with milled rock or soil sample material. In this case a frequency quadruplicated Nd:YAG laser is used for laser desorption and ionisation of a small area of the sample sur-face. The generated ions will be guided by an ion guide to the mass spectrometer for mass spectrographic analysis. This is the LD-MS mode of the instrument.

Quantitative metrics for assessment of chemical image quality and spatial resolution

DOE PAGES

Kertesz, Vilmos; Cahill, John F.; Van Berkel, Gary J.

2016-02-28

Rationale: Currently objective/quantitative descriptions of the quality and spatial resolution of mass spectrometry derived chemical images are not standardized. Development of these standardized metrics is required to objectively describe chemical imaging capabilities of existing and/or new mass spectrometry imaging technologies. Such metrics would allow unbiased judgment of intra-laboratory advancement and/or inter-laboratory comparison for these technologies if used together with standardized surfaces. Methods: We developed two image metrics, viz., chemical image contrast (ChemIC) based on signal-to-noise related statistical measures on chemical image pixels and corrected resolving power factor (cRPF) constructed from statistical analysis of mass-to-charge chronograms across features of interest inmore » an image. These metrics, quantifying chemical image quality and spatial resolution, respectively, were used to evaluate chemical images of a model photoresist patterned surface collected using a laser ablation/liquid vortex capture mass spectrometry imaging system under different instrument operational parameters. Results: The calculated ChemIC and cRPF metrics determined in an unbiased fashion the relative ranking of chemical image quality obtained with the laser ablation/liquid vortex capture mass spectrometry imaging system. These rankings were used to show that both chemical image contrast and spatial resolution deteriorated with increasing surface scan speed, increased lane spacing and decreasing size of surface features. Conclusions: ChemIC and cRPF, respectively, were developed and successfully applied for the objective description of chemical image quality and spatial resolution of chemical images collected from model surfaces using a laser ablation/liquid vortex capture mass spectrometry imaging system.« less

Quantitative metrics for assessment of chemical image quality and spatial resolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kertesz, Vilmos; Cahill, John F.; Van Berkel, Gary J.

Rationale: Currently objective/quantitative descriptions of the quality and spatial resolution of mass spectrometry derived chemical images are not standardized. Development of these standardized metrics is required to objectively describe chemical imaging capabilities of existing and/or new mass spectrometry imaging technologies. Such metrics would allow unbiased judgment of intra-laboratory advancement and/or inter-laboratory comparison for these technologies if used together with standardized surfaces. Methods: We developed two image metrics, viz., chemical image contrast (ChemIC) based on signal-to-noise related statistical measures on chemical image pixels and corrected resolving power factor (cRPF) constructed from statistical analysis of mass-to-charge chronograms across features of interest inmore » an image. These metrics, quantifying chemical image quality and spatial resolution, respectively, were used to evaluate chemical images of a model photoresist patterned surface collected using a laser ablation/liquid vortex capture mass spectrometry imaging system under different instrument operational parameters. Results: The calculated ChemIC and cRPF metrics determined in an unbiased fashion the relative ranking of chemical image quality obtained with the laser ablation/liquid vortex capture mass spectrometry imaging system. These rankings were used to show that both chemical image contrast and spatial resolution deteriorated with increasing surface scan speed, increased lane spacing and decreasing size of surface features. Conclusions: ChemIC and cRPF, respectively, were developed and successfully applied for the objective description of chemical image quality and spatial resolution of chemical images collected from model surfaces using a laser ablation/liquid vortex capture mass spectrometry imaging system.« less

Time-of-flights and traps: from the Histone Code to Mars.

PubMed

Cotter, Robert J; Swatkoski, Stepehen; Becker, Luann; Evans-Nguyen, Theresa

2010-01-01

Two very different analytical instruments are featured in this perspective paper on mass spectrometer design and development. The first instrument, based upon the curved-field reflectron developed in the Johns Hopkins Middle Atlantic Mass Spectrometry Laboratory, is a tandem time-of-flight mass spectrometer whose performance and practicality are illustrated by applications to a series of research projects addressing the acetylation, deacetylation and ADP-ribosylation of histone proteins. The chemical derivatization of lysine-rich, hyperacetylated histones as their deuteroacetylated analogs enables one to obtain an accurate quantitative assessment of the extent of acetylation at each site. Chemical acetylation of histone mixtures is also used to determine the lysine targets of sirtuins, an important class of histone deacetylases (HDACs), by replacing the deacetylated residues with biotin. Histone deacetylation by sirtuins requires the co-factor NAD+, as does the attachment of ADP-ribose. The second instrument, a low voltage and low power ion trap mass spectrometer known as the Mars Organic Mass Analyzer (MOMA), is a prototype for an instrument expected to be launched in 2018. Like the tandem mass spectrometer, it is also expected to have applicability to environmental and biological analyses and, ultimately, to clinical care.

Time-of-flights and traps: from the Histone Code to Mars*

PubMed Central

Swatkoski, Stephen; Becker, Luann; Evans-Nguyen, Theresa

2011-01-01

Two very different analytical instruments are featured in this perspective paper on mass spectrometer design and development. The first instrument, based upon the curved-field reflectron developed in the Johns Hopkins Middle Atlantic Mass Spectrometry Laboratory, is a tandem time-of-flight mass spectrometer whose performance and practicality are illustrated by applications to a series of research projects addressing the acetylation, deacetylation and ADP-ribosylation of histone proteins. The chemical derivatization of lysine-rich, hyperacetylated histones as their deuteroacetylated analogs enables one to obtain an accurate quantitative assessment of the extent of acetylation at each site. Chemical acetylation of histone mixtures is also used to determine the lysine targets of sirtuins, an important class of histone deacetylases (HDACs), by replacing the deacetylated residues with biotin. Histone deacetylation by sirtuins requires the co-factor NAD+, as does the attachment of ADP-ribose. The second instrument, a low voltage and low power ion trap mass spectrometer known as the Mars Organic Mass Analyzer (MOMA), is a prototype for an instrument expected to be launched in 2018. Like the tandem mass spectrometer, it is also expected to have applicability to environmental and biological analyses and, ultimately, to clinical care. PMID:20530839

Aptamer-facilitated mass cytometry.

PubMed

Mironov, Gleb G; Bouzekri, Alexandre; Watson, Jessica; Loboda, Olga; Ornatsky, Olga; Berezovski, Maxim V

2018-05-01

Mass cytometry is a novel cell-by-cell analysis technique, which uses elemental tags instead of fluorophores. Sample cells undergo rapid ionization in inductively coupled plasma and the ionized elemental tags are then analyzed by means of time-of-flight mass spectrometry. Benefits of the mass cytometry approach are in no need for compensation, the high number of detection channels (up to 100) and low background noise. In this work, we applied a biotinylated aptamer against human PTK7 receptor for characterization of positive (human acute lymphoblastic leukemia) and negative (human Burkitt's lymphoma) cells by a mass cytometry instrument. Our proof of principal experiments showed that biotinylated aptamers in conjunction with metal-labeled neutravidin can be successfully utilized for mass cytometry experiments at par with commercially available antibodies. Graphical abstract Biotinylated aptamers in conjunction with metal-labeled neutravidin bind to cell biomarkers, and then injected into the inductively coupled plasma (ICP) source, where cells are vaporized, atomized, and ionized in the plasma for subsequent mass spectrometry (MS) analysis of lanthanide metals.

multiplierz v2.0: A Python-based ecosystem for shared access and analysis of native mass spectrometry data.

PubMed

Alexander, William M; Ficarro, Scott B; Adelmant, Guillaume; Marto, Jarrod A

2017-08-01

The continued evolution of modern mass spectrometry instrumentation and associated methods represents a critical component in efforts to decipher the molecular mechanisms which underlie normal physiology and understand how dysregulation of biological pathways contributes to human disease. The increasing scale of these experiments combined with the technological diversity of mass spectrometers presents several challenges for community-wide data access, analysis, and distribution. Here we detail a redesigned version of multiplierz, our Python software library which leverages our common application programming interface (mzAPI) for analysis and distribution of proteomic data. New features include support for a wider range of native mass spectrometry file types, interfaces to additional database search engines, compatibility with new reporting formats, and high-level tools to perform post-search proteomic analyses. A GUI desktop environment, mzDesktop, provides access to multiplierz functionality through a user friendly interface. multiplierz is available for download from: https://github.com/BlaisProteomics/multiplierz; and mzDesktop is available for download from: https://sourceforge.net/projects/multiplierz/. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Detection of trace organics in Mars analog samples containing perchlorate by laser desorption/ionization mass spectrometry.

PubMed

Li, Xiang; Danell, Ryan M; Brinckerhoff, William B; Pinnick, Veronica T; van Amerom, Friso; Arevalo, Ricardo D; Getty, Stephanie A; Mahaffy, Paul R; Steininger, Harald; Goesmann, Fred

2015-02-01

Evidence from recent Mars missions indicates the presence of perchlorate salts up to 1 wt % level in the near-surface materials. Mixed perchlorates and other oxychlorine species may complicate the detection of organic molecules in bulk martian samples when using pyrolysis techniques. To address this analytical challenge, we report here results of laboratory measurements with laser desorption mass spectrometry, including analyses performed on both commercial and Mars Organic Molecule Analyzer (MOMA) breadboard instruments. We demonstrate that the detection of nonvolatile organics in selected spiked mineral-matrix materials by laser desorption/ionization (LDI) mass spectrometry is not inhibited by the presence of up to 1 wt % perchlorate salt. The organics in the sample are not significantly degraded or combusted in the LDI process, and the parent molecular ion is retained in the mass spectrum. The LDI technique provides distinct potential benefits for the detection of organics in situ on the martian surface and has the potential to aid in the search for signs of life on Mars.

Qualification and initial characterization of a high-purity 233U spike for use in uranium analyses

DOE PAGES

Mathew, K. J.; Canaan, R. D.; Hexel, C.; ...

2015-08-20

Several high-purity 233U items potentially useful as isotope dilution mass spectrometry standards for safeguards, non-proliferation, and nuclear forensics measurements are identified and rescued from downblending. By preserving the supply of 233U materials of different pedigree for use as source materials for certified reference materials (CRMs), it is ensured that the safeguards community has high quality uranium isotopic standards required for calibration of the analytical instruments. One of the items identified as a source material for a high-purity CRM is characterized for the uranium isotope-amount ratios using thermal ionization mass spectrometry (TIMS). Additional verification measurements on this material using quadrupole inductivelymore » coupled plasma mass spectrometry (ICPMS) are also performed. As a result, the comparison of the ICPMS uranium isotope-amount ratios with the TIMS data, with much smaller uncertainties, validated the ICPMS measurement practices. ICPMS is proposed for the initial screening of the purity of items in the rescue campaign.« less

Improved Steroids Detection and Evidence for Their Regiospecific Decompositions Using Anion Attachment Mass Spectrometry.

PubMed

Dumont, Quentin; Bárcenas, Mariana; Dossmann, Héloïse; Bailloux, Isabelle; Buisson, Corinne; Mechin, Nathalie; Molina, Adeline; Lasne, Françoise; Rannulu, Nalaka S; Cole, Richard B

2016-04-05

Nonpolar anabolic steroids are doping agents that typically do not provide strong signals by electrospray ionization-mass spectrometry (ESI-MS) owing especially to the low polarity of the functional groups present. We have investigated the addition of anions, in ammonium salt form, to anabolic steroid samples as ionization enhancers and have confirmed that lower instrumental limits of detection (as low as 10 ng/mL for fluoxymesterone-M) are obtained by fluoride anion attachment mass spectrometry, as compared to ESI(+)/(-) or atmospheric pressure photoionization (APPI)(+). Moreover, collision-induced decomposition (CID) spectra of precursor fluoride adducts of the bifunctional steroid "reduced pregnenolone" (containing two hydroxyl groups) and its d4-analogue provide evidence of regiospecific decompositions after attachment of fluoride anion to a specific hydroxyl group of the steroid. This type of charting of specific CID reaction pathways can offer value to selected reaction monitoring experiments (SRM) as it may result in a gain in selectivity in detection as well as in improvements in quantification.

Analytical considerations for mass spectrometry profiling in serum biomarker discovery.

PubMed

Whiteley, Gordon R; Colantonio, Simona; Sacconi, Andrea; Saul, Richard G

2009-03-01

The potential of using mass spectrometry profiling as a diagnostic tool has been demonstrated for a wide variety of diseases. Various cancers and cancer-related diseases have been the focus of much of this work because of both the paucity of good diagnostic markers and the knowledge that early diagnosis is the most powerful weapon in treating cancer. The implementation of mass spectrometry as a routine diagnostic tool has proved to be difficult, however, primarily because of the stringent controls that are required for the method to be reproducible. The method is evolving as a powerful guide to the discovery of biomarkers that could, in turn, be used either individually or in an array or panel of tests for early disease detection. Using proteomic patterns to guide biomarker discovery and the possibility of deployment in the clinical laboratory environment on current instrumentation or in a hybrid technology has the possibility of being the early diagnosis tool that is needed.

DIGE Analysis Software and Protein Identification Approaches.

PubMed

Hmmier, Abduladim; Dowling, Paul

2018-01-01

DIGE is a high-resolution two-dimensional gel electrophoresis method, with excellent dynamic range obtained by fluorescent tag labeling of protein samples. Scanned images of DIGE gels show thousands of protein spots, each spot representing a single or a group of protein isoforms. By using commercially available software, each protein spot is defined by an outline, which is digitized and correlated with the quantity of proteins present in each spot. Software packages include DeCyder, SameSpots, and Dymension 3. In addition, proteins of interest can be excised from post-stained gels and identified with conventional mass spectrometry techniques. High-throughput mass spectrometry is performed using sophisticated instrumentation including matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF), MALDI-TOF/TOF, and liquid chromatography tandem mass spectrometry (LC-MS/MS). Tandem MS (MALDI-TOF/TOF or LC-MS/MS), analyzes fragmented peptides, resulting in amino acid sequence information, especially useful when protein spots are low abundant or where a mixture of proteins is present.

Profiling of patterned metal layers by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS)

NASA Astrophysics Data System (ADS)

Bi, Melody; Ruiz, Antonio M.; Gornushkin, Igor; Smith, Ben W.; Winefordner, James D.

2000-02-01

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used for profiling patterned thin metal layers on a polymer/silicon substrate. The parameters of the laser and ICP-MS operating conditions have been studied and optimized for this purpose. A new laser ablation chamber was designed and built to achieve the best spatial resolution. The results of the profiling by LA-ICP-MS were compared to those obtained from a laser ablation optical emission spectrometry (LA-OES) instrument, which measured the emission of the plasma at the sample surface, and thus, eliminated the time delay caused by the sample transport into the ICP-MS system. Emission spectra gave better spatial resolution than mass spectra. However, LA-ICP-MS provided much better sensitivity and was able to profile thin metal layers (on the order of a few nanometers) on the silicon surface. A lateral spatial resolution of 45 μm was achieved.

Using ProHits to store, annotate and analyze affinity purification - mass spectrometry (AP-MS) data

PubMed Central

Liu, Guomin; Zhang, Jianping; Choi, Hyungwon; Lambert, Jean-Philippe; Srikumar, Tharan; Larsen, Brett; Nesvizhskii, Alexey I.; Raught, Brian; Tyers, Mike; Gingras, Anne-Claude

2012-01-01

Affinity purification coupled with mass spectrometry (AP-MS) is a robust technique used to identify protein-protein interactions. With recent improvements in sample preparation, and dramatic advances in MS instrumentation speed and sensitivity, this technique is becoming more widely used throughout the scientific community. To meet the needs of research groups both large and small, we have developed software solutions for tracking, scoring and analyzing AP-MS data. Here, we provide details for the installation and utilization of ProHits, a Laboratory Information Management System designed specifically for AP-MS interaction proteomics. This protocol explains: (i) how to install the complete ProHits system, including modules for the management of mass spectrometry files and the analysis of interaction data, and (ii) alternative options for the use of pre-existing search results in simpler versions of ProHits, including a virtual machine implementation of our ProHits Lite software. We also describe how to use the main features of the software to analyze AP-MS data. PMID:22948730

On the calibration of continuous, high-precision delta18O and delta2H measurements using an off-axis integrated cavity output spectrometer.

PubMed

Wang, Lixin; Caylor, Kelly K; Dragoni, Danilo

2009-02-01

The (18)O and (2)H of water vapor serve as powerful tracers of hydrological processes. The typical method for determining water vapor delta(18)O and delta(2)H involves cryogenic trapping and isotope ratio mass spectrometry. Even with recent technical advances, these methods cannot resolve vapor composition at high temporal resolutions. In recent years, a few groups have developed continuous laser absorption spectroscopy (LAS) approaches for measuring delta(18)O and delta(2)H which achieve accuracy levels similar to those of lab-based mass spectrometry methods. Unfortunately, most LAS systems need cryogenic cooling and constant calibration to a reference gas, and have substantial power requirements, making them unsuitable for long-term field deployment at remote field sites. A new method called Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS) has been developed which requires extremely low-energy consumption and neither reference gas nor cryogenic cooling. In this report, we develop a relatively simple pumping system coupled to a dew point generator to calibrate an ICOS-based instrument (Los Gatos Research Water Vapor Isotope Analyzer (WVIA) DLT-100) under various pressures using liquid water with known isotopic signatures. Results show that the WVIA can be successfully calibrated using this customized system for different pressure settings, which ensure that this instrument can be combined with other gas-sampling systems. The precisions of this instrument and the associated calibration method can reach approximately 0.08 per thousand for delta(18)O and approximately 0.4 per thousand for delta(2)H. Compared with conventional mass spectrometry and other LAS-based methods, the OA-ICOS technique provides a promising alternative tool for continuous water vapor isotopic measurements in field deployments. Copyright 2009 John Wiley & Sons, Ltd.

Optimization of biological and instrumental detection of explosives and ignitable liquid residues including canines, SPME/ITMS and GC/MSn

NASA Astrophysics Data System (ADS)

Furton, Kenneth G.; Harper, Ross J.; Perr, Jeannette M.; Almirall, Jose R.

2003-09-01

A comprehensive study and comparison is underway using biological detectors and instrumental methods for the rapid detection of ignitable liquid residues (ILR) and high explosives. Headspace solid phase microextraction (SPME) has been demonstrated to be an effective sampling method helping to identify active odor signature chemicals used by detector dogs to locate forensic specimens as well as a rapid pre-concentration technique prior to instrumental detection. Common ignitable liquids and common military and industrial explosives have been studied including trinitrotoluene, tetryl, RDX, HMX, EGDN, PETN and nitroglycerine. This study focuses on identifying volatile odor signature chemicals present, which can be used to enhance the level and reliability of detection of ILR and explosives by canines and instrumental methods. While most instrumental methods currently in use focus on particles and on parent organic compounds, which are often involatile, characteristic volatile organics are generally also present and can be exploited to enhance detection particularly for well-concealed devices. Specific examples include the volatile odor chemicals 2-ethyl-1-hexanol and cyclohexanone, which are readily available in the headspace of the high explosive composition C-4; whereas, the active chemical cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX) is not. The analysis and identification of these headspace 'fingerprint' organics is followed by double-blind dog trials of the individual components using certified teams in an attempt to isolate and understand the target compounds to which dogs are sensitive. Studies to compare commonly used training aids with the actual target explosive have also been undertaken to determine their suitability and effectiveness. The optimization of solid phase microextraction (SPME) combined with ion trap mobility spectrometry (ITMS) and gas chromatography/mass spectrometry/mass spectrometry (GC/MSn) is detailed including interface development and comparisons of limits of detection. These instrumental methods are being optimized in order to detect the same target odor chemicals used by detector dogs to reliably locate explosives and ignitable liquids.

Making Mass Spectrometry See the Light: The Promises and Challenges of Cryogenic Infrared Ion Spectroscopy as a Bioanalytical Technique

PubMed Central

Cismesia, Adam P.; Bailey, Laura S.; Bell, Matthew R.; Tesler, Larry F.; Polfer, Nicolas C.

2016-01-01

The detailed chemical information contained in the vibrational spectrum of a cryogenically cooled analyte would, in principle, make infrared (IR) ion spectroscopy a gold standard technique for molecular identification in mass spectrometry. Despite this immense potential, there are considerable challenges in both instrumentation and methodology to overcome before the technique is analytically useful. Here, we discuss the promise of IR ion spectroscopy for small molecule analysis in the context of metabolite identification. Experimental strategies to address sensitivity constraints, poor overall duty cycle, and speed of the experiment are intimately tied to the development of a mass-selective cryogenic trap. Therefore, the most likely avenues for success, in the authors? opinion, are presented here, alongside alternative approaches and some thoughts on data interpretation. PMID:26975370

Isotope ratio analysis by Orbitrap mass spectrometry

NASA Astrophysics Data System (ADS)

Eiler, J. M.; Chimiak, L. M.; Dallas, B.; Griep-Raming, J.; Juchelka, D.; Makarov, A.; Schwieters, J. B.

2016-12-01

Several technologies are being developed to examine the intramolecular isotopic structures of molecules (i.e., site-specific and multiple substitution), but various limitations in sample size and type or (for IRMS) resolution have so far prevented the creation of a truly general technique. We will discuss the initial findings of a technique based on Fourier transform mass spectrometry, using the Thermo Scientific Q Exactive GC — an instrument that contains an Orbitrap mass analyzer. Fourier transform mass spectrometry is marked by exceptionally high mass resolutions (the Orbitrap reaches M/ΔM in the range 250,000-1M in the mass range of greatest interest, 50-200 amu). This allows for resolution of a large range of nearly isobaric interferences for isotopologues of volatile and semi-volatile compounds (i.e., involving isotopes of H, C, N, O and S). It also provides potential to solve very challenging mass resolution problems for isotopic analysis of other, heavier elements. Both internal and external experimental reproducibilities of isotope ratio analyses using the Orbitrap typically conform to shot-noise limits down to levels of 0.2 ‰ (1SE), and routinely in the range 0.5-1.0 ‰, with similar accuracy when standardized to concurrently run reference materials. Such measurements can be made without modifications to the ion optics of the Q Exactive GC, but do require specially designed sample introduction devices to permit sample/standard comparison and long integration times. The sensitivity of the Q Exactive GC permits analysis of sub-nanomolar samples and quantification of multiply-substituted species. The site-specific capability of this instrument arises from the fact that mass spectra of molecular analytes commonly contain diverse fragment ion species, each of which samples a specific sub-set of molecular sites. We will present applications of this technique to the biological and abiological chemistry of amino acids, forensic identification of hydrocarbon environmental pollutants, and study of the origins of isotope anomalies in meteoritic organics.

ToF-SIMS Parallel Imaging MS/MS of Lipid Species in Thin Tissue Sections.

PubMed

Bruinen, Anne Lisa; Fisher, Gregory L; Heeren, Ron M A

2017-01-01

Unambiguous identification of detected species is essential in complex biomedical samples. To date, there are not many mass spectrometry imaging techniques that can provide both high spatial resolution and identification capabilities. A new and patented imaging tandem mass spectrometer, exploiting the unique characteristics of the nanoTOF II (Physical Electronics, USA) TOF-SIMS TRIFT instrument, was developed to address this.Tandem mass spectrometry is based on the selection of precursor ions from the full secondary ion spectrum (MS 1 ), followed by energetic activation and fragmentation, and collection of the fragment ions to obtain a tandem MS spectrum (MS 2 ). The PHI NanoTOF II mass spectrometer is equipped with a high-energy collision induced dissociation (CID) fragmentation cell as well as a second time-of-flight analyzer developed for simultaneous ToF-SIMS and tandem MS imaging experiments.We describe here the results of a ToF-SIMS imaging experiment on a thin tissue section of an infected zebrafish as a model organism for tuberculosis. The focus is on the obtained ion distribution plot of a fatty acid as well as its identification by tandem mass spectrometry.

Applications of mass spectrometry to metabolomics and metabonomics: detection of biomarkers of aging and of age-related diseases.

PubMed

Mishur, Robert J; Rea, Shane L

2012-01-01

Every 5 years or so new technologies, or new combinations of old ones, seemingly burst onto the science scene and are then sought after until they reach the point of becoming commonplace. Advances in mass spectrometry instrumentation, coupled with the establishment of standardized chemical fragmentation libraries, increased computing power, novel data-analysis algorithms, new scientific applications, and commercial prospects have made mass spectrometry-based metabolomics the latest sought-after technology. This methodology affords the ability to dynamically catalogue and quantify, in parallel, femtomole quantities of cellular metabolites. The study of aging, and the diseases that accompany it, has accelerated significantly in the last decade. Mutant genes that alter the rate of aging have been found that increase lifespan by up to 10-fold in some model organisms, and substantial progress has been made in understanding fundamental alterations that occur at both the mRNA and protein level in tissues of aging organisms. The application of metabolomics to aging research is still relatively new, but has already added significant insight into the aging process. In this review we summarize these findings. We have targeted our manuscript to two audiences: mass spectrometrists interested in applying their technical knowledge to unanswered questions in the aging field, and gerontologists interested in expanding their knowledge of both mass spectrometry and the most recent advances in aging-related metabolomics. Copyright © 2011 Wiley Periodicals, Inc.

Development and Applications of Portable Gas Chromatography-Mass Spectrometry for Emergency Responders, the Military, and Law-Enforcement Organizations.

PubMed

Leary, Pauline E; Dobson, Gareth S; Reffner, John A

2016-05-01

Portable gas chromatography-mass spectrometry (GC-MS) systems are being deployed for field use, and are designed with this goal in mind. Performance characteristics of instruments that are successful in the field are different from those of equivalent technologies that are successful in a laboratory setting. These field-portable systems are extending the capabilities of the field user, providing investigative leads and confirmatory identifications in real time. Many different types of users benefit from the availability of this technology including emergency responders, the military, and law-enforcement organizations. This manuscript describes performance characteristics that are important for field-portable instruments, especially field-portable GC-MS systems, and demonstrates the value of this equipment to the disciplines of explosives investigations, fire investigations, and counterfeit-drug detection. This paper describes the current state of portable GC-MS technology, including a review of the development of portable GC-MS, as well as a demonstration of the value of this capability using different examples. © The Author(s) 2016.

MS-Based Analytical Techniques: Advances in Spray-Based Methods and EI-LC-MS Applications

PubMed Central

Medina, Isabel; Cappiello, Achille; Careri, Maria

2018-01-01

Mass spectrometry is the most powerful technique for the detection and identification of organic compounds. It can provide molecular weight information and a wealth of structural details that give a unique fingerprint for each analyte. Due to these characteristics, mass spectrometry-based analytical methods are showing an increasing interest in the scientific community, especially in food safety, environmental, and forensic investigation areas where the simultaneous detection of targeted and nontargeted compounds represents a key factor. In addition, safety risks can be identified at the early stage through online and real-time analytical methodologies. In this context, several efforts have been made to achieve analytical instrumentation able to perform real-time analysis in the native environment of samples and to generate highly informative spectra. This review article provides a survey of some instrumental innovations and their applications with particular attention to spray-based MS methods and food analysis issues. The survey will attempt to cover the state of the art from 2012 up to 2017. PMID:29850370

Rocket-borne time-of-flight mass spectrometry

NASA Technical Reports Server (NTRS)

Reiter, R. F.

1976-01-01

Theoretical and numerical analyses are made of planar, cylindrical and spherical-electrode two-field time-of-flight mass spectrometers in order to optimize their operating conditions. A method is introduced which can improve the resolving power of these instruments by a factor of 7.5. Potential barrier gating in time-of-flight mass spectrometers is also analyzed. Experimental studies of a miniature cylindrical-electrode and a hemispherical-electrode time-of-flight mass spectrometer are presented. Their sensitivity and ability to operate at D-region pressures with an open source make them ideal instruments for D-region ion composition measurements. A sounding rocket experiment package carrying a cylindrical electrode time-of-flight mass spectrometer was launched. The data indicate that essentially 100% of the positive electric charge on positive ions is carried by ions with mass-to-charge ratios greater than 500 below an altitude of 92 km. These heavy charge carriers were present at altitudes up to about 100 km.

Isotope ratio mass spectrometry in nutrition research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luke, A.H.

Many of the biochemical pathways and processes that form the foundation of modern nutrition research was elucidated using stable isotopes as physiological tracers. Since the discovery of stable isotopes, improvements and innovations in mass spectrometry and chromatography have led to greatly expanded applications. This research project was designed to evaluate gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) as a tool for isotopic tracer studies and to delineate the operational parameters for the analysis of {sup 13}C-labeled cholesterol, leucine and {alpha}-ketoisocaproate. The same isotope ratio mass spectrometer was then used as the base instrument for the ratio mass spectrometer was then usedmore » as the base instrument for the development of two additional inlet systems: a continuous-flow inlet for the analyses of {sup 13}C and {sup 18}O as CO{sub 2} and a filament inlet for on-line combustion and isotopic analysis of non-volatile organic compounds. Each of these three inlets was evaluated and their utility in nutrition research illustrated. GC/C/IRMS was used to analyze cholesterol, leucine and {alpha}-ketoisocaproate with good accuracy, precision and little isotopic memory. For all three compounds the detection limits achieved well surpassed currently used technologies. For compounds that can be well separated by GC, GC/C/IRMS is a valuable analytical tool. The continuous-flow inlet provided good accuracy and precision for measurements of {sup 13}CO{sub 2} from breath tests and {sup 18}O as CO{sub 2} from total energy expenditure tests. Most importantly, the continuous-flow inlet increased sample throughput by at least a factor of three over conventional analytical techniques. The filament inlet provided accurate and precise {sup 13}C ratio measurements of both natural abundance and enriched standards of non-volatile organic compounds of physiological interest.« less

Multi-instrument comparison and compilation of non-methane organic gas emissions from biomass burning and implications for smoke-derived secondary organic aerosol precursors

NASA Astrophysics Data System (ADS)

Hatch, Lindsay E.; Yokelson, Robert J.; Stockwell, Chelsea E.; Veres, Patrick R.; Simpson, Isobel J.; Blake, Donald R.; Orlando, John J.; Barsanti, Kelley C.

2017-01-01

Multiple trace-gas instruments were deployed during the fourth Fire Lab at Missoula Experiment (FLAME-4), including the first application of proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOFMS) and comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC-TOFMS) for laboratory biomass burning (BB) measurements. Open-path Fourier transform infrared spectroscopy (OP-FTIR) was also deployed, as well as whole-air sampling (WAS) with one-dimensional gas chromatography-mass spectrometry (GC-MS) analysis. This combination of instruments provided an unprecedented level of detection and chemical speciation. The chemical composition and emission factors (EFs) determined by these four analytical techniques were compared for four representative fuels. The results demonstrate that the instruments are highly complementary, with each covering some unique and important ranges of compositional space, thus demonstrating the need for multi-instrument approaches to adequately characterize BB smoke emissions. Emission factors for overlapping compounds generally compared within experimental uncertainty, despite some outliers, including monoterpenes. Data from all measurements were synthesized into a single EF database that includes over 500 non-methane organic gases (NMOGs) to provide a comprehensive picture of speciated, gaseous BB emissions. The identified compounds were assessed as a function of volatility; 6-11 % of the total NMOG EF was associated with intermediate-volatility organic compounds (IVOCs). These atmospherically relevant compounds historically have been unresolved in BB smoke measurements and thus are largely missing from emission inventories. Additionally, the identified compounds were screened for published secondary organic aerosol (SOA) yields. Of the total reactive carbon (defined as EF scaled by the OH rate constant and carbon number of each compound) in the BB emissions, 55-77 % was associated with compounds for which SOA yields are unknown or understudied. The best candidates for future smog chamber experiments were identified based on the relative abundance and ubiquity of the understudied compounds, and they included furfural, 2-methyl furan, 2-furan methanol, and 1,3-cyclopentadiene. Laboratory study of these compounds will facilitate future modeling efforts.

Screening of pharmaceuticals and illicit drugs in wastewater and surface waters of Spain and Italy by high resolution mass spectrometry using UHPLC-QTOF MS and LC-LTQ-Orbitrap MS.

PubMed

Bade, Richard; Rousis, Nikolaos I; Bijlsma, Lubertus; Gracia-Lor, Emma; Castiglioni, Sara; Sancho, Juan V; Hernandez, Felix

2015-12-01

The existence of pharmaceuticals and illicit drugs (PIDs) in environmental waters has led many analytical chemists to develop screening methods for monitoring purposes. Water samples can contain a huge number of possible contaminants, commonly at low concentrations, which makes their detection and identification problematic. Liquid chromatography coupled with high resolution mass spectrometry (LC-HRMS) has proven itself effective in the screening of environmental contaminants. The present work investigates the use of the most popular HRMS instruments, quadrupole time-of-flight and linear trap quadrupole-Orbitrap, from two different laboratories. A suspect screening for PIDs was carried out on wastewater (influent and effluent) and surface water samples from Castellón, Eastern Spain, and Cremona, Northern Italy, incorporating a database of 107 PIDs (including 220 fragment ions). A comparison between the findings of both instruments and of the samples was made which highlights the advantages and drawbacks of the strategies applied in each case. In total, 28 compounds were detected and/or identified by either/both instruments with irbesartan, valsartan, benzoylecgonine and caffeine being the most commonly found compounds across all samples.

Recent Advances and Future Challenges in Modified Mycotoxin Analysis: Why HRMS Has Become a Key Instrument in Food Contaminant Research

PubMed Central

Righetti, Laura; Paglia, Giuseppe; Galaverna, Gianni; Dall’Asta, Chiara

2016-01-01

Mycotoxins are secondary metabolites produced by pathogenic fungi in crops worldwide. These compounds can undergo modification in plants, leading to the formation of a large number of possible modified forms, whose toxicological relevance and occurrence in food and feed is still largely unexplored. The analysis of modified mycotoxins by liquid chromatography–mass spectrometry remains a challenge because of their chemical diversity, the large number of isomeric forms, and the lack of analytical standards. Here, the potential benefits of high-resolution and ion mobility mass spectrometry as a tool for separation and structure confirmation of modified mycotoxins have been investigated/reviewed. PMID:27918432

LMJ Points Plus v2.6

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kertesz, Vilmos

Short summary of the software's functionality: • built-in scan feature to acquire optical image of the surface to be analyzed • click-and-point selection of points of interest on the surface • supporting standalone autosampler/HPLC/MS operation: creating independent batch files after points of interests are selected for LEAPShell (autosampler control software from Leap Technologies) and Analyst® (mass spectrometry (MS) software from AB Sciex) • supporting integrated autosampler/HPLC/MS operation: creating one batch file for all instruments controlled by Analyst® (mass spectrometry software from AB Sciex) after points of interests are selected •creating heatmaps of analytes of interests from collected MS files inmore » a hand-off fashion« less

Organic Molecules in the Sheepbed Mudstone, Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Freissinet, C.; Glavin, D. P.; Mahaffy, P. R.; Miller, K. E.; Eigenbrode, J. L.; Summons, R. E.; Brunner, A. E.; Buch, A.; Szopa, C.; Archer, P. D.;

A review on recent developments in mass spectrometry instrumentation and quantitative tools advancing bacterial proteomics.

PubMed

Van Oudenhove, Laurence; Devreese, Bart

2013-06-01

Proteomics has evolved substantially since its early days, some 20 years ago. In this mini-review, we aim to provide an overview of general methodologies and more recent developments in mass spectrometric approaches used for relative and absolute quantitation of proteins. Enhancement of sensitivity of the mass spectrometers as well as improved sample preparation and protein fractionation methods are resulting in a more comprehensive analysis of proteomes. We also document some upcoming trends for quantitative proteomics such as the use of label-free quantification methods. Hopefully, microbiologists will continue to explore proteomics as a tool in their research to understand the adaptation of microorganisms to their ever changing environment. We encourage them to incorporate some of the described new developments in mass spectrometry to facilitate their analyses and improve the general knowledge of the fascinating world of microorganisms.

Mechanical and electrostatic experiments with dust particles collected in the inner coma of comet 67P by COSIMA onboard Rosetta.

PubMed

Hilchenbach, Martin; Fischer, Henning; Langevin, Yves; Merouane, Sihane; Paquette, John; Rynö, Jouni; Stenzel, Oliver; Briois, Christelle; Kissel, Jochen; Koch, Andreas; Schulz, Rita; Silen, Johan; Altobelli, Nicolas; Baklouti, Donia; Bardyn, Anais; Cottin, Herve; Engrand, Cecile; Fray, Nicolas; Haerendel, Gerhard; Henkel, Hartmut; Höfner, Herwig; Hornung, Klaus; Lehto, Harry; Mellado, Eva Maria; Modica, Paola; Le Roy, Lena; Siljeström, Sandra; Steiger, Wolfgang; Thirkell, Laurent; Thomas, Roger; Torkar, Klaus; Varmuza, Kurt; Zaprudin, Boris

2017-07-13

The in situ cometary dust particle instrument COSIMA (COmetary Secondary Ion Mass Analyser) onboard ESA's Rosetta mission has collected about 31 000 dust particles in the inner coma of comet 67P/Churyumov-Gerasimenko since August 2014. The particles are identified by optical microscope imaging and analysed by time-of-flight secondary ion mass spectrometry. After dust particle collection by low speed impact on metal targets, the collected particle morphology points towards four families of cometary dust particles. COSIMA is an in situ laboratory that operates remotely controlled next to the comet nucleus. The particles can be further manipulated within the instrument by mechanical and electrostatic means after their collection by impact. The particles are stored above 0°C in the instrument and the experiments are carried out on the refractory, ice-free matter of the captured cometary dust particles. An interesting particle morphology class, the compact particles, is not fragmented on impact. One of these particles was mechanically pressed and thereby crushed into large fragments. The particles are good electrical insulators and transform into rubble pile agglomerates by the application of an energetic indium ion beam during the secondary ion mass spectrometry analysis.This article is part of the themed issue 'Cometary science after Rosetta'. © 2017 The Author(s).

Estimating the Efficiency of Phosphopeptide Identification by Tandem Mass Spectrometry

NASA Astrophysics Data System (ADS)

Hsu, Chuan-Chih; Xue, Liang; Arrington, Justine V.; Wang, Pengcheng; Paez Paez, Juan Sebastian; Zhou, Yuan; Zhu, Jian-Kang; Tao, W. Andy

2017-06-01

Mass spectrometry has played a significant role in the identification of unknown phosphoproteins and sites of phosphorylation in biological samples. Analyses of protein phosphorylation, particularly large scale phosphoproteomic experiments, have recently been enhanced by efficient enrichment, fast and accurate instrumentation, and better software, but challenges remain because of the low stoichiometry of phosphorylation and poor phosphopeptide ionization efficiency and fragmentation due to neutral loss. Phosphoproteomics has become an important dimension in systems biology studies, and it is essential to have efficient analytical tools to cover a broad range of signaling events. To evaluate current mass spectrometric performance, we present here a novel method to estimate the efficiency of phosphopeptide identification by tandem mass spectrometry. Phosphopeptides were directly isolated from whole plant cell extracts, dephosphorylated, and then incubated with one of three purified kinases—casein kinase II, mitogen-activated protein kinase 6, and SNF-related protein kinase 2.6—along with 16O4- and 18O4-ATP separately for in vitro kinase reactions. Phosphopeptides were enriched and analyzed by LC-MS. The phosphopeptide identification rate was estimated by comparing phosphopeptides identified by tandem mass spectrometry with phosphopeptide pairs generated by stable isotope labeled kinase reactions. Overall, we found that current high speed and high accuracy mass spectrometers can only identify 20%-40% of total phosphopeptides primarily due to relatively poor fragmentation, additional modifications, and low abundance, highlighting the urgent need for continuous efforts to improve phosphopeptide identification efficiency. [Figure not available: see fulltext.

Continued Development of in Situ Geochronology for Planetary Missions

NASA Technical Reports Server (NTRS)

Devismes, D.; Cohen, B. A.

2015-01-01

The instrument 'Potassium (K) Argon Laser Experiment' (KArLE) is developed and designed for in situ absolute dating of rocks on planetary surfaces. It is based on the K-Ar dating method and uses the Laser Induced Breakdown Spectroscopy - Laser Ablation - Quadrupole Mass Spectrometry (LIBSLA- QMS) technique. We use a dedicated interface to combine two instruments similar to SAM of Mars Science Laboratory (for the QMS) and ChemCam (for the LA and LIBS). The prototype has demonstrated that KArLE is a suitable and promising instrument for in situ absolute dating.

An in-depth evaluation of accuracy and precision in Hg isotopic analysis via pneumatic nebulization and cold vapor generation multi-collector ICP-mass spectrometry.

PubMed

Rua-Ibarz, Ana; Bolea-Fernandez, Eduardo; Vanhaecke, Frank

2016-01-01

Mercury (Hg) isotopic analysis via multi-collector inductively coupled plasma (ICP)-mass spectrometry (MC-ICP-MS) can provide relevant biogeochemical information by revealing sources, pathways, and sinks of this highly toxic metal. In this work, the capabilities and limitations of two different sample introduction systems, based on pneumatic nebulization (PN) and cold vapor generation (CVG), respectively, were evaluated in the context of Hg isotopic analysis via MC-ICP-MS. The effect of (i) instrument settings and acquisition parameters, (ii) concentration of analyte element (Hg), and internal standard (Tl)-used for mass discrimination correction purposes-and (iii) different mass bias correction approaches on the accuracy and precision of Hg isotope ratio results was evaluated. The extent and stability of mass bias were assessed in a long-term study (18 months, n = 250), demonstrating a precision ≤0.006% relative standard deviation (RSD). CVG-MC-ICP-MS showed an approximately 20-fold enhancement in Hg signal intensity compared with PN-MC-ICP-MS. For CVG-MC-ICP-MS, the mass bias induced by instrumental mass discrimination was accurately corrected for by using either external correction in a sample-standard bracketing approach (SSB) or double correction, consisting of the use of Tl as internal standard in a revised version of the Russell law (Baxter approach), followed by SSB. Concomitant matrix elements did not affect CVG-ICP-MS results. Neither with PN, nor with CVG, any evidence for mass-independent discrimination effects in the instrument was observed within the experimental precision obtained. CVG-MC-ICP-MS was finally used for Hg isotopic analysis of reference materials (RMs) of relevant environmental origin. The isotopic composition of Hg in RMs of marine biological origin testified of mass-independent fractionation that affected the odd-numbered Hg isotopes. While older RMs were used for validation purposes, novel Hg isotopic data are provided for the latest generations of some biological RMs.

Correcting systematic bias and instrument measurement drift with mzRefinery

DOE PAGES

Gibbons, Bryson C.; Chambers, Matthew C.; Monroe, Matthew E.; ...

2015-08-04

Systematic bias in mass measurement adversely affects data quality and negates the advantages of high precision instruments. We introduce the mzRefinery tool into the ProteoWizard package for calibration of mass spectrometry data files. Using confident peptide spectrum matches, three different calibration methods are explored and the optimal transform function is chosen. After calibration, systematic bias is removed and the mass measurement errors are centered at zero ppm. Because it is part of the ProteoWizard package, mzRefinery can read and write a wide variety of file formats. In conclusion, we report on availability; the mzRefinery tool is part of msConvert, availablemore » with the ProteoWizard open source package at http://proteowizard.sourceforge.net/« less

High energy collisions on tandem time-of-flight mass spectrometers†

PubMed Central

Cotter, Robert J.

2013-01-01

Long before the introduction of matrix-assisted laser desorption (MALDI), electrospray ionization (ESI), Orbitraps and any of the other tools that are now used ubiquitously for proteomics and metabolomics, the highest performance mass spectrometers were sector instruments, providing high resolution mass measurements by combining an electrostatic energy analyzer (E) with a high field magnet (B). In its heyday, the four sector mass spectrometer (or EBEB) was the crown jewel, providing the highest performance tandem mass spectrometry using single, high energy collisions to induce fragmentation. During a time in which quadrupole and tandem triple quadrupole instruments were also enjoying increased usage and popularity, there were nonetheless some clear advantages for sectors over their low collision energy counterparts. Time-of-flight mass spectrometers are high voltage, high vacuum instruments that have much in common with sectors and have inspired the development of tandem instruments exploiting single high energy collisions. In this retrospective we recount our own journey to produce high performance time-of-flights and tandems, describing the basic theory, problems and the advantages for such instruments. An experiment testing impulse collision theory (ICT) underscores the similarities with sector mass spectrometers where this concept was first developed. Applications provide examples of more extensive fragmentation, side chain cleavages and charge-remote fragmentation, also characteristic of high energy sector mass spectrometers. Moreover, the so-called curved-field reflectron has enabled the design of instruments that are simpler, collect and focus all of the ions, and may provide the future technology for the clinic, for tissue imaging and the characterization of microorganisms. PMID:23519928

FieldSpec: A field portable mass spectrometer prototype for high frequency measurements of δ (2) H and δ (18) O ratios in water

NASA Astrophysics Data System (ADS)

López Días, Veneranda; Quang Hoang, Hung; Martínez-Carreras, Núria; Barnich, François; Wirtz, Tom; Pfister, Laurent; McDonnell, Jeffrey

2016-04-01

Hydrological studies relying on stable water isotopes to better understand water sources, flowpaths and transit times are currently limited by the coarse temporal resolution of sampling and analysis protocols. At present, two kinds of lab-based instruments are used : (i) the standard isotope ratio mass spectrometers (IRMS) [1] and (ii) the laser-based instruments [2, 3]. In both cases, samples need to be collected in the field and then transferred to the laboratory for the water isotopic ratio measurements (even further complex sample preparation is required for the IRMS). Hence, past and ongoing research targets the development of field deployable instruments for measuring stable water isotopes at high temporal frequencies. While recent studies have demonstrated that laser-based instruments may be taken to the field [4, 5], their size and power consumption still restrict their use to sites equipped with mains power or generators. Here, we present progress on the development of a field portable mass spectrometer (FieldSpec) for direct high frequency measurements of δ2H and δ18O ratios in water. The FieldSpec instrument is based upon the use of a double focusing magnetic sector mass spectrometer in combination with an electron impact ion source and a membrane dual inlet system. The instrument directly collects liquid water samples in the field, which are then converted into water vapour before being injected into the mass spectrometer for the stable isotope analysis. δ2H and δ18O are derived from the measured mass spectra. All the components are arranged in a vacuum case having a suit case type dimension with portable electronics and battery. Proof-of-concept experiments have been carried out to characterize the instrument. The results show that the FieldSpec instrument has good linearity (R2 = 0.99). The reproducibility of the instrument ranges between 1 and 4 ‰ for δ2H and between 0.1 and 0.4 ‰ for δ18O isotopic ratio measurements. A measurement frequency of less than 60 minutes per sample has been achieved. We intend to further increase the measurement frequency in the near future. In this presentation, we will describe the instrument, present experimental data reflecting its performance and discuss applications. [1] de Groot, P.A., 2004. Handbook of Stable Isotope Analytical Techniques, Vol.1. Elsevier, Amsterdam, 1234 pp [2] Lis, G., Wassenaar, L.I., Hendry, M.J., 2008. Analytical Chemistry 80 (1), 287-293. [3] Brand, W.A., Geilmann, H., Crosson, E.R., Rella, C.W., 2009. Rapid Communications in Mass Spectrometry 23, 1879-1884. [4] Berman, E.S.F., Gupta, M., Gabrielli, C., Garland, T., McDonnell, J.J., 2009. Water Resources Research 45 W1020, 1-7. [5] Munksgaard, N.C., Wurster, C.M., Bird, M.I., 2011. Rapid Communication Mass Spectrometry 25, 3706-3712.

