Sample records for high-sensitivity mass spectrometry

  1. Sputtered gas-phase dianions detected by high-sensitivity mass spectrometry (United States)

    Gnaser, Hubert; Golser, Robin


    The detection of small doubly-charged molecular anions by means of highly sensitive mass spectrometry is discussed. The production of these gas-phase dianions is accomplished by sputtering the specimen with Cs + ions with an energy of a few keV. It is demonstrated that dianions can be detected most easily when the molecular ion has an odd total mass; then, the dianions will show up at half-integral mass numbers in the mass spectrum. In addition, the agreement of the relative abundances of several isotopomers of a dianion with the nominal isotopic pattern corroborates the identification of a dianionic species in the mass spectrum. These features are exemplified by monitoring mixed silicon-oxygen dianions of the general form OO52-[28], Sn2-[29], SiC62-[30], BeCn2-[31], and PtX62- (X = F, Cl, Br) [32]. More recent work of this group investigated the existence of long-lived dianions containing tetrahedrally coordinated oxygen atoms, namely, O(C)42- and O(BN)42-[33], of cyclic carbon cluster dianions [34], of tetraborates [35], of derivatives of the closo-hexaborate dianion BH62-[36], and of aromatic dianions [37]. Apart from identifying (meta)stable dianions, these computations indicated a possible general formation principle: small dianions are expected to be particularly stable if they consist of a central, at least partially positively charged atom and several equivalent negatively charged ligands [2,6,30,38]. Furthermore, it was pointed out [31,39,40] that for multiply charged anions a repulsive Coulomb barrier for electron emission exists which may result in small metastable dianions which can be detected by mass spectrometry. In fact, the existence of such a Coulomb barrier was inferred from various experiments [41-47]. Apart from dianions, Cederbaum and coworkers studied different small MCAs [19,24,25,48-50]. Theoretical work by other groups [51-59] corroborated and diversified these results. Following the experimental detection of Cn2-[12], several different

  2. Highly sensitive and selective analysis of widely targeted metabolomics using gas chromatography/triple-quadrupole mass spectrometry. (United States)

    Tsugawa, Hiroshi; Tsujimoto, Yuki; Sugitate, Kuniyo; Sakui, Norihiro; Nishiumi, Shin; Bamba, Takeshi; Fukusaki, Eiichiro


    In metabolomics studies, gas chromatography coupled with time-of-flight or quadrupole mass spectrometry has frequently been used for the non-targeted analysis of hydrophilic metabolites. However, because the analytical platform employs the deconvolution method to extract single-metabolite information from co-eluted peaks and background noise, the extracted peak is artificial product depending on the mathematical parameters and is not completely compatible with the pure component obtained by analyzing a standard compound. Moreover, it has insufficient ability for quantitative metabolomics. Therefore, highly sensitive and selective methods capable of pure peak extraction without any complicated mathematical techniques are needed. For this purpose, we have developed a novel analytical method using gas chromatography coupled with triple-quadrupole mass spectrometry (GC-QqQ/MS). We developed a selected reaction monitoring (SRM) method to analyze the trimethylsilyl derivatives of 110 metabolites, using electron ionization. This methodology enables us to utilize two complementary techniques-non-targeted and widely targeted metabolomics in the same sample preparation protocol, which would facilitate the formulation or verification of novel hypotheses in biological sciences. The GC-QqQ/MS analysis can accurately identify a metabolite using multichannel SRM transitions and intensity ratios in the analysis of living organisms. In addition, our methodology offers a wide dynamic range, high sensitivity, and highly reproducible metabolite profiles, which will contribute to the biomarker discoveries and quality evaluations in biology, medicine, and food sciences. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  3. Mass Spectrometry-based Assay for High Throughput and High Sensitivity Biomarker Verification

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Xuejiang; Tang, Keqi


    Searching for disease specific biomarkers has become a major undertaking in the biomedical research field as the effective diagnosis, prognosis and treatment of many complex human diseases are largely determined by the availability and the quality of the biomarkers. A successful biomarker as an indicator to a specific biological or pathological process is usually selected from a large group of candidates by a strict verification and validation process. To be clinically useful, the validated biomarkers must be detectable and quantifiable by the selected testing techniques in their related tissues or body fluids. Due to its easy accessibility, protein biomarkers would ideally be identified in blood plasma or serum. However, most disease related protein biomarkers in blood exist at very low concentrations (<1ng/mL) and are “masked” by many none significant species at orders of magnitude higher concentrations. The extreme requirements of measurement sensitivity, dynamic range and specificity make the method development extremely challenging. The current clinical protein biomarker measurement primarily relies on antibody based immunoassays, such as ELISA. Although the technique is sensitive and highly specific, the development of high quality protein antibody is both expensive and time consuming. The limited capability of assay multiplexing also makes the measurement an extremely low throughput one rendering it impractical when hundreds to thousands potential biomarkers need to be quantitatively measured across multiple samples. Mass spectrometry (MS)-based assays have recently shown to be a viable alternative for high throughput and quantitative candidate protein biomarker verification. Among them, the triple quadrupole MS based assay is the most promising one. When it is coupled with liquid chromatography (LC) separation and electrospray ionization (ESI) source, a triple quadrupole mass spectrometer operating in a special selected reaction monitoring (SRM) mode

  4. [High-sensitivity analysis of purines in alcoholic beverages using hydrophilic interaction chromatography coupled with tandem mass spectrometry]. (United States)

    Kakigi, Yasuhiro; Yoshioka, Toshiaki; Nagatomi, Yasushi; Uyama, Atsuo; Mochizuki, Naoki


    In this study, we established a high-sensitivity analytical method for purines in alcoholic beverages using hydrophilic interaction chromatography coupled with tandem mass spectrometry. The alcoholic beverages were hydrolyzed with perchloric acid (60%) and subjected to strong cation exchange solid-phase extraction (Bond Elut SCX). The four purine bases (hypoxanthine, adenine, xanthine, guanine) in the extracted solution were separated by hydrophilic interaction chromatography with TSKgel Amide-80 as a separation column, 10 mM ammonium formate (pH 2.0) as mobile phase A, and acetonitrile/100 mM ammonium formate (pH 2.0) (90/10) as mobile phase B. The detection of purine bases was performed by tandem mass spectrometry with ESI. The linearity of this analytical method was not less than 0.996, and the repeatability was not more than 8.4% for each purine base. The recovery was in the range of 60-105%, and the detection limit was not more than 0.005 mg/100 mL. This established method is expected to be useful for quality control and surveillance of purines in alcoholic beverages.

  5. Highly sensitive determination of estrone and estradiol in human serum by liquid chromatography-electrospray ionization tandem mass spectrometry. (United States)

    Yamashita, Kouwa; Okuyama, Mitsunobu; Watanabe, Yoko; Honma, Seijiro; Kobayashi, Sayuri; Numazawa, Mitsuteru


    A highly sensitive and specific quantification method of estrone and estradiol in human serum was described based upon the use of picolinoyl derivatization and liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) in a positive mode. Estrogens were treated with picolinoyl chloride hydrochloride or picolinic acid and 2-methyl-6-nitrobenzoic anhydride followed by a solid-phase extraction with ODS cartridge. Picolinoyl derivatization proceeded quantitatively even in a microscale, and the picolinoyl esters provided simple positive ESI-mass spectra showing [M+H](+) as base peaks for these estrogens. The picolinoyl derivatives of these estrogens showed 100-fold higher detection response compared to underivatized intact molecules by LC-ESI-MS (selected reaction monitoring). Using this derivatization, estrogens spiked in the charcoal treated human serum samples were analyzed with limit of quantification (LOQ), intra-day accuracy and precision of 1.0pg/ml, 96.0% and 9.9% for estrone, and 0.5pg/ml, 84.4% and 12.8% for estradiol, respectively. Estrone and estradiol added to the crude serum samples were recovered with comparable LOQ and accuracy obtained for the charcoal treated serum samples as well.

  6. Highly sensitive protein detection by combination of atomic force microscopy fishing with charge generation and mass spectrometry analysis. (United States)

    Ivanov, Yuri D; Pleshakova, Tatyana; Malsagova, Krystina; Kozlov, Andrey; Kaysheva, Anna; Kopylov, Arthur; Izotov, Alexander; Andreeva, Elena; Kanashenko, Sergey; Usanov, Sergey; Archakov, Alexander


    An approach combining atomic force microscopy (AFM) fishing and mass spectrometry (MS) analysis to detect proteins at ultra-low concentrations is proposed. Fishing out protein molecules onto a highly oriented pyrolytic graphite surface coated with polytetrafluoroethylene film was carried out with and without application of an external electric field. After that they were visualized by AFM and identified by MS. It was found that injection of solution leads to charge generation in the solution, and an electric potential within the measuring cell is induced. It was demonstrated that without an external electric field in the rapid injection input of diluted protein solution the fishing is efficient, as opposed to slow fluid input. The high sensitivity of this method was demonstrated by detection of human serum albumin and human cytochrome b5 in 10(-17) -10(-18) m water solutions. It was shown that an external negative voltage applied to highly oriented pyrolytic graphite hinders the protein fishing. The efficiency of fishing with an external positive voltage was similar to that obtained without applying any voltage. © 2014 FEBS.

  7. Bioanalytical strategies for developing highly sensitive liquid chromatography/tandem mass spectrometry based methods for the peptide GLP-1 agonists in support of discovery PK/PD studies. (United States)

    Zhang, Hongwei; Xin, Baomin; Caporuscio, Christian; Olah, Timothy V


    Highly sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS)-based methods have been developed and implemented for the quantitative determination of a number of peptides under evaluation in our Glucagon-Like Peptide-1 (GLP-1) discovery program for the treatment of diabetes. These peptides are GLP-1 receptor agonists. Due to the high potency, low dose, and low exposure of these peptides, LC/MS/MS-based methods with Lower Limits of Quantitation (LLOQs) (low picomolar range) were required to support discovery pharmacokinetic/ pharmacodynamic (PK/PD) studies. Compared with small molecules, many of these peptides posed significant bioanalytical challenges in the development of highly sensitive methods because of their parent signal splitting as a result of the formation of multiply charged states, the unfavorable fragmentation patterns for Selected Reaction Monitoring (SRM) transitions due to the generation of a large number of small mass product ions with relative low intensities, and adsorption issues observed during sample preparation. This paper details the strategies developed to maximize the sensitivity and improve LLOQs from aspects of mass spectrometry, chromatography, and sample preparation. A LLOQ of 10 picomolar was achieved for all of the investigated peptides using 100 μL of mouse plasma. This is a 100-fold improvement on LLOQs over generic LC/MS/MS-based methods when the same sample volume and the same mass spectrometer platform were used. The methods have been implemented in the support of discovery PK/PD studies. Copyright © 2011 John Wiley & Sons, Ltd.

  8. A highly sensitive carbapenemase assay using laser desorption/ionization mass spectrometry based on a parylene-matrix chip. (United States)

    Park, Jong-Min; Kim, Jo-Il; Noh, Joo-Yoon; Kim, Mira; Kang, Min-Jung; Pyun, Jae-Chul


    A quantitative carbapenemase assay was developed using laser desorption/ionization mass spectrometry (LDI-MS) based on a parylene-matrix chip. As a first step, the reproducibility (spot-to-spot, shot-to-shot, and day-to-day) of LDI-MS based on a parylene-matrix chip and the quantification ranges for four carbapenem antibiotics (doripenem, ertapenem, imipenem, and meropenem) were determined. A carbapenem-susceptibility test was performed using the four carbapenems and 51 bacterial strains that displayed (1) carbapenem resistance with carbapenemase, (2) carbapenem resistance without carbapenemase, or (3) carbapenem susceptibility. The susceptibility test results showed that LDI-MS based on a parylene-matrix chip was more sensitive and selective for detecting the carbapenemase reaction than conventional MALDI-TOF MS based on a 2,5-dihydroxybenzoic acid matrix. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. High sensitivity quantitative lipidomics analysis of fatty acids in biological samples by gas chromatography-mass spectrometry. (United States)

    Quehenberger, Oswald; Armando, Aaron M; Dennis, Edward A


    Historically considered to be simple membrane components serving as structural elements and energy storing entities, fatty acids are now increasingly recognized as potent signaling molecules involved in many metabolic processes. Quantitative determination of fatty acids and exploration of fatty acid profiles have become common place in lipid analysis. We present here a reliable and sensitive method for comprehensive analysis of free fatty acids and fatty acid composition of complex lipids in biological material. The separation and quantitation of fatty acids are achieved by capillary gas chromatography. The analytical method uses pentafluorobenzyl bromide derivatization and negative chemical ionization gas chromatography-mass spectrometry. The chromatographic procedure provides base line separation between saturated and unsaturated fatty acids of different chain lengths as well as between most positional isomers. Fatty acids are extracted in the presence of isotope-labeled internal standards for high quantitation accuracy. Mass spectrometer conditions are optimized for broad detection capacity and sensitivity capable of measuring trace amounts of fatty acids in complex biological samples. . Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Ultra-High Sensitivity Techniques for the Determination of 3 He /4 He Abundances in Helium by Accelerator Mass Spectrometry (United States)

    Mumm, H. P.; Huber, M.; Bauder, W.; Abrams, N.; Deibel, C.; Huffer, C.; Huffman, P.; Schelhammer, K.; Janssens, R.; Jiang, C.; Scott, R.; Pardo, R.; Rehm, K.; Vondrasek, R.; Swank, C.; O'Shaughnessy, C.; Paul, M.; Yang, L.


    We report the development of an Accelerator Mass Spectrometry technique to measure the 3He/4He isotopic ratio using a radio frequency (RF) discharge source and the ATLAS facility at Argonne National Laboratory. Control over 3He/4He ratio in helium several orders of magnitude lower than natural abundance is critical for neutron lifetime and source experiments using liquid helium. Due to low ultimate beam currents, the ATLAS accelerator and beam line were tuned using a succession of species of the same M/q. A unique RF source was developed for the experiment due to large natural 3He backgrounds. Analog H_3 + and DH + molecular ions are eliminated by dissociation via a gold stripper foil near the detector. The stripped ions were dispersed in a magnetic spectrograph and 3He2 + ions counted in the focal plane detector. This technique is sensitive to 3 He /4 He ratios in the regime of 10-12 with backgrounds that appear to be below 10-14. The techniques used to reduce the backgrounds and remaining outstanding problems will be presented along with results from measurements on high purity 4He samples.

  11. Surface Acoustic Wave Nebulisation Mass Spectrometry for the Fast and Highly Sensitive Characterisation of Synthetic Dyes in Textile Samples (United States)

    Astefanei, Alina; van Bommel, Maarten; Corthals, Garry L.


    Surface acoustic wave nebulisation (SAWN) mass spectrometry (MS) is a method to generate gaseous ions compatible with direct MS of minute samples at femtomole sensitivity. To perform SAWN, acoustic waves are propagated through a LiNbO3 sampling chip, and are conducted to the liquid sample, which ultimately leads to the generation of a fine mist containing droplets of nanometre to micrometre diameter. Through fission and evaporation, the droplets undergo a phase change from liquid to gaseous analyte ions in a non-destructive manner. We have developed SAWN technology for the characterisation of organic colourants in textiles. It generates electrospray-ionisation-like ions in a non-destructive manner during ionisation, as can be observed by the unmodified chemical structure. The sample size is decreased by tenfold to 1000-fold when compared with currently used liquid chromatography-MS methods, with equal or better sensitivity. This work underscores SAWN-MS as an ideal tool for molecular analysis of art objects as it is non-destructive, is rapid, involves minimally invasive sampling and is more sensitive than current MS-based methods. [Figure not available: see fulltext.

  12. Development of highly sensitive quantification method for testosterone and dihydrotestosterone in human serum and prostate tissue by liquid chromatography-electrospray ionization tandem mass spectrometry. (United States)

    Yamashita, Kouwa; Miyashiro, Yoshimichi; Maekubo, Hitoe; Okuyama, Mitsunobu; Honma, Seijiro; Takahashi, Madoka; Numazawa, Mitsuteru


    We developed highly sensitive detection of testosterone (T) and 5alpha-dihydrotestosterone (DHT) by liquid chromatography-electrospray ionization tandem mass spectrometry using high proton affinitive derivatization of 17beta-hydroxyl group of T and DHT with picolinic acid, mobile phase consisting of MeCN-MeOH-H(2)O-formic acid and conventional octadecylsilica (ODS) column. Purification of the derivatives was carried out using solid-phase extraction with ODS cartridge. By this method, T and DHT were determined simultaneously with limits of quantification (LOQs) of 1 pg/0.2 ml in serum, and T and DHT with LOQs of 0.5 pg and 1 pg/3mg in prostate tissue, respectively, under acceptable assay performance (intra-assay and inter-assay accuracy and precision). The present method provides reliable and reproducible results for quantification of T and DHT in small volumes of serum and prostate samples for diagnosis in prostatic disorders and male climacteric.

  13. Application of flowerlike MgO for highly sensitive determination of lead via matrix-assisted laser desorption/ionization mass spectrometry. (United States)

    Hou, Jian; Chen, Suming; Cao, Changyan; Liu, Huihui; Xiong, Caiqiao; Zhang, Ning; He, Qing; Song, Weiguo; Nie, Zongxiu


    Matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) is a high-throughput method to achieve fast and accurate identification of lead (Pb) exposure, but is seldom used because of low ionization efficiency and insufficient sensitivity. Nanomaterials applied in MS are a promising technique to overcome the obstacles of MALDI. Flowerlike MgO nanostructures are applied for highly sensitive lead profiling in real samples. They can be used in two ways: (a) MgO is mixed with N-naphthylethylenediamine dihydrochloride (NEDC) as a novel matrix MgO/NEDC; (b) MgO is applied as an absorbent to enrich Pb ions in very dilute solution. The signal intensities of lead by MgO/NEDC were ten times higher than the NEDC matrix. It also shows superior anti-interference ability when analyzing 10 μmol/L Pb ions in the presence of organic substances or interfering metal ions. By applying MgO as adsorbent, the LOD of lead before enrichment is 1 nmol/L. Blood lead test can be achieved using this enrichment process. Besides, MgO can play the role of internal standard to achieve quantitative analysis. Flowerlike MgO nanostructures were applied for highly sensitive lead profiling in real samples. The method is helpful to prevent Pb contamination in a wide range. Further, the combination of MgO with MALDI MS could inspire more nanomaterials being applied in highly sensitive profiling of pollutants. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  14. Development of a method for comprehensive and quantitative analysis of plant hormones by highly sensitive nanoflow liquid chromatography-electrospray ionization-ion trap mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Izumi, Yoshihiro; Okazawa, Atsushi; Bamba, Takeshi; Kobayashi, Akio [Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Fukusaki, Eiichiro, E-mail: [Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)


    In recent plant hormone research, there is an increased demand for a highly sensitive and comprehensive analytical approach to elucidate the hormonal signaling networks, functions, and dynamics. We have demonstrated the high sensitivity of a comprehensive and quantitative analytical method developed with nanoflow liquid chromatography-electrospray ionization-ion trap mass spectrometry (LC-ESI-IT-MS/MS) under multiple-reaction monitoring (MRM) in plant hormone profiling. Unlabeled and deuterium-labeled isotopomers of four classes of plant hormones and their derivatives, auxins, cytokinins (CK), abscisic acid (ABA), and gibberellins (GA), were analyzed by this method. The optimized nanoflow-LC-ESI-IT-MS/MS method showed ca. 5-10-fold greater sensitivity than capillary-LC-ESI-IT-MS/MS, and the detection limits (S/N = 3) of several plant hormones were in the sub-fmol range. The results showed excellent linearity (R{sup 2} values of 0.9937-1.0000) and reproducibility of elution times (relative standard deviations, RSDs, <1.1%) and peak areas (RSDs, <10.7%) for all target compounds. Further, sample purification using Oasis HLB and Oasis MCX cartridges significantly decreased the ion-suppressing effects of biological matrix as compared to the purification using only Oasis HLB cartridge. The optimized nanoflow-LC-ESI-IT-MS/MS method was successfully used to analyze endogenous plant hormones in Arabidopsis and tobacco samples. The samples used in this analysis were extracted from only 17 tobacco dry seeds (1 mg DW), indicating that the efficiency of analysis of endogenous plant hormones strongly depends on the detection sensitivity of the method. Our analytical approach will be useful for in-depth studies on complex plant hormonal metabolism.

  15. Aluminum nanocantilevers for high sensitivity mass sensors

    DEFF Research Database (Denmark)

    Davis, Zachary James; Boisen, Anja


    We have fabricated Al nanocantilevers using a simple, one mask contact UV lithography technique with lateral and vertical dimensions under 500 and 100 nm, respectively. These devices are demonstrated as highly sensitive mass sensors by measuring their dynamic properties. Furthermore, it is shown...... that Al has a potential higher sensitivity than Si based dynamic sensors. Initial testing of these devices has been conducted using a scanning electron microscope setup were the devices were tested under high vacuum conditions. The Q factor was measured to be approximately 200 and the mass sensitivity...

  16. Micro-pulverized extraction pretreatment for highly sensitive analysis of 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol in hair by liquid chromatography/tandem mass spectrometry. (United States)

    Kuwayama, Kenji; Miyaguchi, Hajime; Yamamuro, Tadashi; Tsujikawa, Kenji; Kanamori, Tatsuyuki; Iwata, Yuko T; Inoue, Hiroyuki


    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.

  17. Inorganic arsenic contents in ready-to-eat rice products and various Korean rice determined by a highly sensitive gas chromatography-tandem mass spectrometry. (United States)

    Jung, Mun Yhung; Kang, Ju Hee; Jung, Hyun Jeong; Ma, Sang Yong


    Rice and rice products have been reported to contain high contents of toxic inorganic arsenic (iAs). The inorganic arsenic contents in microwavable ready-to-eat rice products (n=30) and different types of Korean rice (n=102) were determined by a gas chromatography-tandem mass spectrometry (GC-MS/MS). The method showed low limit of detection (0.015pg), high intra- and inter-day repeatability (rice products was 59μgkg-1 (dry weight basis). The mean iAs contents in polished white, brown, black, and waxy rice were 65, 109, 91, and 66μgkg-1, respectively. The percentages of ready-to-eat rice products, white, brown, black, and waxy rice containing iAs over the maximum level (100μgkg-1) set by EU for the infant foods were 17, 4, 70, 36 and 0%, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Mass spectrometry

    DEFF Research Database (Denmark)

    Nyvang Hartmeyer, Gitte; Jensen, Anne Kvistholm; Böcher, Sidsel


    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is currently being introduced for the rapid and accurate identification of bacteria. We describe 2 MALDI-TOF MS identification cases - 1 directly on spinal fluid and 1 on grown bacteria. Rapidly obtained r...