ARSENIC DETERMINATION IN SALINE WATERS BY HYDRIDE GENERATION - INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY.

EPA Science Inventory

The determination of arsenic in estuarine waters usually involves a matrix removal and/or pre-concentration prior to analysis because of the high salt content in these waters. The salinity also produces analytical challenges in terms of interferences and instrument stability. A...

Advanced Laser Architecture for Two-Step Laser Tandem Mass Spectrometer

NASA Technical Reports Server (NTRS)

Fahey, Molly E.; Li, Steven X.; Yu, Anthony W.; Getty, Stephanie A.

2016-01-01

Future astrobiology missions will focus on planets with significant astrochemical or potential astrobiological features, such as small, primitive bodies and the icy moons of the outer planets that may host diverse organic compounds. These missions require advanced instrument techniques to fully and unambiguously characterize the composition of surface and dust materials. Laser desorptionionization mass spectrometry (LDMS) is an emerging instrument technology for in situ mass analysis of non-volatile sample composition. A recent Goddard LDMS advancement is the two-step laser tandem mass spectrometer (L2MS) instrument to address the need for future flight instrumentation to deconvolve complex organic signatures. The L2MS prototype uses a resonance enhanced multi-photon laser ionization mechanism to selectively detect aromatic species from a more complex sample. By neglecting the aliphatic and inorganic mineral signatures in the two-step mass spectrum, the L2MS approach can provide both mass assignments and clues to structural information for an in situ investigation of non-volatile sample composition. In this paper we will describe our development effort on a new laser architecture that is based on the previously flown Lunar Orbiter Laser Altimeter (LOLA) laser transmitter for the L2MS instrument. The laser provides two discrete midinfrared wavelengths (2.8 m and 3.4 m) using monolithic optical parametric oscillators and ultraviolet (UV) wavelength (266 nm) on a single laser bench with a straightforward development path toward flight readiness.

Measurement and Visualization of Mass Transport for the Flowing Atmospheric Pressure Afterglow (FAPA) Ambient Mass-Spectrometry Source

PubMed Central

Pfeuffer, Kevin P.; Ray, Steven J.; Hieftje, Gary M.

2014-01-01

Ambient desorption/ionization mass spectrometry (ADI-MS) has developed into an important analytical field over the last nine years. The ability to analyze samples under ambient conditions while retaining the sensitivity and specificity of mass spectrometry has led to numerous applications and a corresponding jump in the popularity of this field. Despite the great potential of ADI-MS, problems remain in the areas of ion identification and quantification. Difficulties with ion identification can be solved through modified instrumentation, including accurate-mass or MS/MS capabilities for analyte identification. More difficult problems include quantification due to the ambient nature of the sampling process. To characterize and improve sample volatilization, ionization, and introduction into the mass-spectrometer interface, a method of visualizing mass transport into the mass spectrometer is needed. Schlieren imaging is a well-established technique that renders small changes in refractive index visible. Here, schlieren imaging was used to visualize helium flow from a plasma-based ADI-MS source into a mass spectrometer while ion signals were recorded. Optimal sample positions for melting-point capillary and transmission-mode (stainless steel mesh) introduction were found to be near (within 1 mm of) the mass spectrometer inlet. Additionally, the orientation of the sampled surface plays a significant role. More efficient mass transport resulted for analyte deposits directly facing the MS inlet. Different surfaces (glass slide and rough surface) were also examined; for both it was found that the optimal position is immediately beneath the MS inlet. PMID:24658804

Measurement and visualization of mass transport for the flowing atmospheric pressure afterglow (FAPA) ambient mass-spectrometry source.

PubMed

Pfeuffer, Kevin P; Ray, Steven J; Hieftje, Gary M

2014-05-01

Ambient desorption/ionization mass spectrometry (ADI-MS) has developed into an important analytical field over the last 9 years. The ability to analyze samples under ambient conditions while retaining the sensitivity and specificity of mass spectrometry has led to numerous applications and a corresponding jump in the popularity of this field. Despite the great potential of ADI-MS, problems remain in the areas of ion identification and quantification. Difficulties with ion identification can be solved through modified instrumentation, including accurate-mass or MS/MS capabilities for analyte identification. More difficult problems include quantification because of the ambient nature of the sampling process. To characterize and improve sample volatilization, ionization, and introduction into the mass spectrometer interface, a method of visualizing mass transport into the mass spectrometer is needed. Schlieren imaging is a well-established technique that renders small changes in refractive index visible. Here, schlieren imaging was used to visualize helium flow from a plasma-based ADI-MS source into a mass spectrometer while ion signals were recorded. Optimal sample positions for melting-point capillary and transmission-mode (stainless steel mesh) introduction were found to be near (within 1 mm of) the mass spectrometer inlet. Additionally, the orientation of the sampled surface plays a significant role. More efficient mass transport resulted for analyte deposits directly facing the MS inlet. Different surfaces (glass slide and rough surface) were also examined; for both it was found that the optimal position is immediately beneath the MS inlet.

Measurement and Visualization of Mass Transport for the Flowing Atmospheric Pressure Afterglow (FAPA) Ambient Mass-Spectrometry Source

NASA Astrophysics Data System (ADS)

Pfeuffer, Kevin P.; Ray, Steven J.; Hieftje, Gary M.

2014-05-01

Ambient desorption/ionization mass spectrometry (ADI-MS) has developed into an important analytical field over the last 9 years. The ability to analyze samples under ambient conditions while retaining the sensitivity and specificity of mass spectrometry has led to numerous applications and a corresponding jump in the popularity of this field. Despite the great potential of ADI-MS, problems remain in the areas of ion identification and quantification. Difficulties with ion identification can be solved through modified instrumentation, including accurate-mass or MS/MS capabilities for analyte identification. More difficult problems include quantification because of the ambient nature of the sampling process. To characterize and improve sample volatilization, ionization, and introduction into the mass spectrometer interface, a method of visualizing mass transport into the mass spectrometer is needed. Schlieren imaging is a well-established technique that renders small changes in refractive index visible. Here, schlieren imaging was used to visualize helium flow from a plasma-based ADI-MS source into a mass spectrometer while ion signals were recorded. Optimal sample positions for melting-point capillary and transmission-mode (stainless steel mesh) introduction were found to be near (within 1 mm of) the mass spectrometer inlet. Additionally, the orientation of the sampled surface plays a significant role. More efficient mass transport resulted for analyte deposits directly facing the MS inlet. Different surfaces (glass slide and rough surface) were also examined; for both it was found that the optimal position is immediately beneath the MS inlet.

Protein Sequencing with Tandem Mass Spectrometry

NASA Astrophysics Data System (ADS)

Ziady, Assem G.; Kinter, Michael

The recent introduction of electrospray ionization techniques that are suitable for peptides and whole proteins has allowed for the design of mass spectrometric protocols that provide accurate sequence information for proteins. The advantages gained by these approaches over traditional Edman Degradation sequencing include faster analysis and femtomole, sometimes attomole, sensitivity. The ability to efficiently identify proteins has allowed investigators to conduct studies on their differential expression or modification in response to various treatments or disease states. In this chapter, we discuss the use of electrospray tandem mass spectrometry, a technique whereby protein-derived peptides are subjected to fragmentation in the gas phase, revealing sequence information for the protein. This powerful technique has been instrumental for the study of proteins and markers associated with various disorders, including heart disease, cancer, and cystic fibrosis. We use the study of protein expression in cystic fibrosis as an example.

Sequencing of Oligourea Foldamers by Tandem Mass Spectrometry

NASA Astrophysics Data System (ADS)

Bathany, Katell; Owens, Neil W.; Guichard, Gilles; Schmitter, Jean-Marie

2013-03-01

This study is focused on sequence analysis of peptidomimetic helical oligoureas by means of tandem mass spectrometry, to build a basis for de novo sequencing for future high-throughput combinatorial library screening of oligourea foldamers. After the evaluation of MS/MS spectra obtained for model compounds with either MALDI or ESI sources, we found that the MALDI-TOF-TOF instrument gave more satisfactory results. MS/MS spectra of oligoureas generated by decay of singly charged precursor ions show major ion series corresponding to fragmentation across both CO-NH and N'H-CO urea bonds. Oligourea backbones fragment to produce a pattern of a, x, b, and y type fragment ions. De novo decoding of spectral information is facilitated by the occurrence of low mass reporter ions, representative of constitutive monomers, in an analogous manner to the use of immonium ions for peptide sequencing.

In Situ Pre-Selection of Return Samples with Bio-Signatures by Combined Laser Mass Spectrometry and Optical Microscopy

NASA Astrophysics Data System (ADS)

Wiesendanger, R.; Wurz, P.; Tulej, M.; Wacey, D.; Neubeck, A.; Grimaudo, V.; Riedo, A.; Moreno, P.; Cedeño-López, A.; Ivarsson, M.

2018-04-01

The University of Bern developed instrument prototypes that allow analysis of samples on Mars prior to bringing them back to Earth, allowing to maximize the scientific outcome of the returned samples. We will present the systems and first results.

Current and state-of-the-art approaches for detecting mycotoxins in commodities

USDA-ARS?s Scientific Manuscript database

The tools that have been applied to detection of mycotoxins in commodities are numerous and powerful. These include everything from simple to use diagnostic test strips to complex, instrument intensive, methods such as ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS). This wi...

Laser spectrometer for CO2 clumped isotope analysis

NASA Astrophysics Data System (ADS)

Prokhorov, Ivan; Kluge, Tobias; Janssen, Christof

2017-04-01

Carbon dioxide clumped isotope thermometry has proven to be a reliable method for biogeochemical and atmospheric research. We present a new laser spectroscopic instrument for doubly-substituted isotopologues analysis. In contrast to a conventional isotope ratio mass spectrometry (IRMS), tunable laser direct absorption spectroscopy (TLDAS) has the advantage of isotopologue-specific determination free of isobaric interferences. Tunable infrared laser based spectrometer for clumped isotope analysis is being developed in collaboration between Heidelberg University, Germany, and LERMA-IPSL, CNRS, France. The instrument employs two continuous intraband cascade lasers (ICL) tuned at 4439 and 4329 nm. The spectral windows covered by the lasers contain absorption lines of the six most abundant CO2 isotopologues, including the two doubly substituted species 16O13C18O and 16O13C17O, and all singly substituted isotopologues with 13C, 18O and 17O. A Herriott-type multi-pass cell provides two different absorption pathlengths to compensate the abundance difference between singly- and doubly-substituted isotopologues. We have reached the sub-permill precision required for clumped isotope measurements within the integration time of several seconds. The test version of the instrument demonstrates a performance comparable to state of the art IRMS. We highlight the following features of the instrument that are strong advantages compared to conventional mass spectrometry: measurement cycle in the minute range, simplified sample preparation routine, table-top layout with a potential for in-situ applications.

Generic sample preparation combined with high-resolution liquid chromatography-time-of-flight mass spectrometry for unification of urine screening in doping-control laboratories.

PubMed

Peters, R J B; Oosterink, J E; Stolker, A A M; Georgakopoulos, C; Nielen, M W F

2010-04-01

A unification of doping-control screening procedures of prohibited small molecule substances--including stimulants, narcotics, steroids, beta2-agonists and diuretics--is highly urgent in order to free resources for new classes such as banned proteins. Conceptually this may be achieved by the use of a combination of one gas chromatography-time-of-flight mass spectrometry method and one liquid chromatography-time-of-flight mass spectrometry method. In this work a quantitative screening method using high-resolution liquid chromatography in combination with accurate-mass time-of-flight mass spectrometry was developed and validated for determination of glucocorticosteroids, beta2-agonists, thiazide diuretics, and narcotics and stimulants in urine. To enable the simultaneous isolation of all the compounds of interest and the necessary purification of the resulting extracts, a generic extraction and hydrolysis procedure was combined with a solid-phase extraction modified for these groups of compounds. All 56 compounds are determined using positive electrospray ionisation with the exception of the thiazide diuretics for which the best sensitivity was obtained by using negative electrospray ionisation. The results show that, with the exception of clenhexyl, procaterol, and reproterol, all compounds can be detected below the respective minimum required performance level and the results for linearity, repeatability, within-lab reproducibility, and accuracy show that the method can be used for quantitative screening. If qualitative screening is sufficient the instrumental analysis may be limited to positive ionisation, because all analytes including the thiazides can be detected at the respective minimum required levels in the positive mode. The results show that the application of accurate-mass time-of-flight mass spectrometry in combination with generic extraction and purification procedures is suitable for unification and expansion of the window of screening methods of doping laboratories. Moreover, the full-scan accurate-mass data sets obtained still allow retrospective examination for emerging doping agents, without re-analyzing the samples.

Characterization of Long-Chain Fatty Acid as N-(4-Aminomethylphenyl) Pyridinium Derivative by MALDI LIFT-TOF/TOF Mass Spectrometry

NASA Astrophysics Data System (ADS)

Frankfater, Cheryl; Jiang, Xuntian; Hsu, Fong-Fu

2018-05-01

Charge remote fragmentation (CRF) elimination of CnH2n+2 residues along the aliphatic tail of long chain fatty acid is hall mark of keV high-energy CID fragmentation process. It is an important fragmentation pathway leading to structural characterization of biomolecules by CID tandem mass spectrometry. In this report, we describe MALDI LIFT TOF-TOF mass spectrometric approach to study a wide variety of fatty acids (FAs), which were derivatized to N-(4-aminomethylphenyl) pyridinium (AMPP) derivative, and desorbed as M+ ions by laser with or without matrix. The high-energy MALDI LIFT TOF-TOF mass spectra of FA-AMPP contain fragment ions mainly deriving from CRF cleavages of CnH2n+2 residues, as expected. These ions together with ions from specific cleavages of the bond(s) involving the functional group within the molecule provide more complete structural identification than those produced by low-energy CID/HCD using a linear ion-trap instrument. However, this LIFT TOF-TOF mass spectrometric approach inherits low sensitivity, a typical feature of high-energy CID tandem mass spectrometry. Because of the lack of unit mass precursor ion selection with sufficient sensitivity of the current LIFT TOF-TOF technology, product ion spectra from same chain length fatty acids with difference in one or two double bonds in a mixture are not distinguishable.

Electrospray ionization tandem mass spectrometry of ammonium cationized polyethers.

PubMed

Nasioudis, Andreas; Heeren, Ron M A; van Doormalen, Irene; de Wijs-Rot, Nicolette; van den Brink, Oscar F

2011-05-01

Quaternary ammonium salts (Quats) and amines are known to facilitate the MS analysis of high molar mass polyethers by forming low charge state adduct ions. The formation, stability, and behavior upon collision-induced dissociation (CID) of adduct ions of polyethers with a variety of Quats and amines were studied by electrospray ionization quadrupole time-of-flight, quadrupole ion trap, and linear ion trap tandem mass spectrometry (MS/MS). The linear ion trap instrument was part of an Orbitrap hybrid mass spectrometer that allowed accurate mass MS/MS measurements. The Quats and amines studied were of different degree of substitution, structure, and size. The stability of the adduct ions was related to the structure of the cation, especially the amine's degree of substitution. CID of singly/doubly charged primary and tertiary ammonium cationized polymers resulted in the neutral loss of the amine followed by fragmentation of the protonated product ions. The latter reveals information about the monomer unit, polymer sequence, and endgroup structure. In addition, the detection of product ions retaining the ammonium ion was observed. The predominant process in the CID of singly charged quaternary ammonium cationized polymers was cation detachment, whereas their doubly charged adduct ions provided the same information as the primary and tertiary ammonium cationized adduct ions. This study shows the potential of specific amines as tools for the structural elucidation of high molar mass polyethers. © American Society for Mass Spectrometry, 2011

Stable isotope labelling methods in mass spectrometry-based quantitative proteomics.

PubMed

Chahrour, Osama; Cobice, Diego; Malone, John

2015-09-10

Mass-spectrometry based proteomics has evolved as a promising technology over the last decade and is undergoing a dramatic development in a number of different areas, such as; mass spectrometric instrumentation, peptide identification algorithms and bioinformatic computational data analysis. The improved methodology allows quantitative measurement of relative or absolute protein amounts, which is essential for gaining insights into their functions and dynamics in biological systems. Several different strategies involving stable isotopes label (ICAT, ICPL, IDBEST, iTRAQ, TMT, IPTL, SILAC), label-free statistical assessment approaches (MRM, SWATH) and absolute quantification methods (AQUA) are possible, each having specific strengths and weaknesses. Inductively coupled plasma mass spectrometry (ICP-MS), which is still widely recognised as elemental detector, has recently emerged as a complementary technique to the previous methods. The new application area for ICP-MS is targeting the fast growing field of proteomics related research, allowing absolute protein quantification using suitable elemental based tags. This document describes the different stable isotope labelling methods which incorporate metabolic labelling in live cells, ICP-MS based detection and post-harvest chemical label tagging for protein quantification, in addition to summarising their pros and cons. Copyright © 2015 Elsevier B.V. All rights reserved.

Background correction in separation techniques hyphenated to high-resolution mass spectrometry - Thorough correction with mass spectrometry scans recorded as profile spectra.

PubMed

Erny, Guillaume L; Acunha, Tanize; Simó, Carolina; Cifuentes, Alejandro; Alves, Arminda

2017-04-07

Separation techniques hyphenated with high-resolution mass spectrometry have been a true revolution in analytical separation techniques. Such instruments not only provide unmatched resolution, but they also allow measuring the peaks accurate masses that permit identifying monoisotopic formulae. However, data files can be large, with a major contribution from background noise and background ions. Such unnecessary contribution to the overall signal can hide important features as well as decrease the accuracy of the centroid determination, especially with minor features. Thus, noise and baseline correction can be a valuable pre-processing step. The methodology that is described here, unlike any other approach, is used to correct the original dataset with the MS scans recorded as profiles spectrum. Using urine metabolic studies as examples, we demonstrate that this thorough correction reduces the data complexity by more than 90%. Such correction not only permits an improved visualisation of secondary peaks in the chromatographic domain, but it also facilitates the complete assignment of each MS scan which is invaluable to detect possible comigration/coeluting species. Copyright © 2017 Elsevier B.V. All rights reserved.

Time‐of‐flight secondary ion mass spectrometry imaging of biological samples with delayed extraction for high mass and high spatial resolutions

PubMed Central

Vanbellingen, Quentin P.; Elie, Nicolas; Eller, Michael J.; Della‐Negra, Serge; Touboul, David

2015-01-01

Rationale In Time‐of‐Flight Secondary Ion Mass Spectrometry (TOF‐SIMS), pulsed and focused primary ion beams enable mass spectrometry imaging, a method which is particularly useful to map various small molecules such as lipids at the surface of biological samples. When using TOF‐SIMS instruments, the focusing modes of the primary ion beam delivered by liquid metal ion guns can provide either a mass resolution of several thousand or a sub‐µm lateral resolution, but the combination of both is generally not possible. Methods With a TOF‐SIMS setup, a delayed extraction applied to secondary ions has been studied extensively on rat cerebellum sections in order to compensate for the effect of long primary ion bunches. Results The use of a delayed extraction has been proven to be an efficient solution leading to unique features, i.e. a mass resolution up to 10000 at m/z 385.4 combined with a lateral resolution of about 400 nm. Simulations of ion trajectories confirm the experimental determination of optimal delayed extraction and allow understanding of the behavior of ions as a function of their mass‐to‐charge ratio. Conclusions Although the use of a delayed extraction has been well known for many years and is very popular in MALDI, it is much less used in TOF‐SIMS. Its full characterization now enables secondary ion images to be recorded in a single run with a submicron spatial resolution and with a mass resolution of several thousand. This improvement is very useful when analyzing lipids on tissue sections, or rare, precious, or very small size samples. © 2015 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons Ltd. PMID:26395603

Mass spectrometry of peptides and proteins from human blood.

PubMed

Zhu, Peihong; Bowden, Peter; Zhang, Du; Marshall, John G

2011-01-01

It is difficult to convey the accelerating rate and growing importance of mass spectrometry applications to human blood proteins and peptides. Mass spectrometry can rapidly detect and identify the ionizable peptides from the proteins in a simple mixture and reveal many of their post-translational modifications. However, blood is a complex mixture that may contain many proteins first expressed in cells and tissues. The complete analysis of blood proteins is a daunting task that will rely on a wide range of disciplines from physics, chemistry, biochemistry, genetics, electromagnetic instrumentation, mathematics and computation. Therefore the comprehensive discovery and analysis of blood proteins will rank among the great technical challenges and require the cumulative sum of many of mankind's scientific achievements together. A variety of methods have been used to fractionate, analyze and identify proteins from blood, each yielding a small piece of the whole and throwing the great size of the task into sharp relief. The approaches attempted to date clearly indicate that enumerating the proteins and peptides of blood can be accomplished. There is no doubt that the mass spectrometry of blood will be crucial to the discovery and analysis of proteins, enzyme activities, and post-translational processes that underlay the mechanisms of disease. At present both discovery and quantification of proteins from blood are commonly reaching sensitivities of ∼1 ng/mL. Copyright © 2010 Wiley Periodicals, Inc.

Mass spectrometry of the photolysis of sulfonylurea herbicides in Prairie waters.

PubMed

Headley, John V; Du, Jing-Long; Peru, Kerry M; McMartin, Dena W

2010-01-01

This review of mass spectrometry of sulfonylurea herbicides includes a focus on studies relevant to Canadian Prairie waters. Emphasis is given to data gaps in the literature for the rates of photolysis of selected sulfonylurea herbicides in different water matrices. Specifically, results are evaluated for positive ion electrospray tandem mass spectrometry with liquid chromatography separation for the study of the photolysis of chlorsulfuron, tribenuron-methyl, thifensulfuron-methyl, metsulfuron-methyl, and ethametsulfuron-methyl. LC-MS/MS is shown to be the method of choice for the quantification of sulfonylurea herbicides with instrumental detection limits ranging from 1.3 to 7.2 pg (on-column). Tandem mass spectrometry coupled with the use of authentic standards likewise has proven to be well suited for the identification of transformation products. To date, however, the power of time-of-flight MS and ultrahigh resolution MS has not been exploited fully for the identification of unknown photolysis products. Dissipation of the herbicides under natural sunlight fit pseudo-first-order kinetics with half-life values ranging from 4.4 to 99 days. For simulated sunlight, radiation wavelengths shorter than 400 nm are required to induce significant photolytic reactions. The correlation between field dissipation studies and laboratory photolysis experiments suggests that photolysis is a major pathway for the dissipation of some sulfonylurea herbicides in natural Prairie waters. 2009 Wiley Periodicals, Inc.

Determining Double Bond Position in Lipids Using Online Ozonolysis Coupled to Liquid Chromatography and Ion Mobility-Mass Spectrometry.

PubMed

Harris, Rachel A; May, Jody C; Stinson, Craig A; Xia, Yu; McLean, John A

2018-02-06

The increasing focus on lipid metabolism has revealed a need for analytical techniques capable of structurally characterizing lipids with a high degree of specificity. Lipids can exist as any one of a large number of double bond positional isomers, which are indistinguishable by single-stage mass spectrometry alone. Ozonolysis reactions coupled to mass spectrometry have previously been demonstrated as a means for localizing double bonds in unsaturated lipids. Here we describe an online, solution-phase reactor using ozone produced via a low-pressure mercury lamp, which generates aldehyde products diagnostic of cleavage at a particular double bond position. This flow-cell device is utilized in conjunction with structurally selective ion mobility-mass spectrometry. The lamp-mediated reaction was found to be effective for multiple lipid species in both positive and negative ionization modes, and the conversion efficiency from precursor to product ions was tunable across a wide range (20-95%) by varying the flow rate through the ozonolysis device. Ion mobility separation of the ozonolysis products generated additional structural information and revealed the presence of saturated species in a complex mixture. The method presented here is simple, robust, and readily coupled to existing instrument platforms with minimal modifications necessary. For these reasons, application to standard lipidomic workflows is possible and aids in more comprehensive structural characterization of a myriad of lipid species.

MALDI-TOF mass spectrometry and high-consequence bacteria: safety and stability of biothreat bacterial sample testing in clinical diagnostic laboratories.

PubMed

Tracz, Dobryan M; Tober, Ashley D; Antonation, Kym S; Corbett, Cindi R

2018-03-01

We considered the application of MALDI-TOF mass spectrometry for BSL-3 bacterial diagnostics, with a focus on the biosafety of live-culture direct-colony testing and the stability of stored extracts. Biosafety level 2 (BSL-2) bacterial species were used as surrogates for BSL-3 high-consequence pathogens in all live-culture MALDI-TOF experiments. Viable BSL-2 bacteria were isolated from MALDI-TOF mass spectrometry target plates after 'direct-colony' and 'on-plate' extraction testing, suggesting that the matrix chemicals alone cannot be considered sufficient to inactivate bacterial culture and spores in all samples. Sampling of the instrument interior after direct-colony analysis did not recover viable organisms, suggesting that any potential risks to the laboratory technician are associated with preparation of the MALDI-TOF target plate before or after testing. Secondly, a long-term stability study (3 years) of stored MALDI-TOF extracts showed that match scores can decrease below the threshold for reliable species identification (<1.7), which has implications for proficiency test panel item storage and distribution.

High-resolution measurement of DMS and volatile organic compounds dissolved in seawater using equilibrator inlet-proton transfer reaction-mass spectrometry (EI-PTR-MS)

NASA Astrophysics Data System (ADS)

Kameyama, S.; Tanimoto, H.; Inomata, S.; Tsunogai, U.; Ooki, A.; Yokouchi, Y.; Takeda, S.; Obata, H.; Tsuda, A.; Uematsu, M.

2010-12-01

We developed an equilibrator inlet-proton transfer reaction-mass spectrometry (EI-PTR-MS) for high-resolution measurement of multiple volatile organic compounds (VOCs) dissolved in seawater. The equilibration of six VOC species (dimethyl sulfide (DMS), isoprene, propene, acetone, acetaldehyde, and methanol) between seawater and carrier gas, and the response time of the system were evaluated in the laboratory. While isoprene and propene are not in equilibrium associated with slow response time (≈ 15 min) due to low solubility, other species achieve complete equilibrium with overall response time within 2 min under the condition without water droplets on the inner wall of the headspace of the equilibrator. The EI-PTR-MS instrument was deployed during a cruise in the western North Pacific. For DMS and isoprene, comparison of EI-PTR-MS with a membrane tube equilibrator-gas chromatography/mass spectrometry was made, showing generally good agreement. EI-PTR-MS captured temporal variations of dissolved VOCs including small-scale variability, demonstrating the performance of EI-PTR-MS technique for continuous measurement of multiple VOCs in seawater.

Categorizing Cells on the Basis of their Chemical Profiles: Progress in Single-Cell Mass Spectrometry.

PubMed

Comi, Troy J; Do, Thanh D; Rubakhin, Stanislav S; Sweedler, Jonathan V

2017-03-22

The chemical differences between individual cells within large cellular populations provide unique information on organisms' homeostasis and the development of diseased states. Even genetically identical cell lineages diverge due to local microenvironments and stochastic processes. The minute sample volumes and low abundance of some constituents in cells hinder our understanding of cellular heterogeneity. Although amplification methods facilitate single-cell genomics and transcriptomics, the characterization of metabolites and proteins remains challenging both because of the lack of effective amplification approaches and the wide diversity in cellular constituents. Mass spectrometry has become an enabling technology for the investigation of individual cellular metabolite profiles with its exquisite sensitivity, large dynamic range, and ability to characterize hundreds to thousands of compounds. While advances in instrumentation have improved figures of merit, acquiring measurements at high throughput and sampling from large populations of cells are still not routine. In this Perspective, we highlight the current trends and progress in mass-spectrometry-based analysis of single cells, with a focus on the technologies that will enable the next generation of single-cell measurements.

Trans-Proteomic Pipeline, a standardized data processing pipeline for large-scale reproducible proteomics informatics

PubMed Central

Deutsch, Eric W.; Mendoza, Luis; Shteynberg, David; Slagel, Joseph; Sun, Zhi; Moritz, Robert L.

2015-01-01

Democratization of genomics technologies has enabled the rapid determination of genotypes. More recently the democratization of comprehensive proteomics technologies is enabling the determination of the cellular phenotype and the molecular events that define its dynamic state. Core proteomic technologies include mass spectrometry to define protein sequence, protein:protein interactions, and protein post-translational modifications. Key enabling technologies for proteomics are bioinformatic pipelines to identify, quantitate, and summarize these events. The Trans-Proteomics Pipeline (TPP) is a robust open-source standardized data processing pipeline for large-scale reproducible quantitative mass spectrometry proteomics. It supports all major operating systems and instrument vendors via open data formats. Here we provide a review of the overall proteomics workflow supported by the TPP, its major tools, and how it can be used in its various modes from desktop to cloud computing. We describe new features for the TPP, including data visualization functionality. We conclude by describing some common perils that affect the analysis of tandem mass spectrometry datasets, as well as some major upcoming features. PMID:25631240

Principles and Applications of Liquid Chromatography-Mass Spectrometry in Clinical Biochemistry

PubMed Central

Pitt, James J

2009-01-01

Liquid chromatography-mass spectrometry (LC-MS) is now a routine technique with the development of electrospray ionisation (ESI) providing a simple and robust interface. It can be applied to a wide range of biological molecules and the use of tandem MS and stable isotope internal standards allows highly sensitive and accurate assays to be developed although some method optimisation is required to minimise ion suppression effects. Fast scanning speeds allow a high degree of multiplexing and many compounds can be measured in a single analytical run. With the development of more affordable and reliable instruments, LC-MS is starting to play an important role in several areas of clinical biochemistry and compete with conventional liquid chromatography and other techniques such as immunoassay. PMID:19224008

Stable isotope dilution analysis of hydrologic samples by inductively coupled plasma mass spectrometry

USGS Publications Warehouse

Garbarino, John R.; Taylor, Howard E.

1987-01-01

Inductively coupled plasma mass spectrometry is employed in the determination of Ni, Cu, Sr, Cd, Ba, Ti, and Pb in nonsaline, natural water samples by stable isotope dilution analysis. Hydrologic samples were directly analyzed without any unusual pretreatment. Interference effects related to overlapping isobars, formation of metal oxide and multiply charged ions, and matrix composition were identified and suitable methods of correction evaluated. A comparability study snowed that single-element isotope dilution analysis was only marginally better than sequential multielement isotope dilution analysis. Accuracy and precision of the single-element method were determined on the basis of results obtained for standard reference materials. The instrumental technique was shown to be ideally suited for programs associated with certification of standard reference materials.

Liulin-type spectrometry-dosimetry instruments.

PubMed

Dachev, Ts; Dimitrov, Pl; Tomov, B; Matviichuk, Yu; Spurny, F; Ploc, O; Brabcova, K; Jadrnickova, I

2011-03-01

The main purpose of Liulin-type spectrometry-dosimetry instruments (LSDIs) is cosmic radiation monitoring at the workplaces. An LSDI functionally is a low mass, low power consumption or battery-operated dosemeter. LSDIs were calibrated in a wide range of radiation fields, including radiation sources, proton and heavy-ion accelerators and CERN-EC high-energy reference field. Since 2000, LSDIs have been used in the scientific programmes of four manned space flights on the American Laboratory and ESA Columbus modules and on the Russian segment of the International Space Station, one Moon spacecraft and three spacecraft around the Earth, one rocket, two balloons and many aircraft flights. In addition to relative low price, LSDIs have proved their ability to qualify the radiation field on the ground and on the above-mentioned carriers.

High-resolution quantitative imaging of mammalian and bacterial cells using stable isotope mass spectrometry.

PubMed

Lechene, Claude; Hillion, Francois; McMahon, Greg; Benson, Douglas; Kleinfeld, Alan M; Kampf, J Patrick; Distel, Daniel; Luyten, Yvette; Bonventre, Joseph; Hentschel, Dirk; Park, Kwon Moo; Ito, Susumu; Schwartz, Martin; Benichou, Gilles; Slodzian, Georges

2006-01-01

Secondary-ion mass spectrometry (SIMS) is an important tool for investigating isotopic composition in the chemical and materials sciences, but its use in biology has been limited by technical considerations. Multi-isotope imaging mass spectrometry (MIMS), which combines a new generation of SIMS instrument with sophisticated ion optics, labeling with stable isotopes, and quantitative image-analysis software, was developed to study biological materials. The new instrument allows the production of mass images of high lateral resolution (down to 33 nm), as well as the counting or imaging of several isotopes simultaneously. As MIMS can distinguish between ions of very similar mass, such as 12C15N- and 13C14N-, it enables the precise and reproducible measurement of isotope ratios, and thus of the levels of enrichment in specific isotopic labels, within volumes of less than a cubic micrometer. The sensitivity of MIMS is at least 1,000 times that of 14C autoradiography. The depth resolution can be smaller than 1 nm because only a few atomic layers are needed to create an atomic mass image. We illustrate the use of MIMS to image unlabeled mammalian cultured cells and tissue sections; to analyze fatty-acid transport in adipocyte lipid droplets using 13C-oleic acid; to examine nitrogen fixation in bacteria using 15N gaseous nitrogen; to measure levels of protein renewal in the cochlea and in post-ischemic kidney cells using 15N-leucine; to study DNA and RNA co-distribution and uridine incorporation in the nucleolus using 15N-uridine and 81Br of bromodeoxyuridine or 14C-thymidine; to reveal domains in cultured endothelial cells using the native isotopes 12C, 16O, 14N and 31P; and to track a few 15N-labeled donor spleen cells in the lymph nodes of the host mouse. MIMS makes it possible for the first time to both image and quantify molecules labeled with stable or radioactive isotopes within subcellular compartments.

Targeted screening of pesticides, veterinary drugs and mycotoxins in bakery ingredients and food commodities by liquid chromatography-high-resolution single-stage Orbitrap mass spectrometry.

PubMed

De Dominicis, Emiliano; Commissati, Italo; Suman, Michele

2012-09-01

In the food industry, it is frequently necessary to check the quality of an ingredient to decide whether to use it in production and/or to have an idea of the final possible contamination of the finished product. The current need to quickly separate and identify relevant contaminants within different classes, often with legal residue limits on the order of 1-100 µg kg(-1), has led to the need for more effective analytical methods. With thousands of organic compounds present in complex food matrices, the development of new analytical solutions leaned towards simplified extraction/clean-up procedures and chromatography coupled with mass spectrometry. Efforts must also be made regarding the instrumental phase to overcome sensitivity/selectivity limits and interferences. For this purpose, high-resolution full scan analysis in mass spectrometry is an interesting alternative to the traditional tandem mass approach. A fast method for extracting and purifying bakery matrices was therefore developed and combined with the exploitation of ultra-high-pressure liquid chromatography (UHPLC) coupled to a Orbitrap Exactive™ high-resolution mass spectrometer (HRMS). Extracts of blank, naturally contaminated and fortified minicakes, prepared through a combined use of industrial and pilot plant production lines, were analyzed at different concentration levels (1-100 µg kg(-1)) of various contaminants: a limit of detection at 10 µg kg(-1) was possible for most of the analytes within all the categories analyzed, including pesticides, aflatoxins, trichothecene toxins and veterinary drugs. The application of accurate mass targeted screening described in this article demonstrates that current single-stage HRMS analytical instrumentation is well equipped to meet the challenges posed by chemical contaminants in the screening of both bakery raw materials and finished products. Copyright © 2012 John Wiley & Sons, Ltd.

Pentaerythritol Tetranitrate (PETN) Surveillance by HPLC-MS: Instrumental Parameters Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harvey, C A; Meissner, R

Surveillance of PETN Homologs in the stockpile here at LLNL is currently carried out by high performance liquid chromatography (HPLC) with ultra violet (UV) detection. Identification of unknown chromatographic peaks with this detection scheme is severely limited. The design agency is aware of the limitations of this methodology and ordered this study to develop instrumental parameters for the use of a currently owned mass spectrometer (MS) as the detection system. The resulting procedure would be a ''drop-in'' replacement for the current surveillance method (ERD04-524). The addition of quadrupole mass spectrometry provides qualitative identification of PETN and its homologs (Petrin, DiPEHN,more » TriPEON, and TetraPEDN) using a LLNL generated database, while providing mass clues to the identity of unknown chromatographic peaks.« less

Combining Two-Dimensional Diffusion-Ordered Nuclear Magnetic Resonance Spectroscopy, Imaging Desorption Electrospray Ionization Mass Spectrometry, and Direct Analysis in Real-Time Mass Spectrometry for the Integral Investigation of Counterfeit Pharmaceuticals

PubMed Central

Nyadong, Leonard; Harris, Glenn A.; Balayssac, Stéphane; Galhena, Asiri S.; Malet-Martino, Myriam; Martino, Robert; Parry, R. Mitchell; Wang, May Dongmei; Fernández, Facundo M.; Gilard, Véronique

2016-01-01

During the past decade, there has been a marked increase in the number of reported cases involving counterfeit medicines in developing and developed countries. Particularly, artesunate-based antimalarial drugs have been targeted, because of their high demand and cost. Counterfeit antimalarials can cause death and can contribute to the growing problem of drug resistance, particularly in southeast Asia. In this study, the complementarity of two-dimensional diffusion-ordered 1H nuclear magnetic resonance spectroscopy (2D DOSY 1H NMR) with direct analysis in real-time mass spectrometry (DART MS) and desorption electrospray ionization mass spectrometry (DESI MS) was assessed for pharmaceutical forensic purposes. Fourteen different artesunate tablets, representative of what can be purchased from informal sources in southeast Asia, were investigated with these techniques. The expected active pharmaceutical ingredient was detected in only five formulations via both nuclear magnetic resonance (NMR) and mass spectrometry (MS) methods. Common organic excipients such as sucrose, lactose, stearate, dextrin, and starch were also detected. The graphical representation of DOSY 1H NMR results proved very useful for establishing similarities among groups of samples, enabling counterfeit drug “chemotyping”. In addition to bulk- and surface-average analyses, spatially resolved information on the surface composition of counterfeit and genuine antimalarial formulations was obtained using DESI MS that was performed in the imaging mode, which enabled one to visualize the homogeneity of both genuine and counterfeit drug samples. Overall, this study suggests that 2D DOSY 1H NMR, combined with ambient MS, comprises a powerful suite of instrumental analysis methodologies for the integral characterization of counterfeit antimalarials. PMID:19453162

Combining two-dimensional diffusion-ordered nuclear magnetic resonance spectroscopy, imaging desorption electrospray ionization mass spectrometry, and direct analysis in real-time mass spectrometry for the integral investigation of counterfeit pharmaceuticals.

PubMed

Nyadong, Leonard; Harris, Glenn A; Balayssac, Stéphane; Galhena, Asiri S; Malet-Martino, Myriam; Martino, Robert; Parry, R Mitchell; Wang, May Dongmei; Fernández, Facundo M; Gilard, Véronique

2009-06-15

During the past decade, there has been a marked increase in the number of reported cases involving counterfeit medicines in developing and developed countries. Particularly, artesunate-based antimalarial drugs have been targeted, because of their high demand and cost. Counterfeit antimalarials can cause death and can contribute to the growing problem of drug resistance, particularly in southeast Asia. In this study, the complementarity of two-dimensional diffusion-ordered (1)H nuclear magnetic resonance spectroscopy (2D DOSY (1)H NMR) with direct analysis in real-time mass spectrometry (DART MS) and desorption electrospray ionization mass spectrometry (DESI MS) was assessed for pharmaceutical forensic purposes. Fourteen different artesunate tablets, representative of what can be purchased from informal sources in southeast Asia, were investigated with these techniques. The expected active pharmaceutical ingredient was detected in only five formulations via both nuclear magnetic resonance (NMR) and mass spectrometry (MS) methods. Common organic excipients such as sucrose, lactose, stearate, dextrin, and starch were also detected. The graphical representation of DOSY (1)H NMR results proved very useful for establishing similarities among groups of samples, enabling counterfeit drug "chemotyping". In addition to bulk- and surface-average analyses, spatially resolved information on the surface composition of counterfeit and genuine antimalarial formulations was obtained using DESI MS that was performed in the imaging mode, which enabled one to visualize the homogeneity of both genuine and counterfeit drug samples. Overall, this study suggests that 2D DOSY (1)H NMR, combined with ambient MS, comprises a powerful suite of instrumental analysis methodologies for the integral characterization of counterfeit antimalarials.

Enhancement of concentration range of chromatographically detectable components with array detector mass spectrometry

DOEpatents

Enke, Christie

2013-02-19

Methods and instruments for high dynamic range analysis of sample components are described. A sample is subjected to time-dependent separation, ionized, and the ions dispersed with a constant integration time across an array of detectors according to the ions m/z values. Each of the detectors in the array has a dynamically adjustable gain or a logarithmic response function, producing an instrument capable of detecting a ratio of responses or 4 or more orders of magnitude.

Portable FAIMS: Applications and Future Perspectives.

PubMed

Costanzo, Michael T; Boock, Jared J; Kemperman, Robin H J; Wei, Michael S; Beekman, Christopher R; Yost, Richard A

2017-11-01

Miniaturized mass spectrometry (MMS) is optimal for a wide variety of applications that benefit from field-portable instrumentation. Like MMS, field asymmetric ion mobility spectrometry (FAIMS) has proven capable of providing in situ analysis, allowing researchers to bring the lab to the sample. FAIMS compliments MMS very well, but has the added benefit of operating at atmospheric pressure, unlike MS. This distinct advantage makes FAIMS uniquely suited for portability. Since its inception, FAIMS has been envisioned as a field-portable device, as it affords less expense and greater simplicity than many similar methods. Ideally, these are simple, robust devices that may be operated by non-professional personnel, yet still provide adequate data when in the field. While reducing the size and complexity tends to bring with it a loss of performance and accuracy, this is made up for by the incredibly high throughput and overall convenience of the instrument. Moreover, the FAIMS device used in the field can be brought back to the lab, and coupled to a conventional mass spectrometer to provide any necessary method development and compound validation. This work discusses the various considerations, uses, and applications for portable FAIMS instrumentation, and how the future of each applicable field may benefit from the development and acceptance of such a device.

Universal absolute quantification of biomolecules using element mass spectrometry and generic standards.

PubMed

Calderón-Celis, Francisco; Sanz-Medel, Alfredo; Encinar, Jorge Ruiz

2018-01-23

We present a novel and highly sensitive ICP-MS approach for absolute quantification of all important target biomolecule containing P, S, Se, As, Br, and/or I (e.g., proteins and phosphoproteins, metabolites, pesticides, drugs), under the same simple instrumental conditions and without requiring any specific and/or isotopically enriched standard.

QCloud: A cloud-based quality control system for mass spectrometry-based proteomics laboratories

PubMed Central

Chiva, Cristina; Olivella, Roger; Borràs, Eva; Espadas, Guadalupe; Pastor, Olga; Solé, Amanda

2018-01-01

The increasing number of biomedical and translational applications in mass spectrometry-based proteomics poses new analytical challenges and raises the need for automated quality control systems. Despite previous efforts to set standard file formats, data processing workflows and key evaluation parameters for quality control, automated quality control systems are not yet widespread among proteomics laboratories, which limits the acquisition of high-quality results, inter-laboratory comparisons and the assessment of variability of instrumental platforms. Here we present QCloud, a cloud-based system to support proteomics laboratories in daily quality assessment using a user-friendly interface, easy setup, automated data processing and archiving, and unbiased instrument evaluation. QCloud supports the most common targeted and untargeted proteomics workflows, it accepts data formats from different vendors and it enables the annotation of acquired data and reporting incidences. A complete version of the QCloud system has successfully been developed and it is now open to the proteomics community (http://qcloud.crg.eu). QCloud system is an open source project, publicly available under a Creative Commons License Attribution-ShareAlike 4.0. PMID:29324744

Rapid Quantitative Analysis of Multiple Explosive Compound Classes on a Single Instrument via Flow-Injection Analysis Tandem Mass Spectrometry.

PubMed

Ostrinskaya, Alla; Kunz, Roderick R; Clark, Michelle; Kingsborough, Richard P; Ong, Ta-Hsuan; Deneault, Sandra

2018-05-24

A flow-injection analysis tandem mass spectrometry (FIA MSMS) method was developed for rapid quantitative analysis of 10 different inorganic and organic explosives. Performance is optimized by tailoring the ionization method (APCI/ESI), de-clustering potentials, and collision energies for each specific analyte. In doing so, a single instrument can be used to detect urea nitrate, potassium chlorate, 2,4,6-trinitrotoluene, 2,4,6-trinitrophenylmethylnitramine, triacetone triperoxide, hexamethylene triperoxide diamine, pentaerythritol tetranitrate, 1,3,5-trinitroperhydro-1,3,5-triazine, nitroglycerin, and octohy-dro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine with sensitivities all in the picogram per milliliter range. In conclusion, FIA APCI/ESI MSMS is a fast (<1 min/sample), sensitive (~pg/mL LOQ), and precise (intraday RSD < 10%) method for trace explosive detection that can play an important role in criminal and attributional forensics, counterterrorism, and environmental protection areas, and has the potential to augment or replace several of the existing explosive detection methods. © 2018 American Academy of Forensic Sciences.

Proteomics: from hypothesis to quantitative assay on a single platform. Guidelines for developing MRM assays using ion trap mass spectrometers.

PubMed

Han, Bomie; Higgs, Richard E

2008-09-01

High-throughput HPLC-mass spectrometry (HPLC-MS) is routinely used to profile biological samples for potential protein markers of disease, drug efficacy and toxicity. The discovery technology has advanced to the point where translating hypotheses from proteomic profiling studies into clinical use is the bottleneck to realizing the full potential of these approaches. The first step in this translation is the development and analytical validation of a higher throughput assay with improved sensitivity and selectivity relative to typical profiling assays. Multiple reaction monitoring (MRM) assays are an attractive approach for this stage of biomarker development given their improved sensitivity and specificity, the speed at which the assays can be developed and the quantitative nature of the assay. While the profiling assays are performed with ion trap mass spectrometers, MRM assays are traditionally developed in quadrupole-based mass spectrometers. Development of MRM assays from the same instrument used in the profiling analysis enables a seamless and rapid transition from hypothesis generation to validation. This report provides guidelines for rapidly developing an MRM assay using the same mass spectrometry platform used for profiling experiments (typically ion traps) and reviews methodological and analytical validation considerations. The analytical validation guidelines presented are drawn from existing practices on immunological assays and are applicable to any mass spectrometry platform technology.

Whole Microorganisms Studied by Pyrolysis-Gas Chromatography-Mass Spectrometry: Significance for Extraterrestrial Life Detection Experiments 1

PubMed Central

Simmonds, Peter G.

1970-01-01

Pyrolysis-gas chromatography-mass spectrometric studies of two microorganisms, Micrococcus luteus and Bacillus subtilis var. niger, indicate that the majority of thermal fragments originate from the principal classes of bio-organic matter found in living systems such as protein and carbohydrate. Furthermore, there is a close qualitative similarity between the type of pyrolysis products found in microorganisms and the pyrolysates of other biological materials. Conversely, there is very little correlation between microbial pyrolysates and comparable pyrolysis studies of meteoritic and fossil organic matter. These observations will aid in the interpretation of a soil organic analysis experiment to be performed on the surface of Mars in 1975. The science payload of this landed mission will include a combined pyrolysis-gas chromatography-mass spectrometry instrument as well as several “direct biology experiments” which are designed to search for extraterrestrial life. PMID:16349890

Identification of metal species by ESI-MS/MS through release of free metals from the corresponding metal-ligand complexes

PubMed Central

Tsednee, Munkhtsetseg; Huang, Yu-Chen; Chen, Yet-Ran; Yeh, Kuo-Chen

2016-01-01

Electrospray ionization-mass spectrometry (ESI-MS) is used to analyze metal species in a variety of samples. Here, we describe an application for identifying metal species by tandem mass spectrometry (ESI-MS/MS) with the release of free metals from the corresponding metal–ligand complexes. The MS/MS data were used to elucidate the possible fragmentation pathways of different metal–deoxymugineic acid (–DMA) and metal–nicotianamine (–NA) complexes and select the product ions with highest abundance that may be useful for quantitative multiple reaction monitoring. This method can be used for identifying different metal–ligand complexes, especially for metal species whose mass spectra peaks are clustered close together. Different metal–DMA/NA complexes were simultaneously identified under different physiological pH conditions with this method. We further demonstrated the application of the technique for different plant samples and with different MS instruments. PMID:27240899

Characterization of ambient aerosols at the San Francisco International Airport using BioAerosol Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steele, P T; McJimpsey, E L; Coffee, K R

2006-03-16

The BioAerosol Mass Spectrometry (BAMS) system is a rapidly fieldable, fully autonomous instrument that can perform correlated measurements of multiple orthogonal properties of individual aerosol particles. The BAMS front end uses optical techniques to nondestructively measure a particle's aerodynamic diameter and fluorescence properties. Fluorescence can be excited at 266nm or 355nm and is detected in two broad wavelength bands. Individual particles with appropriate size and fluorescence properties can then be analyzed more thoroughly in a dual-polarity time-of-flight mass spectrometer. Over the course of two deployments to the San Francisco International Airport, more than 6.5 million individual aerosol particles were fullymore » analyzed by the system. Analysis of the resulting data has provided a number of important insights relevant to rapid bioaerosol detection, which are described here.« less

Biological Matrix Effects in Quantitative Tandem Mass Spectrometry-Based Analytical Methods: Advancing Biomonitoring

PubMed Central

Panuwet, Parinya; Hunter, Ronald E.; D’Souza, Priya E.; Chen, Xianyu; Radford, Samantha A.; Cohen, Jordan R.; Marder, M. Elizabeth; Kartavenka, Kostya; Ryan, P. Barry; Barr, Dana Boyd

2015-01-01

The ability to quantify levels of target analytes in biological samples accurately and precisely, in biomonitoring, involves the use of highly sensitive and selective instrumentation such as tandem mass spectrometers and a thorough understanding of highly variable matrix effects. Typically, matrix effects are caused by co-eluting matrix components that alter the ionization of target analytes as well as the chromatographic response of target analytes, leading to reduced or increased sensitivity of the analysis. Thus, before the desired accuracy and precision standards of laboratory data are achieved, these effects must be characterized and controlled. Here we present our review and observations of matrix effects encountered during the validation and implementation of tandem mass spectrometry-based analytical methods. We also provide systematic, comprehensive laboratory strategies needed to control challenges posed by matrix effects in order to ensure delivery of the most accurate data for biomonitoring studies assessing exposure to environmental toxicants. PMID:25562585

Clinical protein mass spectrometry.

PubMed

Scherl, Alexander

2015-06-15

Quantitative protein analysis is routinely performed in clinical chemistry laboratories for diagnosis, therapeutic monitoring, and prognosis. Today, protein assays are mostly performed either with non-specific detection methods or immunoassays. Mass spectrometry (MS) is a very specific analytical method potentially very well suited for clinical laboratories. Its unique advantage relies in the high specificity of the detection. Any protein sequence variant, the presence of a post-translational modification or degradation will differ in mass and structure, and these differences will appear in the mass spectrum of the protein. On the other hand, protein MS is a relatively young technique, demanding specialized personnel and expensive instrumentation. Many scientists and opinion leaders predict MS to replace immunoassays for routine protein analysis, but there are only few protein MS applications routinely used in clinical chemistry laboratories today. The present review consists of a didactical introduction summarizing the pros and cons of MS assays compared to immunoassays, the different instrumentations, and various MS protein assays that have been proposed and/or are used in clinical laboratories. An important distinction is made between full length protein analysis (top-down method) and peptide analysis after enzymatic digestion of the proteins (bottom-up method) and its implication for the protein assay. The document ends with an outlook on what type of analyses could be used in the future, and for what type of applications MS has a clear advantage compared to immunoassays. Copyright © 2015 Elsevier Inc. All rights reserved.

Co-Registered In Situ Secondary Electron and Mass Spectral Imaging on the Helium Ion Microscope Demonstrated Using Lithium Titanate and Magnesium Oxide Nanoparticles.

PubMed

Dowsett, D; Wirtz, T

2017-09-05

The development of a high resolution elemental imaging platform combining coregistered secondary ion mass spectrometry and high resolution secondary electron imaging is reported. The basic instrument setup and operation are discussed and in situ image correlation is demonstrated on a lithium titanate and magnesium oxide nanoparticle mixture. The instrument uses both helium and neon ion beams generated by a gas field ion source to irradiate the sample. Both secondary electrons and secondary ions may be detected. Secondary ion mass spectrometry (SIMS) is performed using an in-house developed double focusing magnetic sector spectrometer with parallel detection. Spatial resolutions of 10 nm have been obtained in SIMS mode. Both the secondary electron and SIMS image data are very surface sensitive and have approximately the same information depth. While the spatial resolutions are approximately a factor of 10 different, switching between the different images modes may be done in situ and extremely rapidly, allowing for simple imaging of the same region of interest and excellent coregistration of data sets. The ability to correlate mass spectral images on the 10 nm scale with secondary electron images on the nanometer scale in situ has the potential to provide a step change in our understanding of nanoscale phenomena in fields from materials science to life science.

Conformational ordering of biomolecules in the gas phase: nitrogen collision cross sections measured on a prototype high resolution drift tube ion mobility-mass spectrometer.

PubMed

May, Jody C; Goodwin, Cody R; Lareau, Nichole M; Leaptrot, Katrina L; Morris, Caleb B; Kurulugama, Ruwan T; Mordehai, Alex; Klein, Christian; Barry, William; Darland, Ed; Overney, Gregor; Imatani, Kenneth; Stafford, George C; Fjeldsted, John C; McLean, John A

2014-02-18

Ion mobility-mass spectrometry measurements which describe the gas-phase scaling of molecular size and mass are of both fundamental and pragmatic utility. Fundamentally, such measurements expand our understanding of intrinsic intramolecular folding forces in the absence of solvent. Practically, reproducible transport properties, such as gas-phase collision cross-section (CCS), are analytically useful metrics for identification and characterization purposes. Here, we report 594 CCS values obtained in nitrogen drift gas on an electrostatic drift tube ion mobility-mass spectrometry (IM-MS) instrument. The instrument platform is a newly developed prototype incorporating a uniform-field drift tube bracketed by electrodynamic ion funnels and coupled to a high resolution quadrupole time-of-flight mass spectrometer. The CCS values reported here are of high experimental precision (±0.5% or better) and represent four chemically distinct classes of molecules (quaternary ammonium salts, lipids, peptides, and carbohydrates), which enables structural comparisons to be made between molecules of different chemical compositions for the rapid "omni-omic" characterization of complex biological samples. Comparisons made between helium and nitrogen-derived CCS measurements demonstrate that nitrogen CCS values are systematically larger than helium values; however, general separation trends between chemical classes are retained regardless of the drift gas. These results underscore that, for the highest CCS accuracy, care must be exercised when utilizing helium-derived CCS values to calibrate measurements obtained in nitrogen, as is the common practice in the field.

Conformational Ordering of Biomolecules in the Gas Phase: Nitrogen Collision Cross Sections Measured on a Prototype High Resolution Drift Tube Ion Mobility-Mass Spectrometer

PubMed Central

2014-01-01

Ion mobility-mass spectrometry measurements which describe the gas-phase scaling of molecular size and mass are of both fundamental and pragmatic utility. Fundamentally, such measurements expand our understanding of intrinsic intramolecular folding forces in the absence of solvent. Practically, reproducible transport properties, such as gas-phase collision cross-section (CCS), are analytically useful metrics for identification and characterization purposes. Here, we report 594 CCS values obtained in nitrogen drift gas on an electrostatic drift tube ion mobility-mass spectrometry (IM-MS) instrument. The instrument platform is a newly developed prototype incorporating a uniform-field drift tube bracketed by electrodynamic ion funnels and coupled to a high resolution quadrupole time-of-flight mass spectrometer. The CCS values reported here are of high experimental precision (±0.5% or better) and represent four chemically distinct classes of molecules (quaternary ammonium salts, lipids, peptides, and carbohydrates), which enables structural comparisons to be made between molecules of different chemical compositions for the rapid “omni-omic” characterization of complex biological samples. Comparisons made between helium and nitrogen-derived CCS measurements demonstrate that nitrogen CCS values are systematically larger than helium values; however, general separation trends between chemical classes are retained regardless of the drift gas. These results underscore that, for the highest CCS accuracy, care must be exercised when utilizing helium-derived CCS values to calibrate measurements obtained in nitrogen, as is the common practice in the field. PMID:24446877

Time-of-flight mass spectrometry of mineral volatilization: Toward direct composition analysis of shocked mineral vapor

NASA Astrophysics Data System (ADS)

Austin, Daniel E.; Shen, Andy H. T.; Beauchamp, J. L.; Ahrens, Thomas J.

2012-04-01

We have developed an orthogonal-acceleration time-of-flight mass spectrometer to study the volatiles produced when a mineral's shock-compressed state is isentropically released, as occurs when a shock wave, driven into the mineral by an impact, reflects upon reaching a free surface. The instrument is designed to use a gun or explosive-launched projectile as the source of the shock wave, impact onto a flange separating a poor vacuum and the high vacuum (10-7 Torr) interior of the mass spectrometer, and transmission of the shock wave through the flange to a mineral sample mounted on the high-vacuum side of the flange. The device extracts and analyzes the neutrals and ions produced from the shocked mineral prior to the possible occurrence of collateral instrument damage from the shock-inducing impact. The instrument has been tested using laser ablation of various mineral surfaces, and the resulting spectra are presented. Mass spectra are compared with theoretical distributions of molecular species, and with expected distributions from laser desorption.

Quantitative mass spectrometry methods for pharmaceutical analysis

PubMed Central

Loos, Glenn; Van Schepdael, Ann

2016-01-01

Quantitative pharmaceutical analysis is nowadays frequently executed using mass spectrometry. Electrospray ionization coupled to a (hybrid) triple quadrupole mass spectrometer is generally used in combination with solid-phase extraction and liquid chromatography. Furthermore, isotopically labelled standards are often used to correct for ion suppression. The challenges in producing sensitive but reliable quantitative data depend on the instrumentation, sample preparation and hyphenated techniques. In this contribution, different approaches to enhance the ionization efficiencies using modified source geometries and improved ion guidance are provided. Furthermore, possibilities to minimize, assess and correct for matrix interferences caused by co-eluting substances are described. With the focus on pharmaceuticals in the environment and bioanalysis, different separation techniques, trends in liquid chromatography and sample preparation methods to minimize matrix effects and increase sensitivity are discussed. Although highly sensitive methods are generally aimed for to provide automated multi-residue analysis, (less sensitive) miniaturized set-ups have a great potential due to their ability for in-field usage. This article is part of the themed issue ‘Quantitative mass spectrometry’. PMID:27644982

Triple Quadrupole Versus High Resolution Quadrupole-Time-of-Flight Mass Spectrometry for Quantitative LC-MS/MS Analysis of 25-Hydroxyvitamin D in Human Serum

NASA Astrophysics Data System (ADS)

Geib, Timon; Sleno, Lekha; Hall, Rabea A.; Stokes, Caroline S.; Volmer, Dietrich A.

2016-08-01

We describe a systematic comparison of high and low resolution LC-MS/MS assays for quantification of 25-hydroxyvitamin D3 in human serum. Identical sample preparation, chromatography separations, electrospray ionization sources, precursor ion selection, and ion activation were used; the two assays differed only in the implemented final mass analyzer stage; viz. high resolution quadrupole-quadrupole-time-of-flight (QqTOF) versus low resolution triple quadrupole instruments. The results were assessed against measured concentration levels from a routine clinical chemiluminescence immunoassay. Isobaric interferences prevented the simple use of TOF-MS spectra for extraction of accurate masses and necessitated the application of collision-induced dissociation on the QqTOF platform. The two mass spectrometry assays provided very similar analytical figures of merit, reflecting the lack of relevant isobaric interferences in the MS/MS domain, and were successfully applied to determine the levels of 25-hydroxyvitamin D for patients with chronic liver disease.

Improvements on high-precision measurement of bromine isotope ratios by multicollector inductively coupled plasma mass spectrometry.

PubMed

Wei, Hai-Zhen; Jiang, Shao-Yong; Zhu, Zhi-Yong; Yang, Tao; Yang, Jing-Hong; Yan, Xiong; Wu, He-Pin; Yang, Tang-Li

2015-10-01

A new, feasible procedure for high-precision bromine isotope analysis using multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) is described. With a combination of HR mass resolution mode and accurate optimization of the Zoom Optics parameters (Focus Quad: -1.30; Zoom Quad: 0.00), the challenging problem of the isobaric interferences ((40)Ar(38)ArH(+) and (40)Ar(40)ArH(+)) in the measurement of bromine isotopes ((79)Br(+), (81)Br(+)) has been effectively solved. The external reproducibility of the measured (81)Br/(79)Br ratios in the selected standard reference materials ranged from ±0.03‰ to ±0.14‰, which is superior to or equivalent to the best results from previous contributions. The effect of counter cations on the Br(+) signal intensity and the instrumental-induced mass bias was evaluated as the loss of HBr aerosol in nebulizer and potential diffusive isotope fractionations. Copyright © 2015 Elsevier B.V. All rights reserved.

Introduction of organic/hydro-organic matrices in inductively coupled plasma optical emission spectrometry and mass spectrometry: a tutorial review. Part I. Theoretical considerations.

PubMed

Leclercq, Amélie; Nonell, Anthony; Todolí Torró, José Luis; Bresson, Carole; Vio, Laurent; Vercouter, Thomas; Chartier, Frédéric

2015-07-23

Due to their outstanding analytical performances, inductively coupled plasma optical emission spectrometry (ICP-OES) and mass spectrometry (ICP-MS) are widely used for multi-elemental measurements and also for isotopic characterization in the case of ICP-MS. While most studies are carried out in aqueous matrices, applications involving organic/hydro-organic matrices become increasingly widespread. This kind of matrices is introduced in ICP based instruments when classical "matrix removal" approaches such as acid digestion or extraction procedures cannot be implemented. Due to the physico-chemical properties of organic/hydro-organic matrices and their associated effects on instrumentation and analytical performances, their introduction into ICP sources is particularly challenging and has become a full topic. In this framework, numerous theoretical and phenomenological studies of these effects have been performed in the past, mainly by ICP-OES, while recent literature is more focused on applications and associated instrumental developments. This tutorial review, divided in two parts, explores the rich literature related to the introduction of organic/hydro-organic matrices in ICP-OES and ICP-MS. The present Part I, provides theoretical considerations in connection with the physico-chemical properties of organic/hydro-organic matrices, in order to better understand the induced phenomena. This focal point is divided in four chapters highlighting: (i) the impact of organic/hydro-organic matrices from aerosol generation to atomization/excitation/ionization processes; (ii) the production of carbon molecular constituents and their spatial distribution in the plasma with respect to analytes repartition; (iii) the subsequent modifications of plasma fundamental properties; and (iv) the resulting spectroscopic and non spectroscopic interferences. This first part of this tutorial review is addressed either to beginners or to more experienced scientists who are interested in the analysis of organic/hydro-organic matrices by ICP sources and would like to consider the theoretical background of effects induced by such matrices. The second part of this tutorial review will be dedicated to more practical consideration on instrumentation, such as adapted introductions devices, as well as instrumental and operating parameters optimization. The analytical strategies for elemental quantification in such matrices will also be addressed. Copyright © 2015 Elsevier B.V. All rights reserved.

Electrospray Ionization Efficiency Is Dependent on Different Molecular Descriptors with Respect to Solvent pH and Instrumental Configuration

PubMed Central

Kiontke, Andreas; Oliveira-Birkmeier, Ariana; Opitz, Andreas

2016-01-01

Over the past decades, electrospray ionization for mass spectrometry (ESI-MS) has become one of the most commonly employed techniques in analytical chemistry, mainly due to its broad applicability to polar and semipolar compounds and the superior selectivity which is achieved in combination with high resolution separation techniques. However, responsiveness of an analytical method also determines its suitability for the quantitation of chemical compounds; and in electrospray ionization for mass spectrometry, it can vary significantly among different analytes with identical solution concentrations. Therefore, we investigated the ESI-response behavior of 56 nitrogen-containing compounds including aromatic amines and pyridines, two compound classes of high importance to both, synthetic organic chemistry as well as to pharmaceutical sciences. These compounds are increasingly analyzed employing ESI mass spectrometry detection due to their polar, basic character. Signal intensities of the peaks from the protonated molecular ion (MH+) were acquired under different conditions and related to compound properties such as basicity, polarity, volatility and molecular size exploring their quantitative impact on ionization efficiency. As a result, we found that though solution basicity of a compound is the main factor initially determining the ESI response of the protonated molecular ion, other factors such as polarity and vaporability become more important under acidic solvent conditions and may nearly outweigh the importance of basicity under these conditions. Moreover, we show that different molecular descriptors may become important when using different types of instruments for such investigations, a fact not detailed so far in the available literature. PMID:27907110

Highly multiparametric analysis by mass cytometry.

PubMed

Ornatsky, Olga; Bandura, Dmitry; Baranov, Vladimir; Nitz, Mark; Winnik, Mitchell A; Tanner, Scott

2010-09-30

This review paper describes a new technology, mass cytometry, that addresses applications typically run by flow cytometer analyzers, but extends the capability to highly multiparametric analysis. The detection technology is based on atomic mass spectrometry. It offers quantitation, specificity and dynamic range of mass spectrometry in a format that is familiar to flow cytometry practitioners. The mass cytometer does not require compensation, allowing the application of statistical techniques; this has been impossible given the constraints of fluorescence noise with traditional cytometry instruments. Instead of "colors" the mass cytometer "reads" the stable isotope tags attached to antibodies using metal-chelating labeling reagents. Because there are many available stable isotopes, and the mass spectrometer provides exquisite resolution between detection channels, many parameters can be measured as easily as one. For example, in a single tube the technique allows for the ready detection and characterization of the major cell subsets in blood or bone marrow. Here we describe mass cytometric immunophenotyping of human leukemia cell lines and leukemia patient samples, differential cell analysis of normal peripheral and umbilical cord blood; intracellular protein identification and metal-encoded bead arrays. Copyright © 2010 Elsevier B.V. All rights reserved.

Targeted analyte deconvolution and identification by four-way parallel factor analysis using three-dimensional gas chromatography with mass spectrometry data.

PubMed

Watson, Nathanial E; Prebihalo, Sarah E; Synovec, Robert E

2017-08-29

Comprehensive three-dimensional gas chromatography with time-of-flight mass spectrometry (GC 3 -TOFMS) creates an opportunity to explore a new paradigm in chemometric analysis. Using this newly described instrument and the well understood Parallel Factor Analysis (PARAFAC) model we present one option for utilization of the novel GC 3 -TOFMS data structure. We present a method which builds upon previous work in both GC 3 and targeted analysis using PARAFAC to simplify some of the implementation challenges previously discovered. Conceptualizing the GC 3 -TOFMS instead as a one-dimensional gas chromatograph with GC × GC-TOFMS detection we allow the instrument to create the PARAFAC target window natively. Each first dimension modulation thus creates a full GC × GC-TOFMS chromatogram fully amenable to PARAFAC. A simple mixture of 115 compounds and a diesel sample are interrogated through this methodology. All test analyte targets are successfully identified in both mixtures. In addition, mass spectral matching of the PARAFAC loadings to library spectra yielded results greater than 900 in 40 of 42 test analyte cases. Twenty-nine of these cases produced match values greater than 950. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparison of Total Evaporation (TE) and Direct Total Evaporation (DTE) methods in TIMS by using NBL CRMs

NASA Astrophysics Data System (ADS)

Hasözbek, Altug; Mathew, Kattathu; Wegener, Michael

2013-04-01

The total evaporation (TE) is a well-established analytical method for safeguards measurement of uranium and plutonium isotope-amount ratios using the thermal ionization mass spectrometry (TIMS). High accuracy and precision isotopic measurements find many applications in nuclear safeguards, for e.g. assay measurements using isotope dilution mass spectrometry. To achieve high accuracy and precision in TIMS measurements, mass dependent fractionation effects are minimized by either the measurement technique or changes in the hardware components that are used to control sample heating and evaporation process. At NBL, direct total evaporation (DTE) method on the modified MAT261 instrument, uses the data system to read the ion signal intensity and its difference from a pre-determined target intensity, is used to control the incremental step at which the evaporation filament is heated. The feedback and control is achieved by proprietary hardware from SPECTROMAT that uses an analog regulator in the filament power supply with direct feedback of the detector intensity. Compared to traditional TE method on this instrument, DTE provides better precision (relative standard deviation, expressed as a percent) and accuracy (relative difference, expressed as a percent) of 0.05 to 0.08 % for low enriched and high enriched NBL uranium certified reference materials.

A new HF-resistant tandem spray chamber for improved determination of trace elements and Pb isotopes using inductively coupled plasma-mass spectrometry

NASA Astrophysics Data System (ADS)

Krachler, Michael; Rausch, Nicole; Feuerbacher, Helmut; Klemens, Patrick

2005-07-01

The use of a new HF-resistant tandem spray chamber arrangement consisting of a cyclonic spray chamber and a Scott-type spray chamber made from PFA and PEEK provides a straightforward approach for improving the performance of inductively coupled-mass spectrometry (ICP-MS). The characteristics of the tandem spray chamber were critically evaluated against a PEEK cyclonic and a PFA Scott-type spray chamber, respectively. Sensitivity across the entire mass range was increased by about three times compared to the conventional setup utilizing only one spray chamber. Precision of the results, especially at low signal intensities, improved by 160% and 31% compared to the cyclonic and Scott-type spray chamber, respectively. Using the tandem spray chamber, the oxide formation rate was lowered by about 50%. Signals as low as 30 counts could be determined under routine measurement conditions with a RSD of 2.4% thus allowing to precisely quantify small concentration differences at the ng l - 1 concentration level. The excellent precision (0.02-0.07%) of 206Pb / 207Pb and 206Pb / 208Pb ratios determined in pore water samples was rather limited by the instrumental capabilities of the single collector ICP-MS instrument than by the performance of the tandem spray chamber.

Simulation of the oxidative metabolism of diclofenac by electrochemistry/(liquid chromatography/)mass spectrometry.

PubMed

Faber, Helene; Melles, Daniel; Brauckmann, Christine; Wehe, Christoph Alexander; Wentker, Kristina; Karst, Uwe

2012-04-01

Diclofenac is a frequently prescribed drug for rheumatic diseases and muscle pain. In rare cases, it may be associated with a severe hepatotoxicity. In literature, it is discussed whether this toxicity is related to the oxidative phase I metabolism, resulting in electrophilic quinone imines, which can subsequently react with nucleophiles present in the liver in form of glutathione or proteins. In this work, electrochemistry coupled to mass spectrometry is used as a tool for the simulation of the oxidative pathway of diclofenac. Using this purely instrumental approach, diclofenac was oxidized in a thin layer cell equipped with a boron doped diamond working electrode. Sum formulae of generated oxidation products were calculated based on accurate mass measurements with deviations below 2 ppm. Quinone imines from diclofenac were detected using this approach. It could be shown for the first time that these quinone imines do not react with glutathione exclusively but also with larger molecules such as the model protein β-lactoglobulin A. A tryptic digest of the generated drug-protein adduct confirms that the protein is modified at the only free thiol-containing peptide. This simple and purely instrumental set-up offers the possibility of generating reactive metabolites of diclofenac and to assess their reactivity rapidly and easily.

Fast parallel tandem mass spectral library searching using GPU hardware acceleration.

PubMed

Baumgardner, Lydia Ashleigh; Shanmugam, Avinash Kumar; Lam, Henry; Eng, Jimmy K; Martin, Daniel B

2011-06-03

Mass spectrometry-based proteomics is a maturing discipline of biologic research that is experiencing substantial growth. Instrumentation has steadily improved over time with the advent of faster and more sensitive instruments collecting ever larger data files. Consequently, the computational process of matching a peptide fragmentation pattern to its sequence, traditionally accomplished by sequence database searching and more recently also by spectral library searching, has become a bottleneck in many mass spectrometry experiments. In both of these methods, the main rate-limiting step is the comparison of an acquired spectrum with all potential matches from a spectral library or sequence database. This is a highly parallelizable process because the core computational element can be represented as a simple but arithmetically intense multiplication of two vectors. In this paper, we present a proof of concept project taking advantage of the massively parallel computing available on graphics processing units (GPUs) to distribute and accelerate the process of spectral assignment using spectral library searching. This program, which we have named FastPaSS (for Fast Parallelized Spectral Searching), is implemented in CUDA (Compute Unified Device Architecture) from NVIDIA, which allows direct access to the processors in an NVIDIA GPU. Our efforts demonstrate the feasibility of GPU computing for spectral assignment, through implementation of the validated spectral searching algorithm SpectraST in the CUDA environment.

AMINO ACID ANALYSES OF THE ANTARCTIC CM2 METEORITES ALH 83100 AND LEW 90500 USING LIQUID CHROMATOGRAPHY-TIME OF FLIGHT-MASS SPECTROMETRY

NASA Technical Reports Server (NTRS)

Glavin, D. P.; Dworkin, J. P.; Aubrey, A.; Botta, O.; Doty, J. H., III; Bada, J. L.

2001-01-01

The investigation of organic compounds in primitive carbonaceous meteorites provides a record of the chemical processes that occurred in the early solar system. In particular, amino acids have been shown to be potential indicators in tracing the nature of carbonaceous chondrite parent bodies [ 13. The delivery of amino acids by carbonaceous chondrites to the early Earth could have been any important source of the Earth's prebiotic organic inventory [2]. Over 80 different amino acids have been detected in the Murchison CM2 meteorite, most of them completely non-existent in the terrestrial biosphere [3]. We have optimized a new liquid chromatography-time-of-flight-mass spectrometry (LC-ToF-MS) technique coupled with OPAMAC derivatization in order to detect amino acids in meteorite extracts by UV fluorescence and exact mass simultaneously. The detection limit of the LC-ToF-MS instrument for amino acids is at least 3 orders of magnitude lower than traditional GC-MS techniques. Here we report on the first analyses of amino acids and their enantiomeric abundances in the CM2 carbonaceous meteorites ALH 83100, LEW 90500, and Murchison using this new LC-ToF-MS instrument configuration. Amino acid analyses of any kind for the CM meteorite ALH 83100 have not previously been reported.

The Role of the Ion Microprobe in Solid-Earth Geochemistry

NASA Astrophysics Data System (ADS)

Hauri, E. H.

2002-12-01

Despite the early success of the electron microprobe in taking petrology to the micron scale, and the widespread use of mass spectrometers in geochemistry and geochronology, it was not until the mid-1970s that the ion microprobe came into its own as an in situ analytical tool in the Earth sciences. Despite this inauspicious beginning, secondary ion mass spectrometry (SIMS) was widely advertised as a technology that would eventually eclipse thermal ion mass spectrometry (TIMS) in isotope geology. However this was not to happen. While various technical issues in SIMS such as interferences and matrix effects became increasingly clear, an appreciation grew for the complimentary abilities of SIMS and TIMS that, even with the advent of ICP-MS, continues to this day. Today the ion microprobe is capable of abundance measurements in the parts-per-billion range across nearly the entire periodic table, and SIMS stable isotope data quality is now routinely crossing the 1 per mil threshold, all at the micron scale. Much of this success is due to the existence of multi-user community facilities for SIMS research, and the substantial efforts of interested scientists to understand the fundamentals of sputtered ion formation and their application to geochemistry. Recent discoveries of evidence for the existence of ancient crust and oceans, the emergence of life on Earth, the large-scale cycling of surficial materials into the deep Earth, and illumination of fundamental high-pressure phenomena have all been made possible by SIMS, and these (and many more) discoveries owe a debt to the vision of creating and supporting multi-user community facilities for SIMS. The ion microprobe remains an expensive instrument to purchase and maintain, yet it is also exceedingly diverse in application. Major improvements in SIMS, indeed in all mass spectrometry, are visible on the near horizon. Yet the geochemical community cannot depend on commercial manufacturers alone to design and build the next generation of instrumentation for geochemistry. Such will be the role of instrument-minded scientists asking questions that simply cannot be answered by extant means. And it will be multi-user facilities that will make such advancements available to the wider geochemical community.

High-resolution mass spectrometric analysis of biomass pyrolysis vapors

DOE PAGES

Christensen, Earl; Evans, Robert J.; Carpenter, Daniel

2017-01-19

Vapors generated from the pyrolysis of lignocellulosic biomass are made up of a complex mixture of oxygenated compounds. Direct analysis of these vapors provides insight into the mechanisms of depolymerization of cellulose, hemicellulose, and lignin as well as insight into reactions that may occur during condensation of pyrolysis vapors into bio-oil. Studies utilizing pyrolysis molecular beam mass spectrometry have provided valuable information regarding the chemical composition of pyrolysis vapors. Mass spectrometers generally employed with these instruments have low mass resolution of approximately a mass unit. The presence of chemical species with identical unit mass but differing elemental formulas cannot bemore » resolved with these instruments and are therefore detected as a single ion. In this study we analyzed the pyrolysis vapors of several biomass sources using a high-resolution double focusing mass spectrometer. High-resolution analysis of pyrolysis vapors allowed for speciation of several compounds that would be detected as a single ion with unit mass resolution. Lastly, these data not only provide greater detail into the composition of pyrolysis vapors but also highlight differences between vapors generated from multiple biomass feedstocks.« less

Characterization of high explosive particles using cluster secondary ion mass spectrometry.

PubMed

Gillen, Greg; Mahoney, Christine; Wight, Scott; Lareau, Richard

2006-01-01

The use of secondary ion mass spectrometry (SIMS) for the detection and spatially resolved analysis of individual high explosive particles is described. A C(8) (-) carbon cluster primary ion beam was used in a commercial SIMS instrument to analyze samples of high explosives dispersed as particles on silicon substrates. In comparison with monatomic primary ion bombardment, the carbon cluster primary ion beam was found to greatly enhance characteristic secondary ion signals from the explosive compounds while causing minimal beam-induced degradation. The resistance of these compounds to degradation under ion bombardment allows explosive particles to be analyzed under high primary ion dose bombardment (dynamic SIMS) conditions, facilitating the rapid acquisition of spatially resolved molecular information. The use of cluster SIMS combined with computer control of the sample stage position allows for the automated identification and counting of explosive particle distributions on silicon surfaces. This will be useful for characterizing the efficiency of transfer of particulates in trace explosive detection portal collectors and/or swipes utilized for ion mobility spectrometry applications.

Comprehensive chemical comparison of fuel composition and aerosol particles emitted from a ship diesel engine by gas chromatography atmospheric pressure chemical ionisation ultra-high resolution mass spectrometry with improved data processing routines.

PubMed

Rüger, Christopher P; Schwemer, Theo; Sklorz, Martin; O'Connor, Peter B; Barrow, Mark P; Zimmermann, Ralf

2017-02-01

The analysis of petrochemical materials and particulate matter originating from combustion sources remains a challenging task for instrumental analytical techniques. A detailed chemical characterisation is essential for addressing health and environmental effects. Sophisticated instrumentation, such as mass spectrometry coupled with chromatographic separation, is capable of a comprehensive characterisation, but needs advanced data processing methods. In this study, we present an improved data processing routine for the mass chromatogram obtained from gas chromatography hyphenated to atmospheric pressure chemical ionisation and ultra high resolution mass spectrometry. The focus of the investigation was the primary combustion aerosol samples, i.e. particulate matter extracts, as well as the corresponding fossil fuels fed to the engine. We demonstrate that utilisation of the entire transient and chromatographic information results in advantages including minimisation of ionisation artefacts and a reliable peak assignment. A comprehensive comparison of the aerosol and the feed fuel was performed by applying intensity weighted average values, compound class distribution and principle component analysis. Certain differences between the aerosol generated with the two feed fuels, diesel fuel and heavy fuel oil, as well as between the aerosol and the feed were revealed. For the aerosol from heavy fuel oil, oxidised species from the CHN and CHS class precursors of the feed were predominant, whereas the CHO x class is predominant in the combustion aerosol from light fuel oil. Furthermore, the complexity of the aerosol increases significantly compared to the feed and incorporating a higher chemical space. Coupling of atmospheric pressure chemical ionisation to gas chromatography was found to be a useful additional approach for characterisation of a combustion aerosol, especially with an automated utilisation of the information from the ultra-high resolution mass spectrometer and the chromatographic separation.

A Report on the Activities, Publications, and Pending Research of DHS/DOD Sponsored Post-doctoral Research Associate at Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stanley, Floyd E.; Tandon, Lav

Since beginning at Los Alamos National Laboratory in February of 2012, I have been working as a DHS./DNDO Postdoctoral Research Associate under the mentorship of Lav Tandon and Khalil Spencer (NA-22 and mass spectrometry). The focus of my efforts, in addition to pursuing needed training and qualifications, has been the application of various instrumental approaches (e.g. Thermal Ionization Mass Spectrometry; TIMS) to a range of systems of interest in materials characterization and nuclear forensics. Research to be pursued in the coming months shall include the continued use of such approaches to advance current methods for: modified total evaporation, monitoring criticalmore » minor isotope systems, and chronometry. Each of the above points will be discussed.« less

Targeting the untargeted in molecular phenomics with structurally-selective ion mobility-mass spectrometry.

PubMed

May, Jody Christopher; Gant-Branum, Randi Lee; McLean, John Allen

2016-06-01

Systems-wide molecular phenomics is rapidly expanding through technological advances in instrumentation and bioinformatics. Strategies such as structural mass spectrometry, which utilizes size and shape measurements with molecular weight, serve to characterize the sum of molecular expression in biological contexts, where broad-scale measurements are made that are interpreted through big data statistical techniques to reveal underlying patterns corresponding to phenotype. The data density, data dimensionality, data projection, and data interrogation are all critical aspects of these approaches to turn data into salient information. Untargeted molecular phenomics is already having a dramatic impact in discovery science from drug discovery to synthetic biology. It is evident that these emerging techniques will integrate closely in broad efforts aimed at precision medicine. Copyright © 2016 Elsevier Ltd. All rights reserved.

A short review of applications of liquid chromatography mass spectrometry based metabolomics techniques to the analysis of human urine.

PubMed

Zhang, Tong; Watson, David G

2015-05-07

The applications of metabolomics as a methodology for providing better treatment and understanding human disease continue to expand rapidly. In this review, covering the last two years, the focus is on liquid chromatography-mass spectrometry (LC-MS) profiling of metabolites in urine. In LC-MS based metabolomics there are still problems with regard to: chromatographic separation, peak picking and alignment, metabolite identification, metabolite coverage, instrument sensitivity and data interpretation and in the case of urine sample normalisation. Progress has been made with regard to all of these issues during the period of the review. Of particular interest are the increasing use of orthogonal chromatographic methods for optimal metabolite coverage and the increasing adoption of receiver operator characteristic (ROC) curves for biomarker validation.

Challenging developments in three decades of accelerator mass spectrometry at ETH: from large particle accelerators to table size instruments.

PubMed

Suter, Martin

2010-01-01

Accelerator mass spectrometry (AMS) was invented for the detection of radiocarbon at natural isotopic concentrations (10(-12) to 10(-15)) more than 30 years ago. Meanwhile this method has also been applied for the analysis of many other long-lived radioisotopes, which are found at very low concentrations. The first investigations were made at large tandem accelerators originally built for nuclear physics research and operating at voltages of 6-12 MV. Today dedicated instruments are mostly used for AMS, which are optimized for associated applications. In the past 15 years, a new generation of much smaller instruments has been developed. For many years it was believed that accelerators with voltages of 2 MV or higher are needed to eliminate the molecular interferences. At these energies the ions are predominantly stripped to charge state 3+, thereby removing the binding electrons of the molecules. In contrast, the new compact facilities use 1+ or 2+ ions. In this case the molecular destruction process is based on molecule-atom collisions in the gas cell. The cross sections for this destruction are sufficiently large that the intensity of molecular components such as (12)CH(2) and (13)CH can be reduced by 10 orders of magnitude. These new facilities can be built much smaller due to the lower energies. Universal instruments providing analysis for many isotopes over the whole range of periodic table have a space requirement of about 4 x 6 m(2); dedicated radiocarbon facilities based on a 200 kV accelerator have a footprint of about 2.5 x 3 m(2). This smallest category of instruments use special technologies: The high voltage terminal with the gas stripper canal is vacuum insulated and the gas is pumped to ground potential through a ceramic pipe. A conventional 200 kV power supply provides the terminal voltage from outside. A review of this new generation of compact AMS facilities is given. Design considerations and performance of these new instruments will be presented. With these developments, new AMS instruments are not much larger than conventional mass spectrometers, allowing a significant reduction in cost.

Rapid sample classification using an open port sampling interface coupled with liquid introduction atmospheric pressure ionization mass spectrometry

DOE PAGES

Van Berkel, Gary J.; Kertesz, Vilmos

2016-11-15

An “Open Access”-like mass spectrometric platform to fully utilize the simplicity of the manual open port sampling interface for rapid characterization of unprocessed samples by liquid introduction atmospheric pressure ionization mass spectrometry has been lacking. The in-house developed integrated software with a simple, small and relatively low-cost mass spectrometry system introduced here fills this void. Software was developed to operate the mass spectrometer, to collect and process mass spectrometric data files, to build a database and to classify samples using such a database. These tasks were accomplished via the vendorprovided software libraries. Sample classification based on spectral comparison utilized themore » spectral contrast angle method. As a result, using the developed software platform near real-time sample classification is exemplified using a series of commercially available blue ink rollerball pens and vegetable oils. In the case of the inks, full scan positive and negative ion ESI mass spectra were both used for database generation and sample classification. For the vegetable oils, full scan positive ion mode APCI mass spectra were recorded. The overall accuracy of the employed spectral contrast angle statistical model was 95.3% and 98% in case of the inks and oils, respectively, using leave-one-out cross-validation. In conclusion, this work illustrates that an open port sampling interface/mass spectrometer combination, with appropriate instrument control and data processing software, is a viable direct liquid extraction sampling and analysis system suitable for the non-expert user and near real-time sample classification via database matching.« less

Rapid sample classification using an open port sampling interface coupled with liquid introduction atmospheric pressure ionization mass spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Berkel, Gary J.; Kertesz, Vilmos

An “Open Access”-like mass spectrometric platform to fully utilize the simplicity of the manual open port sampling interface for rapid characterization of unprocessed samples by liquid introduction atmospheric pressure ionization mass spectrometry has been lacking. The in-house developed integrated software with a simple, small and relatively low-cost mass spectrometry system introduced here fills this void. Software was developed to operate the mass spectrometer, to collect and process mass spectrometric data files, to build a database and to classify samples using such a database. These tasks were accomplished via the vendorprovided software libraries. Sample classification based on spectral comparison utilized themore » spectral contrast angle method. As a result, using the developed software platform near real-time sample classification is exemplified using a series of commercially available blue ink rollerball pens and vegetable oils. In the case of the inks, full scan positive and negative ion ESI mass spectra were both used for database generation and sample classification. For the vegetable oils, full scan positive ion mode APCI mass spectra were recorded. The overall accuracy of the employed spectral contrast angle statistical model was 95.3% and 98% in case of the inks and oils, respectively, using leave-one-out cross-validation. In conclusion, this work illustrates that an open port sampling interface/mass spectrometer combination, with appropriate instrument control and data processing software, is a viable direct liquid extraction sampling and analysis system suitable for the non-expert user and near real-time sample classification via database matching.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smentkowski, Vincent S., E-mail: smentkow@ge.com

Changes in the oxidation state of an element can result in significant changes in the ionization efficiency and hence signal intensity during secondary ion mass spectrometry (SIMS) analysis; this is referred to as the SIMS matrix effect [Secondary Ion Mass Spectrometry: A Practical Handbook for Depth Profiling and Bulk Impurity Analysis, edited by R. G. Wilson, F. A. Stevie, and C. W. Magee (Wiley, New York, 1990)]. The SIMS matrix effect complicates quantitative analysis. Quantification of SIMS data requires the determination of relative sensitivity factors (RSFs), which can be used to convert the as measured intensity into concentration units [Secondarymore » Ion Mass Spectrometry: A Practical Handbook for Depth Profiling and Bulk Impurity Analysis, edited by R. G. Wilson, F. A. Stevie, and C. W. Magee (Wiley, New York, 1990)]. In this manuscript, the authors report both: RSFs which were determined for quantification of B in Si and SiO{sub 2} matrices using a dual beam time of flight secondary ion mass spectrometry (ToF-SIMS) instrument and the protocol they are using to provide quantitative ToF-SIMS images and line scan traces. The authors also compare RSF values that were determined using oxygen and Ar ion beams for erosion, discuss the problems that can be encountered when bulk calibration samples are used to determine RSFs, and remind the reader that errors in molecular details of the matrix (density, volume, etc.) that are used to convert from atoms/cm{sup 3} to other concentration units will propagate into errors in the determined concentrations.« less

Identification of trace levels of selenomethionine and related organic selenium species in high-ionic-strength waters.

PubMed

LeBlanc, Kelly L; Ruzicka, Josef; Wallschläger, Dirk

2016-02-01

A new anion-exchange chromatographic separation method was used for the simultaneous speciation analysis of selenoamino acids and the more ubiquitous inorganic selenium oxyanions, selenite and selenate. For quantification, this separation was coupled to inductively coupled plasma-mass spectrometry to achieve an instrumental detection limit of 5 ng Se L(-1) for all species. This chromatographic method was also coupled to electrospray tandem mass spectrometry to observe the negative ion mode fragmentation of selenomethionine and one of its oxidation products. Low detection limits were achieved, which were similar to those obtained using inductively coupled plasma-mass spectrometry. An extensive preconcentration and cleanup procedure using cation-exchange solid-phase extraction was developed for the identification and quantification of trace levels of selenomethionine in environmental samples. Preconcentration factors of up to five were observed for selenomethionine, which in addition to the removal of high concentrations of sulphate and chloride from industrial process waters, allowed for an unambiguous analysis that would have been impossible otherwise. Following these methods, selenomethionine was identified at an original concentration of 3.2 ng Se L(-1) in samples of effluent collected at a coal-fired power plant's biological remediation site. It is the first time that this species has been identified in the environment, outside of a biological entity. Additionally, oxidation products of selenomethionine were identified in river water and laboratory algal culture samples. High-resolution mass spectrometry was employed to postulate the chemical structures of these species.

Simultaneous drug identification in urine of sexual assault victims by using liquid chromatography tandem mass spectrometry.