  19. An application of mass spectrometry for quality control of biologicals: Highly sensitive profiling of plasma residuals in human plasma-derived immunoglobulin. (United States)

    Limonier, Franck; Van Steendam, Katleen; Waeterloos, Geneviève; Brusselmans, Koen; Sneyers, Myriam; Deforce, Dieter


    Thromboembolic events (TEE) associated to trace amounts of plasmatic activated coagulation factor XI (FXIa) in administrated immunoglobulin (Ig) have recently raised concerns and hence there is a need for highly sensitive profiling of residual plasma source proteins. This study aims to consider LC-ESI-QTOF data-dependent acquisition in combination with sample fractionation for this purpose. Sample fractionation proved mandatory to enable identification of plasma residuals. Two approaches were compared: Ig depletion with protein G - protein A affinity chromatography and low-abundant protein enrichment with a combinatorial peptide ligand library (ProteoMiner™, Bio-Rad). The latter allowed a higher number of identifications. Highly sensitive detection of prothrombotic FXIa was assessed with confident identification of a 1ng/mg spike. Moreover, different residuals compositions were profiled for various commercial Ig products. Using a quantitative label free analysis, a TEE-positive Ig batch was distinguished from other regular Ig products, with increased levels of FXIa but also other unique proteins. This could have prevented the recently observed TEE problems with Ig. The method is a convenient tool to better characterize Ig products after any plasma pool or manufacture process change, gaining insights in the product quality profile without any prior information required. This study characterized residual plasma proteins in Ig products, using bottom-up LC-MS/MS with conventional data-dependent acquisition, preceded by sample fractionation. Without any prior information or target-specific development, >30 proteins were identified in a commercial Ig product. Quality control relevance was demonstrated with the identification of FXIa spiked at 1ng/mg in Ig, which is below the minimal thrombotic dose of 3ng/mg observed in an in vivo model. Relative label-free quantitation highlighted significant differences in normalized abundances of residual proteins between Ig

  20. Capillary Electrophoresis-Nanoelectrospray Ionization-Selected Reaction Monitoring Mass Spectrometry via a True Sheathless Metal-Coated Emitter Interface for Robust and High-Sensitivity Sample Quantification. (United States)

    Guo, Xuejiang; Fillmore, Thomas L; Gao, Yuqian; Tang, Keqi


    A new sheathless transient capillary isotachophoresis (CITP)/capillary zone electrophoresis (CZE)-MS interface, based on a commercially available capillary with an integrated metal-coated ESI emitter, was developed in this study aiming at overcoming the reproducibility and ruggedness problems suffered to a certain degree by almost all the available CE-MS interfaces, and pushing the CE-MS technology suitable for routine sample analysis with high sensitivity. The new CITP/CZE-MS interface allows the electric contact between ESI voltage power supply and the CE separation liquid by using a conductive liquid that comes in contact with the metal-coated surface of the ESI emitter, making it a true sheathless CE-MS interface. Stable electrospray was established by avoiding the formation of gas bubbles from electrochemical reaction inside the CE capillary. Crucial operating parameters, such as sample loading volume, flow rate, and separation voltage, were systematically evaluated for their effects on both CITP/CZE separation efficiency and MS detection sensitivity. Around one hundred CITP/CZE-MS analyses can be easily achieved by using the new sheathless CITP/CZE interface without a noticeable loss of metal coating on the ESI emitter surface, or degrading of the ESI emitter performance. The reproducibility in analyte migration time and quantitative performance of the new interface was experimentally evaluated to demonstrate a LOQ below 5 attomole.

  1. High mass resolution time of flight mass spectrometer for measuring products in heterogeneous catalysis in highly sensitive microreactors

    DEFF Research Database (Denmark)

    Andersen, Thomas; Jensen, Robert; Christensen, M. K.


    We demonstrate a combined microreactor and time of flight system for testing and characterization of heterogeneous catalysts with high resolution mass spectrometry and high sensitivity. Catalyst testing is performed in silicon-based microreactors which have high sensitivity and fast thermal...

  2. Development and validation of a highly sensitive liquid chromatography/mass spectrometry method for simultaneous quantification of lenalidomide and flavopiridol in human plasma. (United States)

    Liu, Qing; Farley, Katherine L; Johnson, Amy J; Muthusamy, Natarajan; Hofmeister, Craig C; Blum, Kristie A; Schaaf, Larry J; Grever, Michael R; Byrd, John C; Dalton, James T; Phelps, Mitch A


    Lenalidomide, an immunomodulatory agent, and flavopiridol, a broad cyclin-dependent kinase inhibitor, are active therapies for clinical use in genomic high-risk chronic lymphocytic leukemia. A high-performance liquid chromatographic assay with tandem mass spectrometric detection has been developed to simultaneously quantify lenalidomide and flavopiridol in human and mouse plasma to facilitate their combined clinical development. Samples were prepared by liquid-liquid extraction with acetonitrile (ACN)-containing internal standard, genistein, followed by evaporation of solvent and reconstitution in 95/5 H2O/ACN. Lenalidomide and internal standard were separated by reversed-phase liquid chromatography on a C-18 column using a gradient of H2O and ACN, each with 0.1% formic acid. Atmospheric pressure chemical ionization in positive ion mode with single reaction monitoring on a triple quadrupole mass spectrometer was applied to detect transitions of lenalidomide (260.06 > 149.10) and flavopiridol (402.09 > 341.02). Lower limits of quantification of lenalidomide and flavopiridol were 1 and 0.3 nM, respectively. Recoveries of lenalidomide and flavopiridol from human plasma ranged from 99% to 116% throughout their linear ranges. Within- and between-run precision and accuracy of replicate samples were all less than 15%. This is the most sensitive analytical method reported to date for both lenalidomide and flavopiridol. This sensitivity will enable late terminal phase concentration measurements and accurate pharmacokinetic parameter estimation in a planned clinical trial with lenalidomide and flavopiridol in patients with chronic lymphocytic leukemia.

  3. Economical Alternatives for High Sensitivity in Atomic Spectrometry Laboratory

    Directory of Open Access Journals (Sweden)

    O. Yavuz Ataman


    Full Text Available The most commonly used analytical tools for determination of elements at trace levels are atomic absorption spectrometry (AAS, inductively coupled plasma, optical emission and mass spectrometry (ICP-OES and ICP-MS and atomic fluorescence spectrometry (AFS. Although sensitive plasma techniques are becoming predominant in most of the western laboratories, AAS keeps its importance in developing countries. Simple and inexpensive ways of enhancing sensitivity will be described for laboratories equipped with only a flame AA spectrometer. Although there are many chemical preconcentration procedures to improve sensitivity of flame AAS, only some atom trapping techniques will be included here. One kind of atom trapping device is a slotted quartz tube (SQT used for in situ preconcentration of analyte species followed by a rapid revolatilization cycle to obtain an enhanced signal. These devices provide limits of detection at a level of µg L-1. Another kind of atom trapping involves use of vapor generation technique and quartz or tungsten atom trapping surfaces. The analytical steps consist of the generation of volatile species, usually by hydride formation using NaBH4, trapping these species at the surface of an atom trap held at an optimized temperature and finally re-volatilizing analyte species by rapid heating of trap. These species are transported using a carrier gas to an externally heated quartz tube as commonly used in hydride generation AAS systems; a transient signal is formed and measured. These traps have limits of detection in the order of ng L-1.

  4. High-sensitivity matrix-assisted laser desorption/ionization Fourier transform mass spectrometry analyses of small carbohydrates and amino acids using oxidized carbon nanotubes prepared by chemical vapor deposition as matrix. (United States)

    Wang, Cui-hong; Li, Jian; Yao, Sheng-jun; Guo, Yin-long; Xia, Xing-hua


    In matrix-assisted laser desorption/ionization (MALDI) Fourier transform mass spectrometry (FTMS) analyses of small oligosaccharides and amino acids, high sensitivities for oligosaccharides (10 fmol) were obtained by introducing oxidized carbon nanotubes (CNTs) with short and open-end structure as valuable matrix. The CNTs were deposited in porous anodic alumina (PAA) templates by chemical vapor deposition. Transmission electron microscopy (TEM) images show that those CNTs include low levels of amorphous carbon. Thus, the background interference signals generally caused by amorphous carbon powder in CNTs can be reduced effectively. Experiments also confirmed that the FTMS signal intensity of CNTs prepared in PAA template is much lower than that of commercial multi-wall carbon nanotubes (MCNTs). Moreover, the purified process for CNTs with mixed acid (H2SO4 and HNO3) also contributed to the minimization of background. Intense signals corresponding to alkali cation adduct of neutral carbohydrates and amino acids have been acquired. In addition, reliable quantitative analyses for urine and corn root were also achieved successfully. The present work will open a new way to the application of oxidized CNTs as an effective matrix in MALDI MS research.

  5. Aluminum nano-cantilevers for high sensitivity mass sensors

    DEFF Research Database (Denmark)

    Davis, Zachary James; Boisen, Anja


    We have fabricated Al nano-cantilevers using a very simple one mask contact UV lithography technique with lateral dimensions under 500 nm and vertical dimensions of approximately 100 nm. These devices are demonstrated as highly sensitive mass sensors by measuring their dynamic properties. Further...

  6. Molecular Imaging Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Kovac, S.


    Full Text Available Molecular imaging mass spectrometry (IMS is a recently developed method for direct determination of spatial distribution of biopolymers, preferably proteins on cell surface and tissues. Imaging mass spectrometry data are mainly based on Matrix-Assisted Laser Desorption/Ionization- Time of Flight (MALDI TOF. The MALDI TOF based imaging mass spectrometry was applied for determination of changes in kidney tissue of sensitive mice after poisoning with aristolochic acid I. The second application presented here were changes in the gastric tissue in mice after infection with Helicobacter pylori, as a model of gastric cancer in humans caused by this pathogen microorganism. Molecular imaging mass spectrometry can be applied in medicine, mostly for identification of candidate biomarkers for malignant and non-malignant diseases. Furthermore, imaging MS has almost unlimited capacity in agriculture, food technology and biotechnology, e. g. for monitoring, process development and quality control of manufactured tissue of animal, plant and microbial origin.

  7. Fourier Transform Mass Spectrometry. (United States)

    Gross, Michael L.; Rempel, Don L.


    Discusses the nature of Fourier transform mass spectrometry and its unique combination of high mass resolution, high upper mass limit, and multichannel advantage. Examines its operation, capabilities and limitations, applications (ion storage, ion manipulation, ion chemistry), and future applications and developments. (JN)

  8. Laser sputter neutral mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    King, B.V.; Clarke, M.; Hu, H.; Betz [Newcastle Univ., NSW (Australia). Dept. of Physics


    Laser sputter neutral mass spectrometry (LSNMS) is an emerging technique for highly sensitive surface analysis. In this technique a target is bombarded with a pulsed beam of keV ions. The sputtered particles are intercepted by a high intensity pulsed laser beam above the surface and ionised with almost 100% efficiency. The photions may then be mass analysed using a quadrupole or, more commonly, using time of flight (TOF) techniques. In this method photoions are extracted from the ionisation region, accelerated to a known energy E{sub o} and strike a channelplate detector a distance `d` away. The flight time `t` of the photoions is then related to their mass by `d` {radical}m / {radical} 2E{sub o} so measurement of `t` allows mass spectra to be obtained. It is found that LSNMS is an emerging technique of great sensitivity and flexibility, useful for both applied analysis and to investigate basic sputtering processes. 4 refs., 3 figs.

  9. Fast determination of pesticides and other contaminants of emerging concern in treated wastewater using direct injection coupled to highly sensitive ultra-high performance liquid chromatography-tandem mass spectrometry. (United States)

    Campos-Mañas, Marina Celia; Plaza-Bolaños, Patricia; Sánchez-Pérez, José Antonio; Malato, Sixto; Agüera, Ana


    It is well known that wastewater treatment plant (WWTP) effluents usually contain micropollutants such as pharmaceuticals (or their transformation products, TPs) or pesticides, which is a major issue when evaluating their possible reuse (e.g. for irrigation in agriculture). In search for an improved accuracy and simplicity, methods based on the direct injection of the sample (DI) represent a recent trend taking advantage of the increasing sensitivity of new mass spectrometry (MS) instruments. Thus, the present study shows the development and validation of a DI-based method by ultra-high-performance liquid chromatography quadrupole-linear ion trap analyser (UHPLC-QqLIT-MS/MS). The proposed method was applied to the monitoring of 115 organic microcontaminants (including pharmaceuticals, TPs and pesticides) at the ngL -1 /μgL -1 level in wastewater effluents from urban WWTPs. Sample pre-treatment was reduced to acetonitrile addition and filtration of the mixture previous to LC-MS analysis. Total analysis time was <15min. A subsequent validation protocol was carried out in treated WW (TWW), following indications of SANTE and Eurachem Guidelines. Linearity and matrix effect were evaluated in the range of 10-1000ngL -1 . 70% of the analytes showed a moderate matrix effect (≤25%). Trueness (expressed as recovery) and precision (calculated as relative standard deviation, RSD) were evaluated at four concentration levels (20, 50, 500 and 1000ngL -1 ) in TWW samples. The LODs ranged from 1 to 357ngL -1 and the LOQs from 10 to 500ngL -1 . 92% of the compounds showed limits of quantification ≤100ngL -1 . In most cases, mean recoveries were in the range 70-120%, and RSD values were ≤20%. The validated method was successfully applied to the analysis of 10 TWW samples, demonstrating the occurrence of 67 target compounds at concentration levels from 26705ngL -1 (4-aminoantipyrine) to 10ngL -1 (tebuconazole and bezafibrate). Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Ambient ionization mass spectrometry (United States)

    Lebedev, A. T.


    Ambient ionization mass spectrometry emerged as a new scientific discipline only about ten years ago. A considerable body of information has been reported since that time. Keeping the sensitivity, performance and informativity of classical mass spectrometry methods, the new approach made it possible to eliminate laborious sample preparation procedures and triggered the development of miniaturized instruments to work directly in the field. The review concerns the theoretical foundations and design of ambient ionization methods. Their advantages and drawbacks, as well as prospects for application in chemistry, biology, medicine, environmetal analysis, etc., are discussed. The bibliography includes 194 references.

  11. High-throughput and high-sensitivity quantitative analysis of serum unsaturated fatty acids by chip-based nanoelectrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry: early stage diagnostic biomarkers of pancreatic cancer. (United States)

    Zhang, Yaping; Qiu, Ling; Wang, Yanmin; Qin, Xuzhen; Li, Zhili


    In this study, Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) coupled with chip-based direct-infusion nanoelectrospray ionization source (CBDInanoESI) in a negative ion mode is first employed to evaluate the effect of serum and its corresponding supernatant matrixes on the recoveries of serum free fatty acids (FFAs) based on spike-and-recovery experimental strategy by adding analytes along with analog internal standard (IS). The recoveries between serum (69.8-115.6%) and the supernatant (73.6-99.0%) matrixes are almost identical. Multiple point internal standard calibration curves between the concentration ratios of individual fatty acids to ISs, (C(17:1) as IS of C(16:1), C(18:3), C(18:2), or C(18:1) or C(21:0) as IS of C(20:4) or C(22:6)) versus their corresponding intensity ratios were constructed for C(16:1), C(18:3), C(18:2), C(18:1), C(20:4) and C(22:6), respectively, with correlation coefficients of greater than 0.99, lower limits of detection between 0.3 and 1.8 nM, and intra- and inter-day precision (relative standard deviations <18%), along with the linear dynamic range of three orders of magnitude. Sequentially, this advanced analytical platform was applied to perform simultaneous quantitative and qualitative analysis of multiple targets, e.g., serum supernatant unsaturated FFAs from 361 participants including 95 patients with pancreatic cancer (PC), 61 patients with pancreatitis and 205 healthy controls. Experimental results indicate that the levels of C(18:1), C(18:2), C(18:3), C(20:4) and C(22:6), as well as the level ratios of C(18:2)/C(18:1) and C(18:3)/C(18:1) of the PC patients were significantly decreased compared with those of healthy controls and the patients with pancreatitis (p < 0.01). It is worth noting that the ratio of C(18:2)/C(18:1), polyunsaturated fatty acids (PUFAs) (C(18:2), C(18:3), C(20:4), and C(22:6)), panel a (C(16:1), C(18:3), C(18:2), C(20:4) and C(22:6)) and panel b (C(18:2)/C(18:1) and C(18:3)/C(18

  12. Miniaturization and Mass Spectrometry

    NARCIS (Netherlands)

    le Gac, S.; le Gac, Severine; van den Berg, Albert; van den Berg, A.; Unknown, [Unknown


    With this book we want to illustrate how two quickly growing fields of instrumentation and technology, both applied to life sciences, mass spectrometry and microfluidics (or microfabrication) naturally came to meet at the end of the last century and how this marriage impacts on several types of

  13. Mass spectrometry imaging for biomedical applications. (United States)

    Liu, Jiangjiang; Ouyang, Zheng


    The development of technologies for mass spectrometry imaging is of substantial research interest. Mass spectrometry is potentially capable of providing highly specific information about the distribution of compounds in tissues, with high sensitivity. The in-situ analysis needed for tissue imaging requires MS to be performed under conditions different from the traditional ones, typically with intensive sample preparation and optimized for pharmaceutical applications. In this paper we critically review the current status of MS imaging with different methods of sample ionization and discuss the 3D and quantitative imaging capabilities which need further development, the importance of the multi-modal imaging, and the balance between the pursuit of high-resolution imaging and the practical application of MS imaging in biomedicine.

  14. Mass Spectrometry of Halopyrazolium Salts

    DEFF Research Database (Denmark)

    Larsen, Elfinn; Egsgaard, Helge; Pande, U. C.


    Eleven halogen substituted 1-methyl-2-phenylpyrazolium bromides or chlorides were investigated by field desorption, field ionization, and electron impact mass spectrometry. Dealkylation was found to be the predominant thermal decomposition. An exchange between covalent and ionic halogen prior...

  15. Cluster secondary ion mass spectrometry microscope mode mass spectrometry imaging. (United States)

    Kiss, András; Smith, Donald F; Jungmann, Julia H; Heeren, Ron M A


    Microscope mode imaging for secondary ion mass spectrometry is a technique with the promise of simultaneous high spatial resolution and high-speed imaging of biomolecules from complex surfaces. Technological developments such as new position-sensitive detectors, in combination with polyatomic primary ion sources, are required to exploit the full potential of microscope mode mass spectrometry imaging, i.e. to efficiently push the limits of ultra-high spatial resolution, sample throughput and sensitivity. In this work, a C60 primary source was combined with a commercial mass microscope for microscope mode secondary ion mass spectrometry imaging. The detector setup is a pixelated detector from the Medipix/Timepix family with high-voltage post-acceleration capabilities. The system's mass spectral and imaging performance is tested with various benchmark samples and thin tissue sections. The high secondary ion yield (with respect to 'traditional' monatomic primary ion sources) of the C60 primary ion source and the increased sensitivity of the high voltage detector setup improve microscope mode secondary ion mass spectrometry imaging. The analysis time and the signal-to-noise ratio are improved compared with other microscope mode imaging systems, all at high spatial resolution. We have demonstrated the unique capabilities of a C60 ion microscope with a Timepix detector for high spatial resolution microscope mode secondary ion mass spectrometry imaging. Copyright © 2013 John Wiley & Sons, Ltd.

  16. Mass spectrometry. [in organic chemistry (United States)

    Burlingame, A. L.; Shackleton, C. H. L.; Howe, I.; Chizhov, O. S.


    A review of mass spectrometry in organic chemistry is given, dealing with advances in instrumentation and computer techniques, selected topics in gas-phase ion chemistry, and applications in such fields as biomedicine, natural-product studies, and environmental pollution analysis. Innovative techniques and instrumentation are discussed, along with chromatographic-mass spectrometric on-line computer techniques, mass spectral interpretation and management techniques, and such topics in gas-phase ion chemistry as electron-impact ionization and decomposition, photoionization, field ionization and desorption, high-pressure mass spectrometry, ion cyclotron resonance, and isomerization reactions of organic ions. Applications of mass spectrometry are examined with respect to bio-oligomers and their constituents, biomedically important substances, microbiology, environmental organic analysis, and organic geochemistry.

  17. Instrumentation for mass spectrometry: 1997

    Energy Technology Data Exchange (ETDEWEB)

    McLuckey, S.A.


    All mass spectrometry experiments involve the manipulation of material, an interface with the mass spectrometer, ionization, ion manipulation/analysis, detection and data collection/reduction. Each of these elements involve instrumentation. The wide range of species now amenable to mass spectrometry and the diverse areas of physical science in which it plays a role have led to a seemingly unlimited array of instrumental combinations. However, only a limited number of mass analyzers, and their combinations, dominate. The dominant analyzers include time-of-flight, Fourier transform ion cyclotron resonance, the Paul trap, the mass filter, and the sector mass spectrometer. Why there are so few (or so many, depending upon one`s point of view) can be understood upon consideration of a set of mass analyzer figures of merit. These include mass resolution, mass accuracy, mass range, dynamic range, abundance sensitivity, precision, efficiency, speed, MS{sup n} capability, compatibility with the ionizer, cost, and size. The most appropriate form of mass spectrometry is determined by the priorities of the particular measurement placed on the various mass analyzer characteristics and the relative strengths of the analyzers in meeting the requirements. Each of the analyzer types has a unique set of figures of merit that makes it optimally suited for particular applications. This paper discusses these figures of merit, provides data illustrating recent developments for each analyzer type, and gives the figures of merit of each type of analyzer as they stand in 1997. 101 refs., 24 figs.

  18. Protein Quantitation Using Mass Spectrometry (United States)

    Zhang, Guoan; Ueberheide, Beatrix M.; Waldemarson, Sofia; Myung, Sunnie; Molloy, Kelly; Eriksson, Jan; Chait, Brian T.; Neubert, Thomas A.; Fenyö, David


    Mass spectrometry is a method of choice for quantifying low-abundance proteins and peptides in many biological studies. Here, we describe a range of computational aspects of protein and peptide quantitation, including methods for finding and integrating mass spectrometric peptide peaks, and detecting interference to obtain a robust measure of the amount of proteins present in samples. PMID:20835801

  19. Advances in Clinical Mass Spectrometry. (United States)

    French, D

    Although mass spectrometry has been used clinically for decades, the advent of immunoassay technology moved the clinical laboratory to more labor saving automated platforms requiring little if any sample preparation. It became clear, however, that immunoassays lacked sufficient sensitivity and specificity necessary for measurement of certain analytes or for measurement of analytes in specific patient populations. This limitation prompted clinical laboratories to revisit mass spectrometry which could additionally be used to develop assays for which there was no commercial source. In this chapter, the clinical applications of mass spectrometry in therapeutic drug monitoring, toxicology, and steroid hormone analysis will be reviewed. Technologic advances and new clinical applications will also be discussed. © 2017 Elsevier Inc. All rights reserved.

  20. Symposium on accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)



    The area of accelerator mass spectrometry has expanded considerably over the past few years and established itself as an independent and interdisciplinary research field. Three years have passed since the first meeting was held at Rochester. A Symposium on Accelerator Mass Spectrometry was held at Argonne on May 11-13, 1981. In attendance were 96 scientists of whom 26 were from outside the United States. The present proceedings document the program and excitement of the field. Papers are arranged according to the original program. A few papers not presented at the meeting have been added to complete the information on the status of accelerator mass spectrometry. Individual papers were prepared separately for the data base.

  1. Cluster secondary ion mass spectrometry microscope mode mass spectrometry imaging

    NARCIS (Netherlands)

    Kiss, A.; Smith, D.F.; Jungmann, JH|info:eu-repo/dai/nl/351240020; Heeren, R.M.A.|info:eu-repo/dai/nl/105188476


    RATIONALE: Microscope mode imaging for secondary ion mass spectrometry is a technique with the promise of simultaneous high spatial resolution and high-speed imaging of biomolecules from complex surfaces. Technological developments such as new position-sensitive detectors, in combination with

  2. Quantitative mass spectrometry methods for pharmaceutical analysis. (United States)

    Loos, Glenn; Van Schepdael, Ann; Cabooter, Deirdre


    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'. © 2016 The Author(s).

  3. Mass Spectrometry in Polymer Chemistry

    CERN Document Server

    Barner-Kowollik, Christopher; Falkenhagen, Jana; Weidner, Steffen


    Combining an up-to-date insight into mass-spectrometric polymer analysis beyond MALDI with application details of the instrumentation, this is a balanced and thorough presentation of the most important and widely used mass-spectrometric methods.Written by the world's most proficient experts in the field, the book focuses on the latest developments, covering such technologies and applications as ionization protocols, tandem and liquid chromatography mass spectrometry, gas-phase ion-separation techniques and automated data processing. Chapters on sample preparation, polymer degradation and the u

  4. Mass spectrometry. [review of techniques (United States)

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


    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.

  5. Atomic mass spectrometry of materials (United States)

    Anthony, J. M.; Matteson, S.; Duggan, J. L.; Elliott, P.; Marble, D.; McDaniel, F. D.; Weathers, D.


    Texas Instruments and the University of North Texas (UNT) are collaborating on the design of an accelerator mass spectrometry (AMS) system dedicated primarily to the analysis of impurities in electronic materials and metals. An AMS beamline consisting of high-resolution magnetic ( {M}/{dM } > 350) and electrostatic ( {E}/{dE } > 700) analysis followed by a surface barrier detector has been installed on the NEC 9SDH pelletron at UNT, and a "clean" ion source is under development. An existing ion source (NEC Cs sputter source) has been used in conjunction with the AMS beamline to generate computer controlled molecule-free mass analyses of solid samples. Through a careful choice of isotopes and charge states a robust algorithm can be developed for removing molecular interferences from the mass analysis for essentially all materials. Examples using graphite, Si and CdZnTe are discussed.

  6. Mass spectrometry in epigenetic research

    DEFF Research Database (Denmark)

    Beck, Hans Christian


    cancers has gained tremendous interest in recent years, and many of these inhibitors are currently undergoing clinical trials. Despite intense research, however, the exact molecular mechanisms of action of these molecules remain, to a wide extent, unclear. The recent application of mass spectrometry......-based proteomics techniques to histone biology has gained new insight into the function of the nucleosome: Novel posttranslational modifications have been discovered at the lateral surface of the nucleosome. These modifications regulate histone-DNA interactions, adding a new dimension to the epigenetic regulation...

  7. Protein Analysis by Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Cindic, M.


    Full Text Available Soft ionization techniques, electrospray (ESI and matrix-assisted laser desorption/ionization (MALDI make the analysis of biomolecules by mass spectrometry (MS possible. MS is used for determination of the molecular weight of peptides and protein, sequence analysis, characterization of protein-ligand interactions etc. The detection limit, resolution and mass accuracy depend on instrument used (Table 1. Impurities (buffers, salts, detergents can reduce the ion intensities or even totally suppress them, so a separation method (chromatography, 2D-gel electrophoresis must be used for purification of the sample.Molecular mass of intact protein can be determined by ESI or MALDI MS. Multiply charged ions are produced by ESI MS, while singly charged ions are predominant in MALDI spectra (Fig. 2.Sequence analysis of proteins by MS can be performed using peptide mass fingerprint. In this method, proteins are separated by 2-D gel electrophoresis and digested with specific protease (Table 2 or digested and then separated by two-dimensional chromatography (Fig. 1. The obtained peptide mixtures are analyzed by MS or MALDI-TOF technique. The masses determined by MS are compared with calculated masses from database entries. Different algorithms have been developed for protein identification. Example of posttranslational modifications (N- and O-glycosylation and protein sequence complex analysis after dual digestion (endoproteinase digestion followed by endoglycosidase digestion is shown in Fig. 3.It is known that detection of peptides by MS is influenced by intrinsic properties like amino acid composition, the basicity of the C-terminal amino acid, hydrophobicity, etc. Arginine-containing peptides dominate in MS spectra of tryptic digest, so the chemical derivatization of lysine terminal residue by O-methilisourea or 2-methoxy-4,5-1H-imidazole was suggested (Fig. 4.The peptide mass fingerprint method can be improved further by peptide fragmentation using tandem

  8. Neuroscience and Accelerator Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Palmblad, M N; Buchholz, B A; Hillegonds, D J; Vogel, J S


    Accelerator mass spectrometry (AMS) is a mass spectrometric method for quantifying rare isotopes. It has had great impact in geochronology and archaeology and is now being applied in biomedicine. AMS measures radioisotopes such as {sup 3}H, {sup 14}C, {sup 26}Al, {sup 36}Cl and {sup 41}Ca, with zepto- or attomole sensitivity and high precision and throughput, enabling safe human pharmacokinetic studies involving: microgram doses, agents having low bioavailability, or toxicology studies where administered doses must be kept low (<1 {micro}g/kg). It is used to study long-term pharmacokinetics, to identify biomolecular interactions, to determine chronic and low-dose effects or molecular targets of neurotoxic substances, to quantify transport across the blood-brain barrier and to resolve molecular turnover rates in the human brain on the timescale of decades. We will here review how AMS is applied in neurotoxicology and neuroscience.

  9. The allure of mass spectrometry: From an earlyday chemist's perspective (United States)


    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

  10. Mass spectrometry-based analysis of whole-grain phytochemicals. (United States)

    Koistinen, Ville Mikael; Hanhineva, Kati


    Whole grains are a rich source of several classes of phytochemicals, such as alkylresorcinols, benzoxazinoids, flavonoids, lignans, and phytosterols. A high intake of whole grains has been linked to a reduced risk of some major noncommunicable diseases, and it has been postulated that a complex mixture of phytochemicals works in synergy to generate beneficial health effects. Mass spectrometry, especially when coupled with liquid chromatography, is a widely used method for the analysis of phytochemicals owing to its high sensitivity and dynamic range. In this review, the current knowledge of the mass spectral properties of the most important classes of phytochemicals found in cereals of common wheat, barley, oats, and rye is discussed.

  11. NICHD Biomedical Mass Spectrometry Core Facility (United States)

    Federal Laboratory Consortium — The NICHD Biomedical Mass Spectrometry Core Facility was created under the auspices of the Office of the Scientific Director to provide high-end mass-spectrometric...

  12. Improved sensitivity using liquid chromatography mass spectrometry ...

    African Journals Online (AJOL)

    Triple quadrupole mass spectrometry (MS/MS) was used to confirm the identity of BMAA in cyanobacteria based on product ions. We show a 10-fold increase in sensitivity with the LC-MS method compared to the previously published gas chromatography mass spectrometry (GC-MS) method with pre-column derivatised ...

  13. Development of stereotactic mass spectrometry for brain tumor surgery. (United States)

    Agar, Nathalie Y R; Golby, Alexandra J; Ligon, Keith L; Norton, Isaiah; Mohan, Vandana; Wiseman, Justin M; Tannenbaum, Allen; Jolesz, Ferenc A


    Surgery remains the first and most important treatment modality for the majority of solid tumors. Across a range of brain tumor types and grades, postoperative residual tumor has a great impact on prognosis. The principal challenge and objective of neurosurgical intervention is therefore to maximize tumor resection while minimizing the potential for neurological deficit by preserving critical tissue. To introduce the integration of desorption electrospray ionization mass spectrometry into surgery for in vivo molecular tissue characterization and intraoperative definition of tumor boundaries without systemic injection of contrast agents. Using a frameless stereotactic sampling approach and by integrating a 3-dimensional navigation system with an ultrasonic surgical probe, we obtained image-registered surgical specimens. The samples were analyzed with ambient desorption/ionization mass spectrometry and validated against standard histopathology. This new approach will enable neurosurgeons to detect tumor infiltration of the normal brain intraoperatively with mass spectrometry and to obtain spatially resolved molecular tissue characterization without any exogenous agent and with high sensitivity and specificity. Proof of concept is presented in using mass spectrometry intraoperatively for real-time measurement of molecular structure and using that tissue characterization method to detect tumor boundaries. Multiple sampling sites within the tumor mass were defined for a patient with a recurrent left frontal oligodendroglioma, World Health Organization grade II with chromosome 1p/19q codeletion, and mass spectrometry data indicated a correlation between lipid constitution and tumor cell prevalence. The mass spectrometry measurements reflect a complex molecular structure and are integrated with frameless stereotaxy and imaging, providing 3-dimensional molecular imaging without systemic injection of any agents, which can be implemented for surgical margins delineation of

  14. Absorption Mode FTICR Mass Spectrometry Imaging

    NARCIS (Netherlands)

    Smith, D.F.; Kilgour, D.P.A.; Konijnenburg, M.; O'Connor, P.B.; Heeren, R.M.A.|info:eu-repo/dai/nl/105188476


    Fourier transform ion cyclotron resonance mass spectrometry offers the highest mass resolving power for molecular imaging experiments. This high mass resolving power ensures that closely spaced peaks at the same nominal mass are resolved for proper image generation. Typically higher magnetic fields

  15. Zero voltage mass spectrometry probes and systems

    Energy Technology Data Exchange (ETDEWEB)

    Cooks, Robert Graham; Wleklinski, Michael Stanley; Bag, Soumabha; Li, Yafeng


    The invention generally relates to zero volt mass spectrometry probes and systems. In certain embodiments, the invention provides a system including a mass spectrometry probe including a porous material, and a mass spectrometer (bench-top or miniature mass spectrometer). The system operates without an application of voltage to the probe. In certain embodiments, the probe is oriented such that a distal end faces an inlet of the mass spectrometer. In other embodiments, the distal end of the probe is 5 mm or less from an inlet of the mass spectrometer.

  16. Development of Accelerator Mass Spectrometry at the Lund Pelletron (United States)

    Hellborg, R.; Curtis, L. J.; Erlandsson, B.; Faarinen, M.; Kiisk, M.; Magnusson, C.-E.; Persson, P.; Skog, G.; Stenström, K.

    Accelerator mass spectrometry (AMS) is a highly sensitive method for counting atoms. It is used for detecting very low concentrations of both radionuclides and stable nuclides. The main advantages of AMS compared to conventional radiometric methods are the use of smaller samples (mg size) and shorter measuring times (less than one hour). In AMS, rare isotopes from a sample material placed in the ion source of an electrostatic tandem accelerator are measured by counting individual atoms with nuclear detection techniques after acceleration to energies in the MeV range. A dramatic improvement in background rejection for AMS systems has, in the best cases, led to a 108 increase in sensitivity for isotope ratio measurements compared to the older technique of mass spectrometry. In this report some current applications of the AMS technique at the Lund Pelletron accelerator, as well as the recent improvements of the Lund system, are presented.

  17. Native Mass Spectrometry in Fragment-Based Drug Discovery

    Directory of Open Access Journals (Sweden)

    Liliana Pedro


    Full Text Available 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.

  18. Introduction to mass spectrometry-based proteomics

    DEFF Research Database (Denmark)

    Matthiesen, R.; Bunkenborg, J.


    Mass spectrometry has been widely applied to study biomolecules and one rapidly developing field is the global analysis of proteins, proteomics. Understanding and handling mass spectrometry data is a multifaceted task that requires many decisions to be made to get the most comprehensive information...... from an experiment. Later chapters in this book deal in-depth with various aspects of the process and how different tools can be applied to the many analytical challenges. This introductory chapter is intended as a basic introduction to mass spectrometry (MS)-based proteomics to set the scene....... © Springer Science+Business Media, LLC 2013....

  19. Mass spectrometry of long-lived radionuclides (United States)

    Becker, Johanna Sabine


    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

  20. Highly sensitive solids mass spectrometer uses inert-gas ion source (United States)


    Mass spectrometer provides a recorded analysis of solid material surfaces and bulk. A beam of high-energy inert-gas ions bombards the surface atoms of a sample and converts a percentage into an ionized vapor. The mass spectrum analyzer separates the vapor ionic constituents by mass-to-charge ratio.

  1. Pyrolysis - gas chromatography - mass spectrometry of lignins

    Energy Technology Data Exchange (ETDEWEB)

    Martin, F.; Saiz-Jimenez, C.; Gonzalez-Vila, F.J.


    Milled wood lignins from spruce, beech and bamboo were pyrolysed. The high-boiling products of pyrolysis were studied by GLC and mass spectrometry. The forty-three products identified provide information on the structural units of lignin.

  2. Ion sampling and transport in Inductively Coupled Plasma Mass Spectrometry (United States)

    Farnsworth, Paul B.; Spencer, Ross L.


    Quantitative accuracy and high sensitivity in inductively coupled plasma mass spectrometry (ICP-MS) depend on consistent and efficient extraction and transport of analyte ions from an inductively coupled plasma to a mass analyzer, where they are sorted and detected. In this review we examine the fundamental physical processes that control ion sampling and transport in ICP-MS and compare the results of theory and computerized models with experimental efforts to characterize the flow of ions through plasma mass spectrometers' vacuum interfaces. We trace the flow of ions from their generation in the plasma, into the sampling cone, through the supersonic expansion in the first vacuum stage, through the skimmer, and into the ion optics that deliver the ions to the mass analyzer. At each stage we consider idealized behavior and departures from ideal behavior that affect the performance of ICP-MS as an analytical tool.

  3. Computational Mass Spectrometry (Dagstuhl Seminar 13491)


    Aebersbold, Ruedi; Kohlbacher, Oliver; Vitek, Olga


    The last decade has brought tremendous technological advances in mass spectrometry, which in turn have enabled new applications of mass spectrometry in the life sciences. Proteomics, metabolomics, lipidomics, glycomics and related fields have gotten a massive boost, which also resulted in vastly increased amount of data produced and increased complexity of these data sets. An efficient and accurate analysis of these data sets has become the key bottleneck in the field. The seminar 'Com...

  4. Highly sensitive mass detection and identification using vibration localization in coupled microcantilever arrays (United States)

    Spletzer, Matthew; Raman, Arvind; Sumali, Hartono; Sullivan, John P.


    We study the use of vibration localization in large arrays of mechanically coupled, nearly identical microcantilevers for ultrasensitive mass detection and identification. We demonstrate that eigenmode changes in such an array can be two to three orders of magnitude greater than relative changes in resonance frequencies when an analyte mass is added. Moreover, the changes in eigenmodes are unique to the cantilever to which mass is added, thereby providing a characteristic "fingerprint" that identifies the particular cantilever where mass has been added. This opens the door to ultrasensitive detection and identification of multiple analytes with a single coupled array.

  5. Mass Spectrometry as a Powerful Analytical Technique for the Structural Characterization of Synthesized and Natural Products (United States)

    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.

  6. Wireless, Low Mass, High Sensitivity Sensing Sheet for Structural Sensing and Long Term Analysis Project (United States)

    National Aeronautics and Space Administration — NASA needs sensor systems to inspect space structures with minimum human interaction. These systems must be highly integrated and self-sufficient, low mass, simple...

  7. Accurate Protein Complex Retrieval by Affinity Enrichment Mass Spectrometry (AE-MS) Rather than Affinity Purification Mass Spectrometry (AP-MS)


    Keilhauer, E.; Hein, M; Mann, M


    Protein?protein interactions are fundamental to the understanding of biological processes. Affinity purification coupled to mass spectrometry (AP-MS) is one of the most promising methods for their investigation. Previously, complexes were purified as much as possible, frequently followed by identification of individual gel bands. However, todays mass spectrometers are highly sensitive, and powerful quantitative proteomics strategies are available to distinguish true interactors from backgroun...

  8. Mass spectrometry for fragment screening. (United States)

    Chan, Daniel Shiu-Hin; Whitehouse, Andrew J; Coyne, Anthony G; Abell, Chris


    Fragment-based approaches in chemical biology and drug discovery have been widely adopted worldwide in both academia and industry. Fragment hits tend to interact weakly with their targets, necessitating the use of sensitive biophysical techniques to detect their binding. Common fragment screening techniques include differential scanning fluorimetry (DSF) and ligand-observed NMR. Validation and characterization of hits is usually performed using a combination of protein-observed NMR, isothermal titration calorimetry (ITC) and X-ray crystallography. In this context, MS is a relatively underutilized technique in fragment screening for drug discovery. MS-based techniques have the advantage of high sensitivity, low sample consumption and being label-free. This review highlights recent examples of the emerging use of MS-based techniques in fragment screening. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  9. Analysis of mass spectrometry data in proteomics

    DEFF Research Database (Denmark)

    Matthiesen, Rune; Jensen, Ole N


    The systematic study of proteins and protein networks, that is, proteomics, calls for qualitative and quantitative analysis of proteins and peptides. Mass spectrometry (MS) is a key analytical technology in current proteomics and modern mass spectrometers generate large amounts of high-quality da...... some of the basic concepts and current approaches to the analysis of MS and MS/MS data in proteomics....

  10. A highly sensitive quartz crystal microbalance immunosensor based on magnetic bead-supported bienzymes catalyzed mass enhancement strategy. (United States)

    Akter, Rashida; Rhee, Choong Kyun; Rahman, Md Aminur


    A highly sensitive quartz crystal microbalance (QCM) immunosensor based on magnetic bead-supported bienzyme catalyzed mass enhanced strategy was developed for the detection of human immunoglobulin G (hIgG) protein. The high sensitive detection was achieved by increasing the deposited mass on the QCM crystal through the enhanced precipitation of 4-chloro-1-naphthol (CN) using higher amounts of horseradish peroxidase (HRP) and glucose oxidase (GOx) bienzymes attached on the magnetic beads (MB). The protein A (PA) and capture antibody (monoclonal anti-human IgG antibody produced in mouse, Ab1)-based QCM probe and the detection antibody (anti-human IgG antibody produced in goat, Ab2)-based MB/HRP/GOx bienzymatic bioconjugates were characterized using scanning electron microscope, transmission electron microscope, cyclic voltammetry, and electrochemical impedance spectroscopy techniques. Under the optimized experimental condition, the linear range and the detection limit of hIgG immunosensor were determined to be 5.0pg/mL-20.0ng/mL and 5.0±0.18pg/mL, respectively. The applicability of the present hIgG immunosensor was examined in hIgG spiked human serum samples and excellent recoveries of hIgG were obtained. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Mass Spectrometry Instrumentation in Proteomics

    DEFF Research Database (Denmark)

    Sprenger, Richard Remko; Roepstorff, Peter


    , Orbitrap and ion mobility instruments. Together they offer various and complementary capabilities in terms of ionization, sensitivity, speed, resolution, mass accuracy, dynamic range and methods of fragmentation. Mass spectrometers can acquire qualitative and quantitative information on a large scale....... In terms of desired outcome, cost and time, combining and choosing between available instrumentation and methodologies is key to find the best analytical strategy suiting a particular proteomics experiment....

  12. Mass spectrometry-assisted protease substrate screening

    DEFF Research Database (Denmark)

    Schlüter, Hartmut; Rykl, Jana; Thiemann, Joachim


    Since sequencing of the human genome was completed, more than 500 genes have been annotated as proteases. Exploring the physiological role of each protease requires the identification of their natural substrates. However, the endogenous substrates of many of the human proteases are as yet unknown......-phase chromatography they are analyzed by tandem mass spectrometry and the substrates identified by database searching. The proof of principle in this study is demonstrated by incubating immobilized human plasma proteins with thrombin and by identifying by tandem mass spectrometry the fibrinopeptides, released...

  13. A history of mass spectrometry in Australia. (United States)

    Downard, Kevin M; de Laeter, John R


    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

  14. A history of mass spectrometry in Australia

    Energy Technology Data Exchange (ETDEWEB)

    Downard, K.M.; de Laeter, J.R. [University of Sydney, Sydney, NSW (Australia)


    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. This article traces the history of mass spectrometry in its many guises and applications in the island continent of Australia. It 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.

  15. Targeted quantitation of proteins by mass spectrometry. (United States)

    Liebler, Daniel C; Zimmerman, Lisa J


    Quantitative measurement of proteins is one of the most fundamental analytical tasks in a biochemistry laboratory, but widely used immunochemical methods often have limited specificity and high measurement variation. In this review, we discuss applications of multiple-reaction monitoring (MRM) mass spectrometry, which allows sensitive, precise quantitative analyses of peptides and the proteins from which they are derived. Systematic development of MRM assays is permitted by databases of peptide mass spectra and sequences, software tools for analysis design and data analysis, and rapid evolution of tandem mass spectrometer technology. Key advantages of MRM assays are the ability to target specific peptide sequences, including variants and modified forms, and the capacity for multiplexing that allows analysis of dozens to hundreds of peptides. Different quantitative standardization methods provide options that balance precision, sensitivity, and assay cost. Targeted protein quantitation by MRM and related mass spectrometry methods can advance biochemistry by transforming approaches to protein measurement.

  16. Chemistry Nobel Prize 2002-Mass Spectrometry

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 8; Issue 4. Chemistry Nobel Prize 2002 - Mass Spectrometry. M Vairamani. Research News Volume 8 Issue 4 April 2003 pp 69-76. Fulltext. Click here to view fulltext PDF. Permanent link: ...