PubMed

Lee, Hei Hwa; Chen, Suen Chi; Lee, Jong Feng; Lin, Hsin Yu; Chen, Bai Hsiun

2018-01-01

According to domestic and international epidemiological investigation, the proportion of substance involved sexual assault has the trend of ascent. In the past, laboratory methods that investigated urine sample of the sexual assault victims was to screen with enzyme immunoassay and then confirmed with mass spectrometry. The objective of the study is to simultaneously identify abused drugs in 126 decoded urine samples of sexual assault victims by liquid chromatography tandem mass spectrometry. The instrument was operated in multiple-reaction monitoring with an electro-spray positive ionization mode. Chromatograms were separated with ACE5 C18 column on a gradient of acetonitrile. After liquid-liquid extraction, samples were passed through a 0.22μm PVDF filter before injection into the system. The limits of quantitation ranged from 0.2 to 10ng/mL. The precision (CV) results were below 12.9% (intraday) and 15.0% (interday). The intraday accuracy ranged from 84.8 to 121.0%, interday accuracy ranged from 72.0 to 117.3%. We found that 29 (23.0%) were positive for drugs. The most common drug identified is flunitrazepam (11.1%), followed by nimetazepam and ketamine (7.9%), some new psychoactive substances, such as 2C-B, mephedrone, methylone, PMA and PMMA were also identified. We identified abused drugs, benzodiazepines, and new psychoactive substances in urine of sexual assault victims by using liquid chromatography tandem mass spectrometry. Copyright © 2017 Elsevier B.V. All rights reserved.

Mapping Cellular Polarity Networks Using Mass Spectrometry-based Strategies.

PubMed

Daulat, Avais M; Puvirajesinghe, Tania M; Camoin, Luc; Borg, Jean-Paul

2018-05-18

Cell polarity is a vital biological process involved in the building, maintenance and normal functioning of tissues in invertebrates and vertebrates. Unsurprisingly, molecular defects affecting polarity organization and functions have a strong impact on tissue homeostasis, embryonic development and adult life, and may directly or indirectly lead to diseases. Genetic studies have demonstrated the causative effect of several polarity genes in diseases; however, much remains to be clarified before a comprehensive view of the molecular organization and regulation of the protein networks associated with polarity proteins is obtained. This challenge can be approached head-on using proteomics to identify protein complexes involved in cell polarity and their modifications in a spatio-temporal manner. We review the fundamental basics of mass spectrometry techniques and provide an in-depth analysis of how mass spectrometry has been instrumental in understanding the complex and dynamic nature of some cell polarity networks at the tissue (apico-basal and planar cell polarities) and cellular (cell migration, ciliogenesis) levels, with the fine dissection of the interconnections between prototypic cell polarity proteins and signal transduction cascades in normal and pathological situations. This review primarily focuses on epithelial structures which are the fundamental building blocks for most metazoan tissues, used as the archetypal model to study cellular polarity. This field offers broad perspectives thanks to the ever-increasing sensitivity of mass spectrometry and its use in combination with recently developed molecular strategies able to probe in situ proteomic networks. Copyright © 2018 Elsevier Ltd. All rights reserved.

Detection of Biomarkers of Pathogenic Naegleria fowleri Through Mass Spectrometry and Proteomics

PubMed Central

Moura, Hercules; Izquierdo, Fernando; Woolfitt, Adrian R.; Wagner, Glauber; Pinto, Tatiana; del Aguila, Carmen; Barr, John R.

2017-01-01

Emerging methods based on mass spectrometry (MS) can be used in the rapid identification of microorganisms. Thus far, these practical and rapidly evolving methods have mainly been applied to characterize prokaryotes. We applied matrix-assisted laser-desorption-ionization-time-of-flight mass spectrometry MALDI-TOF MS in the analysis of whole cells of 18 N. fowleri isolates belonging to three genotypes. Fourteen originated from the cerebrospinal fluid or brain tissue of primary amoebic meningoencephalitis patients and four originated from water samples of hot springs, rivers, lakes or municipal water supplies. Whole Naegleria trophozoites grown in axenic cultures were washed and mixed with MALDI matrix. Mass spectra were acquired with a 4700 TOF-TOF instrument. MALDI-TOF MS yielded consistent patterns for all isolates examined. Using a combination of novel data processing methods for visual peak comparison, statistical analysis and proteomics database searching we were able to detect several biomarkers that can differentiate all species and isolates studied, along with common biomarkers for all N. fowleri isolates. Naegleria fowleri could be easily separated from other species within the genus Naegleria. A number of peaks detected were tentatively identified. MALDI-TOF MS fingerprinting is a rapid, reproducible, high-throughput alternative method for identifying Naegleria isolates. This method has potential for studying eukaryotic agents. PMID:25231600

Analytical improvements of hybrid LC-MS/MS techniques for the efficient evaluation of emerging contaminants in river waters: a case study of the Henares River (Madrid, Spain).

PubMed

Pérez-Parada, Andrés; Gómez-Ramos, María del Mar; Martínez Bueno, María Jesús; Uclés, Samanta; Uclés, Ana; Fernández-Alba, Amadeo R

2012-02-01

Instrumental capabilities and software tools of modern hybrid mass spectrometry (MS) instruments such as high-resolution mass spectrometry (HRMS), quadrupole time-of-flight (QTOF), and quadrupole linear ion trap (QLIT) were experimentally investigated for the study of emerging contaminants in Henares River water samples. Automated screening and confirmatory capabilities of QTOF working in full-scan MS and tandem MS (MS/MS) were explored when dealing with real samples. Investigations on the effect of sensitivity and resolution power influence on mass accuracy were studied for the correct assignment of the amoxicillin transformation product 5(R) amoxicillin-diketopiperazine-2',5' as an example of a nontarget compound. On the other hand, a comparison of quantitative and qualitative strategies based on direct injection analysis and off-line solid-phase extraction sample treatment were assayed using two different QLIT instruments for a selected group of emerging contaminants when operating in selected reaction monitoring (SRM) and information-dependent acquisition (IDA) modes. Software-aided screening usually needs a further confirmatory step. Resolving power and MS/MS feature of QTOF showed to confirm/reject most findings in river water, although sensitivity-related limitations are usually found. Superior sensitivity of modern QLIT-MS/MS offered the possibility of direct injection analysis for proper quantitative study of a variety of contaminants, while it simultaneously reduced the matrix effect and increased the reliability of the results. Confirmation of ethylamphetamine, which lacks on a second SRM transition, was accomplished by using the IDA feature. Hybrid MS instruments equipped with high resolution and high sensitivity contributes to enlarge the scope of targeted analytes in river waters. However, in the tested instruments, there is a margin of improvement principally in required sensitivity and data treatment software tools devoted to reliable confirmation and improved automated data processing.

Demonstrating Rapid Qualitative Elemental Analyses of Participant-Supplied Objects at a Public Outreach Event

ERIC Educational Resources Information Center

Schwarz, Gunnar; Burger, Marcel; Guex, Kevin; Gundlach-Graham, Alexander; Ka¨ser, Debora; Koch, Joachim; Velicsanyi, Peter; Wu, Chung-Che; Gu¨nther, Detlef; Hattendorf, Bodo

2016-01-01

A public demonstration of laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) for fast and sensitive qualitative elemental analysis of solid everyday objects is described. This demonstration served as a showcase model for modern instrumentation (and for elemental analysis, in particular) to the public. Several steps were made to…

Top-down proteomic identification of bacterial protein biomarkers and toxins using MALDI-TOF-TOF-MS/MS and post-source decay

USDA-ARS?s Scientific Manuscript database

Matrix-assisted laser desorption/ionization time-of-flight-time-of-flight mass spectrometry(MALDI-TOF-TOF-MS)has provided new capabilities for the rapid identification of digested and non-digested proteins. The tandem (MS/MS) capability of TOF-TOF instruments allows precursor ion selection/isolation...

Identification and Characterization of Human Proteoforms by Top-Down LC-21 Tesla FT-ICR Mass Spectrometry.

PubMed

Anderson, Lissa C; DeHart, Caroline J; Kaiser, Nathan K; Fellers, Ryan T; Smith, Donald F; Greer, Joseph B; LeDuc, Richard D; Blakney, Greg T; Thomas, Paul M; Kelleher, Neil L; Hendrickson, Christopher L

2017-02-03

Successful high-throughput characterization of intact proteins from complex biological samples by mass spectrometry requires instrumentation capable of high mass resolving power, mass accuracy, sensitivity, and spectral acquisition rate. These limitations often necessitate the performance of hundreds of LC-MS/MS experiments to obtain reasonable coverage of the targeted proteome, which is still typically limited to molecular weights below 30 kDa. The National High Magnetic Field Laboratory (NHMFL) recently installed a 21 T FT-ICR mass spectrometer, which is part of the NHMFL FT-ICR User Facility and available to all qualified users. Here we demonstrate top-down LC-21 T FT-ICR MS/MS of intact proteins derived from human colorectal cancer cell lysate. We identified a combined total of 684 unique protein entries observed as 3238 unique proteoforms at a 1% false discovery rate, based on rapid, data-dependent acquisition of collision-induced and electron-transfer dissociation tandem mass spectra from just 40 LC-MS/MS experiments. Our identifications included 372 proteoforms with molecular weights over 30 kDa detected at isotopic resolution, which substantially extends the accessible mass range for high-throughput top-down LC-MS/MS.

Clusters of Monoisotopic Elements for Calibration in (TOF) Mass Spectrometry

NASA Astrophysics Data System (ADS)

Kolářová, Lenka; Prokeš, Lubomír; Kučera, Lukáš; Hampl, Aleš; Peňa-Méndez, Eladia; Vaňhara, Petr; Havel, Josef

2017-03-01

Precise calibration in TOF MS requires suitable and reliable standards, which are not always available for high masses. We evaluated inorganic clusters of the monoisotopic elements gold and phosphorus (Au n +/Au n - and P n +/P n -) as an alternative to peptides or proteins for the external and internal calibration of mass spectra in various experimental and instrumental scenarios. Monoisotopic gold or phosphorus clusters can be easily generated in situ from suitable precursors by laser desorption/ionization (LDI) or matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Their use offers numerous advantages, including simplicity of preparation, biological inertness, and exact mass determination even at lower mass resolution. We used citrate-stabilized gold nanoparticles to generate gold calibration clusters, and red phosphorus powder to generate phosphorus clusters. Both elements can be added to samples to perform internal calibration up to mass-to-charge ( m/z) 10-15,000 without significantly interfering with the analyte. We demonstrated the use of the gold and phosphorous clusters in the MS analysis of complex biological samples, including microbial standards and total extracts of mouse embryonic fibroblasts. We believe that clusters of monoisotopic elements could be used as generally applicable calibrants for complex biological samples.

Evolution of Icy Dust Grains in the Vicinity of a Cometary Nucleus

NASA Astrophysics Data System (ADS)

Hilchenbach, M.

2009-12-01

From late 2014 onwards, ESA's cornerstone mission ROSETTA will orbit the comet 67P/Churyumov-Gerasimenko. One instrument, COSIMA, will collect cometary dust grains and analyze the grains via secondary mass spectrometry. Models of the evolution of icy dust, accelerated by drag forces of subliming gas and exposed to solar radiation, should set constrains on the detection limits of the COSIMA instrument for volatile icy components. A straightforward modeling approach is applied as a baseline for the observational planing schedule of the instrument operations in the years 2014/2015 as ROSETTA escorts the comet nucleus up to perihelion and beyond.

Portable Dew Point Mass Spectrometry System for Real-Time Gas and Moisture Analysis

NASA Technical Reports Server (NTRS)

Arkin, C.; Gillespie, Stacey; Ratzel, Christopher

2010-01-01

A portable instrument incorporates both mass spectrometry and dew point measurement to provide real-time, quantitative gas measurements of helium, nitrogen, oxygen, argon, and carbon dioxide, along with real-time, quantitative moisture analysis. The Portable Dew Point Mass Spectrometry (PDP-MS) system comprises a single quadrupole mass spectrometer and a high vacuum system consisting of a turbopump and a diaphragm-backing pump. A capacitive membrane dew point sensor was placed upstream of the MS, but still within the pressure-flow control pneumatic region. Pressure-flow control was achieved with an upstream precision metering valve, a capacitance diaphragm gauge, and a downstream mass flow controller. User configurable LabVIEW software was developed to provide real-time concentration data for the MS, dew point monitor, and sample delivery system pressure control, pressure and flow monitoring, and recording. The system has been designed to include in situ, NIST-traceable calibration. Certain sample tubing retains sufficient water that even if the sample is dry, the sample tube will desorb water to an amount resulting in moisture concentration errors up to 500 ppm for as long as 10 minutes. It was determined that Bev-A-Line IV was the best sample line to use. As a result of this issue, it is prudent to add a high-level humidity sensor to PDP-MS so such events can be prevented in the future.

A gas chromatography/high-resolution mass spectrometry (GC/HRMS) method for determination of polybrominated diphenyl ethers in fish.

PubMed

Alaee, M; Sergeant, D B; Ikonomou, M G; Luross, J M

2001-09-01

A method for the determination of polybrominated diphenyl ethers (PBDEs) in biota for routine analysis is described. The mass spectroscopic (MS) evaluation of 23 brominated diphenyl ethers, under electron ionization and electron capture negative ion conditions using magnetic sector and quadrupole mass spectrometers, showed that high-resolution mass spectrometry (HRMS) under electron ionization conditions was the most reliable technique, with high selectivity and adequate sensitivity. The instrument detection limit for this method ranged for individual congeners between 4.8 and 0.1 pg for 3-bromodiphenyl ether (BDE-2) and 2,3',4,4'-tetrabromodiphenyl ether (BDE-66), respectively, and method detection limit for each homologue group ranged between 5 pg/g for salmon certified reference material (CRM) and 93 pg/g for lake trout CRM. The effectiveness of this method was evaluated by analyzing the occurrence of PBDEs in commercially available CRMs comprising Lake Ontario lake trout, Pacific herring, and sockeye salmon. The average coefficients of variation for the replicate analyses of PDBEs in several tissue samples were: 25% for lake trout, 36% for Pacific herring, and 34% for sockeye salmon. The average deviations in the inter-laboratory study were: 14% for lake trout, 15% for Pacific herring, and 37% for sockeye salmon. Results indicated that the described method, based on gas chromatography/high-resolution mass spectrometry, is reliable for determining PBDE concentrations in biological tissues.

Range of protein detection by selected/multiple reaction monitoring mass spectrometry in an unfractionated human cell culture lysate.

PubMed

Ebhardt, H Alexander; Sabidó, Eduard; Hüttenhain, Ruth; Collins, Ben; Aebersold, Ruedi

2012-04-01

Selected or multiple reaction monitoring is a targeted mass spectrometry method (S/MRM-MS), in which many peptides are simultaneously and consistently analyzed during a single liquid chromatography-mass spectrometry (LC-S/MRM-MS) measurement. These capabilities make S/MRM-MS an attractive method to monitor a consistent set of proteins over various experimental conditions. To increase throughput for S/MRM-MS it is advantageous to use scheduled methods and unfractionated protein extracts. Here, we established the practically measurable dynamic range of proteins reliably detectable and quantifiable in an unfractionated protein extract from a human cell line using LC-S/MRM-MS. Initially, we analyzed S/MRM transition peak groups in terms of interfering signals and compared S/MRM transition peak groups to MS1-triggered MS2 spectra using dot-product analysis. Finally, using unfractionated protein extract from human cell lysate, we quantified the upper boundary of copies per cell to be 35 million copies per cell, while 7500 copies per cell represents a lower boundary using a single 35 min linear gradient LC-S/MRM-MS measurement on a current, standard commercial instrument. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sensing Technologies for Detection of Acetone in Human Breath for Diabetes Diagnosis and Monitoring

PubMed Central

Saasa, Valentine; Malwela, Thomas; Beukes, Mervyn; Mokgotho, Matlou; Liu, Chaun-Pu; Mwakikunga, Bonex

2018-01-01

The review describes the technologies used in the field of breath analysis to diagnose and monitor diabetes mellitus. Currently the diagnosis and monitoring of blood glucose and ketone bodies that are used in clinical studies involve the use of blood tests. This method entails pricking fingers for a drop of blood and placing a drop on a sensitive area of a strip which is pre-inserted into an electronic reading instrument. Furthermore, it is painful, invasive and expensive, and can be unsafe if proper handling is not undertaken. Human breath analysis offers a non-invasive and rapid method for detecting various volatile organic compounds thatare indicators for different diseases. In patients with diabetes mellitus, the body produces excess amounts of ketones such as acetoacetate, beta-hydroxybutyrate and acetone. Acetone is exhaled during respiration. The production of acetone is a result of the body metabolising fats instead of glucose to produce energy. There are various techniques that are used to analyse exhaled breath including Gas Chromatography Mass Spectrometry (GC–MS), Proton Transfer Reaction Mass Spectrometry (PTR–MS), Selected Ion Flow Tube-Mass Spectrometry (SIFT–MS), laser photoacoustic spectrometry and so on. All these techniques are not portable, therefore this review places emphasis on how nanotechnology, through semiconductor sensing nanomaterials, has the potential to help individuals living with diabetes mellitus monitor their disease with cheap and portable devices. PMID:29385067

Simultaneous Proteomic Discovery and Targeted Monitoring using Liquid Chromatography, Ion Mobility Spectrometry, and Mass Spectrometry*

PubMed Central

Burnum-Johnson, Kristin E.; Nie, Song; Casey, Cameron P.; Monroe, Matthew E.; Orton, Daniel J.; Ibrahim, Yehia M.; Gritsenko, Marina A.; Clauss, Therese R. W.; Shukla, Anil K.; Moore, Ronald J.; Purvine, Samuel O.; Shi, Tujin; Qian, Weijun; Liu, Tao; Baker, Erin S.; Smith, Richard D.

2016-01-01

Current proteomic approaches include both broad discovery measurements and quantitative targeted analyses. In many cases, discovery measurements are initially used to identify potentially important proteins (e.g. candidate biomarkers) and then targeted studies are employed to quantify a limited number of selected proteins. Both approaches, however, suffer from limitations. Discovery measurements aim to sample the whole proteome but have lower sensitivity, accuracy, and quantitation precision than targeted approaches, whereas targeted measurements are significantly more sensitive but only sample a limited portion of the proteome. Herein, we describe a new approach that performs both discovery and targeted monitoring (DTM) in a single analysis by combining liquid chromatography, ion mobility spectrometry and mass spectrometry (LC-IMS-MS). In DTM, heavy labeled target peptides are spiked into tryptic digests and both the labeled and unlabeled peptides are detected using LC-IMS-MS instrumentation. Compared with the broad LC-MS discovery measurements, DTM yields greater peptide/protein coverage and detects lower abundance species. DTM also achieved detection limits similar to selected reaction monitoring (SRM) indicating its potential for combined high quality discovery and targeted analyses, which is a significant step toward the convergence of discovery and targeted approaches. PMID:27670688

Identification of pesticide transformation products in food by liquid chromatography/time-of-flight mass spectrometry via "fragmentation-degradation" relationships.

PubMed

García-Reyes, Juan F; Molina-Díaz, Antonio; Fernandez-Alba, Amadeo R

2007-01-01

The identification of transformation products of pesticides in foodstuffs is a crucial task difficult to tackle, due to the lack of standards and scarce information available. In this work, we describe a methodology for the identification and structural elucidation of pesticide transformation products in food. The proposed strategy is based on the use of liquid chromatography electrospray time-of-flight mass spectrometry (LC/TOFMS): accurate mass measurements of (molecule and fragment) ions of interest are used in order to establish relationships between fragmentation of the parent pesticides in the instrument (in-source CID fragmentation) and possible degradation products of these pesticides in food. Examples of this strategy showing the potential of LC/TOFMS to determine unknown pesticides in food are described in two different real samples, suggesting that pesticides often are transformed into degradation products in the same fashion that they are fragmented in the instrument. Using the proposed approach and without using standards a priori, based solely on accurate mass measurements of ions and "fragmentation-degradation" relationships, we have identified two parent pesticides (amitraz and malathion) along with six degradation products, m/z 253 (N,N'-bisdimethylphenylformamidine), 163 (N-2,4-dimethylphenyl-N-methyl formamidine), 150 (2,4-dimethylformamidine), and 122 (2,4-dimethylaniline) from amitraz, and m/z 317 and 303, due to ether hydrolysis of methyl and ethyl groups from malathion. Structures for these species were proposed, and the potential of the proposed approach was critically discussed.

Trace gas detection from fermentation processes in apples; an intercomparison study between proton-transfer-reaction mass spectrometry and laser photoacoustics

NASA Astrophysics Data System (ADS)

Boamfa, E. I.; Steeghs, M. M. L.; Cristescu, S. M.; Harren, F. J. M.

2004-12-01

A custom-built proton-transfer-reaction mass spectrometry (PTR-MS) instrument was used to monitor the emission of various compounds (aldehydes, alcohols, acids, acetates and C-6 compounds) related to fermentation, aroma and flavour, released by four apple cultivars (Elstar, Jonaglod, Granny Smith and Pink Lady) under short anaerobic (24 h) and post-anaerobic conditions. The novel feature of our instrument is the new design of the collisional dissociation chamber, which separates the high pressure in the drift tube (2 mbar) from the high vacuum pressure in the detection region (10-6 mbar). The geometry of this chamber was changed and a second turbo pump was added to reduce the influence of collisional loss of ions, background signals and cluster ions, which facilitates the interpretation of the mass spectra and increases the signal intensity at the mass of the original protonated compound. With this system, detection limits of similar magnitude to the ones reported in literature are reached. An intercomparison study between PTR-MS and a CO laser-based photoacoustic trace gas detector is presented. The alcoholic fermentation products (acetaldehyde and ethanol) from young rice plants were simultaneously monitored by both methods. A very good agreement was observed for acetaldehyde production. The photoacoustic detector showed about two times lower ethanol concentration as compared to PTR-MS, caused by memory effects due to sticking of compounds to the walls of the nylon tube used to transport the trace gases to the detector.

Online hydrogen/deuterium exchange performed in the ion mobility cell of a hybrid mass spectrometer.

PubMed

Nagy, Kornél; Redeuil, Karine; Rezzi, Serge

2009-11-15

The present paper describes the performance of online, gas-phase hydrogen/deuterium exchange implemented in the ion mobility cell of a quadrupole time-of-flight mass spectrometer. Deuterium oxide and deuterated methanol were utilized to create deuterated vapor that is introduced into the ion mobility region of the mass spectrometer. Hydrogen/deuterium exchange occurs spontaneously in the milliseconds time frame without the need of switching the instrument into ion mobility mode. The exchange was studied in case of low molecular weight molecules and proteins. The observed number of exchanged hydrogens was equal to the number of theoretically exchangeable hydrogens for all low molecular weight compounds. This method needs only minimal instrumental modifications, is simple, cheap, environment friendly, compatible with ultraperformance liquid chromatography, and can be implemented on commercially available instruments. It does not compromise choice of liquid chromatographic solvents and accurate mass or parallel-fragmentation (MS(E)) methods. The performance of this method was compared to that of conventional alternatives where the deuterated solvent is introduced into the cone gas of the instrument. Although the degree of exchange was similar between the two methods, the "cone gas method" requires 10 times higher deuterated solvent volumes (50 muL/min) and offers reduced sensitivity in the tandem mass spectrometry (MS/MS) mode. The presented method is suggested as a standard future element of mass spectrometers to aid online structural characterization of unknowns and to study conformational changes of proteins with hydrogen/deuterium exchange.

Normalization of mass cytometry data with bead standards

PubMed Central

Finck, Rachel; Simonds, Erin F.; Jager, Astraea; Krishnaswamy, Smita; Sachs, Karen; Fantl, Wendy; Pe’er, Dana; Nolan, Garry P.; Bendall, Sean C.

2013-01-01

Mass cytometry uses atomic mass spectrometry combined with isotopically pure reporter elements to currently measure as many as 40 parameters per single cell. As with any quantitative technology, there is a fundamental need for quality assurance and normalization protocols. In the case of mass cytometry, the signal variation over time due to changes in instrument performance combined with intervals between scheduled maintenance must be accounted for and then normalized. Here, samples were mixed with polystyrene beads embedded with metal lanthanides, allowing monitoring of mass cytometry instrument performance over multiple days of data acquisition. The protocol described here includes simultaneous measurements of beads and cells on the mass cytometer, subsequent extraction of the bead-based signature, and the application of an algorithm enabling correction of both short- and long-term signal fluctuations. The variation in the intensity of the beads that remains after normalization may also be used to determine data quality. Application of the algorithm to a one-month longitudinal analysis of a human peripheral blood sample reduced the range of median signal fluctuation from 4.9-fold to 1.3-fold. PMID:23512433

Advanced Multidimensional Separations in Mass Spectrometry: Navigating the Big Data Deluge

PubMed Central

May, Jody C.; McLean, John A.

2017-01-01

Hybrid analytical instrumentation constructed around mass spectrometry (MS) are becoming preferred techniques for addressing many grand challenges in science and medicine. From the omics sciences to drug discovery and synthetic biology, multidimensional separations based on MS provide the high peak capacity and high measurement throughput necessary to obtain large-scale measurements which are used to infer systems-level information. In this review, we describe multidimensional MS configurations as technologies which are big data drivers and discuss some new and emerging strategies for mining information from large-scale datasets. A discussion is included on the information content which can be obtained from individual dimensions, as well as the unique information which can be derived by comparing different levels of data. Finally, we discuss some emerging data visualization strategies which seek to make highly dimensional datasets both accessible and comprehensible. PMID:27306312

Matrix assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) for direct visualization of plant metabolites in situ

DOE PAGES

Sturtevant, Drew; Lee, Young -Jin; Chapman, Kent D.

2015-11-22

Direct visualization of plant tissues by matrix assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) has revealed key insights into the localization of metabolites in situ. Recent efforts have determined the spatial distribution of primary and secondary metabolites in plant tissues and cells. Strategies have been applied in many areas of metabolism including isotope flux analyses, plant interactions, and transcriptional regulation of metabolite accumulation. Technological advances have pushed achievable spatial resolution to subcellular levels and increased instrument sensitivity by several orders of magnitude. Furthermore, it is anticipated that MALDI-MSI and other MSI approaches will bring a new level of understanding tomore » metabolomics as scientists will be encouraged to consider spatial heterogeneity of metabolites in descriptions of metabolic pathway regulation.« less

Stone-age mass spectrometry: the beginnings of "SIMS" at RCA Laboratories, Princeton

NASA Astrophysics Data System (ADS)

Honig, Richard E.

1995-05-01

This paper takes you back almost half a century, to the time when mass spectrometry was young and exciting, and research was exploring new frontiers every day. Our early experiments called "sputtering of surfaces by positive ion beams", now known as "SIMS", were carried out with the simple, yet flexible instrumentation available at that time and produced many interesting results that are still valid today. Since commercial equipment did not exist in those days, just about everything had to be designed and constructed in-house - hardware as well as circuitry. Thus progress was slow, but occasional malfunctioning of a component could be readily rectified. It is gratifying to see how SIMS has developed in the interim from our early feasibility studies into a major research effort carried out worldwide in many laboratories.

Matrix assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) for direct visualization of plant metabolites in situ

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sturtevant, Drew; Lee, Young -Jin; Chapman, Kent D.

Direct visualization of plant tissues by matrix assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) has revealed key insights into the localization of metabolites in situ. Recent efforts have determined the spatial distribution of primary and secondary metabolites in plant tissues and cells. Strategies have been applied in many areas of metabolism including isotope flux analyses, plant interactions, and transcriptional regulation of metabolite accumulation. Technological advances have pushed achievable spatial resolution to subcellular levels and increased instrument sensitivity by several orders of magnitude. Furthermore, it is anticipated that MALDI-MSI and other MSI approaches will bring a new level of understanding tomore » metabolomics as scientists will be encouraged to consider spatial heterogeneity of metabolites in descriptions of metabolic pathway regulation.« less

Fluorocarbon Contamination from the Drill on the Mars Science Laboratory: Potential Science Impact on Detecting Martian Organics by Sample Analysis at Mars (SAM)

NASA Technical Reports Server (NTRS)

Eigenbrode, J. L.; McAdam, A.; Franz, H.; Freissinet, C.; Bower, H.; Floyd, M.; Conrad, P.; Mahaffy, P.; Feldman, J.; Hurowitz, J.;

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, Jian; Casey, Cameron P.; Zheng, Xueyun

Motivation: Drift tube ion mobility spectrometry (DTIMS) is increasingly implemented in high throughput omics workflows, and new informatics approaches are necessary for processing the associated data. To automatically extract arrival times for molecules measured by DTIMS coupled with mass spectrometry and compute their associated collisional cross sections (CCS) we created the PNNL Ion Mobility Cross Section Extractor (PIXiE). The primary application presented for this algorithm is the extraction of information necessary to create a reference library containing accu-rate masses, DTIMS arrival times and CCSs for use in high throughput omics analyses. Results: We demonstrate the utility of this approach bymore » automatically extracting arrival times and calculating the associated CCSs for a set of endogenous metabolites and xenobiotics. The PIXiE-generated CCS values were identical to those calculated by hand and within error of those calcu-lated using commercially available instrument vendor software.« less

Hapsite Gas Chromatography - Mass Spectrometry with Solid Phase Microextraction

DTIC Science & Technology

2005-07-18

Polydimethylsiloxane /Divinylbenzene (PDMS/DVB) 65um/partially crosslinked*** Polar volatiles 60urn/ partially crosslinked General purpose (for HPLC ... Polydimethylsiloxane (PDMS). The HAPSITE with tri-bed concentrator achieved the lowest detection limits. The HAPSITE and the field portable GCUMS... Polydimethylsiloxane (PDMS). The HAPSITE with tri-bed concentrator achieved the lowest detection limits. The HAPSITE and the field portable GC/MS instrument coupled

Analytical Strategies Involved in the Detailed Componential Characterization of Biooil Produced from Lignocellulosic Biomass

PubMed Central

Li, Guo-Sheng; Wei, Xian-Yong

2017-01-01

Elucidation of chemical composition of biooil is essentially important to evaluate the process of lignocellulosic biomass (LCBM) conversion and its upgrading and suggest proper value-added utilization like producing fuel and feedstock for fine chemicals. Although the main components of LCBM are cellulose, hemicelluloses, and lignin, the chemicals derived from LCBM differ significantly due to the various feedstock and methods used for the decomposition. Biooil, produced from pyrolysis of LCBM, contains hundreds of organic chemicals with various classes. This review covers the methodologies used for the componential analysis of biooil, including pretreatments and instrumental analysis techniques. The use of chromatographic and spectrometric methods was highlighted, covering the conventional techniques such as gas chromatography, high performance liquid chromatography, Fourier transform infrared spectroscopy, nuclear magnetic resonance, and mass spectrometry. The combination of preseparation methods and instrumental technologies is a robust pathway for the detailed componential characterization of biooil. The organic species in biooils can be classified into alkanes, alkenes, alkynes, benzene-ring containing hydrocarbons, ethers, alcohols, phenols, aldehydes, ketones, esters, carboxylic acids, and other heteroatomic organic compounds. The recent development of high resolution mass spectrometry and multidimensional hyphenated chromatographic and spectrometric techniques has considerably elucidated the composition of biooils. PMID:29387086

Detection of beryllium in digested autopsy tissues by inductively coupled plasma mass spectrometry using a high matrix interface configuration.

PubMed

Larivière, Dominic; Tremblay, Mélodie; Durand-Jézéquel, Myriam; Tolmachev, Sergei

2012-04-01

This article describes a robust methodology using the combination of instrumental design (high matrix interface-HMI), sample dilution and internal standardization for the quantification of beryllium (Be) in various digested autopsy tissues using inductively coupled plasma mass spectrometry. The applicability of rhodium as a proper internal standard for Be was demonstrated in three types of biological matrices (i.e., femur, hair, lung tissues). Using HMI, it was possible to achieve instrumental detection limits and sensitivity of 0.6 ng L(-1) and 157 cps L ng(-1), respectively. Resilience to high salt matrices of the HMI setup was also highlighted using bone mimicking solution ([Ca(2+)] = 26 to 1,400 mg L(-1)), providing a 14-fold increase in tolerance and a 2.7-fold decrease in method detection limit compared to optimized experimental conditions obtained without the HMI configuration. Precision of the methodology to detect low levels of Be in autopsy samples was demonstrated using hair and blood certified reference materials. Be concentration ranging from 0.015 to 255 μg kg(-1) in autopsy samples obtained from the U.S. Transuranium and Uranium Registries were measured using the methodology presented.

Detection of Ketones by a Novel Technology: Dipolar Proton Transfer Reaction Mass Spectrometry (DP-PTR-MS)

NASA Astrophysics Data System (ADS)

Pan, Yue; Zhang, Qiangling; Zhou, Wenzhao; Zou, Xue; Wang, Hongmei; Huang, Chaoqun; Shen, Chengyin; Chu, Yannan

2017-05-01

Proton transfer reaction mass spectrometry (PTR-MS) has played an important role in the field of real-time monitoring of trace volatile organic compounds (VOCs) due to its advantages such as low limit of detection (LOD) and fast time response. Recently, a new technology of proton extraction reaction mass spectrometry (PER-MS) with negative ions OH- as the reagent ions has also been presented, which can be applied to the detection of VOCs and even inorganic compounds. In this work, we combined the functions of PTR-MS and PER-MS in one instrument, thereby developing a novel technology called dipolar proton transfer reaction mass spectrometry (DP-PTR-MS). The selection of PTR-MS mode and PER-MS mode was achieved in DP-PTR-MS using only water vapor in the ion source and switching the polarity. In this experiment, ketones (denoted by M) were selected as analytes. The ketone (molecular weight denoted by m) was ionized as protonated ketone [M + H]+ [mass-to-charge ratio ( m/z) m + 1] in PTR-MS mode and deprotonated ketone [M - H]- ( m/z m - 1) in PER-MS mode. By comparing the m/z value of the product ions in the two modes, the molecular weight of the ketone can be positively identified as m. Results showed that whether it is a single ketone sample or a mixed sample of eight kinds of ketones, the molecular weights can be detected with DP-PTR-MS. The newly developed DP-PTR-MS not only maintains the original advantages of PTR-MS and PER-MS in sensitive and rapid detection of ketones, but also can estimate molecular weight of ketones.

Mass cytometry: technique for real time single cell multitarget immunoassay based on inductively coupled plasma time-of-flight mass spectrometry.

PubMed

Bandura, Dmitry R; Baranov, Vladimir I; Ornatsky, Olga I; Antonov, Alexei; Kinach, Robert; Lou, Xudong; Pavlov, Serguei; Vorobiev, Sergey; Dick, John E; Tanner, Scott D

2009-08-15

A novel instrument for real time analysis of individual biological cells or other microparticles is described. The instrument is based on inductively coupled plasma time-of-flight mass spectrometry and comprises a three-aperture plasma-vacuum interface, a dc quadrupole turning optics for decoupling ions from neutral components, an rf quadrupole ion guide discriminating against low-mass dominant plasma ions, a point-to-parallel focusing dc quadrupole doublet, an orthogonal acceleration reflectron analyzer, a discrete dynode fast ion detector, and an 8-bit 1 GHz digitizer. A high spectrum generation frequency of 76.8 kHz provides capability for collecting multiple spectra from each particle-induced transient ion cloud, typically of 200-300 micros duration. It is shown that the transients can be resolved and characterized individually at a peak frequency of 1100 particles per second. Design considerations and optimization data are presented. The figures of merit of the instrument are measured under standard inductively coupled plasma (ICP) operating conditions (<3% cerium oxide ratio). At mass resolution (full width at half-maximum) M/DeltaM > 900 for m/z = 159, the sensitivity with a standard sample introduction system of >1.4 x 10(8) ion counts per second per mg L(-1) of Tb and an abundance sensitivity of (6 x 10(-4))-(1.4 x 10(-3)) (trailing and leading masses, respectively) are shown. The mass range (m/z = 125-215) and abundance sensitivity are sufficient for elemental immunoassay with up to 60 distinct available elemental tags. When <15 elemental tags are used, a higher sensitivity mode at lower resolution (M/DeltaM > 500) can be used, which provides >2.4 x 10(8) cps per mg L(-1) of Tb, at (1.5 x 10(-3))-(5.0 x 10(-3)) abundance sensitivity. The real-time simultaneous detection of multiple isotopes from individual 1.8 microm polystyrene beads labeled with lanthanides is shown. A real time single cell 20 antigen expression assay of model cell lines and leukemia patient samples immuno-labeled with lanthanide-tagged antibodies is presented.

Advances in field-portable ion trap GC/MS instrumentation

NASA Astrophysics Data System (ADS)

Diken, Eric G.; Arno, Josep; Skvorc, Ed; Manning, David; Andersson, Greger; Judge, Kevin; Fredeen, Ken; Sadowski, Charles; Oliphant, Joseph L.; Lammert, Stephen A.; Jones, Jeffrey L.; Waite, Randall W.; Grant, Chad; Lee, Edgar D.

2012-06-01

The rapid and accurate detection and identification of chemical warfare agents and toxic industrial chemicals can be critical to the protection of military and civilian personnel. The use of gas chromatography (GC) - mass spectrometry (MS) can provide both the sensitivity and selectivity required to identify unknown chemicals in complex (i.e. real-world) environments. While most widely used as a laboratory-based technique, recent advances in GC, MS, and sampling technologies have led to the development of a hand-portable GC/MS system that is more practical for field-based analyses. The unique toroidal ion trap mass spectrometer (TMS) used in this instrument has multiple benefits related to size, weight, start-up time, ruggedness, and power consumption. Sample separation is achieved in record time (~ 3 minutes) and with high resolution using a state-of-the-art high-performance low-thermal-mass GC column. In addition to providing a system overview highlighting its most important features, the presentation will focus on the chromatographic and mass spectral performance of the system. Results from exhaustive performance testing of the new instrument will be introduced to validate its unique robustness and ability to identify targeted and unknown chemicals.

Derivation from first principles of the statistical distribution of the mass peak intensities of MS data.

PubMed

Ipsen, Andreas

2015-02-03

Despite the widespread use of mass spectrometry (MS) in a broad range of disciplines, the nature of MS data remains very poorly understood, and this places important constraints on the quality of MS data analysis as well as on the effectiveness of MS instrument design. In the following, a procedure for calculating the statistical distribution of the mass peak intensity for MS instruments that use analog-to-digital converters (ADCs) and electron multipliers is presented. It is demonstrated that the physical processes underlying the data-generation process, from the generation of the ions to the signal induced at the detector, and on to the digitization of the resulting voltage pulse, result in data that can be well-approximated by a Gaussian distribution whose mean and variance are determined by physically meaningful instrumental parameters. This allows for a very precise understanding of the signal-to-noise ratio of mass peak intensities and suggests novel ways of improving it. Moreover, it is a prerequisite for being able to address virtually all data analytical problems in downstream analyses in a statistically rigorous manner. The model is validated with experimental data.

Immunodepletion Plasma Proteomics by TripleTOF 5600 and Orbitrap Elite/LTQ-Orbitrap Velos/Q Exactive Mass Spectrometers

PubMed Central

Patel, Bhavinkumar B.; Kelsen, Steven G.; Braverman, Alan; Swinton, Derrick J.; Gafken, Philip R.; Jones, Lisa A.; Lane, William S.; Neveu, John M.; Leung, Hon-Chiu E.; Shaffer, Scott A.; Leszyk, John D.; Stanley, Bruce A.; Fox, Todd E.; Stanley, Anne; Hall, Michael J.; Hampel, Heather; South, Christopher D.; de la Chapelle, Albert; Burt, Randall W.; Jones, David A.; Kopelovich, Levy; Yeung, Anthony T.

2013-01-01

Plasma proteomic experiments performed rapidly and economically using several of the latest high-resolution mass spectrometers were compared. Four quantitative hyperfractionated plasma proteomics experiments were analyzed in replicates by two AB SCIEX TripleTOF 5600 and three Thermo Scientific Orbitrap (Elite/LTQ-Orbitrap Velos/Q Exactive) instruments. Each experiment compared two iTRAQ isobaric-labeled immunodepleted plasma proteomes, provided as 30 labeled peptide fractions. 480 LC-MS/MS runs delivered >250 GB of data in two months. Several analysis algorithms were compared. At 1 % false discovery rate, the relative comparative findings concluded that the Thermo Scientific Q Exactive Mass Spectrometer resulted in the highest number of identified proteins and unique sequences with iTRAQ quantitation. The confidence of iTRAQ fold-change for each protein is dependent on the overall ion statistics (Mascot Protein Score) attainable by each instrument. The benchmarking also suggested how to further improve the mass spectrometry parameters and HPLC conditions. Our findings highlight the special challenges presented by the low abundance peptide ions of iTRAQ plasma proteome because the dynamic range of plasma protein abundance is uniquely high compared with cell lysates, necessitating high instrument sensitivity. PMID:24004147

Rapid sample classification using an open port sampling interface coupled with liquid introduction atmospheric pressure ionization mass spectrometry.

PubMed

Van Berkel, Gary J; Kertesz, Vilmos

2017-02-15

An "Open Access"-like mass spectrometric platform to fully utilize the simplicity of the manual open port sampling interface for rapid characterization of unprocessed samples by liquid introduction atmospheric pressure ionization mass spectrometry has been lacking. The in-house developed integrated software with a simple, small and relatively low-cost mass spectrometry system introduced here fills this void. Software was developed to operate the mass spectrometer, to collect and process mass spectrometric data files, to build a database and to classify samples using such a database. These tasks were accomplished via the vendor-provided software libraries. Sample classification based on spectral comparison utilized the spectral contrast angle method. Using the developed software platform near real-time sample classification is exemplified using a series of commercially available blue ink rollerball pens and vegetable oils. In the case of the inks, full scan positive and negative ion ESI mass spectra were both used for database generation and sample classification. For the vegetable oils, full scan positive ion mode APCI mass spectra were recorded. The overall accuracy of the employed spectral contrast angle statistical model was 95.3% and 98% in case of the inks and oils, respectively, using leave-one-out cross-validation. This work illustrates that an open port sampling interface/mass spectrometer combination, with appropriate instrument control and data processing software, is a viable direct liquid extraction sampling and analysis system suitable for the non-expert user and near real-time sample classification via database matching. Published in 2016. This article is a U.S. Government work and is in the public domain in the USA. Published in 2016. This article is a U.S. Government work and is in the public domain in the USA.

All-solid-state deep ultraviolet laser for single-photon ionization mass spectrometry.

PubMed

Yuan, Chengqian; Liu, Xianhu; Zeng, Chenghui; Zhang, Hanyu; Jia, Meiye; Wu, Yishi; Luo, Zhixun; Fu, Hongbing; Yao, Jiannian

2016-02-01

We report here the development of a reflectron time-of-flight mass spectrometer utilizing single-photon ionization based on an all-solid-state deep ultraviolet (DUV) laser system. The DUV laser was achieved from the second harmonic generation using a novel nonlinear optical crystal KBe2BO3F2 under the condition of high-purity N2 purging. The unique property of this laser system (177.3-nm wavelength, 15.5-ps pulse duration, and small pulse energy at ∼15 μJ) bears a transient low power density but a high single-photon energy up to 7 eV, allowing for ionization of chemicals, especially organic compounds free of fragmentation. Taking this advantage, we have designed both pulsed nanospray and thermal evaporation sources to form supersonic expansion molecular beams for DUV single-photon ionization mass spectrometry (DUV-SPI-MS). Several aromatic amine compounds have been tested revealing the fragmentation-free performance of the DUV-SPI-MS instrument, enabling applications to identify chemicals from an unknown mixture.

Comparison of Quantitative Mass Spectrometry Platforms for Monitoring Kinase ATP Probe Uptake in Lung Cancer.

PubMed

Hoffman, Melissa A; Fang, Bin; Haura, Eric B; Rix, Uwe; Koomen, John M

2018-01-05

Recent developments in instrumentation and bioinformatics have led to new quantitative mass spectrometry platforms including LC-MS/MS with data-independent acquisition (DIA) and targeted analysis using parallel reaction monitoring mass spectrometry (LC-PRM), which provide alternatives to well-established methods, such as LC-MS/MS with data-dependent acquisition (DDA) and targeted analysis using multiple reaction monitoring mass spectrometry (LC-MRM). These tools have been used to identify signaling perturbations in lung cancers and other malignancies, supporting the development of effective kinase inhibitors and, more recently, providing insights into therapeutic resistance mechanisms and drug repurposing opportunities. However, detection of kinases in biological matrices can be challenging; therefore, activity-based protein profiling enrichment of ATP-utilizing proteins was selected as a test case for exploring the limits of detection of low-abundance analytes in complex biological samples. To examine the impact of different MS acquisition platforms, quantification of kinase ATP uptake following kinase inhibitor treatment was analyzed by four different methods: LC-MS/MS with DDA and DIA, LC-MRM, and LC-PRM. For discovery data sets, DIA increased the number of identified kinases by 21% and reduced missingness when compared with DDA. In this context, MRM and PRM were most effective at identifying global kinome responses to inhibitor treatment, highlighting the value of a priori target identification and manual evaluation of quantitative proteomics data sets. We compare results for a selected set of desthiobiotinylated peptides from PRM, MRM, and DIA and identify considerations for selecting a quantification method and postprocessing steps that should be used for each data acquisition strategy.

An Adaptable Multiple Power Source for Mass Spectrometry and other Scientific Instruments

DOE PAGES

Lin, Tzu-Yung; Anderson, Gordon A.; Norheim, Randolph V.; ...

2015-09-18

Power supplies are commonly used in the operation of many types of scientific equipment, including mass spectrometers and ancillary instrumentation. A generic modern mass spectrometer comprises an ionization source, such as electrospray ionization (ESI), ion transfer devices such as ion funnels and multipole ion guides, and ion signal detection apparatus. Very often such platforms include, or are interfaced with ancillary elements in order to manipulate samples before or after ionization. In order to operate such scientific instruments, numerous direct current (DC) channels and radio frequency (RF) signals are required, along with other controls such as temperature regulation. In particular, DCmore » voltages in the range of ±400 V, along with MHz range RF signals with peak-to-peak amplitudes in the hundreds of volts range are commonly used to transfer ionized samples under vacuum. Additionally, an ESI source requires a high voltage (HV) DC source capable of producing several thousand volts and heaters capable of generating temperatures up to 300°C. All of these signals must be properly synchronized and managed in order to carry out ion trapping, accumulation and detection.« less

Heart-cutting two-dimensional gas chromatography in combination with isotope ratio mass spectrometry for the characterization of the wax fraction in plant material.

PubMed

Dumont, Emmie; Tienpont, Bart; Higashi, Nobukazu; Mitsui, Kazuhisa; Ochiai, Nobuo; Kanda, Hirooki; David, Frank; Sandra, Pat

2013-11-22

Gas chromatography coupled to isotope ratio mass spectrometry after on-line combustion (GC-C-IRMS) and high temperature conversion (GC-HTC-IRMS) is used for compound specific isotope ratio determination. This determination can only be performed successfully if the target solutes are fully resolved from other compounds. A new instrumental set-up consisting of heart-cutting two-dimensional GC based on capillary flow technology and a low thermal mass GC oven in combination with an isotope ratio mass spectrometer is presented. Capillary flow technology was also used in all column and interface connections for robust and leak-free operation. The new configuration was applied to the characterization of wax compounds in tobacco leaf and corresponding smoke samples. It is demonstrated that high accuracy is obtained, both in the determination of δ(13)C and δ(2)H values, allowing the study of biosynthesis and delivery mechanisms of naturally occurring compounds in tobacco. Copyright © 2013 Elsevier B.V. All rights reserved.

DISCO: Distance and Spectrum Correlation Optimization Alignment for Two Dimensional Gas Chromatography Time-of-Flight Mass Spectrometry-based Metabolomics

PubMed Central

Wang, Bing; Fang, Aiqin; Heim, John; Bogdanov, Bogdan; Pugh, Scott; Libardoni, Mark; Zhang, Xiang

2010-01-01

A novel peak alignment algorithm using a distance and spectrum correlation optimization (DISCO) method has been developed for two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC/TOF-MS) based metabolomics. This algorithm uses the output of the instrument control software, ChromaTOF, as its input data. It detects and merges multiple peak entries of the same metabolite into one peak entry in each input peak list. After a z-score transformation of metabolite retention times, DISCO selects landmark peaks from all samples based on both two-dimensional retention times and mass spectrum similarity of fragment ions measured by Pearson’s correlation coefficient. A local linear fitting method is employed in the original two-dimensional retention time space to correct retention time shifts. A progressive retention time map searching method is used to align metabolite peaks in all samples together based on optimization of the Euclidean distance and mass spectrum similarity. The effectiveness of the DISCO algorithm is demonstrated using data sets acquired under different experiment conditions and a spiked-in experiment. PMID:20476746

Ga + TOF-SIMS lineshape analysis for resolution enhancement of MALDI MS spectra of a peptide mixture

NASA Astrophysics Data System (ADS)

Malyarenko, D. I.; Chen, H.; Wilkerson, A. L.; Tracy, E. R.; Cooke, W. E.; Manos, D. M.; Sasinowski, M.; Semmes, O. J.

2004-06-01

The use of mass spectrometry to obtain molecular profiles indicative of alteration of concentrations of peptides in body fluids is currently the subject of intense investigation. For surface-based time-of-flight mass spectrometry the reliability and specificity of such profiling methods depend both on the resolution of the measuring instrument and on the preparation of samples. The present work is a part of a program to use Ga + beam TOF-SIMS alone, and as an adjunct to MALDI, in the development of reliable protein and peptide markers for diseases. Here, we describe techniques to prepare samples of relatively high-mass peptides, which serve as calibration standards and proxies for biomarkers. These are: Arg8-vasopressin, human angiotensin II, and somatostatin. Their TOF-SIMS spectra show repeatable characteristic features, with mass resolution exceeding 2000, including parent peaks and chemical adducts. The lineshape analysis for high-resolution parent peaks is shown to be useful for filter construction and deconvolution of inferior resolution SELDI-TOF spectra of calibration peptide mixture.

A Researcher's Guide to Mass Spectrometry-Based Proteomics

PubMed Central

Savaryn, John P.; Toby, Timothy K.; Kelleher, Neil L.

2016-01-01

Mass spectrometry (MS) is widely recognized as a powerful analytical tool for molecular research. MS is used by researchers around the globe to identify, quantify, and characterize biomolecules like proteins from any number of biological conditions or sample types. As instrumentation has advanced, and with the coupling of liquid chromatography (LC) for high-throughput LC-MS/MS, a proteomics experiment measuring hundreds to thousands of proteins/protein groups is now commonplace. While expert practitioners who best understand the operation of LC-MS systems tend to have strong backgrounds in physics and engineering, consumers of proteomics data and technology are not exposed to the physio-chemical principles underlying the information they seek. Since articles and reviews tend not to focus on bridging this divide, our goal here is to span this gap and translate MS ion physics into language intuitive to the general reader active in basic or applied biomedical research. Here, we visually describe what happens to ions as they enter and move around inside a mass spectrometer. We describe basic MS principles, including electric current, ion optics, ion traps, quadrupole mass filters, and Orbitrap FT-analyzers. PMID:27553853

Unprecedented Ionization Processes in Mass Spectrometry Provide Missing Link between ESI and MALDI.

PubMed

Trimpin, Sarah; Lee, Chuping; Weidner, Steffen M; El-Baba, Tarick J; Lutomski, Corinne A; Inutan, Ellen D; Foley, Casey D; Ni, Chi-Kung; McEwen, Charles N

2018-03-05

In the field of mass spectrometry, producing intact, highly-charged protein ions from surfaces is a conundrum with significant potential payoff in application areas ranging from biomedical to clinical research. Here, we report on the ability to form intact, highly-charged protein ions on high vacuum time-of-flight mass spectrometers in the linear and reflectron modes achievable using experimental conditions that allow effective matrix removal from both the sample surfaces and from the charged clusters formed by the laser ablation event. The charge states are the highest reported on high vacuum mass spectrometers, yet they remain at only around a third of the highest charge obtained using laser ablation with a suitable matrix at atmospheric pressure. Other than physical instrument modifications, the key to forming abundant and stable highly-charged ions appears to be the volatility of the matrix used. Cumulative results suggest mechanistic links between the ionization process reported here and traditional ionization methods of electrospray ionization and matrix-assisted laser desorption/ionization. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fast parallel tandem mass spectral library searching using GPU hardware acceleration

PubMed Central

Baumgardner, Lydia Ashleigh; Shanmugam, Avinash Kumar; Lam, Henry; Eng, Jimmy K.; Martin, Daniel B.

2011-01-01

Mass spectrometry-based proteomics is a maturing discipline of biologic research that is experiencing substantial growth. Instrumentation has steadily improved over time with the advent of faster and more sensitive instruments collecting ever larger data files. Consequently, the computational process of matching a peptide fragmentation pattern to its sequence, traditionally accomplished by sequence database searching and more recently also by spectral library searching, has become a bottleneck in many mass spectrometry experiments. In both of these methods, the main rate limiting step is the comparison of an acquired spectrum with all potential matches from a spectral library or sequence database. This is a highly parallelizable process because the core computational element can be represented as a simple but arithmetically intense multiplication of two vectors. In this paper we present a proof of concept project taking advantage of the massively parallel computing available on graphics processing units (GPUs) to distribute and accelerate the process of spectral assignment using spectral library searching. This program, which we have named FastPaSS (for Fast Parallelized Spectral Searching) is implemented in CUDA (Compute Unified Device Architecture) from NVIDIA which allows direct access to the processors in an NVIDIA GPU. Our efforts demonstrate the feasibility of GPU computing for spectral assignment, through implementation of the validated spectral searching algorithm SpectraST in the CUDA environment. PMID:21545112

An ultrahigh-resolution mass spectrometry index to estimate natural organic matter lability

PubMed Central

D'Andrilli, Juliana; Cooper, William T; Foreman, Christine M; Marshall, Alan G

2015-01-01

Rationale Determining the chemical constituents of natural organic matter (NOM) by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICRMS) remains the ultimate measure for probing its source material, evolution, and transport; however, lability and the fate of organic matter (OM) in the environment remain controversial. FTICRMS-derived elemental compositions are presented in this study to validate a new interpretative method to determine the extent of NOM lability from various environments. Methods FTICRMS data collected over the last decade from the same 9.4 tesla instrument using negative electrospray ionization at the National High Magnetic Field Laboratory in Tallahassee, Florida, was used to validate the application of a NOM lability index. Solid-phase extraction cartridges were used to isolate the NOM prior to FTICRMS; mass spectral peaks were calibrated internally by commonly identified NOM homologous series, and molecular formulae were determined for NOM composition and lability analysis. Results A molecular lability boundary (MLB) was developed from the FTICRMS molecular data, visualized from van Krevelen diagrams, dividing the data into more and less labile constituents. NOM constituents above the MLB at H/C ≥1.5 correspond to more labile material, whereas NOM constituents below the MLB, H/C <1.5, exhibit less labile, more recalcitrant character. Of all marine, freshwater, and glacial environments considered for this study, glacial ecosystems were calculated to contain the most labile OM. Conclusions The MLB extends our interpretation of FTICRMS NOM molecular data to include a metric of lability, and generally ranked the OM environments from most to least labile as glacial > marine > freshwater. Applying the MLB is useful not only for individual NOM FTICRMS studies, but also provides a lability threshold to compare and contrast molecular data with other FTICRMS instruments that survey NOM from around the world. Copyright © 2015 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons Ltd. PMID:26563709

Development of a Linear Ion Trap Mass Spectrometer (LITMS) Investigation for Future Planetary Surface Missions

NASA Technical Reports Server (NTRS)

Brinckerhoff, W.; Danell, R.; Van Ameron, F.; Pinnick, V.; Li, X.; Arevalo, R.; Glavin, D.; Getty, S.; Mahaffy, P.; Chu, P.;

Triple quadrupole tandem mass spectrometry: A real alternative to high resolution magnetic sector instrument for the analysis of polychlorinated dibenzo-p-dioxins, furans and dioxin-like polychlorinated biphenyls.

PubMed

García-Bermejo, Ángel; Ábalos, Manuela; Sauló, Jordi; Abad, Esteban; González, María José; Gómara, Belén

2015-08-19

This paper reports on the optimisation, characterisation, validation and applicability of gas chromatography coupled to triple quadrupole mass spectrometry in its tandem operation mode (GC-QqQ(MS/MS) for the quantification of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs, dioxins) and dioxin-like polychlorinated biphenyls (DL-PCBs) in environmental and food matrices. MS/MS parameters were selected to achieve the high sensitivity and selectivity required for the analysis of this type of compounds and samples. Good repeatability for areas (RSD = 1-10%, for PCDD/Fs and DL-PCBs) and for ion transition ratios (RSD = 0.3-10%, for PCDD/Fs, and 0.2-15%, for DL-PCBs) and low instrumental limits of detection, 0.07-0.75 pg μL(-1) (for dioxins) and 0.05-0.63 pg μL(-1) (for DL-PCBs), were obtained. A comparative study of the congener specific determination using both GC-QqQ(MS/MS) and gas chromatography-high resolution mass spectrometry (GC-HRMS) was also performed by analysing several fortified samples and certified reference materials (CRMs) with low (feed and foodstuffs), median (sewage sludge) and high (fly ash) toxic equivalency (TEQ) concentration levels, i.e. 0.60, 1.83, 72.9 and 3609 pg WHO-TEQ(PCDD/Fs) g(-1). The agreement between the results obtained for the total TEQs (dioxins) on GC-QqQ(MS/MS) and GC-HRMS in all the investigated samples were within the range of ±4%, and that of DL-PCBs at concentration levels of 0.84 pg WHO-TEQs (DL-PCBs) g(-1), in the case of feedstuffs, was 0.11%. Both instrumental methods have similar and comparable linearity, precision and accuracy. The GC-QqQ(MS/MS) sensitivity, lower than that of GC-HRMS, is good enough (iLODs in the down to low pg levels) to detect the normal concentrations of these compounds in food and environmental samples. These results make GC-QqQ(MS/MS) suitable for the quantitative analysis of dioxins and DL-PCBs and a real alternative tool to the reference sector HRMS instruments. Copyright © 2015 Elsevier B.V. All rights reserved.

Detection of biomarkers of pathogenic Naegleria fowleri through mass spectrometry and proteomics.

PubMed

Moura, Hercules; Izquierdo, Fernando; Woolfitt, Adrian R; Wagner, Glauber; Pinto, Tatiana; del Aguila, Carmen; Barr, John R

2015-01-01

Emerging methods based on mass spectrometry (MS) can be used in the rapid identification of microorganisms. Thus far, these practical and rapidly evolving methods have mainly been applied to characterize prokaryotes. We applied matrix-assisted laser-desorption-ionization-time-of-flight mass spectrometry MALDI-TOF MS in the analysis of whole cells of 18 N. fowleri isolates belonging to three genotypes. Fourteen originated from the cerebrospinal fluid or brain tissue of primary amoebic meningoencephalitis patients and four originated from water samples of hot springs, rivers, lakes or municipal water supplies. Whole Naegleria trophozoites grown in axenic cultures were washed and mixed with MALDI matrix. Mass spectra were acquired with a 4700 TOF-TOF instrument. MALDI-TOF MS yielded consistent patterns for all isolates examined. Using a combination of novel data processing methods for visual peak comparison, statistical analysis and proteomics database searching we were able to detect several biomarkers that can differentiate all species and isolates studied, along with common biomarkers for all N. fowleri isolates. Naegleria fowleri could be easily separated from other species within the genus Naegleria. A number of peaks detected were tentatively identified. MALDI-TOF MS fingerprinting is a rapid, reproducible, high-throughput alternative method for identifying Naegleria isolates. This method has potential for studying eukaryotic agents. © 2014 The Author(s) Journal of Eukaryotic Microbiology © 2014 International Society of Protistologists.

MASS SPECTROMETRY IMAGING FOR DRUGS AND METABOLITES

PubMed Central

Greer, Tyler; Sturm, Robert; Li, Lingjun

2011-01-01

Mass spectrometric imaging (MSI) is a powerful analytical technique that provides two- and three-dimensional spatial maps of multiple compounds in a single experiment. This technique has been routinely applied to protein, peptide, and lipid molecules with much less research reporting small molecule distributions, especially pharmaceutical drugs. This review’s main focus is to provide readers with an up-to-date description of the substrates and compounds that have been analyzed for drug and metabolite composition using MSI technology. Additionally, ionization techniques, sample preparation, and instrumentation developments are discussed. PMID:21515430

Characterization of a Carbon Nanotube Field Emission Electron Gun for the VAPoR Miniaturized Pyrolysis-Time-of-Flight Mass Spectrometer

NASA Technical Reports Server (NTRS)

Getty, Stephanie; Li, Mary; Costen, Nicholas; Hess, Larry; Feng, Steve; King, Todd; Brinckerhoff, William; Mahaffy, Paul; Glavin, Daniel

2009-01-01

We are developing the VAPoR (Volatile Analysis by Pyrolysis of Regolith) instrument towards studying soil composition, volatiles, and trapped noble gases in the polar regions of the Moon. VAPOR will ingest a soil sample and conduct analysis by pyrolysis and time-of-flight mass spectrometry (ToF-MS). Here, we describe miniaturization efforts within this development, including a carbon nanotube (CNT) field emission electron gun that is under consideration for use as the electron impact ionization source for the ToF-MS.

Metal stable isotopes in low-temperature systems: A primer

USGS Publications Warehouse

Bullen, T.D.; Eisenhauer, A.

2009-01-01

Recent advances in mass spectrometry have allowed isotope scientists to precisely determine stable isotope variations in the metallic elements. Biologically infl uenced and truly inorganic isotope fractionation processes have been demonstrated over the mass range of metals. This Elements issue provides an overview of the application of metal stable isotopes to low-temperature systems, which extend across the borders of several science disciplines: geology, hydrology, biology, environmental science, and biomedicine. Information on instrumentation, fractionation processes, data-reporting terminology, and reference materials presented here will help the reader to better understand this rapidly evolving field.

MASS SPECTROMETRY

DOEpatents

Friedman, L.

1962-01-01

method is described for operating a mass spectrometer to improve its resolution qualities and to extend its period of use substantially between cleanings. In this method, a small amount of a beta emitting gas such as hydrogen titride or carbon-14 methane is added to the sample being supplied to the spectrometer for investigation. The additive establishes leakage paths on the surface of the non-conducting film accumulating within the vacuum chamber of the spectrometer, thereby reducing the effect of an accumulated static charge on the electrostatic and magnetic fields established within the instrument. (AEC)

Optimization of a direct analysis in real time/time-of-flight mass spectrometry method for rapid serum metabolomic fingerprinting.

PubMed

Zhou, Manshui; McDonald, John F; Fernández, Facundo M

2010-01-01

Metabolomic fingerprinting of bodily fluids can reveal the underlying causes of metabolic disorders associated with many diseases, and has thus been recognized as a potential tool for disease diagnosis and prognosis following therapy. Here we report a rapid approach in which direct analysis in real time (DART) coupled with time-of-flight (TOF) mass spectrometry (MS) and hybrid quadrupole TOF (Q-TOF) MS is used as a means for metabolomic fingerprinting of human serum. In this approach, serum samples are first treated to precipitate proteins, and the volatility of the remaining metabolites increased by derivatization, followed by DART MS analysis. Maximum DART MS performance was obtained by optimizing instrumental parameters such as ionizing gas temperature and flow rate for the analysis of identical aliquots of a healthy human serum samples. These variables were observed to have a significant effect on the overall mass range of the metabolites detected as well as the signal-to-noise ratios in DART mass spectra. Each DART run requires only 1.2 min, during which more than 1500 different spectral features are observed in a time-dependent fashion. A repeatability of 4.1% to 4.5% was obtained for the total ion signal using a manual sampling arm. With the appealing features of high-throughput, lack of memory effects, and simplicity, DART MS has shown potential to become an invaluable tool for metabolomic fingerprinting. 2010 American Society for Mass Spectrometry. Published by Elsevier Inc. All rights reserved.

High-performance liquid chromatography separation and intact mass analysis of detergent-solubilized integral membrane proteins

PubMed Central

Berridge, Georgina; Chalk, Rod; D’Avanzo, Nazzareno; Dong, Liang; Doyle, Declan; Kim, Jung-In; Xia, Xiaobing; Burgess-Brown, Nicola; deRiso, Antonio; Carpenter, Elisabeth Paula; Gileadi, Opher

2011-01-01

We have developed a method for intact mass analysis of detergent-solubilized and purified integral membrane proteins using liquid chromatography–mass spectrometry (LC–MS) with methanol as the organic mobile phase. Membrane proteins and detergents are separated chromatographically during the isocratic stage of the gradient profile from a 150-mm C3 reversed-phase column. The mass accuracy is comparable to standard methods employed for soluble proteins; the sensitivity is 10-fold lower, requiring 0.2–5 μg of protein. The method is also compatible with our standard LC–MS method used for intact mass analysis of soluble proteins and may therefore be applied on a multiuser instrument or in a high-throughput environment. PMID:21093405

Development of a new screening method for the detection of antibiotic residues in muscle tissues using liquid chromatography and high resolution mass spectrometry with a LC-LTQ-Orbitrap instrument.

PubMed

Hurtaud-Pessel, D; Jagadeshwar-Reddy, T; Verdon, E

2011-10-01

A liquid chromatography-high resolution mass spectrometry (LC-HRMS) method was developed for screening meat for a wide range of antibiotics used in veterinary medicine. Full-scan mode under high resolution mass spectral conditions using an LTQ-Orbitrap mass spectrometer with resolving power 60,000 full width at half maximum (FWHM) was applied for analysis of the samples. Samples were prepared using two extraction protocols prior to LC-HRMS analysis. The scope of the method focuses on screening the following main families of antibacterial veterinary drugs: penicillins, cephalosporins, sulfonamides, macrolides, tetracyclines, aminoglucosides and quinolones. Compounds were successfully identified in spiked samples from their accurate mass and LC retention times from the acquired full-scan chromatogram. Automated data processing using ToxId software allowed rapid treatment of the data. Analyses of muscle tissues from real samples collected from antibiotic-treated animals was carried out using the above methodology and antibiotic residues were identified unambiguously. Further analysis of the data for real samples allowed the identification of the targeted antibiotic residues but also non-targeted compounds, such as some of their metabolites.

Determination of δ13C, δ15N, or δ34S by isotope-ratio-monitoring mass spectrometry using an elemental analyzer

USGS Publications Warehouse

Johnson, Craig A.; Stricker, Craig A.; Gulbransen, Cayce A.; Emmons, Matthew P.

2018-02-14

This report describes procedures used in the Geology, Geophysics, and Geochemistry Science Center of the U.S. Geological Survey in Denver, Colorado, to determine the stable-isotope ratios 13C/12C, 15N/14N, and 34S/32S in solid materials. The procedures use elemental analyzers connected directly to gas-source isotope-ratio mass spectrometers. A different elemental–analyzer–mass-spectrometer system is used for 13C/12C and 15N/14N than is used for 34S/32S to accommodate differences in reagents, catalysts, and instrument settings.

Instrumentation for Testing Whether the Icy Moons of the Gas and Ice Giants Are Inhabited.

PubMed

Chela-Flores, Julian

2017-10-01

Evidence of life beyond Earth may be closer than we think, given that the forthcoming missions to the jovian system will be equipped with instruments capable of probing Europa's icy surface for possible biosignatures, including chemical biomarkers, despite the strong radiation environment. Geochemical biomarkers may also exist beyond Europa on icy moons of the gas giants. Sulfur is proposed as a reliable geochemical biomarker for approved and forthcoming missions to the outer solar system. Key Words: JUICE mission-Clipper mission-Geochemical biomarkers-Europa-Moons of the ice giants-Geochemistry-Mass spectrometry. Astrobiology 17, 958-961.

Detection of chlorinated and brominated byproducts of drinking water disinfection using electrospray ionization-high-field asymmetric waveform ion mobility spectrometry-mass spectrometry.

PubMed

Ells, B; Barnett, D A; Froese, K; Purves, R W; Hrudey, S; Guevremont, R

1999-10-15

The lower limit of detection for low molecular weight polar and ionic analytes using electrospray ionization-mass spectrometry (ESI-MS) is often severely compromised by an intense background that obscures ions of trace components in solution. Recently, a new technique, referred to as high-field asymmetric waveform ion mobility spectrometry (FAIMS), has been shown to separate gas-phase ions at atmospheric pressure and room temperature. A FAIMS instrument is an ion filter that may be tuned, by control of electrical voltages, to continuously transmit selected ions from a complex mixture. This capability offers significant advantages when FAIMS is coupled with ESI, a source that generates a wide variety of ions, including solvent clusters and salt adducts. In this report, the tandem arrangement of ESI-FAIMS-MS is used for the analysis of haloacetic acids, a class of disinfection byproducts regulated by the US EPA. FAIMS is shown to effectively discriminate against background ions resulting from the electrospray of tap water solutions containing the haloacetic acids. Consequently, mass spectra are simplified, the selectivity of the method is improved, and the limits of detection are lowered compared with conventional ESI-MS. The detection limits of ESI-FAIMS-MS for six haloacetic acids ranged between 0.5 and 4 ng/mL in 9:1 methanol/tap water (5 and 40 ng/mL in the original tap water samples) with no preconcentration, derivatization, or chromatographic separation prior to analysis.

Comparison of methods for determination of total oil sands-derived naphthenic acids in water samples.

PubMed

Hughes, Sarah A; Huang, Rongfu; Mahaffey, Ashley; Chelme-Ayala, Pamela; Klamerth, Nikolaus; Meshref, Mohamed N A; Ibrahim, Mohamed D; Brown, Christine; Peru, Kerry M; Headley, John V; Gamal El-Din, Mohamed

2017-11-01

There are several established methods for the determination of naphthenic acids (NAs) in waters associated with oil sands mining operations. Due to their highly complex nature, measured concentration and composition of NAs vary depending on the method used. This study compared different common sample preparation techniques, analytical instrument methods, and analytical standards to measure NAs in groundwater and process water samples collected from an active oil sands operation. In general, the high- and ultrahigh-resolution methods, namely high performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOF-MS) and Orbitrap mass spectrometry (Orbitrap-MS), were within an order of magnitude of the Fourier transform infrared spectroscopy (FTIR) methods. The gas chromatography mass spectrometry (GC-MS) methods consistently had the highest NA concentrations and greatest standard error. Total NAs concentration was not statistically different between sample preparation of solid phase extraction and liquid-liquid extraction. Calibration standards influenced quantitation results. This work provided a comprehensive understanding of the inherent differences in the various techniques available to measure NAs and hence the potential differences in measured amounts of NAs in samples. Results from this study will contribute to the analytical method standardization for NA analysis in oil sands related water samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

A rapid, automated approach to optimisation of multiple reaction monitoring conditions for quantitative bioanalytical mass spectrometry.

PubMed

Higton, D M

2001-01-01

An improvement to the procedure for the rapid optimisation of mass spectrometry (PROMS), for the development of multiple reaction methods (MRM) for quantitative bioanalytical liquid chromatography/tandem mass spectrometry (LC/MS/MS), is presented. PROMS is an automated protocol that uses flow-injection analysis (FIA) and AppleScripts to create methods and acquire the data for optimisation. The protocol determines the optimum orifice potential, the MRM conditions for each compound, and finally creates the MRM methods needed for sample analysis. The sensitivities of the MRM methods created by PROMS approach those created manually. MRM method development using PROMS currently takes less than three minutes per compound compared to at least fifteen minutes manually. To further enhance throughput, approaches to MRM optimisation using one injection per compound, two injections per pool of five compounds and one injection per pool of five compounds have been investigated. No significant difference in the optimised instrumental parameters for MRM methods were found between the original PROMS approach and these new methods, which are up to ten times faster. The time taken for an AppleScript to determine the optimum conditions and build the MRM methods is the same with all approaches. Copyright 2001 John Wiley & Sons, Ltd.

Quantitative Clinical Chemistry Proteomics (qCCP) using mass spectrometry: general characteristics and application.

PubMed

Lehmann, Sylvain; Hoofnagle, Andrew; Hochstrasser, Denis; Brede, Cato; Glueckmann, Matthias; Cocho, José A; Ceglarek, Uta; Lenz, Christof; Vialaret, Jérôme; Scherl, Alexander; Hirtz, Christophe

2013-05-01

Proteomics studies typically aim to exhaustively detect peptides/proteins in a given biological sample. Over the past decade, the number of publications using proteomics methodologies has exploded. This was made possible due to the availability of high-quality genomic data and many technological advances in the fields of microfluidics and mass spectrometry. Proteomics in biomedical research was initially used in 'functional' studies for the identification of proteins involved in pathophysiological processes, complexes and networks. Improved sensitivity of instrumentation facilitated the analysis of even more complex sample types, including human biological fluids. It is at that point the field of clinical proteomics was born, and its fundamental aim was the discovery and (ideally) validation of biomarkers for the diagnosis, prognosis, or therapeutic monitoring of disease. Eventually, it was recognized that the technologies used in clinical proteomics studies [particularly liquid chromatography-tandem mass spectrometry (LC-MS/MS)] could represent an alternative to classical immunochemical assays. Prior to deploying MS in the measurement of peptides/proteins in the clinical laboratory, it seems likely that traditional proteomics workflows and data management systems will need to adapt to the clinical environment and meet in vitro diagnostic (IVD) regulatory constraints. This defines a new field, as reviewed in this article, that we have termed quantitative Clinical Chemistry Proteomics (qCCP).

Advanced Automation for Ion Trap Mass Spectrometry-New Opportunities for Real-Time Autonomous Analysis

NASA Technical Reports Server (NTRS)

Palmer, Peter T.; Wong, C. M.; Salmonson, J. D.; Yost, R. A.; Griffin, T. P.; Yates, N. A.; Lawless, James G. (Technical Monitor)

1994-01-01

The utility of MS/MS for both target compound analysis and the structure elucidation of unknowns has been described in a number of references. A broader acceptance of this technique has not yet been realized as it requires large, complex, and costly instrumentation which has not been competitive with more conventional techniques. Recent advancements in ion trap mass spectrometry promise to change this situation. Although the ion trap's small size, sensitivity, and ability to perform multiple stages of mass spectrometry have made it eminently suitable for on-line, real-time monitoring applications, advance automation techniques are required to make these capabilities more accessible to non-experts. Towards this end we have developed custom software for the design and implementation of MS/MS experiments. This software allows the user to take full advantage of the ion trap's versatility with respect to ionization techniques, scan proxies, and ion accumulation/ejection methods. Additionally, expert system software has been developed for autonomous target compound analysis. This software has been linked to ion trap control software and a commercial data system to bring all of the steps in the analysis cycle under control of the expert system. These software development efforts and their utilization for a number of trace analysis applications will be described.

Army medical laboratory telemedicine: role of mass spectrometry in telediagnosis for chemical and biological defense.

PubMed

Smith, J R; Shih, M L; Price, E O; Platoff, G E; Schlager, J J

2001-12-01

An army medical field laboratory presently has the capability of performing standard protocols developed at the US Army Medical Research Institute of Chemical Defense for verification of nerve agent or sulfur mustard exposure. The protocols analyze hydrolysis products of chemical warfare agents using gas chromatography/mass spectrometry. Additionally, chemical warfare agents can produce alkylated or phosphorylated proteins following human exposure that have long biological half-lives and can be used as diagnostic biomarkers of chemical agent exposure. An analytical technique known as matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS) currently is being examined for its potential to analyze these biomarkers. The technique is capable of detecting large biomolecules and modifications made to them. Its fast analysis time makes MALDI-TOF/MS technology suitable for screening casualties from chemical or biological attacks. Basic operation requires minimal training and the instrument has the potential to become field-portable. The limitation of the technique is that the generated data may require considerable expertise from knowledgeable personnel for consultation to ensure correct interpretation. The interaction between research scientists and field personnel in the acquisition of data and its interpretation via advanced digital telecommunication technologies can enhance rapid diagnosis and subsequently improve patient care in remote areas. Copyright 2001 John Wiley & Sons, Ltd.

Boosting Sensitivity in Liquid Chromatography–Fourier Transform Ion Cyclotron Resonance–Tandem Mass Spectrometry for Product Ion Analysis of Monoterpene Indole Alkaloids

PubMed Central

Nakabayashi, Ryo; Tsugawa, Hiroshi; Kitajima, Mariko; Takayama, Hiromitsu; Saito, Kazuki

2015-01-01

In metabolomics, the analysis of product ions in tandem mass spectrometry (MS/MS) is noteworthy to chemically assign structural information. However, the development of relevant analytical methods are less advanced. Here, we developed a method to boost sensitivity in liquid chromatography–Fourier transform ion cyclotron resonance–tandem mass spectrometry analysis (MS/MS boost analysis). To verify the MS/MS boost analysis, both quercetin and uniformly labeled 13C quercetin were analyzed, revealing that the origin of the product ions is not the instrument, but the analyzed compounds resulting in sensitive product ions. Next, we applied this method to the analysis of monoterpene indole alkaloids (MIAs). The comparative analyses of MIAs having indole basic skeleton (ajmalicine, catharanthine, hirsuteine, and hirsutine) and oxindole skeleton (formosanine, isoformosanine, pteropodine, isopteropodine, rhynchophylline, isorhynchophylline, and mitraphylline) identified 86 and 73 common monoisotopic ions, respectively. The comparative analyses of the three pairs of stereoisomers showed more than 170 common monoisotopic ions in each pair. This method was also applied to the targeted analysis of MIAs in Catharanthus roseus and Uncaria rhynchophylla to profile indole and oxindole compounds using the product ions. This analysis is suitable for chemically assigning features of the metabolite groups, which contributes to targeted metabolome analysis. PMID:26734034

Protein hydrogen exchange at residue resolution by proteolytic fragmentation mass spectrometry analysis

PubMed Central

Kan, Zhong-Yuan; Walters, Benjamin T.; Mayne, Leland; Englander, S. Walter

2013-01-01

Hydrogen exchange technology provides a uniquely powerful instrument for measuring protein structural and biophysical properties, quantitatively and in a nonperturbing way, and determining how these properties are implemented to produce protein function. A developing hydrogen exchange–mass spectrometry method (HX MS) is able to analyze large biologically important protein systems while requiring only minuscule amounts of experimental material. The major remaining deficiency of the HX MS method is the inability to deconvolve HX results to individual amino acid residue resolution. To pursue this goal we used an iterative optimization program (HDsite) that integrates recent progress in multiple peptide acquisition together with previously unexamined isotopic envelope-shape information and a site-resolved back-exchange correction. To test this approach, residue-resolved HX rates computed from HX MS data were compared with extensive HX NMR measurements, and analogous comparisons were made in simulation trials. These tests found excellent agreement and revealed the important computational determinants. PMID:24019478

Mass spectrometry-assisted gel-based proteomics in cancer biomarker discovery: approaches and application

PubMed Central

Huang, Rongrong; Chen, Zhongsi; He, Lei; He, Nongyue; Xi, Zhijiang; Li, Zhiyang; Deng, Yan; Zeng, Xin

2017-01-01

There is a critical need for the discovery of novel biomarkers for early detection and targeted therapy of cancer, a major cause of deaths worldwide. In this respect, proteomic technologies, such as mass spectrometry (MS), enable the identification of pathologically significant proteins in various types of samples. MS is capable of high-throughput profiling of complex biological samples including blood, tissues, urine, milk, and cells. MS-assisted proteomics has contributed to the development of cancer biomarkers that may form the foundation for new clinical tests. It can also aid in elucidating the molecular mechanisms underlying cancer. In this review, we discuss MS principles and instrumentation as well as approaches in MS-based proteomics, which have been employed in the development of potential biomarkers. Furthermore, the challenges in validation of MS biomarkers for their use in clinical practice are also reviewed. PMID:28912895

Sample processing, protocol, and statistical analysis of the time-of-flight secondary ion mass spectrometry (ToF-SIMS) of protein, cell, and tissue samples.

PubMed

Barreto, Goncalo; Soininen, Antti; Sillat, Tarvo; Konttinen, Yrjö T; Kaivosoja, Emilia

2014-01-01

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is increasingly being used in analysis of biological samples. For example, it has been applied to distinguish healthy and osteoarthritic human cartilage. This chapter discusses ToF-SIMS principle and instrumentation including the three modes of analysis in ToF-SIMS. ToF-SIMS sets certain requirements for the samples to be analyzed; for example, the samples have to be vacuum compatible. Accordingly, sample processing steps for different biological samples, i.e., proteins, cells, frozen and paraffin-embedded tissues and extracellular matrix for the ToF-SIMS are presented. Multivariate analysis of the ToF-SIMS data and the necessary data preprocessing steps (peak selection, data normalization, mean-centering, and scaling and transformation) are discussed in this chapter.

Direct Analysis in Real Time-Mass Spectrometry for the Rapid Detection of Metabolites of Aconite Alkaloids in Intestinal Bacteria

NASA Astrophysics Data System (ADS)

Li, Xue; Hou, Guangyue; Xing, Junpeng; Song, Fengrui; Liu, Zhiqiang; Liu, Shuying

2014-12-01

In the present work, direct analysis of real time ionization combined with multi-stage tandem mass spectrometry (DART-MSn) was used to investigate the metabolic profile of aconite alkaloids in rat intestinal bacteria. A total of 36 metabolites from three aconite alkaloids were identified by using DART-MSn, and the feasibility of quantitative analysis of these analytes was examined. Key parameters of the DART ion source, such as helium gas temperature and pressure, the source-to-MS distance, and the speed of the autosampler, were optimized to achieve high sensitivity, enhance reproducibility, and reduce the occurrence of fragmentation. The instrument analysis time for one sample can be less than 10 s for this method. Compared with ESI-MS and UPLC-MS, the DART-MS is more efficient for directly detecting metabolic samples, and has the advantage of being a simple, high-speed, high-throughput method.

[Study on the determination of 14 inorganic elements in coffee by inductively coupled plasma mass spectrometry].

PubMed

Nie, Xi-Du; Fu, Liang

2013-07-01

Samples of coffee were digested by microwave digestion, and inorganic elements amounts of Na, Mg, P, Ca, Cr, Mn, Fe, Co, Cu, Zn, As, Se, Mo and Pb in sample solutions were determined by inductively coupled plasma mass spectrometry (ICP-MS). HNO3 + H2O2 was used to achieve the complete decomposition of the organic matrix in a closed-vessel microwave oven. The working parameters of the instrument were optimized. The results showed that the relative standard deviation (RSD) was less than 3.84% for all the elements, and the recovery was found to be 92.00% -106.52% by adding standard recovery experiment. This method was simple, sensitive and precise and can perform simultaneous multi-elements determination of coffee, which could satisfy the sample examination request and provide scientific rationale for determining inorganic elements of coffee.

Unassigned MS/MS Spectra: Who Am I?

PubMed

Pathan, Mohashin; Samuel, Monisha; Keerthikumar, Shivakumar; Mathivanan, Suresh

2017-01-01

Recent advances in high resolution tandem mass spectrometry (MS) has resulted in the accumulation of high quality data. Paralleled with these advances in instrumentation, bioinformatics software have been developed to analyze such quality datasets. In spite of these advances, data analysis in mass spectrometry still remains critical for protein identification. In addition, the complexity of the generated MS/MS spectra, unpredictable nature of peptide fragmentation, sequence annotation errors, and posttranslational modifications has impeded the protein identification process. In a typical MS data analysis, about 60 % of the MS/MS spectra remains unassigned. While some of these could attribute to the low quality of the MS/MS spectra, a proportion can be classified as high quality. Further analysis may reveal how much of the unassigned MS spectra attribute to search space, sequence annotation errors, mutations, and/or posttranslational modifications. In this chapter, the tools used to identify proteins and ways to assign unassigned tandem MS spectra are discussed.

Direct analysis in real time-mass spectrometry for the rapid detection of metabolites of aconite alkaloids in intestinal bacteria.

PubMed

Li, Xue; Hou, Guangyue; Xing, Junpeng; Song, Fengrui; Liu, Zhiqiang; Liu, Shuying

2014-12-01

In the present work, direct analysis of real time ionization combined with multi-stage tandem mass spectrometry (DART-MS(n)) was used to investigate the metabolic profile of aconite alkaloids in rat intestinal bacteria. A total of 36 metabolites from three aconite alkaloids were identified by using DART-MS(n), and the feasibility of quantitative analysis of these analytes was examined. Key parameters of the DART ion source, such as helium gas temperature and pressure, the source-to-MS distance, and the speed of the autosampler, were optimized to achieve high sensitivity, enhance reproducibility, and reduce the occurrence of fragmentation. The instrument analysis time for one sample can be less than 10 s for this method. Compared with ESI-MS and UPLC-MS, the DART-MS is more efficient for directly detecting metabolic samples, and has the advantage of being a simple, high-speed, high-throughput method.

Laser Beam Filtration for High Spatial Resolution MALDI Imaging Mass Spectrometry

NASA Astrophysics Data System (ADS)

Zavalin, Andre; Yang, Junhai; Caprioli, Richard

2013-07-01

We describe an easy and inexpensive way to provide a highly defined Gaussian shaped laser spot on target of 5 μm diameter for imaging mass spectrometry using a commercial MALDI TOF instrument that is designed to produce a 20 μm diameter laser beam on target at its lowest setting. A 25 μm pinhole filter on a swivel arm was installed in the laser beam optics outside the vacuum ion source chamber so it is easily flipped into or out of the beam as desired by the operator. The resulting ion images at 5 μm spatial resolution are sharp since the satellite secondary laser beam maxima have been removed by the filter. Ion images are shown to demonstrate the performance and are compared with the method of oversampling to achieve higher spatial resolution when only a larger laser beam spot on target is available.

Detection of Gunshot Residues Using Mass Spectrometry

PubMed Central

Blanes, Lucas; Cole, Nerida; Doble, Philip; Roux, Claude

2014-01-01

In recent years, forensic scientists have become increasingly interested in the detection and interpretation of organic gunshot residues (OGSR) due to the increasing use of lead- and heavy metal-free ammunition. This has also been prompted by the identification of gunshot residue- (GSR-) like particles in environmental and occupational samples. Various techniques have been investigated for their ability to detect OGSR. Mass spectrometry (MS) coupled to a chromatographic system is a powerful tool due to its high selectivity and sensitivity. Further, modern MS instruments can detect and identify a number of explosives and additives which may require different ionization techniques. Finally, MS has been applied to the analysis of both OGSR and inorganic gunshot residue (IGSR), although the “gold standard” for analysis is scanning electron microscopy with energy dispersive X-ray microscopy (SEM-EDX). This review presents an overview of the technical attributes of currently available MS and ionization techniques and their reported applications to GSR analysis. PMID:24977168

Recent progress in microchip electrophoresis-mass spectrometry.

PubMed

Kitagawa, Fumihiko; Otsuka, Koji

2011-06-25

This review highlights the methodological and instrumental developments in microchip electrophoresis (MCE)-mass spectrometry (MS) from 1997. In MCE-MS, the development of ionization interface is one of the most important issues to realize highly sensitive detection and high separation efficiency. Among several interfaces, electrospray ionization (ESI) has been mainly employed to MCE-MS since a simple structure of the ESI interface is suitable for coupling with the microchips. Although the number of publications is still limited, laser desorption ionization (LDI) interface has also been developed for MCE-MS. The characteristics of the ESI and LDI interfaces applied to the electrophoresis microchips are presented in this review. The scope of applications in MCE-MS covers mainly biogenic compounds such as bioactive amines, peptides, tryptic digests and proteins. This review provides a comprehensive table listing the applications in MCE-MS. Copyright © 2010 Elsevier B.V. All rights reserved.

Mass spectrometry based proteomics: existing capabilities and future directions

PubMed Central

Angel, Thomas E.; Aryal, Uma K.; Hengel, Shawna M.; Baker, Erin S.; Kelly, Ryan T.; Robinson, Errol W.; Smith, Richard D.

2012-01-01

Mass spectrometry (MS)-based proteomics is emerging as a broadly effective means for identification, characterization, and quantification of proteins that are integral components of the processes essential for life. Characterization of proteins at the proteome and sub-proteome (e.g., the phosphoproteome, proteoglycome, or degradome/peptidome) levels provides a foundation for understanding fundamental aspects of biology. Emerging technologies such as ion mobility separations coupled with MS and microchip-based-proteome measurements combined with MS instrumentation and chromatographic separation techniques, such as nanoscale reversed phase liquid chromatography and capillary electrophoresis, show great promise for both broad undirected and targeted highly sensitive measurements. MS-based proteomics is increasingly contribute to our understanding of the dynamics, interactions, and roles that proteins and peptides play, advancing our understanding of biology on a systems wide level for a wide range of applications including investigations of microbial communities, bioremediation, and human health. PMID:22498958

A Comparison of Analytical and Data Preprocessing Methods for Spectral Fingerprinting

PubMed Central

LUTHRIA, DEVANAND L.; MUKHOPADHYAY, SUDARSAN; LIN, LONG-ZE; HARNLY, JAMES M.

2013-01-01

Spectral fingerprinting, as a method of discriminating between plant cultivars and growing treatments for a common set of broccoli samples, was compared for six analytical instruments. Spectra were acquired for finely powdered solid samples using Fourier transform infrared (FT-IR) and Fourier transform near-infrared (NIR) spectrometry. Spectra were also acquired for unfractionated aqueous methanol extracts of the powders using molecular absorption in the ultraviolet (UV) and visible (VIS) regions and mass spectrometry with negative (MS−) and positive (MS+) ionization. The spectra were analyzed using nested one-way analysis of variance (ANOVA) and principal component analysis (PCA) to statistically evaluate the quality of discrimination. All six methods showed statistically significant differences between the cultivars and treatments. The significance of the statistical tests was improved by the judicious selection of spectral regions (IR and NIR), masses (MS+ and MS−), and derivatives (IR, NIR, UV, and VIS). PMID:21352644

Sulfur analysis by inductively coupled plasma-mass spectrometry: A review

NASA Astrophysics Data System (ADS)

Giner Martínez-Sierra, J.; Galilea San Blas, O.; Marchante Gayón, J. M.; García Alonso, J. I.

2015-06-01

In recent years the number of applications of sulfur (S) analysis using inductively coupled plasma mass spectrometry (ICP-MS) as detector has increased significantly. In this article we describe in some depth the application of ICP-MS for S analysis with emphasis placed on the sulfur-specific detection by hyphenated techniques such as LC, GC, CE and LA coupled on-line to ICP-MS. The different approaches available for sulfur isotope ratio measurements by ICP-MS are also detailed. Particular attention has been paid to the quantification of peptides/proteins and the analysis of metallopeptides/metalloproteins via sulfur by LC-ICP-MS. Likewise, the speciation analysis of metal-based pharmaceuticals and metallodrugs and non-metal selective detection of pharmaceuticals via S are highlighted. Labeling procedures for metabolic applications are also included. Finally, the measurement of natural variations in S isotope composition with multicollector ICP-MS instruments is also covered in this review.

Simultaneous Proteomic Discovery and Targeted Monitoring using Liquid Chromatography, Ion Mobility Spectrometry, and Mass Spectrometry.