  17. Characterization of microbial siderophores by mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Pluháček, Tomáš; Lemr, Karel; Ghosh, D.; Milde, D.; Novák, Jiří; Havlíček, Vladimír


    Roč. 35, č. 1 (2016), s. 35-47 ISSN 0277-7037 R&D Projects: GA MŠk(CZ) LD13038; GA ČR(CZ) GAP206/12/1150; GA MŠk(CZ) LO1509 Institutional support: RVO:61388971 Keywords : iron * siderophores * mass spectrometry Subject RIV: CE - Biochemistry Impact factor: 9.373, year: 2016

  18. Pyrolysis Mass Spectrometry of Complex Organic Materials. (United States)

    Meuzelaar, Henk L. C.; And Others


    Illustrates the state of the art in pyrolysis mass spectrometry techniques through applications in: (1) structural determination and quality control of synthetic polymers; (2) quantitative analysis of polymer mixtures; (3) classification and structural characterization of fossil organic matter; and (4) nonsupervised numerical extraction of…

  19. Nanostructure-initiator mass spectrometry biometrics

    Energy Technology Data Exchange (ETDEWEB)

    Leclerc, Marion; Bowen, Benjamin; Northen, Trent


    Several embodiments described herein are drawn to methods of identifying an analyte on a subject's skin, methods of generating a fingerprint, methods of determining a physiological change in a subject, methods of diagnosing health status of a subject, and assay systems for detecting an analyte and generating a fingerprint, by nanostructure-initiator mass spectrometry (NIMS).

  20. Atmospheric pressure femtosecond laser imaging mass spectrometry (United States)

    Coello, Yves; Gunaratne, Tissa C.; Dantus, Marcos


    We present a novel imaging mass spectrometry technique that uses femtosecond laser pulses to directly ionize the sample. The method offers significant advantages over current techniques by eliminating the need of a laser-absorbing sample matrix, being suitable for atmospheric pressure sampling, and by providing 10μm resolution, as demonstrated here with a chemical image of vegetable cell walls.

  1. Characterization of Synthetic Peptides by Mass Spectrometry

    DEFF Research Database (Denmark)

    Prabhala, Bala K; Mirza, Osman; Højrup, Peter


    Mass spectrometry (MS) is well suited for analysis of the identity and purity of synthetic peptides. The sequence of a synthetic peptide is most often known, so the analysis is mainly used to confirm the identity and purity of the peptide. Here, simple procedures are described for MALDI...

  2. Four decades of joy in mass spectrometry

    NARCIS (Netherlands)

    Nibbering, N.M.M.


    Tremendous developments in mass spectrometry have taken place in the last 40 years. This holds for both the science and the instrumental revolutions in this field. In chemistry the research was heavily focused on organic molecules that upon electron ionization fragmented via complex mechanistic

  3. Polymer and Additive Mass Spectrometry Literature Review

    Energy Technology Data Exchange (ETDEWEB)

    Shear, Trevor Allan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    The use of mass spectrometry in fields related to polymers has increased significantly over the past three decades and will be explored in this literature review. The importance of this technique is highlighted when exploring how polymers degrade, verifying purchased materials, and as internal requirements change. The primary focus will be on four ionization techniques and the triple quadrupole and quadrupole / time-of-flight mass spectrometers. The advantages and limitations of each will also be explored.

  4. Accelerator mass spectrometry analysis of background 14C-concentrations in human blood: aiming at reference data for further microdosing studies

    National Research Council Canada - National Science Library

    Minamimoto, Ryogo; Hamabe, Yoshimi; Miyaoka, Teiji; Hara, Takamitsu; Yoshida, Keisuke; Oka, Takashi; Inoue, Tomio


    .... The accelerator mass spectrometry (AMS) system is expected to play an important role in the microdosing tests, as it is a highly sensitive measurement system that can be used to determine the drug concentrations in these tests...

  5. Analytical Aspects of Hydrogen Exchange Mass Spectrometry (United States)

    Engen, John R.; Wales, Thomas E.


    This article reviews the analytical aspects of measuring hydrogen exchange by mass spectrometry (HX MS). We describe the nature of analytical selectivity in hydrogen exchange, then review the analytical tools required to accomplish fragmentation, separation, and the mass spectrometry measurements under restrictive exchange quench conditions. In contrast to analytical quantitation that relies on measurements of peak intensity or area, quantitation in HX MS depends on measuring a mass change with respect to an undeuterated or deuterated control, resulting in a value between zero and the maximum amount of deuterium that can be incorporated. Reliable quantitation is a function of experimental fidelity and to achieve high measurement reproducibility, a large number of experimental variables must be controlled during sample preparation and analysis. The method also reports on important qualitative aspects of the sample, including conformational heterogeneity and population dynamics.

  6. Accelerator mass spectrometry: state of the art

    Energy Technology Data Exchange (ETDEWEB)

    Tuniz, C. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)


    Accelerator Mass Spectrometry (AMS) is the analytical technique of choice for the detection of long-lived radionuclides which cannot be practically analysed with decay counting or conventional mass spectrometry. The main use of AMS has been in the analysis of radiocarbon and other cosmogenic radionuclides for archaeological, geological and environmental applications. In addition, AMS has been recently applied in biomedicine to study exposure of human tissues to chemicals and biomolecules at attomole levels. There is also a world-wide effort to analyse rare nuclides of heavier masses, such as long-lived actinides, with important applications in safeguards and nuclear waste disposal. The use of AMS is limited by the expensive accelerator technology required and there are several attempts to develop smaller and cheaper AMS spectrometers. 5 refs.

  7. Guideline on Isotope Dilution Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Gaffney, Amy [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    Isotope dilution mass spectrometry is used to determine the concentration of an element of interest in a bulk sample. It is a destructive analysis technique that is applicable to a wide range of analytes and bulk sample types. With this method, a known amount of a rare isotope, or ‘spike’, of the element of interest is added to a known amount of sample. The element of interest is chemically purified from the bulk sample, the isotope ratio of the spiked sample is measured by mass spectrometry, and the concentration of the element of interest is calculated from this result. This method is widely used, although a mass spectrometer required for this analysis may be fairly expensive.

  8. Space Applications of Mass Spectrometry. Chapter 31 (United States)

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


    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.

  9. Evolution of Orbitrap Mass Spectrometry Instrumentation (United States)

    Eliuk, Shannon; Makarov, Alexander


    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.

  10. Attomole quantitation of protein separations with accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, J S; Grant, P G; Buccholz, B A; Dingley, K; Turteltaub, K W


    Quantification of specific proteins depends on separation by chromatography or electrophoresis followed by chemical detection schemes such as staining and fluorophore adhesion. Chemical exchange of short-lived isotopes, particularly sulfur, is also prevalent despite the inconveniences of counting radioactivity. Physical methods based on isotopic and elemental analyses offer highly sensitive protein quantitation that has linear response over wide dynamic ranges and is independent of protein conformation. Accelerator mass spectrometry quantifies long-lived isotopes such as 14C to sub-attomole sensitivity. We quantified protein interactions with small molecules such as toxins, vitamins, and natural biochemicals at precisions of 1-5% . Micro-proton-induced-xray-emission quantifies elemental abundances in separated metalloprotein samples to nanogram amounts and is capable of quantifying phosphorylated loci in gels. Accelerator-based quantitation is a possible tool for quantifying the genome translation into proteome.

  11. On-line capillary electrophoresis with Fourier transform ion cyclotron resonance mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Hofstadler, S.A.; Wahl, J.H.; Bruce, J.E.; Smith, R.D. (Pacific Northwest Lab., Richland, WA (United States))


    The role of capillary electrophoresis (CE) in chemical and biochemical characterization is growing rapidly due to its speed, resolution, and flexibility for the manipulation of extremely small samples. CE was first combined with mass spectrometry (MS) at our laboratory. In this communication we report results for the first on-line combination of CE with Fourier transform ion cyclotron resonance (FTICR) mass spectrometry, an approach that is capable of providing both high CE and MS resolution and high sensitivity. The advantages of FTICR include the ability to simultaneously realize ultrahigh MS resolution/mass measurement accuracy and high sensitivity, as well as the capability for higher order tandem MS methods (i.e., MS[sup n], where n [ge] 2) for structural studies because of its nondestructive detection method. 20 refs., 3 figs.

  12. Laser-Cooling-Assisted Mass Spectrometry (United States)

    Schneider, Christian; Schowalter, Steven J.; Chen, Kuang; Sullivan, Scott T.; Hudson, Eric R.


    Mass spectrometry is used in a wide range of scientific disciplines including proteomics, pharmaceutics, forensics, and fundamental physics and chemistry. Given this ubiquity, there is a worldwide effort to improve the efficiency and resolution of mass spectrometers. However, the performance of all techniques is ultimately limited by the initial phase-space distribution of the molecules being analyzed. Here, we dramatically reduce the width of this initial phase-space distribution by sympathetically cooling the input molecules with laser-cooled, cotrapped atomic ions, improving both the mass resolution and detection efficiency of a time-of-flight mass spectrometer by over an order of magnitude. Detailed molecular-dynamics simulations verify the technique and aid with evaluating its effectiveness. This technique appears to be applicable to other types of mass spectrometers.

  13. Proof of the quantitative potential of immunofluorescence by mass spectrometry. (United States)

    Toki, Maria I; Cecchi, Fabiola; Hembrough, Todd; Syrigos, Konstantinos N; Rimm, David L


    Protein expression in formalin-fixed, paraffin-embedded patient tissue is routinely measured by Immunohistochemistry (IHC). However, IHC has been shown to be subject to variability in sensitivity, specificity and reproducibility, and is generally, at best, considered semi-quantitative. Mass spectrometry (MS) is considered by many to be the criterion standard for protein measurement, offering high sensitivity, specificity, and objective molecular quantification. Here, we seek to show that quantitative immunofluorescence (QIF) with standardization can achieve quantitative results comparable to MS. Epidermal growth factor receptor (EGFR) was measured by quantitative immunofluorescence in 15 cell lines with a wide range of EGFR expression, using different primary antibody concentrations, including the optimal signal-to-noise concentration after quantitative titration. QIF target measurement was then compared to the absolute EGFR concentration measured by Liquid Tissue-selected reaction monitoring mass spectrometry. The best agreement between the two assays was found when the EGFR primary antibody was used at the optimal signal-to-noise concentration, revealing a strong linear regression (R 2 =0.88). This demonstrates that quantitative optimization of titration by calculation of signal-to-noise ratio allows QIF to be standardized to MS and can therefore be used to assess absolute protein concentration in a linear and reproducible manner.

  14. Mass spectrometry of fluorocarbon-labeled glycosphingolipids

    DEFF Research Database (Denmark)

    Li, Yunsen; Arigi, Emma; Eichert, Heather


    A method for generation of novel fluorocarbon derivatives of glycosphingolipids (GSLs) with high affinity for fluorocarbon phases has been developed, and their potential applications to mass spectrometry (MS)-based methodologies for glycosphingolipidomics have been investigated. Sphingolipid......, and four fungal glycosylinositol phosphorylceramides (GIPCs) were de-N-acylated, derivatized by prototype F-Tags, and recovered by solid phase extraction on fluorocarbon-derivatized silica (F-SPE). The efficacy of SCDase treatment of GIPCs was here demonstrated for the first time. Compatibility...

  15. Detection of Gunshot Residues Using Mass Spectrometry


    Taudte, Regina Verena; Beavis, Alison; Blanes, Lucas; Cole, Nerida; Doble, Philip; Roux, Claude


    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 t...

  16. Biological insights from hydrogen exchange mass spectrometry. (United States)

    Jaswal, Sheila S


    Over the past two decades, hydrogen exchange mass spectrometry (HXMS) has achieved the status of a widespread and routine approach in the structural biology toolbox. The ability of hydrogen exchange to detect a range of protein dynamics coupled with the accessibility of mass spectrometry to mixtures and large complexes at low concentrations result in an unmatched tool for investigating proteins challenging to many other structural techniques. Recent advances in methodology and data analysis are helping HXMS deliver on its potential to uncover the connection between conformation, dynamics and the biological function of proteins and complexes. This review provides a brief overview of the HXMS method and focuses on four recent reports to highlight applications that monitor structure and dynamics of proteins and complexes, track protein folding, and map the thermodynamics and kinetics of protein unfolding at equilibrium. These case studies illustrate typical data, analysis and results for each application and demonstrate a range of biological systems for which the interpretation of HXMS in terms of structure and conformational parameters provides unique insights into function. This article is part of a Special Issue entitled: Mass spectrometry in structural biology. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Laser Ablation Inductively Coupled Plasma Mass Spectrometry Imaging of Plant Metabolites. (United States)

    Seaman, Callie


    LA-ICP-MS (Laser Ablation Inductively Coupled Plasma Mass Spectrometry) is a highly sensitive isotopic and elemental analytical technique that has a wide application for solid samples such as plant material. Within this chapter we describe how to prepare leaf material, seeds, and fruit for 2D elemental distribution maps, preparation of reference materials, method condition optimization, special resolution calculation, and the limit of detection.

  18. Mass spectrometry for the characterisation of nanoparticles. (United States)

    Montoro Bustos, Antonio R; Ruiz Encinar, Jorge; Sanz-Medel, Alfredo


    Mass spectrometry (MS) has gained much importance in recent years as a powerful tool for reliable analytical characterisation of nanoparticles (NPs). The outstanding capabilities of different MS-based techniques including elemental and molecular detection and their coupling with different separation techniques and mechanisms are outlined herein. Examples of highly valuable elemental and molecular information for a more complete characterisation of NPs are given. Some selected applications illustrate the analytical potential of MS for NP sizing and quantitative assessment of the size distribution as well.

  19. Deciphering Dorin M glycosylation by mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Man, Petr; Kovář, Vojtěch; Štěrba, Ján; Strohalm, Martin; Kavan, Daniel; Kopáček, Petr; Grubhoffer, Libor; Havlíček, Vladimír


    Roč. 14, č. 6 (2008), s. 345-354 ISSN 1469-0667 R&D Projects: GA MŠk LC545; GA MŠk(CZ) LC06009; GA ČR GD524/03/H133 Grant - others:CZ(CZ) SGA2008/017; XE(XE) EC MKTD-CT-2004-014407 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z60220518 Keywords : glycosylation * tandem mass spectrometry * lectin Subject RIV: EE - Microbiology, Virology Impact factor: 1.167, year: 2008

  20. Simultaneous mass detection for direct inlet mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, R.L.


    The evolution of analytical techniques for application in trace analysis has led to interest in practical methods for real-time monitoring. Direct inlet mass spectrometry (DIMS) has been the subject of considerable activity in recent years. A DIMS instrument is described which consists of an inlet system designed to permit particles entrained in the inlet air stream to strike a hot, oxidized rhenium filament which serves as a surface ionization source. A mass analyzer and detection system then permits identification of the elemental composition of particulates which strike the filament.

  1. Protein Sequencing with Tandem Mass Spectrometry (United States)

    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.

  2. Study of odor recorder using Mass Spectrometry (United States)

    Miura, Tomohiro; Nakamoto, Takamichi; Moriizumi, Toyosaka

    It is necessary to determine the recipe of a target odor with sufficient accuracy to realize an odor recorder for recording and reproducing it. We studied the recipe measurement method of a target odor using a mass spectrometry. It was confirmed that the linear superposition was valid when the binary mixture of the apple-flavor components such as isobutyric acid and ethyl valerate was measured. The superposition of a mass spectrum pattern may enable the recipe determination of a multi-component odor easily. In this research, we succeeded in the recipe determinations of orange flavor made up of 14 component odors when its typical recipe, the equalized, the citral-enhanced and the citronellol-enhanced ones were measured.

  3. FAPA mass spectrometry of designer drugs. (United States)

    Smoluch, Marek; Gierczyk, Blazej; Reszke, Edward; Babij, Michal; Gotszalk, Teodor; Schroeder, Grzegorz; Silberring, Jerzy


    Application of a flowing atmospheric-pressure afterglow ion source for mass spectrometry (FAPA-MS) for the analysis of designer drugs is described. In this paper, we present application of FAPA MS for identification of exemplary psychotropic drugs: JWH-122, 4BMC, Pentedrone, 3,4-DNNC and ETH-CAT. We have utilized two approaches for introducing samples into the plasma stream; first in the form of a methanolic aerosol from the nebulizer, and the second based on a release of vapors from the electrically heated crucible by thermal desorption. The analytes were ionized by FAPA and identified in the mass analyzer. The order of release of the compounds depends on their volatility. These methods offer fast and reliable structural information, without pre-separation, and can be an alternative to the Electron Impact, GC/MS, and ESI for fast analysis of designer-, and other psychoactive drugs. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Impact of automation on mass spectrometry. (United States)

    Zhang, Yan Victoria; Rockwood, Alan


    Mass spectrometry coupled to liquid chromatography (LC-MS and LC-MS/MS) is an analytical technique that has rapidly grown in popularity in clinical practice. In contrast to traditional technology, mass spectrometry is superior in many respects including resolution, specificity, multiplex capability and has the ability to measure analytes in various matrices. Despite these advantages, LC-MS/MS remains high cost, labor intensive and has limited throughput. This specialized technology requires highly trained personnel and therefore has largely been limited to large institutions, academic organizations and reference laboratories. Advances in automation will be paramount to break through this bottleneck and increase its appeal for routine use. This article reviews these challenges, shares perspectives on essential features for LC-MS/MS total automation and proposes a step-wise and incremental approach to achieve total automation through reducing human intervention, increasing throughput and eventually integrating the LC-MS/MS system into the automated clinical laboratory operations. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Spatial Autocorrelation in Mass Spectrometry Imaging. (United States)

    Cassese, Alberto; Ellis, Shane R; Ogrinc Potočnik, Nina; Burgermeister, Elke; Ebert, Matthias; Walch, Axel; van den Maagdenberg, Arn M J M; McDonnell, Liam A; Heeren, Ron M A; Balluff, Benjamin


    Mass spectrometry imaging (MSI) is a powerful molecular imaging technique. In microprobe MSI, images are created through a grid-wise interrogation of individual spots by mass spectrometry across a surface. Classical statistical tests for within-sample comparisons fail as close-by measurement spots violate the assumption of independence of these tests, which can lead to an increased false-discovery rate. For spatial data, this effect is referred to as spatial autocorrelation. In this study, we investigated spatial autocorrelation in three different matrix-assisted laser desorption/ionization MSI data sets. These data sets cover different molecular classes (metabolites/drugs, lipids, and proteins) and different spatial resolutions ranging from 20 to 100 μm. Significant spatial autocorrelation was detected in all three data sets and found to increase with decreasing pixel size. To enable statistical testing for differences in mass signal intensities between regions of interest within MSI data sets, we propose the use of Conditional Autoregressive (CAR) models. We show that, by accounting for spatial autocorrelation, discovery rates (i.e., the ratio between the features identified and the total number of features) could be reduced between 21% and 69%. The reliability of this approach was validated by control mass signals based on prior knowledge. In light of the advent of larger MSI data sets based on either an increased spatial resolution or 3D data sets, accounting for effects due to spatial autocorrelation becomes even more indispensable. Here, we propose a generic and easily applicable workflow to enable within-sample statistical comparisons.

  6. Isotope ratio analysis by Orbitrap mass spectrometry (United States)

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


    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/∆M 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

  7. Ambient ionization mass spectrometry: A tutorial

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Min-Zong; Cheng, Sy-Chi; Cho, Yi-Tzu [Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Shiea, Jentaie, E-mail: [Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Cancer Center, Kaohsiung Medical University, Kaohsiung, Taiwan (China)


    Highlights: {yields} Ambient ionization technique allows the direct analysis of sample surfaces with little or no sample pretreatment. {yields} We sort ambient ionization techniques into three main analytical strategies, direct ionization, direct desorption/ionization, and two-step ionization. {yields} The underlying principles of operation, ionization processes, detecting mass ranges, sensitivity, and representative applications of these techniques are described and compared. - Abstract: Ambient ionization is a set of mass spectrometric ionization techniques performed under ambient conditions that allows the direct analysis of sample surfaces with little or no sample pretreatment. Using combinations of different types of sample introduction systems and ionization methods, several novel techniques have been developed over the last few years with many applications (e.g., food safety screening; detection of pharmaceuticals and drug abuse; monitoring of environmental pollutants; detection of explosives for antiterrorism and forensics; characterization of biological compounds for proteomics and metabolomics; molecular imaging analysis; and monitoring chemical and biochemical reactions). Electrospray ionization and atmospheric pressure chemical ionization are the two main ionization principles most commonly used in ambient ionization mass spectrometry. This tutorial paper provides a review of the publications related to ambient ionization techniques. We describe and compare the underlying principles of operation, ionization processes, detecting mass ranges, sensitivity, and representative applications of these techniques.

  8. NITPICK: peak identification for mass spectrometry data

    Directory of Open Access Journals (Sweden)

    Steen Hanno


    Full Text Available Abstract Background The reliable extraction of features from mass spectra is a fundamental step in the automated analysis of proteomic mass spectrometry (MS experiments. Results This contribution proposes a sparse template regression approach to peak picking called NITPICK. NITPICK is a Non-greedy, Iterative Template-based peak PICKer that deconvolves complex overlapping isotope distributions in multicomponent mass spectra. NITPICK is based on fractional averagine, a novel extension to Senko's well-known averagine model, and on a modified version of sparse, non-negative least angle regression, for which a suitable, statistically motivated early stopping criterion has been derived. The strength of NITPICK is the deconvolution of overlapping mixture mass spectra. Conclusion Extensive comparative evaluation has been carried out and results are provided for simulated and real-world data sets. NITPICK outperforms pepex, to date the only alternate, publicly available, non-greedy feature extraction routine. NITPICK is available as software package for the R programming language and can be downloaded from

  9. Assay for Glycosaminoglycans by Tandem Mass Spectrometry and its Applications (United States)

    Tomatsu, Shunji; Shimada, Tsutomu; Mason, Robert W; Kelly, Joan; LaMarr, William A; Yasuda, Eriko; Shibata, Yuniko; Futatsumori, Hideyuki; Montaño, Adriana M; Yamaguchi, Seiji; Suzuki, Yasuyuki; Orii, Tadao


    Glycosaminoglycans (GAGs) are distributed in the whole body and play a variety of important physiological roles associated with inflammation, growth, coagulation, fibrinolysis, lipolysis, and cell-matrix biology. Accumulation of undegraded GAGs in lysosomes gives rise to a distinct clinical syndrome, mucopolysaccharidoses. Measurement of each specific GAG in a variety of specimens is urgently required to understand GAG interaction with other molecules, physiological status of patients, and prognosis and pathogenesis of the disease. We established a highly sensitive and accurate tandem mass spectrometry (LC-MS/MS) method for measurements of disaccharides derived from four specific GAGs [dermatan sulfate (DS), heparan sulfate (HS), keratan sulfate (KS), and chondroitin sulfate (CS)]. Disaccharides were produced by specific enzyme digestion of each GAG, and quantified by negative ion mode of multiple reaction monitoring. Subclasses of HS and GAGs with identical molecular weights can be separated using a Hypercarbcolumn (2.0 mm×50 mm, 5 μm) with an aectonitrile gradient in ammonium acetate (pH 11.0). We also developed a GAG assay by RapidFire with tandem mass spectrometry (RF-MS/MS). The RF system consists of an integrated solid phase extraction robot that binds and de-salts samples from assay plates and directly injects them into a MS/MS detector, reducing sample processing time to ten seconds. RF-MS/MS consequently yields much faster throughput than conventional LC-MS/MS-based methods. However, the RF system does not have a chromatographic step, and therefore, cannot distinguish GAGs that have identical molecular weights. Both methods can be applied to analysis of dried blood spots, blood, and urine specimens. In this article, we compare the assay methods for GAGs and describe their potential applications. PMID:25068074

  10. Dynamically multiplexed ion mobility time-of-flight mass spectrometry. (United States)

    Belov, Mikhail E; Clowers, Brian H; Prior, David C; Danielson, William F; Liyu, Andrei V; Petritis, Brianne O; Smith, Richard D


    Ion mobility spectrometry-time-of-flight mass spectrometry (IMS-TOFMS) has been increasingly used in analysis of complex biological samples. A major challenge is to transform IMS-TOFMS to a high-sensitivity, high-throughput platform, for example, for proteomics applications. In this work, we have developed and integrated three advanced technologies, including efficient ion accumulation in an ion funnel trap prior to IMS separation, multiplexing (MP) of ion packet introduction into the IMS drift tube, and signal detection with an analog-to-digital converter, into the IMS-TOFMS system for the high-throughput analysis of highly complex proteolytic digests of, for example, blood plasma. To better address variable sample complexity, we have developed and rigorously evaluated a novel dynamic MP approach that ensures correlation of the analyzer performance with an ion source function and provides the improved dynamic range and sensitivity throughout the experiment. The MP IMS-TOFMS instrument has been shown to reliably detect peptides at a concentration of 1 nM in the presence of a highly complex matrix, as well as to provide a 3 orders of magnitude dynamic range and a mass measurement accuracy of better than 5 ppm. When matched against human blood plasma database, the detected IMS-TOF features were found to yield approximately 700 unique peptide identifications at a false discovery rate (FDR) of approximately 7.5%. Accounting for IMS information gave rise to a projected FDR of approximately 4%. Signal reproducibility was found to be greater than 80%, while the variations in the number of unique peptide identifications were <15%. A single sample analysis was completed in 15 min that constitutes almost 1 order of magnitude improvement compared to a more conventional LC-MS approach.

  11. Field desorption mass spectrometry of oligosaccharides (United States)

    Linscheid, Michael; D'Angona, Jay; Burlingame, Alma L.; Dell, Anne; Ballou, Clinton E.


    Field desorption mass spectrometry has been used to analyze carbohydrate polymers with 5 to 14 hexose units without prior derivatization. In all examples, the molecular weight of the oligosaccharide could be determined by means of the abundant quasimolecular ions of the type MNa+, MH+, MNa22+, and MNa33+. Fragmentation at glycosidic linkages was observed in varying extents. The reduced oligosaccharide Man8GlcNAcH2, obtained from IgM [Cohen, R. E. & Ballou, C. E. (1980) Biochemistry 19, 4345-4358], gave quasimolecular ion signals MNa+ at m/z 1544, MH+ at m/z 1522, MNa22+ at m/z 784, and MNa33+ at m/z 530, all corresponding to its assumed molecular weight of 1519.5. Mycobacterial methylmannose polysaccharides with the general structure ManxMeMany-OCH3 [Yamada, H., Cohen, R. E. & Ballou, C. E. (1979) J. Biol. Chem. 254, 1972-1979] were also successfully analyzed. Man1MeMan13-OCH3, the largest homolog, gave the expected signal of the quasimolecular ion MNa+ at m/z 2506. The larger polysaccharides were analyzed by using a KRATOS MS-50 mass spectrometer with a high-field magnet enabling full sensitivity to be maintained up to 3000 atomic mass units. Polysaccharides up to m/z 1978 were analyzed by using a KRATOS MS-9 mass spectrometer operated at 4 Kv. The signal-to-noise ratio, which becomes a serious problem in field desorption mass spectrometry at low accelerating voltages, and the low instrument sensitivity were improved considerably by our use of a method of adding scans with low total ion currents obtained over a longer desorption time. In this way, we obtained complete sequence information on methylmannose polysaccharides up to Man1MeMan9-OCH3(MNa+ at m/z 1802). Analysis of a presumed Man1MeMan7-OCH3, gave a spectrum consistent only with the structure Man2MeMan6-OCH3, revealing the existence of a methylmannose homolog with 2 unmethylated mannoses at the nonreducing end of the chain. PMID:6940169

  12. Laser Microprobe Mass Spectrometry 1: Basic Principles and Performance Characteristics. (United States)

    Denoyer, Eric; And Others


    Describes the historical development, performance characteristics (sample requirements, analysis time, ionization characteristics, speciation capabilities, and figures of merit), and applications of laser microprobe mass spectrometry. (JN)

  13. [Application of mass spectrometry in mycology]. (United States)

    Quiles Melero, Inmaculada; Peláez, Teresa; Rezusta López, Antonio; Garcia-Rodríguez, Julio


    MALDI-TOF (matrix-assisted laser desorption ionization time-of-flight) mass spectrometry (MS) is becoming an essential tool in most microbiology laboratories. At present, by using a characteristic fungal profile obtained from whole cells or through simple extraction protocols, MALDI-TOF MS allows the identification of pathogenic fungi with a high performance potential. This methodology decreases the laboratory turnaround time, optimizing the detection of mycoses. This article describes the state-of-the-art of the use of MALDI-TOF MS for the detection of human clinical fungal pathogens in the laboratory and discusses the future applications of this technology, which will further improve routine mycological diagnosis. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

  14. Detection of gunshot residues using mass spectrometry. (United States)

    Taudte, Regina Verena; Beavis, Alison; Blanes, Lucas; Cole, Nerida; Doble, Philip; Roux, Claude


    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.

  15. Capillary electrophoresis mass spectrometry based metabolomics

    Directory of Open Access Journals (Sweden)

    Alexander M. Buko


    Full Text Available Capillary electrophoresis–mass spectrometry (CE-MS is a powerful orthogonal technique capable of filling in gaps in the identification, quantitation and isomeric resolution of many small hydrophilic and charged metabolites. The metabolome is a large complex mixture of molecules for which not one technique nor a combination of techniques can optimally identify and measure it in it’s entirety. LC-MS, GC-MS and NMR have been the widely used for metabolomics for the past 20 years for a wide range of applications, each technique having shown uniqueness and advantages, for specific applications or target metabolic chemical space. CE-MS captures a unique metabolic chemical space beyond these standard methods providing another window into metabolomics profiling. This review will focus on the recent publications published within 2016 focusing on biotechnology and pharmaceutical applications of CE-MS.

  16. China's food safety regulation and mass spectrometry. (United States)

    Chu, Xiaogang; Zhang, Feng; Nie, Xuemei; Wang, Wenzhi; Feng, Feng


    Food safety is essential to people's health and people's livelihood. To ensure that food safety is an important current strategy of the governments, both regulation and standardization are important support for implementing this strategic initiative effectively. The status and prospects of China's food laws, regulations, and standards system are introduced. China now has established a complete law regime providing a sound foundation and good environment for keeping the health of people, maintaining the order of social economy and promoting the international trade of food. At the same time, it is undoubtedly important to strengthen standardization and improve the food safety standards system. In the administration of food safety, mass spectrometry is becoming more and more important and many analytical methods developed in China are based on its application.

  17. Deciphering the histone code using mass spectrometry (United States)

    Ueberheide, Beatrix M.; Mollah, Sahana


    During the past decade, studies surrounding chromatin research have grown exponentially. A major focus of chromatin biology is centered on understanding of how histone modifications alter chromatin structure at the molecular and mechanistic levels. Discoveries are being made at a rapid pace due to the advent of new and innovative techniques. Mass spectrometry has emerged as a powerful tool in the field of histone research due to its speed, sensitivity, and ease of use. This has resulted in the identification of a number of novel histone modification sites. In consequence, new roles in biological processes have been discovered and hypothetical models, such as the `histone code' have been reaffirmed or refined. One significant advantage to using mass spectrometric techniques is that the combinations of modifications on different sites can be determined which is crucial to deciphering the `histone code'. In this manuscript, the mass spectrometric approaches developed over the past decade for both qualitative and quantitative analysis of histone post-translational modifications (PTMs) are discussed.

  18. Enantioselectivity of mass spectrometry: challenges and promises. (United States)

    Awad, Hanan; El-Aneed, Anas


    With the fast growing market of pure enantiomer drugs and bioactive molecules, new chiral-selective analytical tools have been instigated including the use of mass spectrometry (MS). Even though MS is one of the best analytical tools that has efficiently been used in several pharmaceutical and biological applications, traditionally MS is considered as a "chiral-blind" technique. This limitation is due to the MS inability to differentiate between two enantiomers of a chiral molecule based merely on their masses. Several approaches have been explored to assess the potential role of MS in chiral analysis. The first approach depends on the use of MS-hyphenated techniques utilizing fast and sensitive chiral separation tools such as liquid chromatography (LC), gas chromatography (GC), and capillary electrophoresis (CE) coupled to MS detector. More recently, several alternative separation techniques have been evaluated such as supercritical fluid chromatography (SFC) and capillary electrochromatography (CEC); the latter being a hybrid technique that combines the efficiency of CE with the selectivity of LC. The second approach is based on using the MS instrument solely for the chiral recognition. This method depends on the behavioral differences between enantiomers towards a foreign molecule and the ability of MS to monitor such differences. These behavioral differences can be divided into three types: (i) differences in the enantiomeric affinity for association with the chiral selector, (ii) differences of the enantiomeric exchange rate with a foreign reagent, and (iii) differences in the complex MS dissociation behaviors of the enantiomers. Most recently, ion mobility spectrometry was introduced to qualitatively and quantitatively evaluate chiral compounds. This article provides an overview of MS role in chiral analysis by discussing MS based methodologies and presenting the challenges and promises associated with each approach. © 2013 Wiley Periodicals, Inc.

  19. Advantageous Uses of Mass Spectrometry for the Quantification of Proteins

    Directory of Open Access Journals (Sweden)

    John E. Hale


    Full Text Available Quantitative protein measurements by mass spectrometry have gained wide acceptance in research settings. However, clinical uptake of mass spectrometric protein assays has not followed suit. In part, this is due to the long-standing acceptance by regulatory agencies of immunological assays such as ELISA assays. In most cases, ELISAs provide highly accurate, sensitive, relatively inexpensive, and simple assays for many analytes. The barrier to acceptance of mass spectrometry in these situations will remain high. However, mass spectrometry provides solutions to certain protein measurements that are difficult, if not impossible, to accomplish by immunological methods. Cases where mass spectrometry can provide solutions to difficult assay development include distinguishing between very closely related protein species and monitoring biological and analytical variability due to sample handling and very high multiplexing capacity. This paper will highlight several examples where mass spectrometry has made certain protein measurements possible where immunological techniques have had a great difficulty.

  20. Solvent jet desorption capillary photoionization-mass spectrometry. (United States)

    Haapala, Markus; Teppo, Jaakko; Ollikainen, Elisa; Kiiski, Iiro; Vaikkinen, Anu; Kauppila, Tiina J; Kostiainen, Risto


    A new ambient mass spectrometry method, solvent jet desorption capillary photoionization (DCPI), is described. The method uses a solvent jet generated by a coaxial nebulizer operated at ambient conditions with nitrogen as nebulizer gas. The solvent jet is directed onto a sample surface, from which analytes are extracted into the solvent and ejected from the surface in secondary droplets formed in collisions between the jet and the sample surface. The secondary droplets are directed into the heated capillary photoionization (CPI) device, where the droplets are vaporized and the gaseous analytes are ionized by 10 eV photons generated by a vacuum ultraviolet (VUV) krypton discharge lamp. As the CPI device is directly connected to the extended capillary inlet of the MS, high ion transfer efficiency to the vacuum of MS is achieved. The solvent jet DCPI provides several advantages: high sensitivity for nonpolar and polar compounds with limit of detection down to low fmol levels, capability of analyzing small and large molecules, and good spatial resolution (250 μm). Two ionization mechanisms are involved in DCPI: atmospheric pressure photoionization, capable of ionizing polar and nonpolar compounds, and solvent assisted inlet ionization capable of ionizing larger molecules like peptides. The feasibility of DCPI was successfully tested in the analysis of polar and nonpolar compounds in sage leaves and chili pepper.

  1. Advanced capabilities for in situ planetary mass spectrometry (United States)

    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.


    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

  2. Chromatography and mass spectrometry of prebiological and biological molecules (United States)

    Navale, Vivek

    growth factor protein was 16175.6 Da. MALDI analysis of trypsin digest of Myeloid progenitor inhibitory factor chemokine verified the disulfide bridging among cysteine residues. Several partially digested trypsin and V8 peptides were detected that verified significant portions of the primary structure of the chemokine. Mass difference amounting to the loss of a single amino acid, serine was also identified. The cyanogen bromide (CNBr) treated chemokine produced three peptides 7051, 6910.1 and 1492 Da. The analysis of Keratinocyte growth factor (KGF) peptide mixtures showed suppression effects during the MALDI ionization process. Several partially digested peptides with mass values 3214, 9980, 10325 and 10497 Da were identified. Direct MALDI-MS analysis of cyanogen bromide treated KGF molecule demonstrated the formation of peptides with mass 7567.3, 4992.6 and 3118.6 Da. The high sensitivity of MALDI-MS provided a rapid method for confirming the fidelity of gene expression in the host system. The present work showed that the combined methods of chromatography and mass spectrometry are efficient means for identification and characterization of prebiological and biological molecules.

  3. MALDI-TOF mass spectrometry in textile industry


    Munteanu, Florentina-Daniela; Dinca, Nicolae; Paulo, Artur Cavaco


    In this paper are presented the possibilities of using matrix assisted laser desorption ionization time of flight (MALDI-TOF) mass spectrometry in textile industry. MALDI-TOF mass spectrometry it is a convenient, versatile method for characterization and identification of dyes and pigments, and also for characterization of fibers and contaminants of the fabrics.

  4. Identification of brassinosteroid signaling complexes by coimmunoprecipitation and mass spectrometry

    NARCIS (Netherlands)

    Dongen, van Walter; Heerde, van Luc; Boeren, Sjef; Vries, de Sacco C.


    A combination of coimmunoprecipitation (coIP) of tagged proteins followed by protein identification and quantitation using Liquid Chromatography Mass Spectrometry/Mass Spectrometry (LCMS/MS) has proven to be a reliable method to qualitatively characterize membrane-bound receptor complexes from

  5. Probing the Composition, Assembly and Activity of Protein Molecular Machines using Native Mass Spectrometry

    NARCIS (Netherlands)

    Waterbeemd, M.J. van de


    Native mass spectrometry and mass spectrometry in general, are powerful analytical tools for studying proteins and protein complexes. Native mass spectrometry may provide accurate mass measurements of large macromolecular assemblies enabling the investigation of their composition and stoichiometry.

  6. Development of lithium attachment mass spectrometry - knudsen effusion and chemical ionisation mass spectrometry (KEMS, CIMS). (United States)

    Booth, A Murray; Bannan, Thomas J; Benyezzar, Med; Bacak, Asan; Alfarra, M Rami; Topping, David; Percival, Carl J


    Lithium ion attachment mass spectrometry provides a non-specific, non-fragmenting, sensitive and robust method for the detection of volatile species in the gas phase. The design, manufacture and results of lithium based ion attachment ionisation sources for two different mass spectrometry systems are presented. In this study trace gas analysis is investigated using a modified Chemical Ionization Mass Spectrometer (CIMS) and vapour pressure measurements are made using a modified Knudsen Effusion Mass Spectrometer (KEMS). In the Li+ CIMS, where the Li+ ionization acts a soft and unselective ionization source, limits of detection of 0.2 ppt for formic acid, 15 ppt for nitric acid and 120 ppt for ammonia were achieved, allowing for ambient measurements of such species at atmospherically relevant concentrations. In the first application of Lithium ion attachment in ultra-high vacuum (UHV), vapor pressures of various atmospherically relevant species were measured with the adapted KEMS, giving measured values equivalent to previous results from electron impact KEMS. In the Li+ KEMS vapour pressures <10-3 mbar can be measured without any fragmentation, as is seen with the initial electron impact (EI) set up, allowing the vapor pressure of individual components within mixtures to be determined.

  7. Mass spectrometry innovations in drug discovery and development. (United States)

    Papac, D I; Shahrokh, Z


    This review highlights the many roles mass spectrometry plays in the discovery and development of new therapeutics by both the pharmaceutical and the biotechnology industries. Innovations in mass spectrometer source design, improvements to mass accuracy, and implementation of computer-controlled automation have accelerated the purification and characterization of compounds derived from combinatorial libraries, as well as the throughput of pharmacokinetics studies. The use of accelerator mass spectrometry, chemical reaction interface-mass spectrometry and continuous flow-isotope ratio mass spectrometry are promising alternatives for conducting mass balance studies in man. To meet the technical challenges of proteomics, discovery groups in biotechnology companies have led the way to development of instruments with greater sensitivity and mass accuracy (e.g., MALDI-TOF, ESI-Q-TOF, Ion Trap), the miniaturization of separation techniques and ion sources (e.g., capillary HPLC and nanospray), and the utilization of bioinformatics. Affinity-based methods coupled to mass spectrometry are allowing rapid and selective identification of both synthetic and biological molecules. With decreasing instrument cost and size and increasing reliability, mass spectrometers are penetrating both the manufacturing and the quality control arenas. The next generation of technologies to simplify the investigation of the complex fate of novel pharmaceutical entities in vitro and in vivo will be chip-based approaches coupled with mass spectrometry.

  8. Illustrating the Concepts of Isotopes and Mass Spectrometry in Introductory Courses: A MALDI-TOF Mass Spectrometry Laboratory Experiment (United States)

    Dopke, Nancy Carter; Lovett, Timothy Neal


    Mass spectrometry is a widely used and versatile tool for scientists in many different fields. Soft ionization techniques such as matrix-assisted laser desorption/ionization (MALDI) allow for the analysis of biomolecules, polymers, and clusters. This article describes a MALDI mass spectrometry experiment designed for students in introductory…

  9. Electrospray ionization mass spectrometry of metalloporphyrins. (United States)

    Vandell, V E; Limbach, P A


    The magnesium, nickel, copper, zinc and vanadium metalloporphyrins from octaethylporphyrin, etioporphyrin I and tetraphenylporphyrin were characterized using electrospray ionization mass spectrometry (ESI-MS). The ion abundance of each of the porphyrins present in binary mixtures was monitored as a function of the porphyrin concentration and is dependent on the metalloporphyrin oxidation potential. It was found that, for binary mixtures of metalloporphyrins whose oxidation potentials differ by less than 0.1 V, the resulting ion abundance of each species is directly proportional to the concentration of each analyte in the mixture. For binary mixtures whose oxidation potentials differ by more than 0.1 V, relative abundances of the radical cations of each metalloporphyrin are determined by the oxidation potential and concentration of each metalloporphyrin with the analyte of lowest oxidation potential being ionized preferentially. The ability to ionize selectively one porphyrin over another in a binary mixture offers the potential to use ESI-MS for the qualitative analysis of porphyrins present in complex mixtures.

  10. Detection of Gunshot Residues Using Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Regina Verena Taudte


    Full Text Available 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.

  11. Applications of graphene in mass spectrometry. (United States)

    Kong, Xianglei; Huang, Yi


    This paper reviews the up-to-date research about the applications of graphene and its related materials in the field of mass spectrometry (MS). Due to its large surface area, delocalized pi-electrons, thermal conductivity, stability and rich interaction chemistry, graphene has been widely used in MS-based analytical chemistry. Graphene-based materials were applied as very effective matrixes or surfaces for many kinds of organic molecules in laser desorption/ionization (LDI) MS analysis. Many advantages of this novel matrix have been proved, which included: low interference ions from matrix itself, good reproducibility, high salt tolerance and so on. The unique properties of graphene also make it a superior sorbent used in solid-phase extraction (SPE). Further development of online SPE methods based on graphene coupling directly with LDI-MS, GC-MS and LC-MS greatly simplifies the MS-based analytical procedure for complex samples and makes the corresponding high-throughput and automatic analysis performable. Their applications as a platform in proteolysis for the rapid identification of proteins have been also developed. In addition, graphene was found to be a unique precursor for the generation of large-sized carbon cluster anions in the gas phase. Finally, the possible challenges and future perspectives in their applications in MS are discussed too.

  12. Charging of Proteins in Native Mass Spectrometry (United States)

    Susa, Anna C.; Xia, Zijie; Tang, Henry Y. H.; Tainer, John A.; Williams, Evan R.


    Factors that influence the charging of protein ions formed by electrospray ionization from aqueous solutions in which proteins have native structures and function were investigated. Protein ions ranging in molecular weight from 12.3 to 79.7 kDa and pI values from 5.4 to 9.6 were formed from different solutions and reacted with volatile bases of gas-phase basicities higher than that of ammonia in the cell of a Fourier-transform ion cyclotron resonance mass spectrometer. The charge-state distribution of cytochrome c ions formed from aqueous ammonium or potassium acetate is the same. Moreover, ions formed from these two solutions do not undergo proton transfer to 2-fluoropyridine, which is 8 kcal/mol more basic than ammonia. These results provide compelling evidence that proton transfer between ammonia and protein ions does not limit protein ion charge in native electrospray ionization. Both circular dichroism and ion mobility measurements indicate that there are differences in conformations of proteins in pure water and aqueous ammonium acetate, and these differences can account for the difference in the extent of charging and proton-transfer reactivities of protein ions formed from these solutions. The extent of proton transfer of the protein ions with higher gas-phase basicity bases trends with how closely the protein ions are charged to the value predicted by the Rayleigh limit for spherical water droplets approximately the same size as the proteins. These results indicate that droplet charge limits protein ion charge in native mass spectrometry and are consistent with these ions being formed by the charged residue mechanism.