PubMed

Burnum-Johnson, Kristin E; Nie, Song; Casey, Cameron P; Monroe, Matthew E; Orton, Daniel J; Ibrahim, Yehia M; Gritsenko, Marina A; Clauss, Therese R W; Shukla, Anil K; Moore, Ronald J; Purvine, Samuel O; Shi, Tujin; Qian, Weijun; Liu, Tao; Baker, Erin S; Smith, Richard D

2016-12-01

Current proteomic approaches include both broad discovery measurements and quantitative targeted analyses. In many cases, discovery measurements are initially used to identify potentially important proteins (e.g. candidate biomarkers) and then targeted studies are employed to quantify a limited number of selected proteins. Both approaches, however, suffer from limitations. Discovery measurements aim to sample the whole proteome but have lower sensitivity, accuracy, and quantitation precision than targeted approaches, whereas targeted measurements are significantly more sensitive but only sample a limited portion of the proteome. Herein, we describe a new approach that performs both discovery and targeted monitoring (DTM) in a single analysis by combining liquid chromatography, ion mobility spectrometry and mass spectrometry (LC-IMS-MS). In DTM, heavy labeled target peptides are spiked into tryptic digests and both the labeled and unlabeled peptides are detected using LC-IMS-MS instrumentation. Compared with the broad LC-MS discovery measurements, DTM yields greater peptide/protein coverage and detects lower abundance species. DTM also achieved detection limits similar to selected reaction monitoring (SRM) indicating its potential for combined high quality discovery and targeted analyses, which is a significant step toward the convergence of discovery and targeted approaches. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Ion Mobility Spectrometry (IMS) and Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shvartsburg, Alexandre A.

2010-04-20

In a media of finite viscosity, the Coulomb force of external electric field moves ions with some terminal speed. This dynamics is controlled by “mobility” - a property of the interaction potential between ions and media molecules. This fact has been used to separate and characterize gas-phase ions in various modes of ion mobility spectrometry (IMS) developed since 1970. Commercial IMS devices were introduced in 1980-s for field detection of volatile traces such as explosives and chemical warfare agents. Coupling to soft-ionization sources, mass spectrometry (MS), and chromatographic methods in 1990-s had allowed IMS to handle complex samples, enabling newmore » applications in biological and environmental analyses, nanoscience, and other areas. Since 2003, the introduction of commercial systems by major instrument vendors started bringing the IMS/MS capability to broad user community. The other major development of last decade has been the differential IMS or “field asymmetric waveform IMS” (FAIMS) that employs asymmetric time-dependent electric field to sort ions not by mobility itself, but by the difference between its values in strong and weak electric fields. Coupling of FAIMS to conventional IMS and stacking of conventional IMS stages have enabled two-dimensional separations that dramatically expand the power of ion mobility methods.« less

Recent Modifications and Validation of QuEChERS-dSPE Coupled to LC-MS and GC-MS Instruments for Determination of Pesticide/Agrochemical Residues in Fruits and Vegetables: Review.

PubMed

Lawal, Abubakar; Wong, Richard Chee Seng; Tan, Guan Huat; Abdulra'uf, Lukman Bola; Alsharif, Ali Mohamed Ali

2018-04-21

Fruits and vegetables constitute a major type of food consumed daily apart from whole grains. Unfortunately, the residual deposits of pesticides in these products are becoming a major health concern for human consumption. Consequently, the outcome of the long-term accumulation of pesticide residues has posed many health issues to both humans and animals in the environment. However, the residues have previously been determined using conventionally known techniques, which include liquid-liquid extraction, solid-phase extraction (SPE) and the recently used liquid-phase microextraction techniques. Despite the positive technological effects of these methods, their limitations include; time-consuming, operational difficulty, use of toxic organic solvents, low selective property and expensive extraction setups, with shorter lifespan of instrumental performances. Thus, the potential and maximum use of these methods for pesticides residue determination has resulted in the urgent need for better techniques that will overcome the highlighted drawbacks. Alternatively, attention has been drawn recently towards the use of quick, easy, cheap, effective, rugged and safe technique (QuEChERS) coupled with dispersive solid-phase extraction (dSPE) to overcome the setback challenges experienced by the previous technologies. Conclusively, the reviewed QuEChERS-dSPE techniques and the recent cleanup modifications justifiably prove to be reliable for routine determination and monitoring the concentration levels of pesticide residues using advanced instruments such as high-performance liquid chromatography, liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry.

Development of primary standards for mass spectrometry to increase accuracy in quantifying environmental contaminants.

PubMed

Oates, R P; Mcmanus, Michelle; Subbiah, Seenivasan; Klein, David M; Kobelski, Robert

2017-07-14

Internal standards are essential in electrospray ionization liquid chromatography-mass spectrometry (ESI-LC-MS) to correct for systematic error associated with ionization suppression and/or enhancement. A wide array of instrument setups and interfaces has created difficulty in comparing the quantitation of absolute analyte response across laboratories. This communication demonstrates the use of primary standards as operational qualification standards for LC-MS instruments and their comparison with commonly accepted internal standards. In monitoring the performance of internal standards for perfluorinated compounds, potassium hydrogen phthalate (KHP) presented lower inter-day variability in instrument response than a commonly accepted deuterated perfluorinated internal standard (d3-PFOS), with percent relative standard deviations less than or equal to 6%. The inter-day precision of KHP was greater than d3-PFOS over a 28-day monitoring of perfluorooctanesulfonic acid (PFOS), across concentrations ranging from 0 to 100μg/L. The primary standard trometamol (Trizma) performed as well as known internal standards simeton and tris (2-chloroisopropyl) phosphate (TCPP), with intra-day precision of Trizma response as low as 7% RSD on day 28. The inter-day precision of Trizma response was found to be greater than simeton and TCPP, across concentrations of neonicotinoids ranging from 1 to 100μg/L. This study explores the potential of primary standards to be incorporated into LC-MS/MS methodology to improve the quantitative accuracy in environmental contaminant analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Counting Molecules by Desorption Ionization and Mass Spectrometry/Mass Spectrometry.

ERIC Educational Resources Information Center

Cooks, R. G.; Busch, K. L.

1982-01-01

Discusses two newer methods in mass spectrometry and shows how they can increase signal and signal-to-noise ratios, respectively. The first method, desorption ionization (DI), increases sensitivity while the second method, mass spectrometry/mass spectrometry (MS/MS), increases specificity. Together, the two methods offer improved analytical…

Final LDRD report : development of sample preparation methods for ChIPMA-based imaging mass spectrometry of tissue samples.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maharrey, Sean P.; Highley, Aaron M.; Behrens, Richard, Jr.

2007-12-01

The objective of this short-term LDRD project was to acquire the tools needed to use our chemical imaging precision mass analyzer (ChIPMA) instrument to analyze tissue samples. This effort was an outgrowth of discussions with oncologists on the need to find the cellular origin of signals in mass spectra of serum samples, which provide biomarkers for ovarian cancer. The ultimate goal would be to collect chemical images of biopsy samples allowing the chemical images of diseased and nondiseased sections of a sample to be compared. The equipment needed to prepare tissue samples have been acquired and built. This equipment includesmore » an cyro-ultramicrotome for preparing thin sections of samples and a coating unit. The coating unit uses an electrospray system to deposit small droplets of a UV-photo absorbing compound on the surface of the tissue samples. Both units are operational. The tissue sample must be coated with the organic compound to enable matrix assisted laser desorption/ionization (MALDI) and matrix enhanced secondary ion mass spectrometry (ME-SIMS) measurements with the ChIPMA instrument Initial plans to test the sample preparation using human tissue samples required development of administrative procedures beyond the scope of this LDRD. Hence, it was decided to make two types of measurements: (1) Testing the spatial resolution of ME-SIMS by preparing a substrate coated with a mixture of an organic matrix and a bio standard and etching a defined pattern in the coating using a liquid metal ion beam, and (2) preparing and imaging C. elegans worms. Difficulties arose in sectioning the C. elegans for analysis and funds and time to overcome these difficulties were not available in this project. The facilities are now available for preparing biological samples for analysis with the ChIPMA instrument. Some further investment of time and resources in sample preparation should make this a useful tool for chemical imaging applications.« less

Coordinated Analyses of Antarctic Sediments as Mars Analog Materials Using Reflectance Spectroscopy and Current Flight-Like Instruments for CheMin, SAM and MOMA

NASA Technical Reports Server (NTRS)

Bishop, Janice L.; Franz, Heather B.; Goetz, Walter; Blake, David F.; Freissinet, Caroline; Steininger, Harald; Goesmann, Fred; Brinckerhoff, William B.; Getty, Stephanie; Pinnick, Veronica T.;

Enhancement of Compound Selectivity Using a Radio Frequency Ion-Funnel Proton Transfer Reaction Mass Spectrometer: Improved Specificity for Explosive Compounds.

PubMed

González-Méndez, Ramón; Watts, Peter; Olivenza-León, David; Reich, D Fraser; Mullock, Stephen J; Corlett, Clive A; Cairns, Stuart; Hickey, Peter; Brookes, Matthew; Mayhew, Chris A

2016-11-01

A key issue with any analytical system based on mass spectrometry with no initial separation of compounds is to have a high level of confidence in chemical assignment. This is particularly true for areas of security, such as airports, and recent terrorist attacks have highlighted the need for reliable analytical instrumentation. Proton transfer reaction mass spectrometry is a useful technology for these purposes because the chances of false positives are small owing to the use of a mass spectrometric analysis. However, the detection of an ion at a given m/z for an explosive does not guarantee that that explosive is present. There is still some ambiguity associated with any chemical assignment owing to the presence of isobaric compounds and, depending on mass resolution, ions with the same nominal m/z. In this article we describe how for the first time the use of a radio frequency ion-funnel (RFIF) in the reaction region (drift tube) of a proton transfer reaction-time-of-flight-mass spectrometer (PTR-ToF-MS) can be used to enhance specificity by manipulating the ion-molecule chemistry through collisional induced processes. Results for trinitrotoluene, dinitrotoluenes, and nitrotoluenes are presented to demonstrate the advantages of this new RFIF-PTR-ToF-MS for analytical chemical purposes.

Final report on CCQM-K125: elements in infant formula

NASA Astrophysics Data System (ADS)

Merrick, J.; Saxby, D.; Dutra, E. S.; Sena, R. C.; Araújo, T. O.; Almeida, M. D.; Yang, L.; Pihillagawa, I. G.; Mester, Z.; Sandoval, S.; Wei, C.; Castillo, M. E. D.; Oster, C.; Fisicaro, P.; Rienitz, O.; Pape, C.; Schulz, U.; Jährling, R.; Görlitz, V.; Lampi, E.; Kakoulides, E.; Sin, D. W. M.; Yip, Y. C.; Tsoi, Y. T.; Zhu, Y.; Okumu, T. O.; Yim, Y. H.; Heo, S. W.; Han, M.; Lim, Y.; Osuna, M. A.; Regalado, L.; Uribe, C.; Buzoianu, M. M.; Duta, S.; Konopelko, L.; Krylov, A.; Shin, R.; Linsky, M.; Botha, A.; Magnusson, B.; Haraldsson, C.; Thiengmanee, U.; Klich, H.; Can, S. Z.; Coskun, F. G.; Tunc, M.; Entwisle, J.; O'Reilly, J.; Hill, S.; Goenaga-Infante, H.; Winchester, M.; Rabb, S. A.; Pérez, R.

2017-01-01

CCQM-K125 was organized by the Inorganic Analysis Working Group (IAWG) of CCQM to assess and document the capabilities of the national metrology institutes (NMIs) or the designated institutes (DIs) to measure the mass fractions of trace elements (K, Cu and I) in infant formula. Government Laboratory, Hong Kong SAR (GLHK) acted as the coordinating laboratory. In CCQM-K125, 25 institutes submitted the results for potassium, 24 institutes submitted the results for copper and 8 institutes submitted the results for iodine. For examination of potassium and copper, most of the participants used microwave-assisted acid digestion methods for sample dissolution. A variety of instrumental techniques including inductively coupled plasma mass spectrometry (ICP-MS), isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS), inductively coupled plasma optical emission spectrometry (ICP-OES), atomic absorption spectrometry (AAS), flame atomic emission spectrometry (FAES) and microwave plasma atomic emission spectroscopy (MP-AES) were employed by the participants for determination. For analysis of iodine, most of the participants used alkaline extraction methods for sample preparation. ICP-MS and ID-ICP-MS were used by the participants for the determination. Generally, the participants' results of CCQM-K125 were found consistent for all measurands according to their equivalence statements. Except with some extreme values, most of the participants obtained the values of di/U(di) within +/- 1 for the measurands. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Laser Ablation-Aerosol Mass Spectrometry-Chemical Ionization Mass Spectrometry for Ambient Surface Imaging

DOE PAGES

Berry, Jennifer L.; Day, Douglas A.; Elseberg, Tim; ...

2018-02-20

Mass spectrometry imaging is becoming an increasingly common analytical technique due to its ability to provide spatially resolved chemical information. In this paper, we report a novel imaging approach combining laser ablation with two mass spectrometric techniques, aerosol mass spectrometry and chemical ionization mass spectrometry, separately and in parallel. Both mass spectrometric methods provide the fast response, rapid data acquisition, low detection limits, and high-resolution peak separation desirable for imaging complex samples. Additionally, the two techniques provide complementary information with aerosol mass spectrometry providing near universal detection of all aerosol molecules and chemical ionization mass spectrometry with a heated inletmore » providing molecular-level detail of both gases and aerosols. The two techniques operate with atmospheric pressure interfaces and require no matrix addition for ionization, allowing for samples to be investigated in their native state under ambient pressure conditions. We demonstrate the ability of laser ablation-aerosol mass spectrometry-chemical ionization mass spectrometry (LA-AMS-CIMS) to create 2D images of both standard compounds and complex mixtures. Finally, the results suggest that LA-AMS-CIMS, particularly when combined with advanced data analysis methods, could have broad applications in mass spectrometry imaging applications.« less

Laser Ablation-Aerosol Mass Spectrometry-Chemical Ionization Mass Spectrometry for Ambient Surface Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berry, Jennifer L.; Day, Douglas A.; Elseberg, Tim

Mass spectrometry imaging is becoming an increasingly common analytical technique due to its ability to provide spatially resolved chemical information. In this paper, we report a novel imaging approach combining laser ablation with two mass spectrometric techniques, aerosol mass spectrometry and chemical ionization mass spectrometry, separately and in parallel. Both mass spectrometric methods provide the fast response, rapid data acquisition, low detection limits, and high-resolution peak separation desirable for imaging complex samples. Additionally, the two techniques provide complementary information with aerosol mass spectrometry providing near universal detection of all aerosol molecules and chemical ionization mass spectrometry with a heated inletmore » providing molecular-level detail of both gases and aerosols. The two techniques operate with atmospheric pressure interfaces and require no matrix addition for ionization, allowing for samples to be investigated in their native state under ambient pressure conditions. We demonstrate the ability of laser ablation-aerosol mass spectrometry-chemical ionization mass spectrometry (LA-AMS-CIMS) to create 2D images of both standard compounds and complex mixtures. Finally, the results suggest that LA-AMS-CIMS, particularly when combined with advanced data analysis methods, could have broad applications in mass spectrometry imaging applications.« less

Secondary organic aerosol formation and composition from the photo-oxidation of methyl chavicol (estragole)

NASA Astrophysics Data System (ADS)

Pereira, K. L.; Hamilton, J. F.; Rickard, A. R.; Bloss, W. J.; Alam, M. S.; Camredon, M.; Muñoz, A.; Vásquez, M.; Borrás, E.; Ródenas, M.

2013-12-01

The increasing demand for palm oil for uses in biofuel and food products is leading to rapid expansion of oil palm agriculture. Methyl chavicol (also known as estragole and 1-allyl-4-methoxybenzene) is an oxygenated biogenic volatile organic compound that was recently identified as the main floral emission from an oil palm plantation in Malaysian Borneo. The emissions of methyl chavicol observed may impact regional atmospheric chemistry, but little is known of its ability to form secondary organic aerosol (SOA). The photo-oxidation of methyl chavicol was investigated at the European Photoreactor chamber as a part of the atmospheric chemistry of methyl chavicol (ATMECH) project. Aerosol samples were collected using a particle into liquid sampler (PILS) and analysed offline using an extensive range of instruments including; high performance liquid chromatography mass spectrometry (HPLC-ITMS), high performance liquid chromatography quadrupole time-of-flight mass spectrometry (HPLC-QTOFMS) and Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). The SOA yield was determined as 18-29% depending on initial precursor (VOC : NOx) mixing ratios. In total, 59 SOA compounds were observed and the structures of 10 compounds have been identified using high resolution tandem mass spectrometry. The addition of hydroxyl and/or nitro functional groups to the aromatic ring appears to be an important mechanistic pathway for aerosol formation. This results in the formation of compounds with both low volatility and high O : C ratios, where functionalisation rather than fragmentation is mainly observed as a~result of the stability of the ring. The SOA species observed can be characterized as semi-volatile to low volatile oxygenated organic aerosol (SVOOA and LVOOA) components and therefore may be important in aerosol formation and growth.

ETD in a traveling wave ion guide at tuned Z-spray ion source conditions allows for site-specific hydrogen/deuterium exchange measurements.

PubMed

Rand, Kasper D; Pringle, Steven D; Morris, Michael; Engen, John R; Brown, Jeffery M

2011-10-01

The recent application of electron transfer dissociation (ETD) to measure the hydrogen exchange of proteins in solution at single-residue resolution (HX-ETD) paves the way for mass spectrometry-based analyses of biomolecular structure at an unprecedented level of detail. The approach requires that activation of polypeptide ions prior to ETD is minimal so as to prevent undesirable gas-phase randomization of the deuterium label from solution (i.e., hydrogen scrambling). Here we explore the use of ETD in a traveling wave ion guide of a quadrupole-time-of-flight (Q-TOF) mass spectrometer with a "Z-spray" type ion source, to measure the deuterium content of individual residues in peptides. We systematically identify key parameters of the Z-spray ion source that contribute to collisional activation and define conditions that allow ETD experiments to be performed in the traveling wave ion guide without gas-phase hydrogen scrambling. We show that ETD and supplemental collisional activation in a subsequent traveling wave ion guide allows for improved extraction of residue-specific deuterium contents in peptides with low charge. Our results demonstrate the feasibility, and illustrate the advantages of performing HX-ETD experiments on a high-resolution Q-TOF instrument equipped with traveling wave ion guides. Determination of parameters of the Z-spray ion source that contribute to ion heating are similarly pertinent to a growing number of MS applications that also rely on an energetically gentle transfer of ions into the gas-phase, such as the analysis of biomolecular structure by native mass spectrometry in combination with gas-phase ion-ion/ion-neutral reactions or ion mobility spectrometry. © American Society for Mass Spectrometry, 2011

Evaluation of the capabilities of atmospheric pressure chemical ionization source coupled to tandem mass spectrometry for the determination of dioxin-like polychlorobiphenyls in complex-matrix food samples.

PubMed

Portolés, T; Sales, C; Abalos, M; Sauló, J; Abad, E

2016-09-21

The use of the novel atmospheric pressure chemical ionization (APCI) source for gas chromatography (GC) coupled to triple quadrupole using tandem mass spectrometry (MS/MS) and its potential for the simultaneous determination of the 12 dioxin-like polychlorobiphenyls (DL-PCBs) in complex food and feed matrices has been evaluated. In first place, ionization and fragmentation behavior of DL-PCBs on the APCI source under charge transfer conditions has been studied followed by their fragmentation in the collision cell. Linearity, repeatability and sensitivity have been studied obtaining instrumental limits of detection and quantification of 0.0025 and 0.005 pg μL(-1) (2.5 and 5 fg on column) respectively for every DL-PCB. Finally, application to real samples has been carried out and DL-PCB congeners (PCB 77, 81, 105, 114, 118, 123, 126, 156, 157, 167, 169, 189) have been detected in the different samples in the range of 0.40-10000 pg g(-1). GC-(APCI)MS/MS has been proved as a suitable alternative to the traditionally accepted confirmation method based on the use of high resolution mass spectrometry and other triple quadrupole tandem mass spectrometry techniques operating with electron ionization. The development of MS/MS methodologies for the analysis of dioxins and DL-PCBs is nowadays particularly important, since this technique was included as a confirmatory method in the present European Union regulations that establish the requirements for the determination of these compounds in food and feed matrices. Copyright © 2016 Elsevier B.V. All rights reserved.

An approach toward quantification of organic compounds in complex environmental samples using high-resolution electrospray ionization mass spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen, Tran B.; Nizkorodov, Sergey; Laskin, Alexander

2013-01-07

Quantitative analysis of individual compounds in complex mixtures using high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) is complicated by differences in the ionization efficiencies of analyte molecules in the mixture, resulting in signal suppression during ionization. However, the ability to obtain concentration estimates of compounds in an environmental sample is important for data interpretation and comparison. We introduce an approach for estimating mass concentrations of analytes observed in a multicomponent mixture by HR-ESI-MS, without prior separation. The approach relies on a calibration of the instrument using appropriate standards added to the mixture of studied analytes. An illustration of how the proposedmore » calibration can be applied in practice is provided for aqueous extracts of isoprene photooxidation organic aerosol, with multifunctional organic acids standards. We show that the observed ion sensitivities in ESI-MS are positively correlated with the “adjusted mass,” defined as a product of the molecular mass and the H/C ratio in the molecule (adjusted mass = H/C x molecular mass). The correlation of the observed ESI sensitivity with adjusted mass is justified by considering trends of the physical and chemical properties of organic compounds that affect ionization in the positive ion mode, i.e., gas-phase basicity, polarizability, and molecular size.« less

High-Resolution Inductively Coupled Plasma Optical Emission Spectrometry for (234)U/(238)Pu Age Dating of Plutonium Materials and Comparison to Sector Field Inductively Coupled Plasma Mass Spectrometry.

PubMed

Krachler, Michael; Alvarez-Sarandes, Rafael; Rasmussen, Gert

2016-09-06

Employing a commercial high-resolution inductively coupled plasma optical emission spectrometry (HR-ICP-OES) instrument, an innovative analytical procedure for the accurate determination of the production age of various Pu materials (Pu powder, cardiac pacemaker battery, (242)Cm heat source, etc.) was developed and validated. This undertaking was based on the fact that the α decay of (238)Pu present in the investigated samples produced (234)U and both mother and daughter could be identified unequivocally using HR-ICP-OES. Benefiting from the high spectral resolution of the instrument (<5 pm) and the isotope shift of the emission lines of both nuclides, (234)U and (238)Pu were selectively and directly determined in the dissolved samples, i.e., without a chemical separation of the two analytes from each other. Exact emission wavelengths as well as emission spectra of (234)U centered around λ = 411.590 nm and λ = 424.408 nm are reported here for the first time. Emission spectra of the isotopic standard reference material IRMM-199, comprising about one-third each of (233)U, (235)U, and (238)U, confirmed the presence of (234)U in the investigated samples. For the assessment of the (234)U/(238)Pu amount ratio, the emission signals of (234)U and (238)Pu were quantified at λ = 424.408 nm and λ = 402.148 nm, respectively. The age of the investigated samples (range: 26.7-44.4 years) was subsequently calculated using the (234)U/(238)Pu chronometer. HR-ICP-OES results were crossed-validated through sector field inductively coupled plasma mass spectrometry (SF-ICPMS) analysis of the (234)U/(238)Pu amount ratio of all samples applying isotope dilution combined with chromatographic separation of U and Pu. Available information on the assumed ages of the analyzed samples was consistent with the ages obtained via the HR-ICP-OES approach. Being based on a different physical detection principle, HR-ICP-OES provides an alternative strategy to the well-established mass spectrometric approach and thus effectively adds to the quality assurance of (234)U/(238)Pu age dates.

Mass spectrometry.

NASA Technical Reports Server (NTRS)

Burlingame, A. L.; Johanson, G. A.

1972-01-01

Review of the current state of mass spectrometry, indicating its unique importance for advanced scientific research. Mass spectrometry applications in computer techniques, gas chromatography, ion cyclotron resonance, molecular fragmentation and ionization, and isotope labeling are covered. Details are given on mass spectrometry applications in bio-organic chemistry and biomedical research. As the subjects of these applications are indicated alkaloids, carbohydrates, lipids, terpenes, quinones, nucleic acid components, peptides, antibiotics, and human and animal metabolisms. Particular attention is given to the mass spectra of organo-inorganic compounds, inorganic mass spectrometry, surface phenomena such as secondary ion and electron emission, and elemental and isotope analysis. Further topics include mass spectrometry in organic geochemistry, applications in geochronology and cosmochemistry, and organic mass spectrometry.

Is "good enough" good enough for portable visible and near-visible spectrometry?

NASA Astrophysics Data System (ADS)

Scheeline, Alexander

2015-06-01

Some uses of portable spectrometers require the same quality as laboratory instruments. Such quality is challenging because of temperature and humidity variation, dust, and vibration. Typically, one chooses materials and mechanical layout to minimize the influence of these noise and background sources. Mechanical stability is constrained by limits on instrument mass and ergonomics. An alternative approach is to make minimally adequate hardware, compensating for variability in software. We describe an instrument developed specifically to use software to compensate for marginal hardware. An initial instantiation of the instrument is limited to 430 - 700 nm. Simple changes will allow expansion to cover 315 - 1000 nm. Outside this range, costs are likely to increase significantly. Inherent wavelength calibration comes from knowing the peak emission wavelength of an LED light source, and fitting of instrument dispersion to a model of order placement with each measurement. Dynamic range is determined by the product of camera response and intentionally wide throughput variation among hundreds of diffraction orders. Resolution degrades gracefully at low light levels, but is limited to ~ 2 nm at high light levels as initially fabricated and ~ 1 nm in principle. Stray light may be measured in real-time. Diffuse stray light can be employed for turbidimetry fluorimetry, and to aid compensation of working curve nonlinearity. While unsuitable for, Raman spectroscopy, the instrument shows promise for absorption, fluorescence, reflectance, and surface plasmon resonance spectrometries. To aid non-expert users, real-time training, measurement sequencing, and outcome interpretation are programmed with QR codes or web-linked instructions.

A new generation of x-ray spectrometry UHV instruments at the SR facilities BESSY II, ELETTRA and SOLEIL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lubeck, J., E-mail: janin.lubeck@ptb.de; Fliegauf, R.; Holfelder, I.

A novel type of ultra-high vacuum instrument for X-ray reflectometry and spectrometry-related techniques for nanoanalytics by means of synchrotron radiation (SR) has been constructed and commissioned at BESSY II. This versa-tile instrument was developed by the PTB, Germany’s national metrology institute, and includes a 9-axis manipulator that allows for an independent alignment of the samples with respect to all degrees of freedom. In addition, it integrates a rotational and translational movement of several photodiodes as well as a translational movement of a beam-geometry-defining aperture system. Thus, the new instrument enables various analytical techniques based on energy dispersive X-ray detectors suchmore » as reference-free X-Ray Fluorescence (XRF) analysis, total-reflection XRF, grazing-incidence XRF, in addition to optional X-Ray Reflectometry (XRR) measurements or polarization-dependent X-ray absorption fine structure analyses (XAFS). Samples having a size of up to (100 × 100) mm{sup 2}; can be analyzed with respect to their mass deposition, elemental, spatial or species composition. Surface contamination, nanolayer composition and thickness, depth pro-file of matrix elements or implants, nanoparticles or buried interfaces as well as molecular orientation of bonds can be accessed. Three technology transfer projects of adapted instruments have enhanced X-Ray Spectrometry (XRS) research activities within Europe at the synchrotron radiation facilities ELETTRA (IAEA) and SOLEIL (CEA/LNE-LNHB) as well as at the X-ray innovation laboratory BLiX (TU Berlin) where different laboratory sources are used. Here, smaller chamber requirements led PTB in cooperation with TU Berlin to develop a modified instrument equipped with a 7-axis manipulator: reduced freedom in the choice of experimental geometry modifications (absence of out-of-SR-plane and reference-free XRS options) has been compensated by encoder-enhanced angular accuracy for GIXRF and XRR.« less

Structural determination of intact proteins using mass spectrometry

DOEpatents

Kruppa, Gary [San Francisco, CA; Schoeniger, Joseph S [Oakland, CA; Young, Malin M [Livermore, CA

2008-05-06

The present invention relates to novel methods of determining the sequence and structure of proteins. Specifically, the present invention allows for the analysis of intact proteins within a mass spectrometer. Therefore, preparatory separations need not be performed prior to introducing a protein sample into the mass spectrometer. Also disclosed herein are new instrumental developments for enhancing the signal from the desired modified proteins, methods for producing controlled protein fragments in the mass spectrometer, eliminating complex microseparations, and protein preparatory chemical steps necessary for cross-linking based protein structure determination.Additionally, the preferred method of the present invention involves the determination of protein structures utilizing a top-down analysis of protein structures to search for covalent modifications. In the preferred method, intact proteins are ionized and fragmented within the mass spectrometer.

ANALYTICAL CHEMISTRY DIVISION ANNUAL PROGRESS REPORT FOR PERIOD ENDING DECEMBER 31, 1961

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1962-02-01

Research and development progress is reported on analytlcal instrumentation, dlssolver-solution analyses, special research problems, reactor projects analyses, x-ray and spectrochemical analyses, mass spectrometry, optical and electron microscopy, radiochemical analyses, nuclear analyses, inorganic preparations, organic preparations, ionic analyses, infrared spectral studies, anodization of sector coils for the Analog II Cyclotron, quality control, process analyses, and the Thermal Breeder Reactor Projects Analytical Chemistry Laboratory. (M.C.G.)

Advances in understanding the surface chemistry of lignocellulosic biomass via time-of-flight secondary ion mass spectrometry

DOE PAGES

Tolbert, Allison K.; Ragauskas, Arthur J.

2016-12-12

Overcoming the natural recalcitrance of lignocellulosic biomass is necessary in order to efficiently convert biomass into biofuels or biomaterials and many times this requires some type of chemical pretreatment and/or biological treatment. While bulk chemical analysis is the traditional method of determining the impact a treatment has on biomass, the chemistry on the surface of the sample can differ from the bulk chemistry. Specifically, enzymes and microorganisms bind to the surface of the biomass and their efficiency could be greatly impacted by the chemistry of the surface. Therefore, it is important to study and understand the chemistry of the biomassmore » at the surface. Time-of- flight secondary ion mass spectrometry (ToF-SIMS) is a powerful tool that can spectrally and spatially analyze the surface chemistry of a sample. This review discusses the advances in understanding lignocellulosic biomass surface chemistry using the ToF-SIMS by addressing the instrument parameters, biomass sample preparation, and characteristic lignocellulosic ion fragmentation peaks along with their typical location in the plant cell wall. Furthermore, the use of the ToF-SIMS in detecting chemical changes due to chemical pretreatments, microbial treatments, and physical or genetic modifications is discussed along with possible future applications of the instrument in lignocellulosic biomass studies.« less

Advances in understanding the surface chemistry of lignocellulosic biomass via time-of-flight secondary ion mass spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tolbert, Allison K.; Ragauskas, Arthur J.

Overcoming the natural recalcitrance of lignocellulosic biomass is necessary in order to efficiently convert biomass into biofuels or biomaterials and many times this requires some type of chemical pretreatment and/or biological treatment. While bulk chemical analysis is the traditional method of determining the impact a treatment has on biomass, the chemistry on the surface of the sample can differ from the bulk chemistry. Specifically, enzymes and microorganisms bind to the surface of the biomass and their efficiency could be greatly impacted by the chemistry of the surface. Therefore, it is important to study and understand the chemistry of the biomassmore » at the surface. Time-of- flight secondary ion mass spectrometry (ToF-SIMS) is a powerful tool that can spectrally and spatially analyze the surface chemistry of a sample. This review discusses the advances in understanding lignocellulosic biomass surface chemistry using the ToF-SIMS by addressing the instrument parameters, biomass sample preparation, and characteristic lignocellulosic ion fragmentation peaks along with their typical location in the plant cell wall. Furthermore, the use of the ToF-SIMS in detecting chemical changes due to chemical pretreatments, microbial treatments, and physical or genetic modifications is discussed along with possible future applications of the instrument in lignocellulosic biomass studies.« less

Challenges and Opportunities for Biological Mass Spectrometry Core Facilities in the Developing World.

PubMed

Bell, Liam; Calder, Bridget; Hiller, Reinhard; Klein, Ashwil; Soares, Nelson C; Stoychev, Stoyan H; Vorster, Barend C; Tabb, David L

2018-04-01

The developing world is seeing rapid growth in the availability of biological mass spectrometry (MS), particularly through core facilities. As proteomics and metabolomics becomes locally feasible for investigators in these nations, application areas associated with high burden in these nations, such as infectious disease, will see greatly increased research output. This article evaluates the rapid growth of MS in South Africa (currently approaching 20 laboratories) as a model for establishing MS core facilities in other nations of the developing world. Facilities should emphasize new services rather than new instruments. The reduction of the delays associated with reagent and other supply acquisition would benefit both facilities and the users who make use of their services. Instrument maintenance and repair, often mediated by an in-country business for an international vendor, is also likely to operate on a slower schedule than in the wealthiest nations. A key challenge to facilities in the developing world is educating potential facility users in how best to design experiments for proteomics and metabolomics, what reagents are most likely to introduce problematic artifacts, and how to interpret results from the facility. Here, we summarize the experience of 6 different institutions to raise the level of biological MS available to researchers in South Africa.

A new basaltic glass microanalytical reference material for multiple techniques

USGS Publications Warehouse

Wilson, Steve; Koenig, Alan; Lowers, Heather

2012-01-01

The U.S. Geological Survey (USGS) has been producing reference materials since the 1950s. Over 50 materials have been developed to cover bulk rock, sediment, and soils for the geological community. These materials are used globally in geochemistry, environmental, and analytical laboratories that perform bulk chemistry and/or microanalysis for instrument calibration and quality assurance testing. To answer the growing demand for higher spatial resolution and sensitivity, there is a need to create a new generation of microanalytical reference materials suitable for a variety of techniques, such as scanning electron microscopy/X-ray spectrometry (SEM/EDS), electron probe microanalysis (EPMA), laser ablation inductively coupled mass spectrometry (LA-ICP-MS), and secondary ion mass spectrometry (SIMS). As such, the microanalytical reference material (MRM) needs to be stable under the beam, be homogeneous at scales of better than 10–25 micrometers for the major to ultra-trace element level, and contain all of the analytes (elements or isotopes) of interest. Previous development of basaltic glasses intended for LA-ICP-MS has resulted in a synthetic basaltic matrix series of glasses (USGS GS-series) and a natural basalt series of glasses (BCR-1G, BHVO-2G, and NKT-1G). These materials have been useful for the LA-ICP-MS community but were not originally intended for use by the electron or ion beam community. A material developed from start to finish with intended use in multiple microanalytical instruments would be useful for inter-laboratory and inter-instrument platform comparisons. This article summarizes the experiments undertaken to produce a basalt glass reference material suitable for distribution as a multiple-technique round robin material. The goal of the analytical work presented here is to demonstrate that the elemental homogeneity of the new glass is acceptable for its use as a reference material. Because the round robin exercise is still underway, only nominal compositional ranges for each element are given in the article.

Performance of the MOMA Gas Chromatograph-Mass Spectrometer onboard the 2018 ExoMars Mission

NASA Astrophysics Data System (ADS)

Buch, Arnaud; Pinnick, Veronica; Szopa, Cyril; Grand, Noël; Freissinet, Caroline; Danell, Ryan; van Ameron, Friso; Arevalo, Ricardo; Brinckerhoff, William; Raulin, François; Mahaffy, Paul; Goesmann, Fred

2015-04-01

The Mars Organic Molecule Analyzer (MOMA) is a dual ion source linear ion trap mass spectrometer that was designed for the 2018 joint ESA-Roscosmos mission to Mars. The main scientific aim of the mission is to search for signs of extant or extinct life in the near subsurface of Mars by acquir-ing samples from as deep as 2 m below the surface. MOMA will be a key analytical tool in providing chemical (molecular) information from the solid samples, with particular focus on the characterization of organic content. The MOMA instrument, itself, is a joint venture for NASA and ESA to develop a mass spectrometer capable of analyzing samples from pyrolysis gas chromatograph (GC) as well as ambient pressure laser desorption ionization (LDI). The combination of the two analytical techniques allows for the chemical characterization of a broad range of compounds, including volatile and non-volatile species. Generally, MOMA can provide in-formation on elemental and molecular makeup, po-larity, chirality and isotopic patterns of analyte spe-cies. Here we report on the current performance of the MOMA prototype instruments, specifically the demonstration of the gas chromatography-mass spec-trometry (GC-MS) mode of operation. Both instruments have been tested separately first and have been coupled in order to test the efficiency of the future MOMA GC-MS instrument. The main objective of the second step has been to test the quantitative response of both instruments while they are coupled and to characterize the combined instrument detection limit for several compounds. A final experiment has been done in order to test the feasibility of the separation and detection of a mixture contained in a soil sample introduced in the MOMA oven.

Comprehensive combinatory standard correction: a calibration method for handling instrumental drifts of gas chromatography-mass spectrometry systems.

PubMed

Deport, Coralie; Ratel, Jérémy; Berdagué, Jean-Louis; Engel, Erwan

2006-05-26

The current work describes a new method, the comprehensive combinatory standard correction (CCSC), for the correction of instrumental signal drifts in GC-MS systems. The method consists in analyzing together with the products of interest a mixture of n selected internal standards, and in normalizing the peak area of each analyte by the sum of standard areas and then, select among the summation operator sigma(p = 1)(n)C(n)p possible sums, the sum that enables the best product discrimination. The CCSC method was compared with classical techniques of data pre-processing like internal normalization (IN) or single standard correction (SSC) on their ability to correct raw data from the main drifts occurring in a dynamic headspace-gas chromatography-mass spectrometry system. Three edible oils with closely similar compositions in volatile compounds were analysed using a device which performance was modulated by using new or used dynamic headspace traps and GC-columns, and by modifying the tuning of the mass spectrometer. According to one-way ANOVA, the CCSC method increased the number of analytes discriminating the products (31 after CCSC versus 25 with raw data or after IN and 26 after SSC). Moreover, CCSC enabled a satisfactory discrimination of the products irrespective of the drifts. In a factorial discriminant analysis, 100% of the samples (n = 121) were well-classified after CCSC versus 45% for raw data, 90 and 93%, respectively after IN and SSC.

Thermoelectrically cooled water trap

DOEpatents

Micheels, Ronald H [Concord, MA

2006-02-21

A water trap system based on a thermoelectric cooling device is employed to remove a major fraction of the water from air samples, prior to analysis of these samples for chemical composition, by a variety of analytical techniques where water vapor interferes with the measurement process. These analytical techniques include infrared spectroscopy, mass spectrometry, ion mobility spectrometry and gas chromatography. The thermoelectric system for trapping water present in air samples can substantially improve detection sensitivity in these analytical techniques when it is necessary to measure trace analytes with concentrations in the ppm (parts per million) or ppb (parts per billion) partial pressure range. The thermoelectric trap design is compact and amenable to use in a portable gas monitoring instrumentation.

The Combustion Experiment on the Sample Analysis at Mars (SAM) Instrument Suite on the Curiosity Rover

NASA Technical Reports Server (NTRS)

Stern, J. C.; Malespin, C. A.; Eigenbrode, J.; Graham, H. V.; Archer, P. D.; Brunner, A.; Freissinet, C.; Franz, H. B.; Fuentes, J.; Glavin, D. P.;

DART - LTQ ORBITRAP as an expedient tool for the identification of synthetic cannabinoids.

PubMed

Habala, Ladislav; Valentová, Jindra; Pechová, Iveta; Fuknová, Mária; Devínsky, Ferdinand

2016-05-01

Synthetic cannabinoids as designer drugs constitute a major problem due to their rapid increase in number and the difficulties connected with their identification in complex mixtures. DART (Direct Analysis in Real Time) has emerged as an advantageous tool for the direct and rapid analysis of complex samples by mass spectrometry. Here we report on the identification of six synthetic cannabinoids originating from seized material in various matrices, employing the combination of ambient pressure ion source DART and hybrid ion trap - LTQ ORBITRAP mass spectrometer. This report also describes the sampling techniques for the provided herbal material containing the cannabinoids, either directly as plant parts or as an extract in methanol and their influence on the outcome of the analysis. The high resolution mass spectra supplied by the LTQ ORBITRAP instrument allowed for an unambiguous assignment of target compounds. The utilized instrumental coupling proved to be a convenient way for the identification of synthetic cannabinoids in real-world samples. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Impact ionisation mass spectrometry of platinum-coated olivine and magnesite-dominated cosmic dust analogues

NASA Astrophysics Data System (ADS)

Hillier, Jon K.; Sternovsky, Z.; Kempf, S.; Trieloff, M.; Guglielmino, M.; Postberg, F.; Price, M. C.

2018-07-01

Impact ionisation mass spectrometry enables the composition of cosmic dust grains to be determined in situ by spacecraft-based instrumentation. The proportion of molecular ions in the impact plasma is a function of the impact velocity, making laboratory calibration vital for the interpretation of the mass spectra, particularly at the low velocities typical of lunar or asteroid encounters. Here we present an analysis of laboratory impact ionisation mass spectra from primarily low (<15 km s-1) velocity impacts of both olivine and magnesite-dominated particles onto the SUrface Dust Mass Analyzer (SUDA) laboratory mass spectrometer. The cation mass spectra show characteristic peaks due to their constituent elements, with Mg, Al, Si, C, Ca, O and Fe frequently present. Contaminant species from the conductive coating process (B, Na, K, C, Pt) also occur, at varying frequencies. Possible saponite or talc inclusions in the magnesite particles are revealed by the presence of Si, Fe, Ca and Al in the magnesite mass spectra. Magnesium is clearly present at the lowest impact velocities (3 km s-1), at which alkali metals were presumed to dominate. Peaks attributed to very minor amounts of water or hydroxyl present in the grains are also seen at low velocities in both cation and anion mass spectra, demonstrating the feasibility of impact ionisation mass spectrometry in identifying hydrated or hydrous minerals, during very low velocity encounters or with very low abundances of water or hydroxy groups, in the impinging grains. Velocity thresholds for the reliable identification of the major elements within the magnesite and olivine cation spectra are presented. Additionally, relative sensitivity factors for Mg (5.1), Fe (1.5) and O (0.6) with respect to Si, in the olivine particles, at impact speeds >19 km s-1, were found to be very similar to those previously determined for orthopyroxene-dominated particles, despite different target and projectile materials. This confirms that quantitative analyses of mineral dust grain composition in space is viable despite initially poorly-constrained mineralogy.

Automated Lipid A Structure Assignment from Hierarchical Tandem Mass Spectrometry Data

NASA Astrophysics Data System (ADS)

Ting, Ying S.; Shaffer, Scott A.; Jones, Jace W.; Ng, Wailap V.; Ernst, Robert K.; Goodlett, David R.

2011-05-01

Infusion-based electrospray ionization (ESI) coupled to multiple-stage tandem mass spectrometry (MS n ) is a standard methodology for investigating lipid A structural diversity (Shaffer et al. J. Am. Soc. Mass. Spectrom. 18(6), 1080-1092, 2007). Annotation of these MS n spectra, however, has remained a manual, expert-driven process. In order to keep up with the data acquisition rates of modern instruments, we devised a computational method to annotate lipid A MS n spectra rapidly and automatically, which we refer to as hierarchical tandem mass spectrometry (HiTMS) algorithm. As a first-pass tool, HiTMS aids expert interpretation of lipid A MS n data by providing the analyst with a set of candidate structures that may then be confirmed or rejected. HiTMS deciphers the signature ions (e.g., A-, Y-, and Z-type ions) and neutral losses of MS n spectra using a species-specific library based on general prior structural knowledge of the given lipid A species under investigation. Candidates are selected by calculating the correlation between theoretical and acquired MS n spectra. At a false discovery rate of less than 0.01, HiTMS correctly assigned 85% of the structures in a library of 133 manually annotated Francisella tularensis subspecies novicida lipid A structures. Additionally, HiTMS correctly assigned 85% of the structures in a smaller library of lipid A species from Yersinia pestis demonstrating that it may be used across species.

A comparative evaluation of software for the analysis of liquid chromatography-tandem mass spectrometry data from isotope coded affinity tag experiments.

PubMed

Moulder, Robert; Filén, Jan-Jonas; Salmi, Jussi; Katajamaa, Mikko; Nevalainen, Olli S; Oresic, Matej; Aittokallio, Tero; Lahesmaa, Riitta; Nyman, Tuula A

2005-07-01

The options available for processing quantitative data from isotope coded affinity tag (ICAT) experiments have mostly been confined to software specific to the instrument of acquisition. However, recent developments with data format conversion have subsequently increased such processing opportunities. In the present study, data sets from ICAT experiments, analysed with liquid chromatography/tandem mass spectrometry (MS/MS), using an Applied Biosystems QSTAR Pulsar quadrupole-TOF mass spectrometer, were processed in triplicate using separate mass spectrometry software packages. The programs Pro ICAT, Spectrum Mill and SEQUEST with XPRESS were employed. Attention was paid towards the extent of common identification and agreement of quantitative results, with additional interest in the flexibility and productivity of these programs. The comparisons were made with data from the analysis of a specifically prepared test mixture, nine proteins at a range of relative concentration ratios from 0.1 to 10 (light to heavy labelled forms), as a known control, and data selected from an ICAT study involving the measurement of cytokine induced protein expression in human lymphoblasts, as an applied example. Dissimilarities were detected in peptide identification that reflected how the associated scoring parameters favoured information from the MS/MS data sets. Accordingly, there were differences in the numbers of peptides and protein identifications, although from these it was apparent that both confirmatory and complementary information was present. In the quantitative results from the three programs, no statistically significant differences were observed.

Surface Desorption Dielectric-Barrier Discharge Ionization Mass Spectrometry.