  13. Correcting mass shifts: A lock mass-free recalibration procedure for mass spectrometry imaging data

    Czech Academy of Sciences Publication Activity Database

    Kulkarni, P.; Kaftan, F.; Kynast, P.; Svatoš, Aleš; Böcker, S.


    Roč. 407, č. 25 (2015), s. 7603-7613 ISSN 1618-2642 Institutional support: RVO:61388963 Keywords : mass spectrometry imaging * recalibration * mass shift correction * data processing Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.125, year: 2015

  14. Interpretation of Tandem Mass Spectrometry (MSMS) Spectra for Peptide Analysis

    DEFF Research Database (Denmark)

    Hjernø, Karin; Højrup, Peter


    The aim of this chapter is to give a short introduction to peptide analysis by mass spectrometry (MS) and interpretation of fragment mass spectra. Through examples and guidelines we demonstrate how to understand and validate search results and how to perform de novo sequencing based on the often ...... very complex fragmentation pattern obtained by tandem mass spectrometry (also referred to as MSMS). The focus is on simple rules for interpretation of MSMS spectra of tryptic as well as non-tryptic peptides....

  15. Relative quantitation in single-cell metabolomics by laser ablation electrospray mass spectrometry. (United States)

    Shrestha, Bindesh; Vertes, Akos


    Single-cell analysis of metabolites by mass spectrometry (MS) is challenging due to the very limited volume and inherent molecular complexity of the sample. Quantitative metabolomic analysis of individual cells provides information on the metabolic heterogeneity of cells unattainable by aggregate analysis of multiple cells. Depending on the ionization method, MS can offer quantitative analysis for a broad class of metabolites exhibiting both high sensitivity and selectivity. Laser ablation electrospray ionization (LAESI) has been successfully exploited to analyze metabolites from broad range of biological samples, including single cells and small cell populations. In this work, we describe a protocol for the relative quantitation of metabolites in single cells by LAESI-mass spectrometry.

  16. High explosives vapor detection by atmospheric sampling glow discharge ionization/tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    McLuckey, S.A.; Goeringer, D.E.; Asano, K.G. [Oak Ridge National Lab., TN (United States). Chemical and Analytical Sciences Div.


    The combination of atmospheric sampling glow discharge ionization with tandem mass spectrometry for the detection of traces of high explosives is described. Particular emphasis is placed on use of the quadrupole ion trap as the type of tandem mass spectrometer. Atmospheric sampling glow discharge provides a simple, rugged, and efficient means for anion formation while the quadrupole ion trap provides for efficient tandem mass spectrometry. Mass selective ion accumulation and non-specific ion activation methods can be used to overcome deleterious effects arising from ion/ion interactions. Such interactions constitute the major potential technical barrier to the use of the ion trap for real-time monitoring of targeted compounds in uncontrolled and highly variable matrices. Tailored waveforms can be used to effect both mass selective ion accumulation and ion activation. Concatenated tailored waveforms allow for both functions in a single experiment thereby providing the capability for monitoring several targeted species simultaneously. The combination of atmospheric sampling glow discharge ionization with a state-of-the-art analytical quadrupole ion trap is a highly sensitive and specific detector for traces of high explosives. The combination is also small and inexpensive relative to virtually any other form of tandem mass spectrometry. The science and technology underlying the glow discharge/ion trap combination is sufficiently mature to form the basis for an engineering effort to make the detector portable. 85 refs.

  17. Resource for the Development of Biomedical Accelerator Mass Spectrometry (AMS)

    Energy Technology Data Exchange (ETDEWEB)

    Turteltaub, K. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bench, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Buchholz, B. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Enright, H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kulp, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McCartt, A. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Malfatti, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ognibene, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Loots, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Stewart, B. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    The NIH Research Resource for Biomedical AMS was originally funded at Lawrence Livermore National Laboratory in 1999 to develop and apply the technology of accelerator mass spectrometry (AMS) in broad- based biomedical research. The Resource’s niche is to fill needs for ultra high sensitivity quantitation when isotope-labeled agents are used. The Research Resource’s Technology Research and Development (TR&D) efforts will focus on the needs of the biomedical research community in the context of seven Driving Biomedical Projects (DBPs) that will drive the Center’s technical capabilities through three core TR&Ds. We will expand our present capabilities by developing a fully integrated HPLC AMS to increase our capabilities for metabolic measurements, we will develop methods to understand cellular processes and we will develop and validate methods for the application of AMS in human studies, which is a growing area of demand by collaborators and service users. In addition, we will continue to support new and ongoing collaborative and service projects that require the capabilities of the Resource. The Center will continue to train researchers in the use of the AMS capabilities being developed, and the results of all efforts will be widely disseminated to advance progress in biomedical research. Towards these goals, our specific aims are to:1.) Increase the value and information content of AMS measurements by combining molecular speciation with quantitation of defined macromolecular isolates. Specifically, develop and validate methods for macromolecule labeling, characterization and quantitation.2.) Develop and validate methods and strategies to enable AMS to become more broadly used in human studies. Specifically, demonstrate robust methods for conducting pharmacokinetic/pharmacodynamics studies in humans and model systems.3.) Increase the accessibility of AMS to the Biomedical research community and the throughput of AMS through direct coupling to separatory

  18. Resource for the Development of Biomedical Accelerator Mass Spectrometry (AMS)

    Energy Technology Data Exchange (ETDEWEB)

    Tuerteltaub, K. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bench, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Buchholz, B. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Enright, H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kulp, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Loots, G. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McCartt, A. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Malfatti, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ognibene, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Stewart, B. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    The NIH Research Resource for Biomedical AMS was originally funded at Lawrence Livermore National Laboratory in 1999 to develop and apply the technology of accelerator mass spectrometry (AMS) in broad- based biomedical research. The Resource’s niche is to fill needs for ultra high sensitivity quantitation when isotope-labeled agents are used. The Research Resource’s Technology Research and Development (TR&D) efforts will focus on the needs of the biomedical research community in the context of seven Driving Biomedical Projects (DBPs) that will drive the Center’s technical capabilities through three core TR&Ds. We will expand our present capabilities by developing a fully integrated HPLC AMS to increase our capabilities for metabolic measurements, we will develop methods to understand cellular processes and we will develop and validate methods for the application of AMS in human studies, which is a growing area of demand by collaborators and service users. In addition, we will continue to support new and ongoing collaborative and service projects that require the capabilities of the Resource. The Center will continue to train researchers in the use of the AMS capabilities being developed, and the results of all efforts will be widely disseminated to advance progress in biomedical research. Towards these goals, our specific aims are to:1.) Increase the value and information content of AMS measurements by combining molecular speciation with quantitation of defined macromolecular isolates. Specifically, develop and validate methods for macromolecule labeling, characterization and quantitation.2.) Develop and validate methods and strategies to enable AMS to become more broadly used in human studies. Specifically, demonstrate robust methods for conducting pharmacokinetic/pharmacodynamics studies in humans and model systems.3.) Increase the accessibility of AMS to the Biomedical research community and the throughput of AMS through direct coupling to separatory


    National Research Council Canada - National Science Library

    Lukáš Hleba; Miroslava Císarová; Mohammad Ali Shariati; Dana Tančinová


    .... In this study, a six mycotoxins, concretely: aflatoxin B1, citrinin, deoxynivalenol, zearalenone, T2-toxin, and griseofulvin were detected by Matrix Assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry (MALDI-TOF MS...

  20. Sequencing of Oligourea Foldamers by Tandem Mass Spectrometry

    National Research Council Canada - National Science Library

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


    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...

  1. Targeting synaptic pathology with a novel affinity mass spectrometry approach

    National Research Council Canada - National Science Library

    Brinkmalm, Ann; Brinkmalm, Gunnar; Honer, William G; Moreno, Julie A; Jakobsson, Joel; Mallucci, Giovanna R; Zetterberg, Henrik; Blennow, Kaj; Öhrfelt, Annika


    .... This method combines affinity purification and mass spectrometry and can be applied directly for studies of SNARE complex proteins in multiple species or modified to target other key elements in neuronal function...

  2. Matrix Assisted Ionization Vacuum (MAIV), a New Ionization Method for Biological Materials Analysis Using Mass Spectrometry* (United States)

    Inutan, Ellen D.; Trimpin, Sarah


    The introduction of electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) for the mass spectrometric analysis of peptides and proteins had a dramatic impact on biological science. We now report that a wide variety of compounds, including peptides, proteins, and protein complexes, are transported directly from a solid-state small molecule matrix to gas-phase ions when placed into the vacuum of a mass spectrometer without the use of high voltage, a laser, or added heat. This ionization process produces ions having charge states similar to ESI, making the method applicable for high performance mass spectrometers designed for atmospheric pressure ionization. We demonstrate highly sensitive ionization using intermediate pressure MALDI and modified ESI sources. This matrix and vacuum assisted soft ionization method is suitable for the direct surface analysis of biological materials, including tissue, via mass spectrometry. PMID:23242551

  3. Subcellular analysis by laser ablation electrospray ionization mass spectrometry (United States)

    Vertes, Akos; Stolee, Jessica A; Shrestha, Bindesh


    In various embodiments, a method of laser ablation electrospray ionization mass spectrometry (LAESI-MS) may generally comprise micro-dissecting a cell comprising at least one of a cell wall and a cell membrane to expose at least one subcellular component therein, ablating the at least one subcellular component by an infrared laser pulse to form an ablation plume, intercepting the ablation plume by an electrospray plume to form ions, and detecting the ions by mass spectrometry.

  4. Confirmatory assay for ivermectin in cattle tissue using chemical ionization mass spectrometry/mass spectrometry (MS/MS). (United States)

    Tway, P C; Downing, G V; Slayback, J R; Rahn, G S; Isensee, R K


    A method based on direct exposure, positive ion, chemical ionization mass spectrometry/mass spectrometry (ms/ms) was developed for the confirmatory assay of the antiparasitic drug, ivermectin, in animal tissue. Following extraction, column and preparative liquid chromatography, mass spectrometric/mass spectrometric analysis of the drug in liver samples provided reliable detection limits to 8-10 parts-per-billion at a signal: noise of greater than 10:1. Blank tissue consistently displayed no chemical/matrix interference. Besides the development of a confirmatory assay, the study also demonstrates the analytical capability and the role of MS/MS vis-a-vis other applied mass spectrometric techniques.

  5. Analysis of posttranslational modifications of proteins by tandem mass spectrometry

    DEFF Research Database (Denmark)

    Larsen, Martin Røssel; Trelle, Morten B; Thingholm, Tine E


    -temporal distribution in cells and tissues. Most PTMs can be detected by protein and peptide analysis by mass spectrometry (MS), either as a mass increment or a mass deficit relative to the nascent unmodified protein. Tandem mass spectrometry (MS/MS) provides a series of analytical features that are highly useful...... for the characterization of modified proteins via amino acid sequencing and specific detection of posttranslationally modified amino acid residues. Large-scale, quantitative analysis of proteins by MS/MS is beginning to reveal novel patterns and functions of PTMs in cellular signaling networks and biomolecular structures....

  6. A High-Sensitivity Lanthanide Nanoparticle Reporter for Mass Cytometry: Tests on Microgels as a Proxy for Cells (United States)


    This paper addresses the question of whether one can use lanthanide nanoparticles (e.g., NaHoF4) to detect surface biomarkers expressed at low levels by mass cytometry. To avoid many of the complications of experiments on live or fixed cells, we carried out proof-of-concept experiments using aqueous microgels with a diameter on the order of 700 nm as a proxy for cells. These microgels were used to test whether nanoparticle (NP) reagents would allow the detection of as few as 100 proteins per “cell” in cell-by-cell assays. Streptavidin (SAv), which served as the model biomarker, was attached to the microgel in two different ways. Covalent coupling to surface carboxyls of the microgel led to large numbers (>104) of proteins per microgel, whereas biotinylation of the microgel followed by exposure to SAv led to much smaller numbers of SAv per microgel. Using mass cytometry, we compared two biotin-containing reagents, which recognized and bound to the SAvs on the microgel. One was a metal chelating polymer (MCP), a biotin end-capped polyaspartamide containing 50 Tb3+ ions per probe. The other was a biotinylated NaHoF4 NP containing 15 000 Ho atoms per probe. Nonspecific binding was determined with bovine serum albumin (BSA) conjugated microgels. The MCP was effective at detecting and quantifying SAvs on the microgel with covalently bound SAv (20 000 SAvs per microgel) but was unable to give a meaningful signal above that of the BSA-coated microgel for the samples with low levels of SAv. Here the NP reagent gave a signal 2 orders of magnitude stronger than that of the MCP and allowed detection of NPs ranging from 100 to 500 per microgel. Sensitivity was limited by the level of nonspecific adsorption. This proof of concept experiment demonstrates the enhanced sensitivity possible with NP reagents in cell-by-cell assays by mass cytometry. PMID:24617504

  7. Electromechanical model of a resonating nano-cantilever-based sensor for high-resolution and high-sensitivity mass detection

    DEFF Research Database (Denmark)

    Abadal, G.; Davis, Zachary James; Helbo, Bjarne


    A simple linear electromechanical model for an electrostatically driven resonating cantilever is derived. The model has been developed in order to determine dynamic quantities such as the capacitive current flowing through the cantilever-driver system at the resonance frequency, and it allows us...... to calculate static magnitudes such as position and voltage of collapse or the voltage versus deflection characteristic. The model is used to demonstrate the theoretical sensitivity on the attogram scale of a mass sensor based on a nanometre-scale cantilever, and to analyse the effect of an extra feedback loop...

  8. Injection optics for fast mass switching for accelerator mass spectrometry (United States)

    Weisser, D. C.; Fifield, L. K.; De Cesare, M.; Tims, S. G.; Lobanov, N. R.; Crook, G. G.; Tsifakis, D.; Tunningley, T. B.


    Accelerator Mass Spectrometry (AMS) measures the ratio of extremely small amounts of a radioactive isotope in the presence of ˜ 1015 times more stable ones. The isotopes are injected sequentially over a repeated period and observed at the exit of the accelerator. so any fluctuations in ion source output or transmission through the accelerator over a time comparable to the measurement time, will reduce the accuracy of such measurements. This compromise in accuracy can be lessened by reducing the switching time between isotopes from several seconds to a few milli-seconds. New AMS systems accomplish fast switching by modifying the beam energy though the 90 injection magnet by pulsing the voltage by several kV on the flight tube in the magnet. That requires that the flight tube be electrically insulated which competes with having the flight tube as large as possible. At the ANU, insulating the magnet flight tube would not only have reduced the acceptance of the injection system, but conflicted with a beam chopper attached to the flight tube, that would also have had to be insulated from the ground. This was not practical so the novel alternative of pulsing the voltage on the high voltage ion source deck is being implemented. Beam optics calculations have been performed and beam tests conducted that demonstrated that, in addition to pulsing the voltage on the 150 kV ion source deck, a pulsed Einzel lens in front of the following electrostatic quadrupole triplet lens is required to maintain isotope-independent transmission through the 14UD Pelletron accelerator. The high voltage rise time performance of the components of the system has been shown to be satisfactory.

  9. Proteomics and Mass Spectrometry for Cancer Biomarker Discovery

    Directory of Open Access Journals (Sweden)

    Ming Lu


    Full Text Available Proteomics is a rapidly advancing field not only in the field of biology but also in translational cancer research. In recent years, mass spectrometry and associated technologies have been explored to identify proteins or a set of proteins specific to a given disease, for the purpose of disease detection and diagnosis. Such biomarkers are being investigated in samples including cells, tissues, serum/plasma, and other types of body fluids. When sufficiently refined, proteomic technologies may pave the way for early detection of cancer or individualized therapy for cancer. Mass spectrometry approaches coupled with bioinformatic tools are being developed for biomarker discovery and validation. Understanding basic concepts and application of such technology by investigators in the field may accelerate the clinical application of protein biomarkers in disease management.Abbreviations: 2DE: two-dimensional gel electrophoresis; ABPP: activity-based protein profiling; CEA: carcinoembryonic antigen; CI: confidence interval; ESI: electrospray ionization; FP: fluorophosphonate; HPLC: high performance liquid chromatography; ICAT: isotope coded affi nitytags; IEF: isoelectric focusing; iTRAQ: isobaric tags for relative and absolute quantification; LCMS: combined liquid chromatography-mass spectrometry; LCMSMS: liquid chromatography tandem mass spectrometry; LOD: limit of detection; m/z: mass to charge ratio; MALDI: matrix-assisted laser desorption ionization; MS: mass spectrometry; MUDPIT: multidimensional protein identification technology; NAF: nipple aspirate fluid; PMF: peptide mass fingerprinting; PSA: prostate specifi c antigen; PTMs: post-translational modifications; RPMA: reverse phase protein microarray; SELDI: surface enhanced laser desorption ionization; TOF: time-of-flight.

  10. Plasma peptide biomarker discovery for amyotrophic lateral sclerosis by MALDI-TOF mass spectrometry profiling.

    Directory of Open Access Journals (Sweden)

    Laurence Conraux

    Full Text Available The diagnostic of Amyotrophic lateral sclerosis (ALS remains based on clinical and neurophysiological observations. The actual delay between the onset of the symptoms and diagnosis is about 1 year, preventing early inclusion of patients into clinical trials and early care of the disease. Therefore, finding biomarkers with high sensitivity and specificity remains urgent. In our study, we looked for peptide biomarkers in plasma samples using reverse phase magnetic beads (C18 and C8 and MALDI-TOF mass spectrometry analysis. From a set of ALS patients (n=30 and healthy age-matched controls (n=30, C18- or C8-SVM-based models for ALS diagnostic were constructed on the base of the minimum of the most discriminant peaks. These two SVM-based models end up in excellent separations between the 2 groups of patients (recognition capability overall classes > 97% and classify blinded samples (10 ALS and 10 healthy age-matched controls with very high sensitivities and specificities (>90%. Some of these discriminant peaks have been identified by Mass Spectrometry (MS analyses and correspond to (or are fragments of major plasma proteins, partly linked to the blood coagulation.

  11. Penning-trap mass spectrometry and neutrino physics

    Energy Technology Data Exchange (ETDEWEB)

    Eliseev, Sergey; Blaum, Klaus [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Novikov, Yuri N. [Petersburg Nuclear Physics Institute, St. Petersburg (Russian Federation); Department of Physics, St. Petersburg State University (Russian Federation)


    Rapidly developing neutrino physics has found in Penning-trap mass spectrometry a staunch ally in investigating a variety of fundamental problems. The most familiar are the absolute neutrino mass, possible existence of resonant neutrinoless double-electron capture and of keV-sterile neutrinos, and investigation of neutrino oscillations. This article is a brief review of the latest achievements and future perspectives of Penning-trap mass spectrometry in the exploration of these problems with a focus on electron capture and double electron capture processes. (copyright 2013 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. AM1 and electron impact mass spectrometry study of the ...

    African Journals Online (AJOL)

    Recently, in electron impact mass spectrometry (EIMS), it has been found a good correlation between the fragmentation processes of coumarins and the electronic charges of the atoms of their skeleton. In this paper, the same analytical method has been applied to 4-acyl isochroman-1,3-diones, whose mass spectra had ...

  13. Proton Transfer Reaction Mass Spectrometry detects rapid changes in volatile metabolite emission by Mycobacterium smegmatis after the addition of specific antimicrobial agents

    NARCIS (Netherlands)

    Crespo, E.; Cristescu, S. M.; de Ronde, H.; Kuijper, S.; Kolk, A.H.J.; Anthony, R.M.; Harren, F. J. M.


    The metabolic activity of plants, animals or microbes can be monitored by gas headspace analysis. This can be achieved using Proton Transfer Reaction Mass Spectrometry (PTR-MS), a highly sensitive detection method for trace gas analysis. PTR-MS is rapid and can detect metabolic responses on-line as

  14. Structural Glycomic Analyses at High Sensitivity: A Decade of Progress (United States)

    Alley, William R.; Novotny, Milos V.


    The field of glycomics has recently advanced in response to the urgent need for structural characterization and quantification of complex carbohydrates in biologically and medically important applications. The recent success of analytical glycobiology at high sensitivity reflects numerous advances in biomolecular mass spectrometry and its instrumentation, capillary and microchip separation techniques, and microchemical manipulations of carbohydrate reactivity. The multimethodological approach appears to be necessary to gain an in-depth understanding of very complex glycomes in different biological systems. PMID:23560930

  15. Probing the hydrophobic effect of noncovalent complexes by mass spectrometry. (United States)

    Bich, Claudia; Baer, Samuel; Jecklin, Matthias C; Zenobi, Renato


    The study of noncovalent interactions by mass spectrometry has become an active field of research in recent years. The role of the different noncovalent intermolecular forces is not yet fully understood since they tend to be modulated upon transfer into the gas phase. The hydrophobic effect, which plays a major role in protein folding, adhesion of lipid bilayers, etc., is absent in the gas phase. Here, noncovalent complexes with different types of interaction forces were investigated by mass spectrometry and compared with the complex present in solution. Creatine kinase (CK), glutathione S-transferase (GST), ribonuclease S (RNase S), and leucine zipper (LZ), which have dissociation constants in the nM range, were studied by native nanoelectrospray mass spectrometry (nanoESI-MS) and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) combined with chemical cross-linking (XL). Complexes interacting with hydrogen bonds survived the transfer into gas phase intact and were observed by nanoESI-MS. Complexes that are bound largely by the hydrophobic effect in solution were not detected or only at very low intensity. Complexes with mixed polar and hydrophobic interactions were detected by nanoESI-MS, most likely due to the contribution from polar interactions. All noncovalent complexes could easily be studied by XL MALDI-MS, which demonstrates that the noncovalently bound complexes are conserved, and a real "snap-shot" of the situation in solution can be obtained. 2010 American Society for Mass Spectrometry. Published by Elsevier Inc. All rights reserved.

  16. Direct analysis of samples by mass spectrometry: From elements to bio-molecules using laser ablation inductively couple plasma mass spectrometry and laser desorption/ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Perdian, David C. [Iowa State Univ., Ames, IA (United States)


    Mass spectrometric methods that are able to analyze solid samples or biological materials with little or no sample preparation are invaluable to science as well as society. Fundamental research that has discovered experimental and instrumental parameters that inhibit fractionation effects that occur during the quantification of elemental species in solid samples by laser ablation inductively coupled plasma mass spectrometry is described. Research that determines the effectiveness of novel laser desorption/ionization mass spectrometric methods for the molecular analysis of biological tissues at atmospheric pressure and at high spatial resolution is also described. A spatial resolution is achieved that is able to analyze samples at the single cell level.

  17. Mass Spectrometry Analysis of Pseudomonas aeruginosa Treated with Azithromycin (United States)

    Phelan, Vanessa V.; Fang, Jinshu; Dorrestein, Pieter C.


    In microbiology, changes in specialized metabolite production (cell-to-cell signaling metabolites, virulence factors, and natural products) are measured using phenotypic assays. However, advances in mass spectrometry-based techniques including imaging mass spectrometry (IMS) now allow researchers to directly visualize the production of specialized metabolites from microbial colony biofilms. In this study, a combination of IMS and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to visualize the effect of the macrolide antibiotic azithromycin (AZM) on colony biofilms of Pseudomonas aeruginosa. Although previous research suggested that AZM may inhibit cell-to-cell signaling of P. aeruginosa and thereby reduce pathogenicity, we observed no clear decrease in specialized metabolite production.

  18. Breaking the histone code with quantitative mass spectrometry. (United States)

    Britton, Laura-Mae P; Gonzales-Cope, Michelle; Zee, Barry M; Garcia, Benjamin A


    Histone post-translational modifications (PTMs) comprise one of the most intricate nuclear signaling networks that govern gene expression in a long-term and dynamic fashion. These PTMs are considered to be 'epigenetic' or heritable from one cell generation to the next and help establish genomic expression patterns. While much of the analyses of histones have historically been performed using site-specific antibodies, these methods are replete with technical obstacles (i.e., cross-reactivity and epitope occlusion). Mass spectrometry-based proteomics has begun to play a significant role in the interrogation of histone PTMs, revealing many new aspects of these modifications that cannot be easily determined with standard biological approaches. Here, we review the accomplishments of mass spectrometry in the histone field, and outline the future roadblocks that must be overcome for mass spectrometry-based proteomics to become the method of choice for chromatin biologists.

  19. Analysis of oxysterols by electrospray tandem mass spectrometry. (United States)

    Griffiths, William J; Wang, Yuqin; Alvelius, Gunvor; Liu, Suya; Bodin, Karl; Sjövall, Jan


    Oxysterols are oxygenated derivatives of cholesterol. They are intermediates in cholesterol excretion pathways and may also be regarded as transport forms of cholesterol. The introduction of additional hydroxyl groups to the cholesterol skeleton facilitates the flux of oxysterols across the blood brain barrier, and oxysterols have been implicated in mediating a number of cholesterol-induced metabolic effects. Oxysterols are difficult to analyze by atmospheric pressure ionization mass spectrometry on account of the absence of basic or acidic functional groups in their structures. In this communication, we report a method for the derivatization and analysis of oxysterols by electrospray mass spectrometry. Oxysterols with a 3beta-hydroxy-Delta5 structure were converted by cholesterol oxidase to 3-oxo-Delta4 steroids and then derivatized with the Girard P reagent to give Girard P hydrazones, which were subsequently analyzed by tandem mass spectrometry. The improvement in sensitivity for the analysis of 25-hydroxycholesterol upon oxidation and derivatization was over 1000.

  20. Sample preparation in biological mass spectrometry

    CERN Document Server

    Ivanov, Alexander R


    The aim of this book is to provide the researcher with important sample preparation strategies in a wide variety of analyte molecules, specimens, methods, and biological applications requiring mass spectrometric analysis as a detection end-point.

  1. Impacts of Accelerator Mass Spectrometry on the Earth Sciences (United States)

    Stone, J. O.; Caffee, M. W.


    Accelerator Mass Spectrometry (AMS) provides a means of detecting rare radionuclides with half-lives in the range 103 - 107 years, at relative isotopic abundances down to 10-15. AMS combines high sensitivity and efficiency with low backgrounds, giving detection limits of 104 - 105 atoms for many nuclides. Due to the cost, complexity and scale of the technology, most AMS analyses are performed at shared, multi-purpose facilities. Recent growth in the availability of AMS analyses has led to major developments in: (i) Radiocarbon dating and related areas of Quaternary climatic and environmental research. Many thousands of geological C-14 measurements are now performed annually, on samples containing ~ 1 mg of carbon. (ii) Chronology of the Earth's surface, and the quantitative study of geomorphic processes, using cosmic-ray-produced nuclides. The ability to measure cosmogenic Be-10, Al-26 and Cl-36 in surficial rocks and minerals has given rise to methods for dating and correlating glacial, fluvial and marine deposits, determining earthquake recurrence patterns and displacement rates on faults, among many other applications. Analogous methods have been developed to study the geomorphic evolution of eroding and aggrading surfaces, at scales ranging from outcrops to drainage basins. Results from these studies complement recent developments in thermochronology, and have helped to advance our understanding of the interplay between tectonic and surficial processes in the evolution of mountain belts. (iii) Radioisotopic tracing of oceanic, hydrologic and atmospheric flows. AMS measurements of natural and man-made nuclides, such as H-3, C-14, Cl-36 and I-129, are contributing to large-scale ocean circulation studies and estimation of the recharge rates and residence times of groundwater. Technological improvements continue to increase efficiency and sample throughput at AMS facilities. Future developments are likely to reduce the size and operating voltage of AMS

  2. Biological Matrix Effects in Quantitative Tandem Mass Spectrometry-Based Analytical Methods: Advancing Biomonitoring (United States)

    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


    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

  3. Pharmaceutical Analysis by Solid-Substrate Electrospray Ionization Mass Spectrometry with Wooden Tips (United States)

    Yang, Yunyun; Deng, Jiewei; Yao, Zhong-Ping


    Electrospray ionization (ESI) using wooden tips as solid substrates allows direct ionization of various samples and their simple and efficient analyses by mass spectrometry (MS). In this study, wooden-tip ESI-MS was used for pharmaceutical analysis. A wide variety of active components present in pharmaceuticals with forms of tablets, capsules, granules, dry suspensions, suspensions, drops, and oral liquids, etc., were all successfully ionized directly for mass spectrometric analysis. Trace degradation products were also sensitively detected using wooden-tip ESI-MS. This strategy was extended to construct chemical fingerprints of herbal products containing complex and unknown components, and the fingerprints provided valuable information for their quality assessment and origin tracing. Our experimental data demonstrated that wooden-tip ESI-MS is a useful tool for rapid pharmaceutical analysis, with high sensitivity and wide applicability, showing promising perspectives for quality assessment and control, authentication, and origin tracing of pharmaceuticals.

  4. Major roles for minor bacterial lipids identified by mass spectrometry. (United States)

    Garrett, Teresa A


    Mass spectrometry of lipids, especially those isolated from bacteria, has ballooned over the past two decades, affirming in the process the complexity of the lipidome. With this has come the identification of new and interesting lipid structures. Here is an overview of several novel lipids, from both Gram-negative and Gram-positive bacteria with roles in health and disease, whose structural identification was facilitated using mass spectrometry. This article is part of a Special Issue entitled: Bacterial Lipids edited by Russell E. Bishop. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Rapid determination of uranium isotopes in urine by inductively coupled plasma-mass spectrometry. (United States)

    Shi, Y; Dai, X; Collins, R; Kramer-Tremblay, S


    Following a radiological or nuclear emergency involving uranium exposure, rapid analytical methods are needed to analyze the concentration of uranium isotopes in human urine samples for early dose assessment. The inductively coupled plasma mass spectrometry (ICP-MS) technique, with its high sample throughput and high sensitivity, has advantages over alpha spectrometry for uranium urinalysis after minimum sample preparation. In this work, a rapid sample preparation method using an anion exchange chromatographic column was developed to separate uranium from the urine matrix. A high-resolution sector field ICP-MS instrument, coupled with a high sensitivity desolvation sample introduction inlet, was used to determine uranium isotopes in the samples. The method can analyze up to 24 urine samples in two hours with the limits of detection of 0.0014, 0.10, and 2.0 pg mL(-1) for (234)U, (235)U, and (238)U, respectively, which meet the requirement for isotopic analysis of uranium in a radiation emergency.

  6. Schottky mass- and lifetime-spectrometry of unstable, stored ions

    CERN Document Server

    Bosch, F


    GSI is presently the only facility where unstable, highly charged ions far from stability can be produced by in-flight fragmentation and subsequently stored and cooled in an ion storage ring. The mass-to-charge ratio of those stored ions is measured by two complementary methods that have been developed at GSI: Schottky mass-spectrometry, based on the recording of the revolution frequencies of electron-cooled ions, and isochronous mass-spectrometry, applied on short-lived, uncooled ions at the 'transition energy'. Both methods provide a highly efficient, precise and sensitive determination of the nuclear mass of many simultaneously stored ion species. Similarly, the beta lifetimes of stored, unstable nuclei can also be determined. The impact of nuclear masses and lifetimes for both nuclear physics and astrophysics is also addressed.

  7. Structure Determination of Natural Products by Mass Spectrometry (United States)

    Biemann, Klaus


    I review laboratory research on the development of mass spectrometric methodology for the determination of the structure of natural products of biological and medical interest, which I conducted from 1958 to the end of the twentieth century. The methodology was developed by converting small peptides to their corresponding polyamino alcohols to make them amenable to mass spectrometry, thereby making it applicable to whole proteins. The structures of alkaloids were determined by analyzing the fragmentation of a known alkaloid and then using the results to deduce the structures of related compounds. Heparin-like structures were investigated by determining their molecular weights from the mass of protonated molecular ions of complexes with highly basic, synthetic peptides. Mass spectrometry was also employed in the analysis of lunar material returned by the Apollo missions. A miniaturized gas chromatograph mass spectrometer was sent to Mars on board of the two Viking 1976 spacecrafts.

  8. Elucidating rhizosphere processes by mass spectrometry – A review

    Energy Technology Data Exchange (ETDEWEB)

    Rugova, Ariana [Division of Analytical Chemistry, Department of Chemistry, University of Natural Resources and Life Sciences-BOKU, Vienna (Austria); Puschenreiter, Markus [Department of Forest and Soil Sciences, Rhizosphere Ecology and Biogeochemistry Group, University of Natural Resources and Life Sciences-BOKU, Vienna (Austria); Koellensperger, Gunda [Institute of Analytical Chemistry, Faculty of Chemistry, University of Vienna, Vienna (Austria); Hann, Stephan, E-mail: [Division of Analytical Chemistry, Department of Chemistry, University of Natural Resources and Life Sciences-BOKU, Vienna (Austria)


    The presented review discusses state-of-the-art mass spectrometric methods, which have been developed and applied for investigation of chemical processes in the soil-root interface, the so-called rhizosphere. Rhizosphere soil's physical and chemical characteristics are to a great extent influenced by a complex mixture of compounds released from plant roots, i.e. root exudates, which have a high impact on nutrient and trace element dynamics in the soil-root interface as well as on microbial activities or soil physico-chemical characteristics. Chemical characterization as well as accurate quantification of the compounds present in the rhizosphere is a major prerequisite for a better understanding of rhizosphere processes and requires the development and application of advanced sampling procedures in combination with highly selective and sensitive analytical techniques. During the last years, targeted and non-targeted mass spectrometry-based methods have emerged and their combination with specific separation methods for various elements and compounds of a wide polarity range have been successfully applied in several studies. With this review we critically discuss the work that has been conducted within the last decade in the context of rhizosphere research and elemental or molecular mass spectrometry emphasizing different separation techniques as GC, LC and CE. Moreover, selected applications such as metal detoxification or nutrient acquisition will be discussed regarding the mass spectrometric techniques applied in studies of root exudates in plant-bacteria interactions. Additionally, a more recent isotope probing technique as novel mass spectrometry based application is highlighted. - Highlights: • State-of-the-art mass spectrometry methods developed and applied in rhizosphere research are reviewed. • Elemental and molecular mass spectrometry emphasizing different separation techniques (GC, LC or CE) are discussed. • Case studies on metal detoxification

  9. Mass spectrometry of pertrimethylsilyl aldosyl oligosaccharides

    NARCIS (Netherlands)

    Vliegenthart, J.F.G.; Kamerling, J.P.; Vink, Jan; Ridder, J.J. de


    The mass spectra of 18 trimethylsilyl disaccharides containing only aldohexoses, connected via all possible linkages (1 -> 1) to (1 -> 6), were compared. These spectra could be divided into three main groups: (1 -> 1) disaccharides, (1 -> 2), (1 -> 3), (1 -> 4) disaccharides and (1 -> 5), (1 -> 6)

  10. Characterizing the lipid and metabolite changes associated with placental function and pregnancy complications using ion mobility spectrometry-mass spectrometry and mass spectrometry imaging

    Energy Technology Data Exchange (ETDEWEB)

    Burnum-Johnson, Kristin E.; Baker, Erin S.; Metz, Thomas O.


    Successful pregnancy is dependent upon discrete biological events, which include embryo implantation, decidualization, and placentation. Problems associated with each of these events can cause infertility or conditions such as preeclampsia. A greater understanding of the molecular changes associated with these complex processes is necessary to aid in identifying treatments for each condition. Previous nuclear magnetic resonance spectroscopy and mass spectrometry studies have been used to identify metabolites and lipids associated with pregnancy-related complications. However, due to limitations associated with conventional implementations of both techniques, novel technology developments are needed to more fully understand the initiation and development of pregnancy related problems at the molecular level. In this perspective, we describe current analytical techniques for metabolomic and lipidomic characterization of pregnancy complications and discuss the potential for new technologies such as ion mobility spectrometry-mass spectrometry and mass spectrometry imaging to contribute to a better understanding of the molecular changes that affect the placenta and pregnancy outcomes.

  11. LC-Mass Spectrometry for Metabolomics. (United States)

    Dailey, Allyson L


    The field of metabolomics is greatly being refined by the addition of new technologies. LC-MS has allowed researchers to explore additional metabolites which were not originally captured through GC-MS. Through the customizability of the LC columns and mass spectrometer, it is now easier to tailor the instrument to your research needs. Herein, we describe a protocol for sample preparation and data acquisition for a global metabolomic analysis of tissues or feces.

  12. Identifying the related compounds using electrospray ionization tandem mass spectrometry: bromotyrosine alkaloids from marine sponge Psammaplysilla purpurea

    Digital Repository Service at National Institute of Oceanography (India)

    Tilvi, S.; DeSouza, L.

    erythrocytes, mouse kidney and fetal calf brain were characterized by matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) MS, liquid secondary ionization mass spectrometry (LSIMS) and MS/MS. 22 Recently, MALDI-MS full scan analysis... sepctrom, 15, 2240 (2001). 22. H. Perreault, X.L. Hronowski, O. Koul, J. Street, R.H. McCluer and C.E. Costello, “High sensitivity mass spectral characterization of glycosphingolipids from bovine erythrocytes, mouse kidney and fetal calf brain”, lnt. J...

  13. Absorption Mode FT-ICR Mass Spectrometry Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Donald F.; Kilgour, David P.; Konijnenburg, Marco; O' Connor, Peter B.; Heeren, Ronald M.


    Fourier transform ion cyclotron resonance mass spectrometry offers the highest mass resolving power for molecular imaging experiments. This high mass resolving power ensures that closely spaced peaks at the same nominal mass are resolved for proper image generation. Typically higher magnetic fields are used to increase mass resolving power. However, a gain in mass resolving power can also be realized by phase correction of the data for absorption mode display. In addition to mass resolving power, absorption mode offers higher mass accuracy and signal-to-noise ratio over the conventional magnitude mode. Here we present the first use of absorption mode for Fourier transform ion cyclotron resonance mass spectrometry imaging. The Autophaser algorithm is used to phase correct each spectrum (pixel) in the image and then these parameters are used by the Chameleon work-flow based data processing software to generate absorption mode ?Datacubes? for image and spectral viewing. Absorption mode reveals new mass and spatial features that are not resolved in magnitude mode and results in improved selected ion image contrast.

  14. High-accuracy mass spectrometry for fundamental studies. (United States)

    Kluge, H-Jürgen


    Mass spectrometry for fundamental studies in metrology and atomic, nuclear and particle physics requires extreme sensitivity and efficiency as well as ultimate resolving power and accuracy. An overview will be given on the global status of high-accuracy mass spectrometry for fundamental physics and metrology. Three quite different examples of modern mass spectrometric experiments in physics are presented: (i) the retardation spectrometer KATRIN at the Forschungszentrum Karlsruhe, employing electrostatic filtering in combination with magnetic-adiabatic collimation-the biggest mass spectrometer for determining the smallest mass, i.e. the mass of the electron anti-neutrino, (ii) the Experimental Cooler-Storage Ring at GSI-a mass spectrometer of medium size, relative to other accelerators, for determining medium-heavy masses and (iii) the Penning trap facility, SHIPTRAP, at GSI-the smallest mass spectrometer for determining the heaviest masses, those of super-heavy elements. Finally, a short view into the future will address the GSI project HITRAP at GSI for fundamental studies with highly-charged ions.

  15. Accurate protein complex retrieval by affinity enrichment mass spectrometry (AE-MS) rather than affinity purification mass spectrometry (AP-MS). (United States)

    Keilhauer, Eva C; Hein, Marco Y; Mann, Matthias


    Protein-protein interactions are fundamental to the understanding of biological processes. Affinity purification coupled to mass spectrometry (AP-MS) is one of the most promising methods for their investigation. Previously, complexes were purified as much as possible, frequently followed by identification of individual gel bands. However, todays mass spectrometers are highly sensitive, and powerful quantitative proteomics strategies are available to distinguish true interactors from background binders. Here we describe a high performance affinity enrichment-mass spectrometry method for investigating protein-protein interactions, in which no attempt at purifying complexes to homogeneity is made. Instead, we developed analysis methods that take advantage of specific enrichment of interactors in the context of a large amount of unspecific background binders. We perform single-step affinity enrichment of endogenously expressed GFP-tagged proteins and their interactors in budding yeast, followed by single-run, intensity-based label-free quantitative LC-MS/MS analysis. Each pull-down contains around 2000 background binders, which are reinterpreted from troubling contaminants to crucial elements in a novel data analysis strategy. First the background serves for accurate normalization. Second, interacting proteins are not identified by comparison to a single untagged control strain, but instead to the other tagged strains. Third, potential interactors are further validated by their intensity profiles across all samples. We demonstrate the power of our AE-MS method using several well-known and challenging yeast complexes of various abundances. AE-MS is not only highly efficient and robust, but also cost effective, broadly applicable, and can be performed in any laboratory with access to high-resolution mass spectrometers. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. Post-translational modifications and mass spectrometry detection. (United States)

    Silva, André M N; Vitorino, Rui; Domingues, M Rosário M; Spickett, Corinne M; Domingues, Pedro


    In this review, we provide a comprehensive bibliographic overview of the role of mass spectrometry and the recent technical developments in the detection of post-translational modifications (PTMs). We briefly describe the principles of mass spectrometry for detecting PTMs and the protein and peptide enrichment strategies for PTM analysis, including phosphorylation, acetylation and oxidation. This review presents a bibliographic overview of the scientific achievements and the recent technical development in the detection of PTMs is provided. In order to ascertain the state of the art in mass spectrometry and proteomics methodologies for the study of PTMs, we analyzed all the PTM data introduced in the Universal Protein Resource (UniProt) and the literature published in the last three years. The evolution of curated data in UniProt for proteins annotated as being post-translationally modified is also analyzed. Additionally, we have undertaken a careful analysis of the research articles published in the years 2010 to 2012 reporting the detection of PTMs in biological samples by mass spectrometry. © 2013 Elsevier Inc. All rights reserved.

  17. Liquid Chromatography – Mass Spectrometry Method for the ...

    African Journals Online (AJOL)

    Purpose: To develop and validate a simple and selective high performance liquid chromatography photo diode array mass spectrometry (HPLC-PDA-MS/MS) method for simultaneous determination and confirmation of seven major active alkaloids (6-Hydroxy-ß-Carboline-1-carboxylic acid, ß-Carboline-1- carboxylic acid, ...


    The combination of micellar electrokinetic chromatography (MEKC) with mass spectrometry (MS) is very attractive for the direct identification of analyte molecules, for the possibility of selectivity enhancement, and for the structure confirmation and analysis in a MS-MS mode. The...

  19. Fast atom bombardment mass spectrometry of condensed tannin sulfonate derivatives (United States)

    J.J. Karchesy; L.Y. Foo; Richard W. Hemingway; E. Barofsky; D.F. Barofsky


    Condensed tannin sulfonate derivatives were studied by fast atom bombardment mass spectrometry (FAB-MS) to assess the feasibility of using this technique for determining molecular weight and structural information about these compounds. Both positive- and negative-ion spectra provided useful data with regard to molecular weight, cation species present, and presence of...

  20. On-Line Synthesis and Analysis by Mass Spectrometry (United States)

    Bain, Ryan M.; Pulliam, Christopher J.; Raab, Shannon A.; Cooks, R. Graham


    In this laboratory experiment, students learn how to use ESI to accelerate chemical synthesis and to couple it with on-line mass spectrometry for structural analysis. The Hantzsch synthesis of symmetric 1,4-dihydropyridines is a classic example of a one-pot reaction in which multiple intermediates can serve to indicate the progress of the reaction…

  1. Oxidative protein labeling in mass-spectrometry-based proteomics

    NARCIS (Netherlands)

    Roeser, Julien; Bischoff, Rainer; Bruins, Andries P.; Permentier, Hjalmar P.

    Oxidation of proteins and peptides is a common phenomenon, and can be employed as a labeling technique for mass-spectrometry-based proteomics. Nonspecific oxidative labeling methods can modify almost any amino acid residue in a protein or only surface-exposed regions. Specific agents may label

  2. Advances in mass spectrometry driven O-glycoproteomics

    DEFF Research Database (Denmark)

    Levery, Steven B; Steentoft, Catharina; Halim, Adnan


    BACKGROUND: Global analyses of proteins and their modifications by mass spectrometry are essential tools in cell biology and biomedical research. Analyses of glycoproteins represent particular challenges and we are only at the beginnings of the glycoproteomic era. Some of the challenges have been...

  3. Specialized Gas Chromatography--Mass Spectrometry Systems for Clinical Chemistry. (United States)

    Gochman, Nathan; And Others


    A discussion of the basic design and characteristics of gas chromatography-mass spectrometry systems used in clinical chemistry. A comparison of three specific systems: the Vitek Olfax IIA, Hewlett-Packard HP5992, and Du Pont DP-102 are included. (BB)

  4. Analysis of essential oils by gas chromatography and mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Masada, Y.


    The book is in two parts: first part Essential Oil includes compositae; labiatae; verbenaceae; oleaceae; umbelliferae; myrtaceae; euphorbiaceae; rutaceae; geraniaceae; rosaceae; lauraceae; myristicaceae; anonaceae; santalaceae; moraceae; piperaceae; zingiberaceae; araceae; gramineae; and cupressaceae written in English and Japanese. Part two includes essential oil; gas chromatography, and mass spectrometry written in Japanese. (DP)

  5. Negative ion-atmospheric pressure photoionization-mass spectrometry

    NARCIS (Netherlands)

    Kauppila, T.J.; Kotiaho, T.; Kostiainen, R; Bruins, A.P.