PubMed

Zhang, Hong; Jiang, Jie; Li, Na; Li, Ming; Wang, Yingying; He, Jing; You, Hong

2017-07-18

A variant of dielectric-barrier discharge named surface desorption dielectric-barrier discharge ionization (SDDBDI) mass spectrometry was developed for high-efficiency ion transmission and high spatial resolution imaging. In SDDBDI, a tungsten nanotip and the inlet of the mass spectrometer are used as electrodes, and a piece of coverslip is used as a sample plate as well as an insulating dielectric barrier, which simplifies the configuration of instrument and thus the operation. Different from volume dielectric-barrier discharge (VDBD), the microdischarges are generated on the surface at SDDBDI, and therefore the plasma density is extremely high. Analyte ions are guided directly into the MS inlet without any deflection. This configuration significantly improves the ion transmission efficiency and thus the sensitivity. The dependence of sensitivity and spatial resolution of the SDDBDI on the operation parameters were systematically investigated. The application of SDDBDI was successfully demonstrated by analysis of multiple species including amino acids, pharmaceuticals, putative cancer biomarkers, and mixtures of both fatty acids and hormones. Limits of detection (S/N = 3) were determined to be 0.84 and 0.18 pmol, respectively, for the analysis of l-alanine and metronidazole. A spatial resolution of 22 μm was obtained for the analysis of an imprinted cyclophosphamide pattern, and imaging of a "T" character was successfully demonstrated under ambient conditions. These results indicate that SDDBDI has high-efficiency ion transmission, high sensitivity, and high spatial resolution, which render it a potential tool for mass spectrometry imaging.

Screening and Quantification of Aliphatic Primary Alkyl Corrosion Inhibitor Amines in Water Samples by Paper Spray Mass Spectrometry.

PubMed

Jjunju, Fred P M; Maher, Simon; Damon, Deidre E; Barrett, Richard M; Syed, S U; Heeren, Ron M A; Taylor, Stephen; Badu-Tawiah, Abraham K

2016-01-19

Direct analysis and identification of long chain aliphatic primary diamine Duomeen O (n-oleyl-1,3-diaminopropane), corrosion inhibitor in raw water samples taken from a large medium pressure water tube boiler plant water samples at low LODs (<0.1 pg) has been demonstrated for the first time, without any sample preparation using paper spray mass spectrometry (PS-MS). The presence of Duomeen O in water samples was confirmed via tandem mass spectrometry using collision-induced dissociation and supported by exact mass measurement and reactive paper spray experiments using an LTQ Orbitrap Exactive instrument. Data shown herein indicate that paper spray ambient ionization can be readily used as a rapid and robust method for in situ direct analysis of polymanine corrosion inhibitors in an industrial water boiler plant and other related samples in the water treatment industry. This approach was applied for the analysis of three complex water samples including feedwater, condensate water, and boiler water, all collected from large medium pressure (MP) water tube boiler plants, known to be dosed with varying amounts of polyamine and amine corrosion inhibitor components. Polyamine chemistry is widely used for example in large high pressure (HP) boilers operating in municipal waste and recycling facilities to prevent corrosion of metals. The samples used in this study are from such a facility in Coventry waste treatment facility, U.K., which has 3 × 40 tonne/hour boilers operating at 17.5 bar.

Cloud parallel processing of tandem mass spectrometry based proteomics data.

PubMed

Mohammed, Yassene; Mostovenko, Ekaterina; Henneman, Alex A; Marissen, Rob J; Deelder, André M; Palmblad, Magnus

2012-10-05

Data analysis in mass spectrometry based proteomics struggles to keep pace with the advances in instrumentation and the increasing rate of data acquisition. Analyzing this data involves multiple steps requiring diverse software, using different algorithms and data formats. Speed and performance of the mass spectral search engines are continuously improving, although not necessarily as needed to face the challenges of acquired big data. Improving and parallelizing the search algorithms is one possibility; data decomposition presents another, simpler strategy for introducing parallelism. We describe a general method for parallelizing identification of tandem mass spectra using data decomposition that keeps the search engine intact and wraps the parallelization around it. We introduce two algorithms for decomposing mzXML files and recomposing resulting pepXML files. This makes the approach applicable to different search engines, including those relying on sequence databases and those searching spectral libraries. We use cloud computing to deliver the computational power and scientific workflow engines to interface and automate the different processing steps. We show how to leverage these technologies to achieve faster data analysis in proteomics and present three scientific workflows for parallel database as well as spectral library search using our data decomposition programs, X!Tandem and SpectraST.

Detection of bio-signature by microscopy and mass spectrometry

NASA Astrophysics Data System (ADS)

Tulej, M.; Wiesendanger, R.; Neuland, M., B.; Meyer, S.; Wurz, P.; Neubeck, A.; Ivarsson, M.; Riedo, V.; Moreno-Garcia, P.; Riedo, A.; Knopp, G.

2017-09-01

We demonstrate detection of micro-sized fossilized bacteria by means of microscopy and mass spectrometry. The characteristic structures of lifelike forms are visualized with a micrometre spatial resolution and mass spectrometric analyses deliver elemental and isotope composition of host and fossilized materials. Our studies show that high selectivity in isolation of fossilized material from host phase can be achieved while applying a microscope visualization (location), a laser ablation ion source with sufficiently small laser spot size and applying depth profiling method. Our investigations shows that fossilized features can be well isolated from host phase. The mass spectrometric measurements can be conducted with sufficiently high accuracy and precision yielding quantitative elemental and isotope composition of micro-sized objects. The current performance of the instrument allows the measurement of the isotope fractionation in per mill level and yield exclusively definition of the origin of the investigated species by combining optical visualization of investigated samples (morphology and texture), chemical characterization of host and embedded in the host micro-sized structure. Our isotope analyses involved bio-relevant B, C, S, and Ni isotopes which could be measured with sufficiently accuracy to conclude about the nature of the micro-sized objects.

Current applications of high-resolution mass spectrometry for the analysis of new psychoactive substances: a critical review.

PubMed

Pasin, Daniel; Cawley, Adam; Bidny, Sergei; Fu, Shanlin

2017-10-01

The proliferation of new psychoactive substances (NPS) in recent years has resulted in the development of numerous analytical methods for the detection and identification of known and unknown NPS derivatives. High-resolution mass spectrometry (HRMS) has been identified as the method of choice for broad screening of NPS in a wide range of analytical contexts because of its ability to measure accurate masses using data-independent acquisition (DIA) techniques. Additionally, it has shown promise for non-targeted screening strategies that have been developed in order to detect and identify novel analogues without the need for certified reference materials (CRMs) or comprehensive mass spectral libraries. This paper reviews the applications of HRMS for the analysis of NPS in forensic drug chemistry and analytical toxicology. It provides an overview of the sample preparation procedures in addition to data acquisition, instrumental analysis, and data processing techniques. Furthermore, it gives an overview of the current state of non-targeted screening strategies with discussion on future directions and perspectives of this technique. Graphical Abstract Missing the bullseye - a graphical respresentation of non-targeted screening. Image courtesy of Christian Alonzo.

Development of a Low Power Gas Chromatograph-Mass Spectrometer for In-Situ Detection of Organics in Martian Soil

NASA Technical Reports Server (NTRS)

Pinnick, Veronica; Buch, Arnaud; VanAmerom, Friso H. W.; Danell, Ryan M.; Brinckerhoff, William; Mahaffy, Paul; Cotter, Robert J.

2011-01-01

The Mars Organic Molecule Analyzer (MOMA) is a joint venture by NASA and the European Space Agency (ESA) to develop a sensitive, light-weight, low-power mass spectrometer for chemical analysis on Mars. MOMA is a key analytical instrument aboard the 2018 ExoMars rover mission seeking signs of past or present life. The current prototype was built to demonstrate operation of gas chromatography (OC) and laser desorption (LD) mass spectrometry under martian ambient conditions (5-7 Torr of CO2-rich atmosphere). Recent reports have discussed the MO MA concept, design and performance. Here, we update the current prototype performance, focusing specifically on the GCMS mode.

Supersonic molecular beam-hyperthermal surface ionisation coupled with time-of-flight mass spectrometry applied to trace level detection of polynuclear aromatic hydrocarbons in drinking water for reduced sample preparation and analysis time.

PubMed

Davis, S C; Makarov, A A; Hughes, J D

1999-01-01

Analysis of sub-ppb levels of polynuclear aromatic hydrocarbons (PAHs) in drinking water by high performance liquid chromatography (HPLC) fluorescence detection typically requires large water samples and lengthy extraction procedures. The detection itself, although selective, does not give compound identity confirmation. Benchtop gas chromatography/mass spectrometry (GC/MS) systems operating in the more sensitive selected ion monitoring (SIM) acquisition mode discard spectral information and, when operating in scanning mode, are less sensitive and scan too slowly. The selectivity of hyperthermal surface ionisation (HSI), the high column flow rate capacity of the supersonic molecular beam (SMB) GC/MS interface, and the high acquisition rate of time-of-flight (TOF) mass analysis, are combined here to facilitate a rapid, specific and sensitive technique for the analysis of trace levels of PAHs in water. This work reports the advantages gained by using the GC/HSI-TOF system over the HPLC fluorescence method, and discusses in some detail the nature of the instrumentation used.

Liquid Chromatography Mass Spectrometry-Based Proteomics: Biological and Technological Aspects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karpievitch, Yuliya V.; Polpitiya, Ashoka D.; Anderson, Gordon A.

2010-12-01

Mass spectrometry-based proteomics has become the tool of choice for identifying and quantifying the proteome of an organism. Though recent years have seen a tremendous improvement in instrument performance and the computational tools used, significant challenges remain, and there are many opportunities for statisticians to make important contributions. In the most widely used "bottom-up" approach to proteomics, complex mixtures of proteins are first subjected to enzymatic cleavage, the resulting peptide products are separated based on chemical or physical properties and analyzed using a mass spectrometer. The two fundamental challenges in the analysis of bottom-up MS-based proteomics are: (1) Identifying themore » proteins that are present in a sample, and (2) Quantifying the abundance levels of the identified proteins. Both of these challenges require knowledge of the biological and technological context that gives rise to observed data, as well as the application of sound statistical principles for estimation and inference. We present an overview of bottom-up proteomics and outline the key statistical issues that arise in protein identification and quantification.« less

Quantification of proteins in urine samples using targeted mass spectrometry methods.

PubMed

Khristenko, Nina; Domon, Bruno

2015-01-01

Numerous clinical proteomics studies are focused on the development of biomarkers to improve either diagnostics for early disease detection or the monitoring of the response to the treatment. Although, a wealth of biomarker candidates are available, their evaluation and validation in a true clinical setup remains challenging. In biomarkers evaluation studies, a panel of proteins of interest are systematically analyzed in a large cohort of samples. However, in spite of the latest progresses in mass spectrometry, the consistent detection of pertinent proteins in high complex biological samples is still a challenging task. Thus, targeted LC-MS/MS methods are better suited for the systematic analysis of biomarkers rather than shotgun approaches. This chapter describes the workflow used to perform targeted quantitative analyses of proteins in urinary samples. The peptides, as surrogates of the protein of interest, are commonly measured using a triple quadrupole mass spectrometers operated in selected reaction monitoring (SRM) mode. More recently, the advances in targeted LC-MS/MS analysis based on parallel reaction monitoring (PRM) performed on a quadrupole-orbitrap instrument have allowed to increase the specificity and selectivity of the measurements.

Ultra-performance liquid chromatography-tandem mass spectrometry for the determination of atypical antipsychotics and some metabolites in in vitro samples.

PubMed

Li, Kun-Yan; Zhou, Yan-Gang; Ren, Hua-Yi; Wang, Feng; Zhang, Bi-Kui; Li, Huan-De

2007-05-01

The ultra-performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-ESI-MS/MS) method has been developed to perform the determination of quetiapine, perospirone, aripiprazole and quetiapine sulfoxide in in vitro samples in less than 3 min. The UPLC separation was carried out using an Acquity UPLC BEH C18 column (100 mm x 2.1mm i.d., 1.7 microm particle size) that provided high efficiency and resolution in combination with high linear velocities. The UPLC system was coupled to a Waters Micromass Quattro Premier XE tandem quadrupole mass spectrometer. This system permits high-speed data acquisition without peak intensity degradation, and produces sharp and narrow chromatographic peaks (w(h) about 2.5s) of compounds. The determination was performed in multiple reaction monitoring (MRM) mode. The quantification parameters of the developed method were established, obtaining instrumental LODs lower than 0.005 microg/l and a repeatability at a low concentration level lower than 10% CV (n=10). Finally, the method was successfully applied to the analysis of atypical antipsychotics and some metabolites in in vitro samples.

Laser-desorption tandem time-of-flight mass spectrometry with continuous liquid introduction

NASA Astrophysics Data System (ADS)

Williams, Evan R.; Jones, Glenn C., Jr.; Fang, LiLing; Nagata, Takeshi; Zare, Richard N.

1992-05-01

A new method to combine aqueous sample introduction with matrix assisted laser desorption mass spectrometry (MS) for interfacing liquid-chromatographic techniques, such as capillary electrophoresis, to MS is described. Aqueous sample solution is introduced directly into the ion source of a time-of-. flight (TOF) mass spectrometer through a fused silica capillary; evaporative cooling results in ice formation at the end of the capillary. The ice can be made to extrude continuously by using localized resistive heating. With direct laser desorption, molecular ions from proteins as large as bovine insulin (5734 Da) can be produced. Two-step desorption/photoionization with a variety of wavelengths is demonstrated, and has the advantages of improved resolution and shot-to-shot reproducibility. Ion structural information is obtained using surface-induced dissociation with an in-line collision device in the reflectron mirror of the TOF instrument. Product ion resolution of ~70 is obtained at m/z77. Extensive fragmentation can be produced with dissociation efficiencies between 7-15% obtained for molecular ions of small organic molecules. Efficiencies approaching 30% are obtained for larger peptide ions.

Probabilistic consensus scoring improves tandem mass spectrometry peptide identification.

PubMed

Nahnsen, Sven; Bertsch, Andreas; Rahnenführer, Jörg; Nordheim, Alfred; Kohlbacher, Oliver

2011-08-05

Database search is a standard technique for identifying peptides from their tandem mass spectra. To increase the number of correctly identified peptides, we suggest a probabilistic framework that allows the combination of scores from different search engines into a joint consensus score. Central to the approach is a novel method to estimate scores for peptides not found by an individual search engine. This approach allows the estimation of p-values for each candidate peptide and their combination across all search engines. The consensus approach works better than any single search engine across all different instrument types considered in this study. Improvements vary strongly from platform to platform and from search engine to search engine. Compared to the industry standard MASCOT, our approach can identify up to 60% more peptides. The software for consensus predictions is implemented in C++ as part of OpenMS, a software framework for mass spectrometry. The source code is available in the current development version of OpenMS and can easily be used as a command line application or via a graphical pipeline designer TOPPAS.

Application of phase correction to improve the interpretation of crude oil spectra obtained using 7 T Fourier transform ion cyclotron resonance mass spectrometry.

PubMed

Cho, Yunju; Qi, Yulin; O'Connor, Peter B; Barrow, Mark P; Kim, Sunghwan

2014-01-01

In this study, a phase-correction technique was applied to the study of crude oil spectra obtained using a 7 T Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). 7 T FT-ICR MS had not been widely used for oil analysis due to the lower resolving power compared with high field FT-ICR MS. For low field instruments, usage of data that has not been phase-corrected results in an inability to resolve critical mass splits of C3 and SH4 (3.4 mDa), and (13)C and CH (4.5 mDa). This results in incorrect assignments of molecular formulae, and discontinuous double bond equivalents (DBE) and carbon number distributions of S1, S2, and hydrocarbon classes are obtained. Application of phase correction to the same data, however, improves the reliability of assignments and produces continuous DBE and carbon number distributions. Therefore, this study clearly demonstrates that phase correction improves data analysis and the reliability of assignments of molecular formulae in crude oil anlayses.

MASH Suite: a user-friendly and versatile software interface for high-resolution mass spectrometry data interpretation and visualization.

PubMed

Guner, Huseyin; Close, Patrick L; Cai, Wenxuan; Zhang, Han; Peng, Ying; Gregorich, Zachery R; Ge, Ying

2014-03-01

The rapid advancements in mass spectrometry (MS) instrumentation, particularly in Fourier transform (FT) MS, have made the acquisition of high-resolution and high-accuracy mass measurements routine. However, the software tools for the interpretation of high-resolution MS data are underdeveloped. Although several algorithms for the automatic processing of high-resolution MS data are available, there is still an urgent need for a user-friendly interface with functions that allow users to visualize and validate the computational output. Therefore, we have developed MASH Suite, a user-friendly and versatile software interface for processing high-resolution MS data. MASH Suite contains a wide range of features that allow users to easily navigate through data analysis, visualize complex high-resolution MS data, and manually validate automatically processed results. Furthermore, it provides easy, fast, and reliable interpretation of top-down, middle-down, and bottom-up MS data. MASH Suite is convenient, easily operated, and freely available. It can greatly facilitate the comprehensive interpretation and validation of high-resolution MS data with high accuracy and reliability.

Polyphenolic profile of butterhead lettuce cultivar by ultrahigh performance liquid chromatography coupled online to UV-visible spectrophotometry and quadrupole time-of-flight mass spectrometry.

PubMed

Viacava, Gabriela E; Roura, Sara I; López-Márquez, Diana M; Berrueta, Luis A; Gallo, Blanca; Alonso-Salces, Rosa M

2018-09-15

In the present study, the butterhead lettuce cultivar was analyzed by ultrahigh performance liquid chromatography (UHPLC) coupled online to diode array detection (DAD), electrospray ionization (ESI) and quadrupole time-of-flight mass spectrometry (QToF/MS) in the positive and negative ion mode in order to characterize its polyphenolic profile for the first time. The instrument acquisition mode MS E was used to collect automatic and simultaneous information of exact mass at high and low collision energies of precursor ions as well as other ions produced as a result of their fragmentation. One hundred eleven phenolic compounds were identified in the acidified hydromethanolic extract of freeze-dried leaves of butterhead lettuce cultivar: 40 hydroxycinnamic acid derivatives, 21 hydroxybenzoic acid derivatives, 2 hydroxyphenylacetic acid derivatives, 18 flavonols, 9 flavones, one flavanone, 7 coumarins, one hydrolysable tannin and 12 lignans. Forty-seven of these compounds have been tentatively identified for the first time in lettuce. Copyright © 2018 Elsevier Ltd. All rights reserved.

The use of mass spectrometry to analyze dried blood spots.

PubMed

Wagner, Michel; Tonoli, David; Varesio, Emmanuel; Hopfgartner, Gérard

2016-01-01

Dried blood spots (DBS) typically consist in the deposition of small volumes of capillary blood onto dedicated paper cards. Comparatively to whole blood or plasma samples, their benefits rely in the fact that sample collection is easier and that logistic aspects related to sample storage and shipment can be relatively limited, respectively, without the need of a refrigerator or dry ice. Originally, this approach has been developed in the sixties to support the analysis of phenylalanine for the detection of phenylketonuria in newborns using bacterial inhibition test. In the nineties tandem mass spectrometry was established as the detection technique for phenylalanine and tyrosine. DBS became rapidly recognized for their clinical value: they were widely implemented in pediatric settings with mass spectrometric detection, and were closely associated to the debut of newborn screening (NBS) programs, as a part of public health policies. Since then, sample collection on paper cards has been explored with various analytical techniques in other areas more or less successfully regarding large-scale applications. Moreover, in the last 5 years a regain of interest for DBS was observed and originated from the bioanalytical community to support drug development (e.g., PK studies) or therapeutic drug monitoring mainly. Those recent applications were essentially driven by improved sensitivity of triple quadrupole mass spectrometers. This review presents an overall view of all instrumental and methodological developments for DBS analysis with mass spectrometric detection, with and without separation techniques. A general introduction to DBS will describe their advantages and historical aspects of their emergence. A second section will focus on blood collection, with a strong emphasis on specific parameters that can impact quantitative analysis, including chromatographic effects, hematocrit effects, blood effects, and analyte stability. A third part of the review is dedicated to sample preparation and will consider off-line and on-line extractions; in particular, instrumental designs that have been developed so far for DBS extraction will be detailed. Flow injection analysis and applications will be discussed in section IV. The application of surface analysis mass spectrometry (DESI, paper spray, DART, APTDCI, MALDI, LDTD-APCI, and ICP) to DBS is described in section V, while applications based on separation techniques (e.g., liquid or gas chromatography) are presented in section VI. To conclude this review, the current status of DBS analysis is summarized, and future perspectives are provided. © 2014 Wiley Periodicals, Inc.

Fast and Efficient XML Data Access for Next-Generation Mass Spectrometry.

PubMed

Röst, Hannes L; Schmitt, Uwe; Aebersold, Ruedi; Malmström, Lars

2015-01-01

In mass spectrometry-based proteomics, XML formats such as mzML and mzXML provide an open and standardized way to store and exchange the raw data (spectra and chromatograms) of mass spectrometric experiments. These file formats are being used by a multitude of open-source and cross-platform tools which allow the proteomics community to access algorithms in a vendor-independent fashion and perform transparent and reproducible data analysis. Recent improvements in mass spectrometry instrumentation have increased the data size produced in a single LC-MS/MS measurement and put substantial strain on open-source tools, particularly those that are not equipped to deal with XML data files that reach dozens of gigabytes in size. Here we present a fast and versatile parsing library for mass spectrometric XML formats available in C++ and Python, based on the mature OpenMS software framework. Our library implements an API for obtaining spectra and chromatograms under memory constraints using random access or sequential access functions, allowing users to process datasets that are much larger than system memory. For fast access to the raw data structures, small XML files can also be completely loaded into memory. In addition, we have improved the parsing speed of the core mzML module by over 4-fold (compared to OpenMS 1.11), making our library suitable for a wide variety of algorithms that need fast access to dozens of gigabytes of raw mass spectrometric data. Our C++ and Python implementations are available for the Linux, Mac, and Windows operating systems. All proposed modifications to the OpenMS code have been merged into the OpenMS mainline codebase and are available to the community at https://github.com/OpenMS/OpenMS.

Fast and Efficient XML Data Access for Next-Generation Mass Spectrometry

PubMed Central

Röst, Hannes L.; Schmitt, Uwe; Aebersold, Ruedi; Malmström, Lars

2015-01-01

Motivation In mass spectrometry-based proteomics, XML formats such as mzML and mzXML provide an open and standardized way to store and exchange the raw data (spectra and chromatograms) of mass spectrometric experiments. These file formats are being used by a multitude of open-source and cross-platform tools which allow the proteomics community to access algorithms in a vendor-independent fashion and perform transparent and reproducible data analysis. Recent improvements in mass spectrometry instrumentation have increased the data size produced in a single LC-MS/MS measurement and put substantial strain on open-source tools, particularly those that are not equipped to deal with XML data files that reach dozens of gigabytes in size. Results Here we present a fast and versatile parsing library for mass spectrometric XML formats available in C++ and Python, based on the mature OpenMS software framework. Our library implements an API for obtaining spectra and chromatograms under memory constraints using random access or sequential access functions, allowing users to process datasets that are much larger than system memory. For fast access to the raw data structures, small XML files can also be completely loaded into memory. In addition, we have improved the parsing speed of the core mzML module by over 4-fold (compared to OpenMS 1.11), making our library suitable for a wide variety of algorithms that need fast access to dozens of gigabytes of raw mass spectrometric data. Availability Our C++ and Python implementations are available for the Linux, Mac, and Windows operating systems. All proposed modifications to the OpenMS code have been merged into the OpenMS mainline codebase and are available to the community at https://github.com/OpenMS/OpenMS. PMID:25927999

Evaluation of Aerosol Mixing State Classes in the GISS Modele-matrix Climate Model Using Single-particle Mass Spectrometry Measurements

NASA Technical Reports Server (NTRS)

Bauer, Susanne E.; Ault, Andrew; Prather, Kimberly A.

2013-01-01

Aerosol particles in the atmosphere are composed of multiple chemical species. The aerosol mixing state, which describes how chemical species are mixed at the single-particle level, provides critical information on microphysical characteristics that determine the interaction of aerosols with the climate system. The evaluation of mixing state has become the next challenge. This study uses aerosol time-of-flight mass spectrometry (ATOFMS) data and compares the results to those of the Goddard Institute for Space Studies modelE-MATRIX (Multiconfiguration Aerosol TRacker of mIXing state) model, a global climate model that includes a detailed aerosol microphysical scheme. We use data from field campaigns that examine a variety of air mass regimens (urban, rural, and maritime). At all locations, polluted areas in California (Riverside, La Jolla, and Long Beach), a remote location in the Sierra Nevada Mountains (Sugar Pine) and observations from Jeju (South Korea), the majority of aerosol species are internally mixed. Coarse aerosol particles, those above 1 micron, are typically aged, such as coated dust or reacted sea-salt particles. Particles below 1 micron contain large fractions of organic material, internally-mixed with sulfate and black carbon, and few external mixtures. We conclude that observations taken over multiple weeks characterize typical air mass types at a given location well; however, due to the instrumentation, we could not evaluate mass budgets. These results represent the first detailed comparison of single-particle mixing states in a global climate model with real-time single-particle mass spectrometry data, an important step in improving the representation of mixing state in global climate models.

Mass spectrometric screening and identification of acidic metabolites in fulvic acid fractions of contaminated groundwater.

PubMed

Jobelius, Carsten; Frimmel, Fritz H; Zwiener, Christian

2014-05-01

The anaerobic microbial degradation of aromatic and heterocyclic compounds is a prevalent process in contaminated groundwater systems. The introduction of functional groups into the contaminant molecules often results in aromatic and heterocyclic and succinic acids. These metabolites can be used as indicators for prevailing degradation processes. Therefore, there is a strong interest in developing analytical methods for screening and identification of these metabolites. In this study, neutral loss scans (NLS) by liquid chromatography-electrospray ionization/tandem mass spectrometry with losses of CO2 (NL ∆m/z = 44) and C2H4(CO2)2 (NL ∆m/z = 116) were applied for the first time successfully to screen selectively for acidic and succinic metabolites of aromatic and heterocyclic contaminants in two fulvic acid fractions from a contaminated site and a downstream region of a tar oil-polluted groundwater. Identification of these preselected signals was performed by high-resolution mass spectrometry with a liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry instrument. High-resolution mass and mass fragmentation data were then compared with a list of known metabolites from a literature search or matched with chemical databases supported with in silico fragmentation. Based on authentic analytical standards, several compounds from NLS were identified (e.g., 4-hydroxy-3-methylbenzoic acid, benzylsuccinic acid, naphthyl-2-methylsuccinic acid, 2-carboxyindane, and 2-carboxybenzothiophene) and tentatively identified (e.g., benzofuranmethylsuccinic acid and dihydrocarboxybenzothiophene) as aromatic, phenolic, heterocyclic, and succinic acids. The acidic metabolites were found exclusively in the contaminated region of the aquifer which indicates active biodegradation processes and no relevant occurrence of acidic metabolites in the downstream region.

Implementation of a Gaussian Beam Laser and Aspheric Optics for High Spatial Resolution MALDI Imaging MS

NASA Astrophysics Data System (ADS)

Zavalin, Andre; Yang, Junhai; Haase, Andreas; Holle, Armin; Caprioli, Richard

2014-06-01

We have investigated the use of a Gaussian beam laser for MALDI Imaging Mass Spectrometry to provide a precisely defined laser spot of 5 μm diameter on target using a commercial MALDI TOF instrument originally designed to produce a 20 μm diameter laser beam spot at its smallest setting. A Gaussian beam laser was installed in the instrument in combination with an aspheric focusing lens. This ion source produced sharp ion images at 5 μm spatial resolution with signals of high intensity as shown for images from thin tissue sections of mouse brain.

Implementation of a Gaussian beam laser and aspheric optics for high spatial resolution MALDI imaging MS.

PubMed

Zavalin, Andre; Yang, Junhai; Haase, Andreas; Holle, Armin; Caprioli, Richard

2014-06-01

We have investigated the use of a Gaussian beam laser for MALDI Imaging Mass Spectrometry to provide a precisely defined laser spot of 5 μm diameter on target using a commercial MALDI TOF instrument originally designed to produce a 20 μm diameter laser beam spot at its smallest setting. A Gaussian beam laser was installed in the instrument in combination with an aspheric focusing lens. This ion source produced sharp ion images at 5 μm spatial resolution with signals of high intensity as shown for images from thin tissue sections of mouse brain.

Developments in the Identification of Glycan Biomarkers for the Detection of Cancer

PubMed Central

Ruhaak, L. Renee; Miyamoto, Suzanne; Lebrilla, Carlito B.

2013-01-01

Changes in glycosylation readily occur in cancer and other disease states. Thanks to recent advances in the development of analytical techniques and instrumentation, especially in mass spectrometry, it is now possible to identify blood-derived glycan-based biomarkers using glycomics strategies. This review is an overview of the developments made in the search for glycan-based cancer biomarkers and the technologies currently in use. It is anticipated that the progressing instrumental and bioinformatics developments will allow the identification of relevant glycan biomarkers for the diagnosis, early detection, and monitoring of cancer treatment with sufficient sensitivity and specificity for clinical use. PMID:23365456

QC-ART: A tool for real-time quality control assessment of mass spectrometry-based proteomics data.

PubMed

Stanfill, Bryan A; Nakayasu, Ernesto S; Bramer, Lisa M; Thompson, Allison M; Ansong, Charles K; Clauss, Therese; Gritsenko, Marina A; Monroe, Matthew E; Moore, Ronald J; Orton, Daniel J; Piehowski, Paul D; Schepmoes, Athena A; Smith, Richard D; Webb-Robertson, Bobbie-Jo; Metz, Thomas O

2018-04-17

Liquid chromatography-mass spectrometry (LC-MS)-based proteomics studies of large sample cohorts can easily require from months to years to complete. Acquiring consistent, high-quality data in such large-scale studies is challenging because of normal variations in instrumentation performance over time, as well as artifacts introduced by the samples themselves, such as those due to collection, storage and processing. Existing quality control methods for proteomics data primarily focus on post-hoc analysis to remove low-quality data that would degrade downstream statistics; they are not designed to evaluate the data in near real-time, which would allow for interventions as soon as deviations in data quality are detected.  In addition to flagging analyses that demonstrate outlier behavior, evaluating how the data structure changes over time can aide in understanding typical instrument performance or identify issues such as a degradation in data quality due to the need for instrument cleaning and/or re-calibration.  To address this gap for proteomics, we developed Quality Control Analysis in Real-Time (QC-ART), a tool for evaluating data as they are acquired in order to dynamically flag potential issues with instrument performance or sample quality.  QC-ART has similar accuracy as standard post-hoc analysis methods with the additional benefit of real-time analysis.  We demonstrate the utility and performance of QC-ART in identifying deviations in data quality due to both instrument and sample issues in near real-time for LC-MS-based plasma proteomics analyses of a sample subset of The Environmental Determinants of Diabetes in the Young cohort. We also present a case where QC-ART facilitated the identification of oxidative modifications, which are often underappreciated in proteomic experiments. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

MASS SPECTROMETRY IN ENVIRONMENTAL SCIENCES

EPA Science Inventory

This review covers applications of mass spectrometry to the environmental sciences. From the early applications of mass spectrometry to environmental research in the 1960s and 1970s, mass spectrometry has played an important role in aiding our understanding of environmental poll...

Aquatic plant-derived changes in oil sands naphthenic acid signatures determined by low-, high- and ultrahigh-resolution mass spectrometry.

PubMed

Headley, John V; Peru, Kerry M; Armstrong, Sarah A; Han, Xiumei; Martin, Jonathan W; Mapolelo, Mmilili M; Smith, Donald F; Rogers, Ryan P; Marshall, Alan G

2009-02-01

Mass spectrometry is a common tool for studying the fate of complex organic compound mixtures in oil sands processed water (OSPW), but a comparison of low-, high- ( approximately 10 000), and ultrahigh-resolution ( approximately 400 000) instrumentation for this purpose has not previously been made. High-resolution quadrupole time-of-flight mass spectrometry (QTOF MS) and ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), with negative-ion electrospray ionization, provided evidence for the selective dissipation of components in OSPW. Dissipation of oil sands naphthenic acids (NAs with general formula C(n)H(2n+z)O(2) where n is the number of carbon atoms, and Z is zero or a negative even number describing the number of rings) was masked (by components such as fatty acids, O(3), O(5), O(6), O(7), SO(2), SO(3), SO(4), SO(5), SO(6), and NO(4) species) at low resolution (1000) when using a triple quadrupole mass spectrometer. Changes observed in the relative composition of components in OSPW appear to be due primarily to the presence of plants, specifically cattails (Typha latifolia) and their associated microorganisms. The observed dissipation included a range of heteratomic species containing O(2), O(3), O(4), and O(5), present in Athabasca oil sands acid extracts. For the heteratomic O(2) species, namely naphthenic acids, an interesting structural relationship suggests that low and high carbon number NAs are dissipated by the plants preferentially, with a minimum around C(14)/C(15). Other heteratomic species containing O(6), O(7), SO(2), SO(3), SO(4), SO(5), SO(6), and NO(4) appear to be relatively recalcitrant to the cattails and were not dissipated to the same extent in planted systems. Copyright 2009 John Wiley & Sons, Ltd.

Charge detection mass spectrometry: Instrumentation & applications to viruses

NASA Astrophysics Data System (ADS)

Pierson, Elizabeth E.

For over three decades, electrospray ionization (ESI) has been used to ionize non-covalent complexes and subsequently transfer the intact ion into the gas phase for mass spectrometry (MS) analysis. ESI generates a distribution of multiple charged ions, resulting in an m/z spectrum comprised of a series of peaks, known as a charge state envelope. To obtain mass information, the number of charges for each peak must be deduced. For smaller biological analytes like peptides, the charge states are sufficiently resolved and this process is straightforward. For macromolecular complexes exceeding ~100 kDa, this process is complicated by the broadening and shifting of charge states due to incomplete desolvation, salt adduction, and inherent mass heterogeneity. As the analyte mass approaches the MDa regime, the m/z spectrum is often comprised of a broad distribution of unresolved charge states. In such cases, mass determination is precluded. Charge detection mass spectrometry (CDMS) is an emerging MS technique for determining the masses of heterogeneous, macromolecular complexes. In CDMS, the m/z and z of single ions are measured concurrently so that mass is easily calculated. With this approach, deconvolution of an m/z spectrum is unnecessary. This measurement is carried out by passing macroions through a conductive cylinder. The induced image charge on the cylindrical detector provides information about m/z and z: the m/z is related to its time-of-flight through the detector, and the z is related to the intensity of the image charge. We have applied CDMS to study the self-assembly of virus capsids. Late-stage intermediates in the assembly of hepatitis B virus, a devastating human pathogen, have been identified. This is the first time that such intermediates have been detected and represent a significant advancement towards understanding virus capsid assembly. CDMS has also been used to identify oversized, non-icosahedral polymorphs in the assembly of woodchuck hepatitis virus capsids. Finally, CDMS has been used to characterize the purity of adeno-associated viral vectors for potential gene therapy applications.

Hands-on Electrospray Ionization-Mass Spectrometry for Upper-Level Undergraduate and Graduate Students

ERIC Educational Resources Information Center

Stock, Naomi L.; March, Raymond E.

2014-01-01

Electrospray ionization-mass spectrometry (ESI-MS) is a powerful technique for the detection, identification, and quantification of organic compounds. As mass spectrometers have become more user-friendly and affordable, many students--often with little experience in mass spectrometry--find themselves needing to incorporate mass spectrometry into…

Derivation of the Statistical Distribution of the Mass Peak Centroids of Mass Spectrometers Employing Analog-to-Digital Converters and Electron Multipliers

DOE PAGES

Ipsen, Andreas

2017-02-03

Here, the mass peak centroid is a quantity that is at the core of mass spectrometry (MS). However, despite its central status in the field, models of its statistical distribution are often chosen quite arbitrarily and without attempts at establishing a proper theoretical justification for their use. Recent work has demonstrated that for mass spectrometers employing analog-to-digital converters (ADCs) and electron multipliers, the statistical distribution of the mass peak intensity can be described via a relatively simple model derived essentially from first principles. Building on this result, the following article derives the corresponding statistical distribution for the mass peak centroidsmore » of such instruments. It is found that for increasing signal strength, the centroid distribution converges to a Gaussian distribution whose mean and variance are determined by physically meaningful parameters and which in turn determine bias and variability of the m/z measurements of the instrument. Through the introduction of the concept of “pulse-peak correlation”, the model also elucidates the complicated relationship between the shape of the voltage pulses produced by the preamplifier and the mean and variance of the centroid distribution. The predictions of the model are validated with empirical data and with Monte Carlo simulations.« less

Derivation of the Statistical Distribution of the Mass Peak Centroids of Mass Spectrometers Employing Analog-to-Digital Converters and Electron Multipliers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ipsen, Andreas

Here, the mass peak centroid is a quantity that is at the core of mass spectrometry (MS). However, despite its central status in the field, models of its statistical distribution are often chosen quite arbitrarily and without attempts at establishing a proper theoretical justification for their use. Recent work has demonstrated that for mass spectrometers employing analog-to-digital converters (ADCs) and electron multipliers, the statistical distribution of the mass peak intensity can be described via a relatively simple model derived essentially from first principles. Building on this result, the following article derives the corresponding statistical distribution for the mass peak centroidsmore » of such instruments. It is found that for increasing signal strength, the centroid distribution converges to a Gaussian distribution whose mean and variance are determined by physically meaningful parameters and which in turn determine bias and variability of the m/z measurements of the instrument. Through the introduction of the concept of “pulse-peak correlation”, the model also elucidates the complicated relationship between the shape of the voltage pulses produced by the preamplifier and the mean and variance of the centroid distribution. The predictions of the model are validated with empirical data and with Monte Carlo simulations.« less

In situ characterization of martian materials and detection of organic compounds with the MOMA investigation onboard the ExoMars rover

NASA Astrophysics Data System (ADS)

Arevalo, R. D., Jr.; Grubisic, A.; van Amerom, F. H. W.; Danell, R.; Li, X.; Kaplan, D.; Pinnick, V. T.; Brinckerhoff, W. B.; Getty, S.; Goesmann, F.

2017-12-01

Ground-based observations (e.g., via the NASA Infrared Telescope Facility) and in situ investigations, including flybys (e.g., Mariner Program), orbiters (most recently MAVEN and ExoMars TGO), stationary landers (i.e., Viking, Pathfinder and Phoenix), and mobile rovers (i.e., Sojourner, Spirit/Opportunity and Curiosity), have enabled the progressive exploration of the Martian surface. Evidence for liquid water, manifest as hydrated and amorphous materials representative of alteration products of primary minerals/lithologies, and geomorphological features such as recurring slope lineae (RSL), valley networks and open-basin lakes, indicates that Mars may have hosted habitable environments, at least on local scales (temporally and spatially). However, the preservation potential of molecular biosignatures in the upper meter(s) of the surface is limited by destructive cosmic radiation and oxidative chemical reactions. Moreover, the determination of indigenous versus exogenous origins, and biotic versus abiotic formation mechanisms of detected organic material, provide additional challenges for future missions to the red planet. The Mars Organic Molecule Analyzer (MOMA) onboard the ExoMars rover, set to launch in 2020, provides an unprecedented opportunity to discover unambiguous indicators of life. The MOMA instrument will investigate the compositions of materials collected during multiple vertical surveys, extending as deep as two meters below the surface, via: i) gas chromatography mass spectrometry, a method geared towards the detection of volatile organics and the determination of molecular chirality, mapping to previous in situ Mars investigations; and, ii) laser desorption mass spectrometry, a technique commonly employed in research laboratories to detect larger, more refractory organic materials, but a first for spaceflight applications. Selective ion excitation and tandem mass spectrometry (MS/MS) techniques support the isolation and disambiguation of complex molecular signatures. Progressive testing of the MOMA Flight Model and Engineering Test Unit, as shown here, demonstrates the capabilities of the instrument to identify mineralogical indices and measure ppb-levels of organic compounds embedded in natural and synthetic Mars analog samples.

Simultaneous Proteomic Discovery and Targeted Monitoring using Liquid Chromatography, Ion Mobility Spectrometry, and Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burnum-Johnson, Kristin E.; Nie, Song; Casey, Cameron P.

Current proteomics approaches are comprised of both broad discovery measurements as well as more quantitative targeted measurements. These two different measurement types are used to initially identify potentially important proteins (e.g., candidate biomarkers) and then enable improved quantification for a limited number of selected proteins. However, both approaches suffer from limitations, particularly the lower sensitivity, accuracy, and quantitation precision for discovery approaches compared to targeted approaches, and the limited proteome coverage provided by targeted approaches. Herein, we describe a new proteomics approach that allows both discovery and targeted monitoring (DTM) in a single analysis using liquid chromatography, ion mobility spectrometrymore » and mass spectrometry (LC-IMS-MS). In DTM, heavy labeled peptides for target ions are spiked into tryptic digests and both the labeled and unlabeled peptides are broadly detected using LC-IMS-MS instrumentation, allowing the benefits of discovery and targeted approaches. To understand the possible improvement of the DTM approach, it was compared to LC-MS broad measurements using an accurate mass and time tag database and selected reaction monitoring (SRM) targeted measurements. The DTM results yielded greater peptide/protein coverage and a significant improvement in the detection of lower abundance species compared to LC-MS discovery measurements. DTM was also observed to have similar detection limits as SRM for the targeted measurements indicating its potential for combining the discovery and targeted approaches.« less

Ultra pressure liquid chromatography-negative electrospray ionization mass spectrometry determination of twelve halobenzoquinones at ng/L levels in drinking water.

PubMed

Huang, Rongfu; Wang, Wei; Qian, Yichao; Boyd, Jessica M; Zhao, Yuli; Li, Xing-Fang

2013-05-07

We report here the characterization of twelve halobenzoquinones (HBQs) using electrospray ionization (ESI) high resolution quadrupole time-of-flight mass spectrometry. The high resolution negative ESI spectra of the twelve HBQs formed two parent ions, [M + H(+) + 2e(-)], and the radical M(-•). The intensities of these two parent ions are dependent on their chemical structures and on instrumental parameters such as the source temperature and flow rate. The characteristic ions of the HBQs were used to develop an ultra pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method. At the UPLC flow rate (400 μL/min) and under the optimized ESI conditions, eleven HBQs showed the stable and abundant transitions [M + H(+) + 2e(-)] → X(-) (X(-) representing Cl(-), Br(-), or I(-)), while dibromo-dimethyl-benzoquinone (DBDMBQ) showed only the transition of M(-•) → Br(-). The UPLC efficiently separates all HBQs including some HBQ isomers, while the MS/MS offers exquisite limits of detection (LODs) at subng/mL levels for all HBQs except DBDMBQ. Combined with solid phase extraction (SPE), the method LOD is down to ng/L. The results from analysis of authentic samples demonstrated that the SPE-UPLC-MS/MS method is reliable, fast, and sensitive for the identification and quantification of the twelve HBQs in drinking water.

Characterization of Chlamydomonas reinhardtii Core Histones by Top-Down Mass Spectrometry Reveals Unique Algae-Specific Variants and Post-Translational Modifications.

PubMed

Khan, Aliyya; Eikani, Carlo K; Khan, Hana; Iavarone, Anthony T; Pesavento, James J

2018-01-05

The unicellular microalga Chlamydomonas reinhardtii has played an instrumental role in the development of many new fields (bioproducts, biofuels, etc.) as well as the advancement of basic science (photosynthetic apparati, flagellar function, etc.). Chlamydomonas' versatility ultimately derives from the genes encoded in its genome and the way that the expression of these genes is regulated, which is largely influenced by a family of DNA binding proteins called histones. We characterize C. reinhardtii core histones, both variants and their post-translational modifications, by chromatographic separation, followed by top-down mass spectrometry (TDMS). Because TDMS has not been previously used to study Chlamydomonas proteins, we show rampant artifactual protein oxidation using established nuclei purification and histone extraction methods. After addressing oxidation, both histones H3 and H4 are found to each have a single polypeptide sequence that is minimally acetylated and methylated. Surprisingly, we uncover a novel monomethylation at lysine 79 on histone H4 present on all observed molecules. Histone H2B and H2A are found to have two and three variants, respectively, and both are minimally modified. This study provides an updated assessment of the core histone proteins in the green alga C. reinhardtii by top-down mass spectrometry and lays the foundation for further investigation of these essential proteins.

Compact Two-step Laser Time-of-Flight Mass Spectrometer for in Situ Analyses of Aromatic Organics on Planetary Missions

NASA Technical Reports Server (NTRS)

Getty, Stephanie; Brickerhoff, William; Cornish, Timothy; Ecelberger, Scott; Floyd, Melissa

2012-01-01

RATIONALE A miniature time-of-flight mass spectrometer has been adapted to demonstrate two-step laser desorption-ionization (LOI) in a compact instrument package for enhanced organics detection. Two-step LDI decouples the desorption and ionization processes, relative to traditional laser ionization-desorption, in order to produce low-fragmentation conditions for complex organic analytes. Tuning UV ionization laser energy allowed control ofthe degree of fragmentation, which may enable better identification of constituent species. METHODS A reflectron time-of-flight mass spectrometer prototype measuring 20 cm in length was adapted to a two-laser configuration, with IR (1064 nm) desorption followed by UV (266 nm) postionization. A relatively low ion extraction voltage of 5 kV was applied at the sample inlet. Instrument capabilities and performance were demonstrated with analysis of a model polycyclic aromatic hydrocarbon, representing a class of compounds important to the fields of Earth and planetary science. RESULTS L2MS analysis of a model PAH standard, pyrene, has been demonstrated, including parent mass identification and the onset o(tunable fragmentation as a function of ionizing laser energy. Mass resolution m/llm = 380 at full width at half-maximum was achieved which is notable for gas-phase ionization of desorbed neutrals in a highly-compact mass analyzer. CONCLUSIONS Achieving two-step laser mass spectrometry (L2MS) in a highly-miniature instrument enables a powerful approach to the detection and characterization of aromatic organics in remote terrestrial and planetary applications. Tunable detection of parent and fragment ions with high mass resolution, diagnostic of molecular structure, is possible on such a compact L2MS instrument. Selectivity of L2MS against low-mass inorganic salt interferences is a key advantage when working with unprocessed, natural samples, and a mechanism for the observed selectivity is presented.

A New Method and Mass-Spectrometric Instrument for Extraterrestrial Microbial Life Detection Using the Elemental Composition Analyses of Martian Regolith and Permafrost/Ice.

PubMed

Managadze, G G; Safronova, A A; Luchnikov, K A; Vorobyova, E A; Duxbury, N S; Wurz, P; Managadze, N G; Chumikov, A E; Khamizov, R Kh

2017-05-01

We propose a new technique for the detection of microorganisms by elemental composition analyses of a sample extracted from regolith, permafrost, and ice of extraterrestrial bodies. We also describe the design of the ABIMAS instrument, which consists of the onboard time-of-flight laser mass-reflectron (TOF LMR) and the sample preparation unit (SPU) for biomass extraction. This instrument was initially approved to fly on board the ExoMars 2020 lander mission. The instrument can be used to analyze the elemental composition of possible extraterrestrial microbial communities and compare it to that of terrestrial microorganisms. We have conducted numerous laboratory studies to confirm the possibility of biomass identification via the following biomarkers: P/S and Ca/K ratios, and C and N abundances. We underline that only the combination of these factors will allow one to discriminate microbial samples from geological ones. Our technique has been tested experimentally in numerous laboratory trials on cultures of microorganisms and polar permafrost samples as terrestrial analogues for martian polar soils. We discuss various methods of extracting microorganisms and sample preparation. The developed technique can be used to search for and identify microorganisms in different martian samples and in the subsurface of other planets, satellites, comets, and asteroids-in particular, Europa, Ganymede, and Enceladus. Key Words: Mass spectrometry-Life-detection instruments-Biomarkers-Earth Mars-Biomass spectra. Astrobiology 17, 448-458.

Online differentiation of mineral phase in aerosol particles by ion formation mechanism using a LAAP-TOF single-particle mass spectrometer

NASA Astrophysics Data System (ADS)

Marsden, Nicholas A.; Flynn, Michael J.; Allan, James D.; Coe, Hugh

2018-01-01

Mineralogy of silicate mineral dust has a strong influence on climate and ecosystems due to variation in physiochemical properties that result from differences in composition and crystal structure (mineral phase). Traditional offline methods of analysing mineral phase are labour intensive and the temporal resolution of the data is much longer than many atmospheric processes. Single-particle mass spectrometry (SPMS) is an established technique for the online size-resolved measurement of particle composition by laser desorption ionisation (LDI) followed by time-of-flight mass spectrometry (TOF-MS). Although non-quantitative, the technique is able to identify the presence of silicate minerals in airborne dust particles from markers of alkali metals and silicate molecular ions in the mass spectra. However, the differentiation of mineral phase in silicate particles by traditional mass spectral peak area measurements is not possible. This is because instrument function and matrix effects in the ionisation process result in variations in instrument response that are greater than the differences in composition between common mineral phases.In this study, we introduce a novel technique that enables the differentiation of mineral phase in silicate mineral particles by ion formation mechanism measured from subtle changes in ion arrival times at the TOF-MS detector. Using a combination of peak area and peak centroid measurements, we show that the arrangement of the interstitial alkali metals in the crystal structure, an important property in silicate mineralogy, influences the ion arrival times of elemental and molecular ion species in the negative ion mass spectra. A classification scheme is presented that allowed for the differentiation of illite-smectite, kaolinite and feldspar minerals on a single-particle basis. Online analysis of mineral dust aerosol generated from clay mineral standards produced mineral fractions that are in agreement with bulk measurements reported by traditional XRD (X-ray diffraction) analysis.

Determination of ion mobility collision cross sections for unresolved isomeric mixtures using tandem mass spectrometry and chemometric deconvolution.

PubMed

Harper, Brett; Neumann, Elizabeth K; Stow, Sarah M; May, Jody C; McLean, John A; Solouki, Touradj

2016-10-05

Ion mobility (IM) is an important analytical technique for determining ion collision cross section (CCS) values in the gas-phase and gaining insight into molecular structures and conformations. However, limited instrument resolving powers for IM may restrict adequate characterization of conformationally similar ions, such as structural isomers, and reduce the accuracy of IM-based CCS calculations. Recently, we introduced an automated technique for extracting "pure" IM and collision-induced dissociation (CID) mass spectra of IM overlapping species using chemometric deconvolution of post-IM/CID mass spectrometry (MS) data [J. Am. Soc. Mass Spectrom., 2014, 25, 1810-1819]. Here we extend those capabilities to demonstrate how extracted IM profiles can be used to calculate accurate CCS values of peptide isomer ions which are not fully resolved by IM. We show that CCS values obtained from deconvoluted IM spectra match with CCS values measured from the individually analyzed corresponding peptides on uniform field IM instrumentation. We introduce an approach that utilizes experimentally determined IM arrival time (AT) "shift factors" to compensate for ion acceleration variations during post-IM/CID and significantly improve the accuracy of the calculated CCS values. Also, we discuss details of this IM deconvolution approach and compare empirical CCS values from traveling wave (TW)IM-MS and drift tube (DT)IM-MS with theoretically calculated CCS values using the projected superposition approximation (PSA). For example, experimentally measured deconvoluted TWIM-MS mean CCS values for doubly-protonated RYGGFM, RMFGYG, MFRYGG, and FRMYGG peptide isomers were 288.8 Å(2), 295.1 Å(2), 296.8 Å(2), and 300.1 Å(2); all four of these CCS values were within 1.5% of independently measured DTIM-MS values. Copyright © 2016 Elsevier B.V. All rights reserved.

Automated measurement and monitoring of bioprocesses: key elements of the M(3)C strategy.

PubMed

Sonnleitner, Bernhard

2013-01-01

The state-of-routine monitoring items established in the bioprocess industry as well as some important state-of-the-art methods are briefly described and the potential pitfalls discussed. Among those are physical and chemical variables such as temperature, pressure, weight, volume, mass and volumetric flow rates, pH, redox potential, gas partial pressures in the liquid and molar fractions in the gas phase, infrared spectral analysis of the liquid phase, and calorimetry over an entire reactor. Classical as well as new optical versions are addressed. Biomass and bio-activity monitoring (as opposed to "measurement") via turbidity, permittivity, in situ microscopy, and fluorescence are critically analyzed. Some new(er) instrumental analytical tools, interfaced to bioprocesses, are explained. Among those are chromatographic methods, mass spectrometry, flow and sequential injection analyses, field flow fractionation, capillary electrophoresis, and flow cytometry. This chapter surveys the principles of monitoring rather than compiling instruments.

Fast ion mass spectrometry and charged particle spectrography investigations of transverse ion acceleration and beam-plasma interactions

NASA Technical Reports Server (NTRS)

Gibson, W. C.; Tomlinson, W. M.; Marshall, J. A.

1987-01-01

Ion acceleration transverse to the magnetic field in the topside ionosphere was investigated. Transverse acceleration is believed to be responsible for the upward-moving conical ion distributions commonly observed along auroral field lines at altitudes from several hundred to several thousand kilometers. Of primary concern in this investigation is the extent of these conic events in space and time. Theoretical predictions indicate very rapid initial heating rates, depending on the ion species. These same theories predict that the events will occur within a narrow vertical region of only a few hundred kilometers. Thus an instrument with very high spatial and temporal resolution was required; further, since different heating rates were predicted for different ions, it was necessary to obtain composition as well as velocity space distributions. The fast ion mass spectrometer (FIMS) was designed to meet these criteria. This instrument and its operation is discussed.

Airborne measurements of sulfur dioxide, dimethyl sulfide, carbon disulfide, and carbonyl sulfide by isotope dilution gas chromatography/mass spectrometry

NASA Technical Reports Server (NTRS)

Bandy, Alan R.; Thornton, Donald C.; Driedger, Arthur R., III

1993-01-01

A gas chromatograph/mass spectrometer is described for determining atmospheric sulfur dioxide, carbon disulfide, dimethyl sulfide, and carbonyl sulfide from aircraft and ship platforms. Isotopically labelled variants of each analyte were used as internal standards to achieve high precision. The lower limit of detection for each species for an integration time of 3 min was 1 pptv for sulfur dioxide and dimethyl sulfide and 0.2 pptv for carbon disulfide and carbonyl sulfide. All four species were simultaneously determined with a sample frequency of one sample per 6 min or greater. When only one or two species were determined, a frequency of one sample per 4 min was achieved. Because a calibration is included in each sample, no separate calibration sequence was needed. Instrument warmup was only a few minutes. The instrument was very robust in field deployments, requiring little maintenance.

Update on Development of the Potassium-Argon Laser Experiment (KArLE) Instrument for In Situ Geochronology

NASA Technical Reports Server (NTRS)

Cohen, Barbara A.; Li, Z.-H.; Miller, J. S.; Brinckerhoff, W. B.; Clegg, S. M.; Mahaffy, P. R.; Swindle, T. D.; Wiens, R. C.

2013-01-01

Absolute dating of planetary samples is an essential tool to establish the chronology of geological events, including crystallization history, magmatic evolution, and alteration. We are addressing this challenge by developing the Potassium (K) -- Argon Laser Experiment (KArLE), building on previous work to develop a K-Ar in situ instrument. KArLE ablates a rock sample, determines the K in the plasma state using laser-induced breakdown spectroscopy (LIBS), measures the liberated Ar using quadrupole mass spectrometry (QMS), and relates the two by the volume of the ablated pit using laser confocal microscopy (LCM). Our goal is for the KArLE instrument to be capable of determining the age of several kinds of planetary samples to address a wide range of geochronolgy problems in planetary science.

The Orbitrap mass analyzer as a space instrument for the understanding of prebiotic chemistry in the Solar System

NASA Astrophysics Data System (ADS)

Vuitton, Véronique; Briois, Christelle; Makarov, Alexander

Over the past decade, it has become apparent that organic molecules are widespread in our Solar System and beyond. The better understand of the prebiotic chemistry leading to their formation is a primary objective of many ongoing space missions. Cassini-Huygens revealed the existence of very large molecular structures in Titan's atmosphere as well as on its surface, in the form of dune deposits, but their exact nature remains elusive. One key science goal of the Mars Science Laboratory Curiosity rover is to assess the presence of organics on the red planet. Rosetta will characterize the elemental and isotopic composition of the gas and dust ejected from comet Churyumov-Gerasimenko, while amino acids have been detected in meteorites. This search for complex organics relies heavily on mass spectrometry, which has the remarkable ability to analyze and quantify species from almost any type of sample (provided that the appropriate sampling and ionizing method is used). Because of the harsh constraints of the spatial environment, the mass resolution of the spectrometers onboard current space probes is quite limited compared to laboratory instruments, leading to significant limitations in the scientific return of the data collected. Therefore, future in situ solar system exploration missions would significantly benefit from instruments relying on High Resolution Mass Spectrometry (HRMS). Since 2009, 5 French laboratories (LPC2E, IPAG, LATMOS, LISA, CSNSM) involved in the chemical investigation of solar system bodies form a Consortium to develop HRMS for future space exploration, based on the use of the Orbitrap technology (C. Briois et al., 2014, to be submitted). The work is undertaken in close collaboration with the Thermo Fisher Scientific Company, which commercializes Orbitrap based laboratory instruments. The Orbitrap is an electrostatic mass analyzer, it is compact, lightweight, and can reach a good sensitivity and dynamic range. A prototype is under development at LPC2E and a mass resolution (m/Deltam FWHM) of 100,000 as been obtained at m/z = 150 for a background pressure of 10(-8) mbar, by laser desorption ionization from metals, minerals and organic species, either pure or in mixtures. Our R&T activities are currently focused on the core elements of the Orbitrap analyzer that are required to reach a sufficient maturity level for allowing design studies of future space instruments. We are indeed pursuing, within international collaborations, the definition of several instrument concepts based on the use of the Orbitrap on an orbiter, a hot air balloon or a lander. In this paper, we describe the principle of operation and the present performances of our prototype. We highlight the required steps to develop an Orbitrap-based space instrument that would meet the required performances to search for biomarkers on Mars, comets, asteroids and the satellites of the outer planets (Europa, Titan, Enceladus). Acknowledgment: This development is carried out in the framework of a Research and Technology (R&T) development program partly funded by the French Space Agency (CNES).

Reproducibility of Differential Proteomic Technologies in CPTAC Fractionated Xenografts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tabb, David L.; Wang, Xia; Carr, Steven A.

2016-03-04

The NCI Clinical Proteomic Tumor Analysis Consortium (CPTAC) employed a pair of reference xenograft proteomes for initial platform validation and ongoing quality control of its data collection for The Cancer Genome Atlas (TCGA) tumors. These two xenografts, representing basal and luminal-B human breast cancer, were fractionated and analyzed on six mass spectrometers in a total of 46 replicates divided between iTRAQ and label-free technologies, spanning a total of 1095 LC-MS/MS experiments. These data represent a unique opportunity to evaluate the stability of proteomic differentiation by mass spectrometry over many months of time for individual instruments or across instruments running dissimilarmore » workflows. We evaluated iTRAQ reporter ions, label-free spectral counts, and label-free extracted ion chromatograms as strategies for data interpretation. From these assessments we found that differential genes from a single replicate were confirmed by other replicates on the same instrument from 61-93% of the time. When comparing across different instruments and quantitative technologies, differential genes were reproduced by other data sets from 67-99% of the time. Projecting gene differences to biological pathways and networks increased the similarities. These overlaps send an encouraging message about the maturity of technologies for proteomic differentiation.« less

Ion mobility mass spectrometry of proteins in a modified commercial mass spectrometer

NASA Astrophysics Data System (ADS)

Thalassinos, K.; Slade, S. E.; Jennings, K. R.; Scrivens, J. H.; Giles, K.; Wildgoose, J.; Hoyes, J.; Bateman, R. H.; Bowers, M. T.

2004-08-01

Ion mobility has emerged as an important technique for determining biopolymer conformations in solvent free environments. These experiments have been nearly exclusively performed on home built systems. In this paper we describe modifications to a commercial high performance mass spectrometer, the Waters UK "Ultima" Q-Tof, that allows high sensitivity measurement of peptide and protein cross sections. Arrival time distributions are obtained for a series of peptides (bradykinin, LHRH, substance P, bombesin) and proteins (bovine and equine cytochrome c, myoglobin, [alpha]-lactalbumin) with good agreement found with literature cross sections where available. In complex ATD's, mass spectra can be obtained for each feature confirming assignments. The increased sensitivity of the commercial instrument is retained along with the convenience of the data system, crucial features for analysis of protein misfolding systems.

Developments in FT-ICR MS instrumentation, ionization techniques, and data interpretation methods for petroleomics.

PubMed

Cho, Yunju; Ahmed, Arif; Islam, Annana; Kim, Sunghwan

2015-01-01

Because of the increasing importance of heavy and unconventional crude oil as an energy source, there is a growing need for petroleomics: the pursuit of more complete and detailed knowledge of the chemical compositions of crude oil. Crude oil has an extremely complex nature; hence, techniques with ultra-high resolving capabilities, such as Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), are necessary. FT-ICR MS has been successfully applied to the study of heavy and unconventional crude oils such as bitumen and shale oil. However, the analysis of crude oil with FT-ICR MS is not trivial, and it has pushed analysis to the limits of instrumental and methodological capabilities. For example, high-resolution mass spectra of crude oils may contain over 100,000 peaks that require interpretation. To visualize large data sets more effectively, data processing methods such as Kendrick mass defect analysis and statistical analyses have been developed. The successful application of FT-ICR MS to the study of crude oil has been critically dependent on key developments in FT-ICR MS instrumentation and data processing methods. This review offers an introduction to the basic principles, FT-ICR MS instrumentation development, ionization techniques, and data interpretation methods for petroleomics and is intended for readers having no prior experience in this field of study. © 2014 Wiley Periodicals, Inc.

EXTENDED-MIRAS: the instrumental approach for the search of traces of extinct and extant life on Mars, measuring scenario

NASA Astrophysics Data System (ADS)

Popp, J.; Tarcea, N.; Thomas, N.; Cockell, C.; Edwards, H. W. G.; Gomez-Elvira, J.; Hilchenbach, M.; Hochleitner, R.; Hofer, S.; Hoffmann, V.; Hofmann, B.; Jessberger, E. K.; Kiefer, W.; Martinez-Frias, J.; Maurice, S.; Rull Pérez, F.; Schmitt, M.; Simon, G.; Sobron, F.; Weigand, W.; Whitby, J. A.; Wurz, P.

2004-03-01

Whether there was or is life on Mars is a question of high interest to man. When looking for evidence of present or ancient life on Mars it might not be sufficient to disclose the chemical composition of the surface or subsurface material. Further information concerning for example the morphology of the sample under investigation or the spatial distribution of the observed chemicals or minerals is of similar relevance. Therefore one needs a reliable, automated, robust and miniaturized apparatus capable of resolving all the above mentioned problems in one effort. EXTENDED-MIRAS is an instrumental approach combining optical microscopy and micro-Raman spectroscopy with additional elementary characterization methods such as LIPS/LIBS (laser induced plasma spectrometry/laser induced breakdown spectrometry) or LMS (laser mass spectrometry). Nevertheless an exhaustive investigation usually requires time/energy which is a limited resource for a planetary mission. The size of the dataset produced might also pose a serious problem since the data link budget is limited (energy constraints). In order to maximize the scientific return, a measuring scenario that will make the most out of the reduced time/energy budget has to be implemented. Such a measuring scenario is described here with exemplification at laboratory scale.

Using Remote Access to Scientific Instrumentation to Create Authentic Learning Activities in Pharmaceutical Analysis

PubMed Central

Albon, Simon P.; Cancilla, Devon A.; Hubball, Harry

2006-01-01

Objectives To pilot test and evaluate a gas chromatography-mass spectrometry (GCMS) case study as a teaching and learning tool. Design A case study incorporating remote access to a GCMS instrument through the Integrated Laboratory Network (ILN) at Western Washington University was developed and implemented. Student surveys, faculty interviews, and examination score data were used to evaluate learning. Assessment While the case study did not impact final examination scores, approximately 70% of students and all faculty members felt the ILN-supported case study improved student learning about GCMS. Faculty members felt the “live” instrument access facilitated more authentic teaching. Students and faculty members felt the ILN should continue to be developed as a teaching tool. Conclusion Remote access to scientific instrumentation can be used to modify case studies to enhance student learning and teaching practice in pharmaceutical analysis. PMID:17149450

High Resolution Mass Spectrometry of Polyfluorinated Polyether-Based Formulation

NASA Astrophysics Data System (ADS)

Dimzon, Ian Ken; Trier, Xenia; Frömel, Tobias; Helmus, Rick; Knepper, Thomas P.; de Voogt, Pim

2016-02-01

High resolution mass spectrometry (HRMS) was successfully applied to elucidate the structure of a polyfluorinated polyether (PFPE)-based formulation. The mass spectrum generated from direct injection into the MS was examined by identifying the different repeating units manually and with the aid of an instrument data processor. Highly accurate mass spectral data enabled the calculation of higher-order mass defects. The different plots of MW and the nth-order mass defects (up to n = 3) could aid in assessing the structure of the different repeating units and estimating their absolute and relative number per molecule. The three major repeating units were -C2H4O-, -C2F4O-, and -CF2O-. Tandem MS was used to identify the end groups that appeared to be phosphates, as well as the possible distribution of the repeating units. Reversed-phase HPLC separated of the polymer molecules on the basis of number of nonpolar repeating units. The elucidated structure resembles the structure in the published manufacturer technical data. This analytical approach to the characterization of a PFPE-based formulation can serve as a guide in analyzing not just other PFPE-based formulations but also other fluorinated and non-fluorinated polymers. The information from MS is essential in studying the physico-chemical properties of PFPEs and can help in assessing the risks they pose to the environment and to human health.

High Resolution Mass Spectrometry of Polyfluorinated Polyether-Based Formulation.

PubMed

Dimzon, Ian Ken; Trier, Xenia; Frömel, Tobias; Helmus, Rick; Knepper, Thomas P; de Voogt, Pim

2016-02-01

High resolution mass spectrometry (HRMS) was successfully applied to elucidate the structure of a polyfluorinated polyether (PFPE)-based formulation. The mass spectrum generated from direct injection into the MS was examined by identifying the different repeating units manually and with the aid of an instrument data processor. Highly accurate mass spectral data enabled the calculation of higher-order mass defects. The different plots of MW and the nth-order mass defects (up to n = 3) could aid in assessing the structure of the different repeating units and estimating their absolute and relative number per molecule. The three major repeating units were -C2H4O-, -C2F4O-, and -CF2O-. Tandem MS was used to identify the end groups that appeared to be phosphates, as well as the possible distribution of the repeating units. Reversed-phase HPLC separated of the polymer molecules on the basis of number of nonpolar repeating units. The elucidated structure resembles the structure in the published manufacturer technical data. This analytical approach to the characterization of a PFPE-based formulation can serve as a guide in analyzing not just other PFPE-based formulations but also other fluorinated and non-fluorinated polymers. The information from MS is essential in studying the physico-chemical properties of PFPEs and can help in assessing the risks they pose to the environment and to human health. Graphical Abstract ᅟ.

Advancements in mass spectrometry for biological samples: Protein chemical cross-linking and metabolite analysis of plant tissues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klein, Adam

2015-01-01

This thesis presents work on advancements and applications of methodology for the analysis of biological samples using mass spectrometry. Included in this work are improvements to chemical cross-linking mass spectrometry (CXMS) for the study of protein structures and mass spectrometry imaging and quantitative analysis to study plant metabolites. Applications include using matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) to further explore metabolic heterogeneity in plant tissues and chemical interactions at the interface between plants and pests. Additional work was focused on developing liquid chromatography-mass spectrometry (LC-MS) methods to investigate metabolites associated with plant-pest interactions.

Mass spectrometry-based proteomics for translational research: a technical overview.

PubMed

Paulo, Joao A; Kadiyala, Vivek; Banks, Peter A; Steen, Hanno; Conwell, Darwin L

2012-03-01

Mass spectrometry-based investigation of clinical samples enables the high-throughput identification of protein biomarkers. We provide an overview of mass spectrometry-based proteomic techniques that are applicable to the investigation of clinical samples. We address sample collection, protein extraction and fractionation, mass spectrometry modalities, and quantitative proteomics. Finally, we examine the limitations and further potential of such technologies. Liquid chromatography fractionation coupled with tandem mass spectrometry is well suited to handle mixtures of hundreds or thousands of proteins. Mass spectrometry-based proteome elucidation can reveal potential biomarkers and aid in the development of hypotheses for downstream investigation of the molecular mechanisms of disease.

Mass Spectrometry-Based Proteomics for Translational Research: A Technical Overview

PubMed Central

Paulo, Joao A.; Kadiyala, Vivek; Banks, Peter A.; Steen, Hanno; Conwell, Darwin L.

2012-01-01

Mass spectrometry-based investigation of clinical samples enables the high-throughput identification of protein biomarkers. We provide an overview of mass spectrometry-based proteomic techniques that are applicable to the investigation of clinical samples. We address sample collection, protein extraction and fractionation, mass spectrometry modalities, and quantitative proteomics. Finally, we examine the limitations and further potential of such technologies. Liquid chromatography fractionation coupled with tandem mass spectrometry is well suited to handle mixtures of hundreds or thousands of proteins. Mass spectrometry-based proteome elucidation can reveal potential biomarkers and aid in the development of hypotheses for downstream investigation of the molecular mechanisms of disease. PMID:22461744

Micro-pulverized extraction pretreatment for highly sensitive analysis of 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol in hair by liquid chromatography/tandem mass spectrometry.

PubMed

Kuwayama, Kenji; Miyaguchi, Hajime; Yamamuro, Tadashi; Tsujikawa, Kenji; Kanamori, Tatsuyuki; Iwata, Yuko T; Inoue, Hiroyuki

2015-11-30

A primary metabolite of Δ(9) -tetrahydrocannabinol, 11-nor-9-carboxytetrahydrocannabinol (THC-COOH), serves as an effective indicator for cannabis intake. According to the recommendations of the Society of Hair Testing, at least 0.2 pg/mg of THC-COOH (cut-off level) must be present in a hair sample to constitute a positive result in a drug test. Typically, hair is digested with an alkaline solution and is subjected to gas chromatography/tandem mass spectrometry (GC/MS/MS) with negative ion chemical ionization (NICI). It is difficult to quantify THC-COOH at the cut-off level using liquid chromatography/tandem mass spectrometry (LC/MS/MS) without acquisition of second-generation product ions in triple quadrupole-ion trap mass spectrometers, because large amounts of matrix components in the low-mass range produced by digestion interfere with the THC-COOH peak. Using the typical pretreatment method (alkaline dissolution) and micro-pulverized extraction (MPE) with a stainless bullet, we compared the quantification of THC-COOH using GC/MS/MS and LC/MS/MS. MPE reduced the amount of matrix components in the low-mass range and enabled the quantification of THC-COOH at 0.2 pg/mg using a conventional triple quadrupole liquid chromatograph coupled to a mass spectrometer. On the other hand, the MPE pretreatment was unsuitable for GC/MS/MS, probably due to matrix components in the high-mass range. The proper combination of pretreatments and instrumental analyses was shown to be important for detecting trace amounts of THC-COOH in hair. In MPE, samples can be prepared rapidly, and LC/MS/MS is readily available, unlike GC/MS/MS with NICI. The combination of MPE and LC/MS/MS might therefore be used in the initial screening for THC-COOH in hair prior to confirmatory analysis using GC/MS/MS with NICI. Copyright © 2015 John Wiley & Sons, Ltd.

Apparatus and method of determining molecular weight of large molecules

DOEpatents

Fuerstenau, S.; Benner, W.H.; Madden, N.M.; Searles, W.

1998-06-23

A mass spectrometer determines the mass of multiply charged high molecular weight molecules. This spectrometer utilizes an ion detector which is capable of simultaneously measuring the charge z and transit time of a single ion as it passes through the detector. From this transit time, the velocity of the single ion may then be derived, thus providing the mass-to-charge ratio m/z for a single ion which has been accelerated through a known potential. Given z and m/z, the mass m of the single ion can then be calculated. Electrospray ions with masses in excess of 1 MDa and charge numbers greater than 425 e{sup {minus}} are readily detected. The on-axis single ion detection configuration enables a duty cycle of nearly 100% and extends the practical application of electrospray mass spectrometry to the analysis of very large molecules with relatively inexpensive instrumentation. 14 figs.

Apparatus and method of determining molecular weight of large molecules

DOEpatents

Fuerstenau, Stephen; Benner, W. Henry; Madden, Norman; Searles, William

1998-01-01

A mass spectrometer determines the mass of multiply charged high molecular weight molecules. This spectrometer utilizes an ion detector which is capable of simultaneously measuring the charge z and transit time of a single ion as it passes through the detector. From this transit time, the velocity of the single ion may then be derived, thus providing the mass-to-charge ratio m/z for a single ion which has been accelerated through a known potential. Given z and m/z, the mass m of the single ion can then be calculated. Electrospray ions with masses in excess of 1 MDa and charge numbers greater than 425 e.sup.- are readily detected. The on-axis single ion detection configuration enables a duty cycle of nearly 100% and extends the practical application of electrospray mass spectrometry to the analysis of very large molecules with relatively inexpensive instrumentation.

Report on Initial Direct Soil Leaching Experiments Using Post-Detonation Debris

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gostic, R.; Knight, K. B.; Borg, L.

2011-08-01

A key challenge of nuclear forensics is reducing the time and manpower effort required to measure nuclear debris compositions. The overall motivation for this work is to explore development of a robust, automated system that can be used to concurrently analyze several elements/isotopes associated with the forensic signature of nuclear materials. The primary focus of this research has been to methodically investigate if rapid partial leaching of post-detonation debris can yield usable elemental and isotopic information for interpretation. The unique requirements of post-detonation nuclear forensics have not been fully adapted to or fully incorporated contemporary chemical separation techniques. Challenges includemore » addressing the range of material matrices or mixed fission product and actinide compositions and concentrations that might be encountered. These include, but are not limited to, puddle melt glass, urban debris, seawater, air filters, iron-rich urban debris, asphalt, and silica sand. Separation of these elements and their subsequent measurement is a key element of related laboratory analysis activity. Existing practices at LLNL rely on proven but time-consuming and labor intensive processes. Significant time and labor savings are possible in chemical separations, however, if rapid processing methods can be adapted to post-detonation debris. Development of a simple and reliable leaching technique could shorten analytical times and would be useful as a field deployable method for the preliminary characterization of actinide isotopic ratios in soils. Measurement of isotopic ratios in the field using modern mass spectrometry capabilities such as Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is desirable, taking advantage of the extended range of isotopic systems measureable using such instruments. Sample introduction to these types of mass spectrometry instruments requires partial leaching or full dissolution of a sample to remove isobaric (same mass) interferences, and, in some cases, to concentrate the elements(s) of interest. To develop a field-deployable mass spectrometry capability, therefore, automated and robust leaching of likely debris samples (ranging from silicates and oxides to metals and urban materials such as concrete and asphalt), followed by separation/purification through cation exchange column chemistry is necessary. In a post-detonation environment, analysis of melt glasses via rapid leaching and ICP-MS could be a viable route to the same goal. This report presents initial leaching experiments on ‘uncontaminated’ soils, as well as data from melt glass from a single nuclear weapons test. Samples were characterized by gamma spectrometry, then aliquoted for rapid leaching experiments. Experiments were conducted using two different rapid acid treatments to leach the soils. Following leaching, the leachate solutions were analyzed by ICP-MS to determine if U isotopic composition. We present these data to address the question as to whether or not rapid (~1 hr) leaching techniques have the potential to yield meaningful U isotopic compositions, without the need for a complete (time consuming) sample dissolution and separation.« less

Current practice of liquid chromatography-mass spectrometry in metabolomics and metabonomics.

PubMed

Gika, Helen G; Theodoridis, Georgios A; Plumb, Robert S; Wilson, Ian D

2014-01-01

Based on publication and citation numbers liquid chromatography (LC-MS) has become the major analytical technology in the field of global metabolite profiling. This dominance reflects significant investments from both the research community and instrument manufacturers. Here an overview of the approaches taken for LC-MS-based metabolomics research is given, describing critical steps in the realisation of such studies: study design and its needs, specific technological problems to be addressed and major obstacles in data treatment and biomarker identification. The current state of the art for LC-MS-based analysis in metabonomics/metabolomics is described including recent developments in liquid chromatography, mass spectrometry and data treatment as these are applied in metabolomics underlining the challenges, limitations and prospects for metabolomics research. Examples of the application of metabolite profiling in the life sciences focusing on disease biomarker discovery are highlighted. In addition, new developments and future prospects are described. Copyright © 2013 Elsevier B.V. All rights reserved.

Round robin test on quantification of amyloid-β 1-42 in cerebrospinal fluid by mass spectrometry.

PubMed

Pannee, Josef; Gobom, Johan; Shaw, Leslie M; Korecka, Magdalena; Chambers, Erin E; Lame, Mary; Jenkins, Rand; Mylott, William; Carrillo, Maria C; Zegers, Ingrid; Zetterberg, Henrik; Blennow, Kaj; Portelius, Erik

2016-01-01

Cerebrospinal fluid (CSF) amyloid-β 1-42 (Aβ42) is an important biomarker for Alzheimer's disease, both in diagnostics and to monitor disease-modifying therapies. However, there is a great need for standardization of methods used for quantification. To overcome problems associated with immunoassays, liquid chromatography-tandem mass spectrometry (LC-MS/MS) has emerged as a critical orthogonal alternative. We compared results for CSF Aβ42 quantification in a round robin study performed in four laboratories using similar sample preparation methods and LC-MS instrumentation. The LC-MS results showed excellent correlation between laboratories (r(2) >0.98), high analytical precision, and good correlation with enzyme-linked immunosorbent assay (r(2) >0.85). The use of a common reference sample further decreased interlaboratory variation. Our results indicate that LC-MS is suitable for absolute quantification of Aβ42 in CSF and highlight the importance of developing a certified reference material. Copyright © 2016 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

Secondary Ion Mass Spectrometry SIMS XI

NASA Astrophysics Data System (ADS)

Gillen, G.; Lareau, R.; Bennett, J.; Stevie, F.

2003-05-01

This volume contains 252 contributions presented as plenary, invited and contributed poster and oral presentations at the 11th International Conference on Secondary Ion Mass Spectrometry (SIMS XI) held at the Hilton Hotel, Walt Disney World Village, Orlando, Florida, 7 12 September, 1997. The book covers a diverse range of research, reflecting the rapid growth in advanced semiconductor characterization, ultra shallow depth profiling, TOF-SIMS and the new areas in which SIMS techniques are being used, for example in biological sciences and organic surface characterization. Papers are presented under the following categories: Isotopic SIMS Biological SIMS Semiconductor Characterization Techniques and Applications Ultra Shallow Depth Profiling Depth Profiling Fundamental/Modelling and Diffusion Sputter-Induced Topography Fundamentals of Molecular Desorption Organic Materials Practical TOF-SIMS Polyatomic Primary Ions Materials/Surface Analysis Postionization Instrumentation Geological SIMS Imaging Fundamentals of Sputtering Ion Formation and Cluster Formation Quantitative Analysis Environmental/Particle Characterization Related Techniques These proceedings provide an invaluable source of reference for both newcomers to the field and experienced SIMS users.

Sensory and instrumental analysis of medium and long shelf-life Charentais cantaloupe melons (Cucumis melo L.) harvested at different maturities

PubMed Central

Lignou, Stella; Parker, Jane K.; Baxter, Charles; Mottram, Donald S.

2014-01-01

The flavour profiles of two genotypes of Charentais cantaloupe melons (medium shelf-life and long shelf-life), harvested at two distinct maturities (immature and mature fruit), were investigated. Dynamic headspace extraction (DHE), solid-phase extraction (SPE), gas chromatography–mass spectrometry (GC–MS) and gas chromatography–olfactometry/mass spectrometry (GC–O/MS) were used to determine volatile and semi-volatile compounds. Qualitative descriptive analysis (QDA) was used to assess the organoleptic impact of the different melons and the sensory data were correlated with the chemical analysis. There were significant, consistent and substantial differences between the mature and immature fruit for the medium shelf-life genotype, the less mature giving a green, cucumber character and lacking the sweet, fruity character of the mature fruit. However, maturity at harvest had a much smaller impact on the long shelf-life melons and fewer differences were detected. These long shelf-life melons tasted sweet, but lacked fruity flavours, instead exhibiting a musty, earthy character. PMID:24262549

Mass spectrometry-based proteomics: basic principles and emerging technologies and directions.

PubMed

Van Riper, Susan K; de Jong, Ebbing P; Carlis, John V; Griffin, Timothy J

2013-01-01

As the main catalytic and structural molecules within living systems, proteins are the most likely biomolecules to be affected by radiation exposure. Proteomics, the comprehensive characterization of proteins within complex biological samples, is therefore a research approach ideally suited to assess the effects of radiation exposure on cells and tissues. For comprehensive characterization of proteomes, an analytical platform capable of quantifying protein abundance, identifying post-translation modifications and revealing members of protein complexes on a system-wide level is necessary. Mass spectrometry (MS), coupled with technologies for sample fractionation and automated data analysis, provides such a versatile and powerful platform. In this chapter we offer a view on the current state of MS-proteomics, and focus on emerging technologies within three areas: (1) New instrumental methods; (2) New computational methods for peptide identification; and (3) Label-free quantification. These emerging technologies should be valuable for researchers seeking to better understand biological effects of radiation on living systems.

Derivatization coupled to headspace programmed-temperature vaporizer gas chromatography with mass spectrometry for the determination of amino acids: Application to urine samples.

PubMed

González Paredes, Rosa María; García Pinto, Carmelo; Pérez Pavón, José Luis; Moreno Cordero, Bernardo

2016-09-01

A new method based on headspace programmed-temperature vaporizer gas chromatography with mass spectrometry has been developed and validated for the determination of amino acids (alanine, sarcosine, ethylglycine, valine, leucine, and proline) in human urine samples. Derivatization with ethyl chloroformate was employed successfully to determine the amino acids. The derivatization reaction conditions as well as the variables of the headspace sampling were optimized. The existence of a matrix effect was checked and the analytical characteristics of the method were determined. The limits of detection were 0.15-2.89 mg/L, and the limits of quantification were 0.46-8.67 mg/L. The instrumental repeatability was 1.6-11.5%. The quantification of the amino acids in six urine samples from healthy subjects was performed with the method developed with the one-point standard additions protocol, with norleucine as the internal standard. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Matrix-Assisted Laser Desorption/Ionisation - High-Energy Collision-Induced Dissociation of Steroids: Analysis of Oxysterols in Rat Brain

PubMed Central

Wang, Yuqin; Hornshaw, Martin; Alvelius, Gunvor; Bodin, Karl; Liu, Suya; Sjövall, Jan; Griffiths, William J.

2008-01-01

Neutral steroids have traditionally been analysed by gas chromatography – mass spectrometry (GC-MS) after necessary derivatisation reactions. However, GC-MS is unsuitable for the analysis of many conjugated steroids and those with unsuspected functional groups. Here we describe an alternative analytical method specifically designed for the analysis of oxosteroids and those with a 3β-hydroxy-Δ5 or 5α-hydrogen-3β-hydroxy structure. Steroids were derivatised with Girard P (GP) hydrazine to give GP hydrazones which are charged species and readily analysed by matrix-assisted laser desorption/ionization mass spectrometry. The resulting [M]+ ions were then subjected to high-energy collision-induced dissociation on a tandem time-of-flight instrument. The product-ion spectra give structurally informative fragment-ion patterns. The sensitivity of the analytical method is such that steroids structures can be determined from low pg (low fmole) amounts of sample. The utility of the method has been demonstrated by the analysis of oxysterols extracted from rat brain. PMID:16383324

A new approach to the analysis of radiopharmaceuticals. Final technical report, January 15, 1987--June 30, 1991

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, A.G.; Davison, A.; Costello, C.E.

The objective of this research was to investigate analytical techniques that could be used in the study of both the basic chemistry and the radiopharmaceutical chemistry of {sup 99m}Tc. First funded in 1981, the work focused initially upon the use of high performance liquid chromatography (HPLC) and various forms of mass spectrometry for the identification of technetium species. This funding allowed the authors to combine HPLC and mass spectrometry to identify radiopharmaceuticals which, although in clinical use, had not previously been characterized. Other techniques that have been examined include resonance Raman spectroscopy and, more significantly, {sup 99}Tc nuclear magnetic resonancemore » spectroscopy (NMR), with the latter not only being used in purely chemical experiments but also in biologic studies. In 1985 a grant to the Department of Chemistry at MIT from DOE allowed the purchase of an X-ray diffractometer and access to this instrument has enabled them to broaden the analytical base with routine structural determinations.« less

Direct analyte-probed nanoextraction coupled to nanospray ionization-mass spectrometry of drug residues from latent fingerprints.

PubMed

Clemons, Kristina; Wiley, Rachel; Waverka, Kristin; Fox, James; Dziekonski, Eric; Verbeck, Guido F

2013-07-01

Here, we present a method of extracting drug residues from fingerprints via Direct Analyte-Probed Nanoextraction coupled to nanospray ionization-mass spectrometry (DAPNe-NSI-MS). This instrumental technique provides higher selectivity and lower detection limits over current methods, greatly reducing sample preparation, and does not compromise the integrity of latent fingerprints. This coupled to Raman microscopy is an advantageous supplement for location and identification of trace particles. DAPNe uses a nanomanipulator for extraction and differing microscopies for localization of chemicals of interest. A capillary tip with solvent of choice is placed in a nanopositioner. The surface to be analyzed is placed under a microscope, and a particle of interest is located. Using a pressure injector, the solvent is injected onto the surface where it dissolves the analyte, and then extracted back into the capillary tip. The solution is then directly analyzed via NSI-MS. Analyses of caffeine, cocaine, crystal methamphetamine, and ecstasy have been performed successfully. © 2013 American Academy of Forensic Sciences.

Food Forensics: Using Mass Spectrometry To Detect Foodborne Protein Contaminants, as Exemplified by Shiga Toxin Variants and Prion Strains.

PubMed

Silva, Christopher J

2018-06-13

Food forensicists need a variety of tools to detect the many possible food contaminants. As a result of its analytical flexibility, mass spectrometry is one of those tools. Use of the multiple reaction monitoring (MRM) method expands its use to quantitation as well as detection of infectious proteins (prions) and protein toxins, such as Shiga toxins. The sample processing steps inactivate prions and Shiga toxins; the proteins are digested with proteases to yield peptides suitable for MRM-based analysis. Prions are detected by their distinct physicochemical properties and differential covalent modification. Shiga toxin analysis is based on detecting peptides derived from the five identical binding B subunits comprising the toxin. 15 N-labeled internal standards are prepared from cloned proteins. These examples illustrate the power of MRM, in that the same instrument can be used to safely detect and quantitate protein toxins, prions, and small molecules that might contaminate our food.

Application of Printed Circuit Board Technology to FT-ICR MS Analyzer Cell Construction and Prototyping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leach, Franklin E.; Norheim, Randolph V.; Anderson, Gordon A.

Although Fourier transform ion cyclotron resonance mass spectrometry (FT-ICRMS) remains themass spectrometry platform that provides the highest levels of performance for mass accuracy and resolving power, there is room for improvement in analyzer cell design as the ideal quadrupolar trapping potential has yet to be generated for a broadband MS experiment. To this end, analyzer cell designs have improved since the field’s inception, yet few research groups participate in this area because of the high cost of instrumentation efforts. As a step towards reducing this barrier to participation and allowing for more designs to be physically tested, we introduce amore » method of FT-ICR analyzer cell prototyping utilizing printed circuit boards at modest vacuum conditions. This method allows for inexpensive devices to be readily fabricated and tested over short intervals and should open the field to laboratories lacking or unable to access high performance machine shop facilities because of the required financial investment.« less

Chemometrics comparison of gas chromatography with mass spectrometry and comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry Daphnia magna metabolic profiles exposed to salinity.

PubMed

Parastar, Hadi; Garreta-Lara, Elba; Campos, Bruno; Barata, Carlos; Lacorte, Silvia; Tauler, Roma

2018-06-01

The performances of gas chromatography with mass spectrometry and of comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry are examined through the comparison of Daphnia magna metabolic profiles. Gas chromatography with mass spectrometry and comprehensive two-dimensional gas chromatography with mass spectrometry were used to compare the concentration changes of metabolites under saline conditions. In this regard, a chemometric strategy based on wavelet compression and multivariate curve resolution-alternating least squares is used to compare the performances of gas chromatography with mass spectrometry and comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry for the untargeted metabolic profiling of Daphnia magna in control and salinity-exposed samples. Examination of the results confirmed the outperformance of comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry over gas chromatography with mass spectrometry for the detection of metabolites in D. magna samples. The peak areas of multivariate curve resolution-alternating least squares resolved elution profiles in every sample analyzed by comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry were arranged in a new data matrix that was then modeled by partial least squares discriminant analysis. The control and salt-exposed daphnids samples were discriminated and the most relevant metabolites were estimated using variable importance in projection and selectivity ratio values. Salinity de-regulated 18 metabolites from metabolic pathways involved in protein translation, transmembrane cell transport, carbon metabolism, secondary metabolism, glycolysis, and osmoregulation. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

First Detection of Non-Chlorinated Organic Molecules Indigenous to a Martian Sample

NASA Technical Reports Server (NTRS)

Freissinet, C.; Glavin, D. P.; Buch, A.; Szopa, C.; Summons, R. E.; Eigenbrode, J. L.; Archer, P. D., Jr.; Brinckerhoff, W. B.; Brunner, A. E.; Cabane, M.;

Discovery and Identification of Dimethylsilanediol as a Contaminant in ISS Potable Water

NASA Technical Reports Server (NTRS)

Rutz, Jeffrey A.; Schultz, John R.; Kuo, C. Mike; Curtis, Matthew; Jones, Patrick R.; Sparkman, O. David; McCoy, J. Torin

2011-01-01

In September 2010, analysis of ISS potable water samples was undertaken to determine the contaminant(s) responsible for a rise of total organic carbon (TOC) in the Water Processor Assembly (WPA) product water. As analysis of the routine target list of organic compounds did not reveal the contaminant, efforts to look for unknown compounds were initiated, resulting in discovery of an unknown peak in the gas chromatography/mass spectrometry (GC/MS) analysis for glycols. A mass spectrum of the contaminant was then generated by concentrating one of the samples and analyzing it by GC/MS in full-scan mode. Although a computer match of the compound identity could not be obtained with the instrument database, a search with a more up-to-date mass spectral library yielded a good match with dimethylsilanediol (DMSD). Inductively coupled plasma/mass spectrometry (ICP/MS) analyses showed abnormally high silicon levels in the samples, confirming that the unknown compound(s) contained silicon. DMSD was then synthesized to confirm the identification and provide a standard to develop a calibration curve. Further confirmation was provided by external direct analysis in real time time of flight (DART TOF) mass spectrometry. To routinely test for DMSD in the future, a quantitative method was needed. A preliminary GC/MS method was developed and archived samples from various locations on ISS were analyzed to determine the extent of the contamination and provide data for troubleshooting. This paper describes these events in more detail as well as problems encountered in routine GC/MS analyses and the subsequent development of high performance liquid chromatography and LC/MS/MS methods for measuring DMSD.

Ultrasensitive detection of explosives and chemical warfare agents by low-pressure photoionization mass spectrometry.

PubMed

Sun, Wanqi; Liang, Miao; Li, Zhen; Shu, Jinian; Yang, Bo; Xu, Ce; Zou, Yao

2016-08-15

On-spot monitoring of threat agents needs high sensitive instrument. In this study, a low-pressure photoionization mass spectrometer (LPPI-MS) was employed to detect trace amounts of vapor-phase explosives and chemical warfare agent mimetics under ambient conditions. Under 10-s detection time, the limits of detection of 2,4-dinitrotoluene, nitrotoluene, nitrobenzene, and dimethyl methyl phosphonate were 30, 0.5, 4, and 1 parts per trillion by volume, respectively. As compared to those obtained previously with PI mass spectrometric techniques, an improvement of 3-4 orders of magnitude was achieved. This study indicates that LPPI-MS will open new opportunities for the sensitive detection of explosives and chemical warfare agents. Copyright © 2016 Elsevier B.V. All rights reserved.