    The ionization mechanism in the novel atmospheric pressure photoionization mass spectrometry (APPI-MS) in negative ion mode was studied thoroughly by the analysis of seven compounds in 17 solvent systems. The compounds possessed either gas-phase acidity or positive electron affinity, whereas the

  6. Detection of biomedically relevant stilbenes from wines by mass spectrometry. (United States)

    Andrei, Veronica; Ngounou Wetie, Armand G; Mihai, Iuliana; Darie, Costel C; Vasilescu, Alina


    Stilbenes represent a class of compounds with a common 1,2-diphenylethylene backbone that have shown extraordinary potential in the biomedical field. As the most well-known example, resveratrol proved to have anti-aging effects and significant potential in the fight against cardiovascular diseases and some types of cancer. Mass spectrometry is an analytical method of critical importance in all studies related to stilbenes that are important in the biomedical field. From the discovery of new natural compounds and mapping the grape metabolome up to advanced investigations of stilbenes' potential for the protection of human health in clinical studies, mass spectrometry has provided critical analytical information. In this review we focus on various approaches related to mass spectrometry for the detection of stilbenes-such as coupling with chromatographic separation methods and direct infusion-with presentation of some illustrative applications. Clearly, the potential of mass spectrometry for assisting in the discovery of new stilbenes of biomedical importance, elucidating their mechanisms of action, and quantifying minute quantities in complex matrices is far from being exhausted.

  7. Mass spectrometry-based biochemical assays for enzymeinhibitor screening

    NARCIS (Netherlands)

    de Boer, A.R.; Lingeman, H.; Niessen, W.M.A.; Irth, H.


    Screening for inhibitors of pharmacologically-relevant enzymes is in many cases an important starting point in drug discovery. While fluorescence-based detection techniques play an important role in high-throughput screening, mass spectrometry (MS)-based assays have gained in importance in recent

  8. Mass Spectrometry Method for Quantification of Telmisartan in Hum

    African Journals Online (AJOL)

    Purpose: To develop and validate a simple, rapid, sensitive and specific ultraperformance liquid chromatography mass spectrometry method for the quantification of the angiotensin II receptor antagonist, telmisartan (TEL), in human plasma. Methods: After simple protein precipitation using acetonitrile and methanol, TEL and ...

  9. Mass Spectrometry Imaging for the Classification of Tumor Tissue

    NARCIS (Netherlands)

    Mascini, N.E.


    Mass spectrometry imaging (MSI) can detect and identify many different molecules without the need for labeling. In addition, it can provide their spatial distributions as ‘molecular maps’. These features make MSI well suited for studying the molecular makeup of tumor tissue. Currently, there is an

  10. Gas chromatography mass spectrometry : key technology in metabolomics

    NARCIS (Netherlands)

    Koek, Maud Marijtje


    Metabolomics involves the unbiased quantitative and qualitative analysis of the complete set of metabolites present in cells, body fluids and tissues. Gas chromatography coupled to mass spectrometry (GC-MS) is very suitable for metabolomics analysis, as it combines high separation power with

  11. Mass spectrometry: Raw protein from the top down (United States)

    Breuker, Kathrin


    Mass spectrometry is a powerful technique for analysing proteins, yet linking higher-order protein structure to amino acid sequence and post-translational modifications is far from simple. Now, a native top-down method has been developed that can provide information on higher-order protein structure and different proteoforms at the same time.

  12. Decoding signalling networks by mass spectrometry-based proteomics

    DEFF Research Database (Denmark)

    Choudhary, Chuna Ram; Mann, Matthias


    Signalling networks regulate essentially all of the biology of cells and organisms in normal and disease states. Signalling is often studied using antibody-based techniques such as western blots. Large-scale 'precision proteomics' based on mass spectrometry now enables the system...

  13. Traveling-wave ion mobility mass spectrometry of protein complexes

    DEFF Research Database (Denmark)

    Salbo, Rune; Bush, Matthew F; Naver, Helle


    The collision cross-section (Ω) of a protein or protein complex ion can be measured using traveling-wave (T-wave) ion mobility (IM) mass spectrometry (MS) via calibration with compounds of known Ω. The T-wave Ω-values depend strongly on instrument parameters and calibrant selection. Optimization...

  14. Data analysis for mass spectrometry imaging : methods and applications

    NARCIS (Netherlands)

    Abdelmoula, Walid Mohamed


    In this dissertation we developed a number of automatic methods for multi-modal data registration, mainly between mass spectrometry imaging, imaging microscopy, and the Allen Brain Atlas. We have shown the importance of these methods for performing large scale preclinical biomarker discovery

  15. Capillary electrophoresis-mass spectrometry for the analysis of biopharmaceuticals

    NARCIS (Netherlands)

    Haselberg, Rob; De Jong, Gerhardus J.; Somsen, Govert W.


    Developments in the fields of protein chemistry and pharmaceutical biotechnology have increased the demand for suitable analytical techniques for the characterization of intact proteins. Capillary electrophoresis (CE) coupled to mass spectrometry (MS) has proven to be a powerful tool for this

  16. Capillary electrophoresis-mass spectrometry for the analysis of Biopharmaceuticals

    NARCIS (Netherlands)

    Haselberg, Rob; de Jong, Gerhardus J.; Somsen, Govert W.


    Developments in the fields of protein chemistry and pharmaceutical biotechnology have increased the demand for suitable analytical techniques for the characterization of intact proteins. Capillary electrophoresis (CE) coupled to mass spectrometry (MS) has proven to be a powerful tool for this

  17. Kinetic Studies of Reactions in Solution Using Fast Mass Spectrometry (United States)


    fuel source. Many hypergols are toxic, corrosive , and/or volatile such that they are difficult to handle and harmful to the environment. Dicyanamide... electrochemistry and the mass spectrometry analysis of the solutions in which an electrocatalyst is present. NN NN ee meetthyll vviioolloogeenn (93

  18. Accelerator mass spectrometry as a bioanalytical tool for nutritional research

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, J.S.; Turteltaub, K.W.


    Accelerator Mass Spectrometry is a mass spectrometric method of detecting long-lived radioisotopes without regard to their decay products or half-life. The technique is normally applied to geochronology, but recently has been developed for bioanalytical tracing. AMS detects isotope concentrations to parts per quadrillion, quantifying labeled biochemicals to attomole levels in milligram- sized samples. Its advantages over non-isotopeic and stable isotope labeling methods are reviewed and examples of analytical integrity, sensitivity, specificity, and applicability are provided.

  19. Capillary electrophoresis-mass spectrometry of carbohydrates (United States)

    Zaia, Joseph


    The development of methods for capillary electrophoresis (CE) with on-line mass spectrometric detection (CE/MS) is driven by the need for accurate, robust and sensitive glycomics analysis for basic biomedicine, biomarker discovery, and analysis of recombinant protein therapeutics. One important capability is to profile glycan mixtures with respect to the patterns of substituents including sialic acids, acetate, sulfate, phosphate, and other groups. There is additional need for an MS-compatible separation system capable of resolving carbohydrate isomers. This review summarizes applications of CS/MS to analysis of carbohydrates, glycoproteins and glycopeptides that have appeared since 2008. Readers are referred to recent comprehensive reviews covering earlier publications. PMID:23386333

  20. Application of Laser Mass Spectrometry to Art and Archaeology (United States)

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


    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.

  1. Frontal affinity chromatography-mass spectrometry. (United States)

    Ng, Ella S M; Chan, Nora W C; Lewis, Darren F; Hindsgaul, Ole; Schriemer, David C


    Frontal affinity chromatography (FAC) is a biophysical method for the discovery and characterization of molecular interactions in a flow-based system. Several different modes of analysis are possible by interfacing to the mass spectrometer, including robust single-compound characterizations as well as high-throughput screening of over 1,000 compounds per run. The method supports thermodynamic and kinetic characterization of interactions for a wide range of molecular species and possesses similarities to flow-based biosensors such as surface plasmon resonance. It offers sensitive detection of ligands present well below their respective dissociation constants, and can be assembled from readily available laboratory components. Direct coupling of the FAC cartridge to the mass spectrometer is useful for the interrogation of single compounds or mixtures of limited complexity. An offline fractionation schema is more appropriate for discovery-mode applications. A high-performance FAC system enabling both modes can be assembled in 2-3 h. Measurements of dissociation constants can be made with such a system in 0.5-3 h, and the system supports higher-throughput screening modes at a rate of 10,000 compounds d(-1).

  2. Liquid chromatography-mass spectrometry in forensic toxicology. (United States)

    Van Bocxlaer, J F; Clauwaert, K M; Lambert, W E; Deforce, D L; Van den Eeckhout, E G; De Leenheer, A P


    Liquid chromatography-mass spectrometry has evolved from a topic of mainly research interest into a routinely usable tool in various application fields. With the advent of new ionization approaches, especially atmospheric pressure, the technique has established itself firmly in many areas of research. Although many applications prove that LC-MS is a valuable complementary analytical tool to GC-MS and has the potential to largely extend the application field of mass spectrometry to hitherto "MS-phobic" molecules, we must recognize that the use of LC-MS in forensic toxicology remains relatively rare. This rarity is all the more surprising because forensic toxicologists find themselves often confronted with the daunting task of actually searching for evidence materials on a scientific basis without any indication of the direction in which to search. Through the years, mass spectrometry, mainly in the GC-MS form, has gained a leading role in the way such quandaries are tackled. The advent of robust, bioanalytically compatible combinations of liquid chromatographic separation with mass spectrometric detection really opens new perspectives in terms of mass spectrometric identification of difficult molecules (e.g., polar metabolites) or biopolymers with toxicological relevance, high throughput, and versatility. Of course, analytical toxicologists are generally mass spectrometry users rather than mass spectrometrists, and this difference certainly explains the slow start of LC-MS in this field. Nevertheless, some valuable applications have been published, and it seems that the introduction of the more universal atmospheric pressure ionization interfaces really has boosted interests. This review presents an overview of what has been realized in forensic toxicological LC-MS. After a short introduction into LC-MS interfacing operational characteristics (or limitations), it covers applications that range from illicit drugs to often abused prescription medicines and some

  3. Metabolic Profiling of Human Benign and Malignant Pulmonary Nodules Using Mass Spectrometry-Based Metabolomics

    Directory of Open Access Journals (Sweden)

    Choon Nam Ong


    Full Text Available Solitary pulmonary nodule (SPN or coin lesion is a mass in the lung and can be commonly found in chest X-rays or computerized tomography (CT scans. However, despite the advancement of imaging technologies, it is still difficult to distinguish malignant cancer from benign SPNs. Here we investigated the metabolic profiling of patients with benign and malignant pulmonary nodules. A combination of gas chromatography/mass spectrometry (GC/MS and liquid chromatography/mass spectrometry (LC/MS was used to profile the plasma metabolites in 17 patients with malignant SPNs, 15 patients with benign SPNs and 20 healthy controls. The metabolic profiles were assayed using OPLS-DA, and further analyzed to identify marker metabolites related to diseases. Both GC/MS- and LC/MS-derived models showed clear discriminations in metabolic profiles among three groups. It was found that 63 metabolites (12 from GC/MS, 51 from LC/MS contributed to the differences. Of these, 48 metabolites showed same change trend in both malignant and benign SPNs as compared with healthy controls, indicating some common pathways including inflammation and oxidative injury shared by two diseases. In contrast, 14 metabolites constituted distinct profiles that differentiated malignant from benign SPNs, which might be a unique biochemical feature associated with lung cancer. Overall, our data suggested that integration of two highly sensitive and complementary metabolomics platforms could enable a comprehensive metabolic profiling and assist in discrimination malignant from benign SPNs.

  4. Multiresidue pesticide analysis by capillary gas chromatography-mass spectrometry. (United States)

    Wong, Jon W; Zhang, Kai; Hayward, Douglas G; Kai-Meng, Chin


    A multiresidue pesticide method using a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) procedure and capillary gas chromatography-mass spectrometry (GC-MS) is described for the determination of 166 organochlorine, organophosphorus, and pyrethroid pesticides, metabolites, and isomers in spinach. The pesticides from spinach were extracted using acetonitrile saturated with magnesium sulfate and sodium chloride, followed by solid-phase dispersive cleanup using primary-secondary amine and graphitized carbon black sorbents and toluene. Analysis is performed using different GC-MS techniques emphasizing the benefits of non-targeted acquisition and targeted screening procedures. Non-targeted data acquisition of pesticides in the spinach was demonstrated using GC coupled to a single quadrupole mass spectrometery (GC-MS) in full scan mode or multidimensional GC-time-of-flight mass spectrometery (GC  ×  GC-TOF/MS), along with deconvolution software and libraries. Targeted screening was achieved using GC-single quadrupole mass spectrometry in selective ion monitoring (GC-MS/SIM) mode or -tandem mass spectrometry (GC-MS/MS) in multiple reaction monitoring mode. The development of these techniques demonstrates the powerful use of GC-MS for the screening, identification, and quantitation of pesticide residues in foods.

  5. Estimating the Efficiency of Phosphopeptide Identification by Tandem Mass Spectrometry (United States)

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


    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.

  6. Imaging mass spectrometry with nuclear microprobes for biological applications

    Energy Technology Data Exchange (ETDEWEB)

    Nakata, Y. [Department of Nuclear Engineering, Kyoto University, Sakyo, Kyoto 606-8501 (Japan)], E-mail:; Yamada, H.; Honda, Y. [Department of Nuclear Engineering, Kyoto University, Sakyo, Kyoto 606-8501 (Japan); Ninomiya, S. [Quantum Science and Engineering Center, Kyoto University, Uji, Kyoto 611-0011 (Japan); Seki, T. [Department of Nuclear Engineering, Kyoto University, Sakyo, Kyoto 606-8501 (Japan); CREST, Japan Science and Technology Agency, Chiyoda, Tokyo 102-0075 (Japan); Aoki, T. [Department of Electronic Science and Engineering, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan); CREST, Japan Science and Technology Agency, Chiyoda, Tokyo 102-0075 (Japan); Matsuo, J. [Quantum Science and Engineering Center, Kyoto University, Uji, Kyoto 611-0011 (Japan); CREST, Japan Science and Technology Agency, Chiyoda, Tokyo 102-0075 (Japan)


    A mass spectrometric technique using nuclear microprobes is presented in this paper for biological applications. In recent years, imaging mass spectrometry has become an increasingly important technique for visualizing the spatial distribution of molecular species in biological tissues and cells. However, due to low yields of large molecular ions, the conventional secondary ion mass spectrometry (SIMS), that uses keV primary ion beams, is typically applied for imaging of either elements or low mass compounds. In this study, we performed imaging mass spectrometry using MeV ion beams collimated to about 10 {mu}m, and successfully obtained molecular ion images from plant and animal cell sections. The molecular ion imaging of the pollen section showed high intensities of PO{sub 3}{sup -} ions in the pollen cytoplasm, compared to the pollen wall, and indicated the heterogeneous distribution in the cytoplasm. The 3T3-L1 cell image revealed the high intensity of PO{sub 3}{sup -} ions, in particular from the cell nucleus. The result showed that not only the individual cell, but also the cell nucleus could be identified with the present imaging technique.

  7. Matrix-assisted laser desorption/ionization imaging mass spectrometry. (United States)

    Zaima, Nobuhiro; Hayasaka, Takahiro; Goto-Inoue, Naoko; Setou, Mitsutoshi


    Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a powerful tool that enables the simultaneous detection and identification of biomolecules in analytes. MALDI-imaging mass spectrometry (MALDI-IMS) is a two-dimensional MALDI-mass spectrometric technique used to visualize the spatial distribution of biomolecules without extraction, purification, separation, or labeling of biological samples. MALDI-IMS has revealed the characteristic distribution of several biomolecules, including proteins, peptides, amino acids, lipids, carbohydrates, and nucleotides, in various tissues. The versatility of MALDI-IMS has opened a new frontier in several fields such as medicine, agriculture, biology, pharmacology, and pathology. MALDI-IMS has a great potential for discovery of unknown biomarkers. In this review, we describe the methodology and applications of MALDI-IMS for biological samples.

  8. T cells recognizing a peptide contaminant undetectable by mass spectrometry

    DEFF Research Database (Denmark)

    Brezar, Vedran; Culina, Slobodan; Østerbye, Thomas


    Synthetic peptides are widely used in immunological research as epitopes to stimulate their cognate T cells. These preparations are never completely pure, but trace contaminants are commonly revealed by mass spectrometry quality controls. In an effort to characterize novel major histocompatibility...... complex (MHC) Class I-restricted ß-cell epitopes in non-obese diabetic (NOD) mice, we identified islet-infiltrating CD8+ T cells recognizing a contaminating peptide. The amount of this contaminant was so small to be undetectable by direct mass spectrometry. Only after concentration by liquid...... chromatography, we observed a mass peak corresponding to an immunodominant islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP)(206-214) epitope described in the literature. Generation of CD8+ T-cell clones recognizing IGRP(206-214) using a novel method confirmed the identity...

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

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


    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.

  10. Velocity map imaging in time of flight mass spectrometry. (United States)

    Brouard, M; Campbell, E K; Johnsen, A J; Vallance, C; Yuen, W H; Nomerotski, A


    A new variation on time of flight mass spectrometry is presented, which uses a fast framing charge coupled device camera to velocity map image multiple product masses in a single acquisition. The technique is demonstrated on two photofragmentation processes, those of CS(2) and CH(3)S(2)CH(3) (dimethyldisulfide) at a photolysis wavelength of 193 nm. In both cases, several mass fragments are imaged simultaneously, and speed distributions and anisotropy parameters are extracted that are comparable to those obtained by imaging each fragment separately in conventional velocity map imaging studies.

  11. Mass Spectrometry Based Ultrasensitive DNA Methylation Profiling Using Target Fragmentation Assay. (United States)

    Lin, Xiang-Cheng; Zhang, Ting; Liu, Lan; Tang, Hao; Yu, Ru-Qin; Jiang, Jian-Hui


    Efficient tools for profiling DNA methylation in specific genes are essential for epigenetics and clinical diagnostics. Current DNA methylation profiling techniques have been limited by inconvenient implementation, requirements of specific reagents, and inferior accuracy in quantifying methylation degree. We develop a novel mass spectrometry method, target fragmentation assay (TFA), which enable to profile methylation in specific sequences. This method combines selective capture of DNA target from restricted cleavage of genomic DNA using magnetic separation with MS detection of the nonenzymatic hydrolysates of target DNA. This method is shown to be highly sensitive with a detection limit as low as 0.056 amol, allowing direct profiling of methylation using genome DNA without preamplification. Moreover, this method offers a unique advantage in accurately determining DNA methylation level. The clinical applicability was demonstrated by DNA methylation analysis using prostate tissue samples, implying the potential of this method as a useful tool for DNA methylation profiling in early detection of related diseases.

  12. Use of nanostructure initiator mass spectrometry (NIMS to deduce selectivity of reaction in glycoside hydrolases

    Directory of Open Access Journals (Sweden)

    Kai eDeng


    Full Text Available Chemically synthesized nanostructure-initiator mass spectrometry (NIMS probes derivatized with tetrasaccharides were used to study the reactivity of representative Clostridium thermocellum β-glucosidase, endoglucanases and cellobiohydrolase. Diagnostic patterns for reactions of these different classes of enzymes were observed. Results show sequential removal of glucose by the β-glucosidase and a progressive increase in specificity of reaction from endoglucanases to cellobiohydrolase. Time-dependent reactions of these polysaccharide-selective enzymes were modeled by numerical integration, which provides a quantitative basis to make functional distinctions among a continuum of naturally evolved catalytic properties. Consequently, our method, which combines automated protein translation with high-sensitivity and time-dependent detection of multiple products, provides a new approach to annotate glycoside hydrolase phylogenetic trees with functional measurements.

  13. A Simple Approach for Obtaining High Resolution, High Sensitivity ¹H NMR Metabolite Spectra of Biofluids with Limited Mass Supply

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jian Zhi; Rommereim, Donald N.; Wind, Robert A.; Minard, Kevin R.; Sears, Jesse A.


    A simple approach is reported that yields high resolution, high sensitivity ¹H NMR spectra of biofluids with limited mass supply. This is achieved by spinning a capillary sample tube containing a biofluid at the magic angle at a frequency of about 80Hz. A 2D pulse sequence called ¹H PASS is then used to produce a high-resolution ¹H NMR spectrum that is free from magnetic susceptibility induced line broadening. With this new approach a high resolution ¹H NMR spectrum of biofluids with a volume less than 1.0 µl can be easily achieved at a magnetic field strength as low as 7.05T. Furthermore, the methodology facilitates easy sample handling, i.e., the samples can be directly collected into inexpensive and disposable capillary tubes at the site of collection and subsequently used for NMR measurements. In addition, slow magic angle spinning improves magnetic field shimming and is especially suitable for high throughput investigations. In this paper first results are shown obtained in a magnetic field of 7.05T on urine samples collected from mice using a modified commercial NMR probe.

  14. Use of mass spectrometry for imaging metabolites in plants. (United States)

    Lee, Young Jin; Perdian, David C; Song, Zhihong; Yeung, Edward S; Nikolau, Basil J


    We discuss and illustrate recent advances that have been made to image the distribution of metabolites among cells and tissues of plants using different mass spectrometry technologies. These technologies include matrix-assisted laser desorption ionization, desorption electrospray ionization, and secondary ion mass spectrometry. These are relatively new technological applications of mass spectrometry and they are providing highly spatially resolved data concerning the cellular distribution of metabolites. We discuss the advantages and limitations of each of these mass spectrometric methods, and provide a description of the technical barriers that are currently limiting the technology to the level of single-cell resolution. However, we anticipate that advances in the next few years will increase the resolving power of the technology to provide unprecedented data on the distribution of metabolites at the subcellular level, which will increase our ability to decipher new knowledge concerning the spatial organization of metabolic processes in plants. Published 2012. This article is a US Government work and is in the public domain in the USA.

  15. Identification of carbohydrate anomers using ion mobility-mass spectrometry (United States)

    Hofmann, J.; Hahm, H. S.; Seeberger, P. H.; Pagel, K.


    Carbohydrates are ubiquitous biological polymers that are important in a broad range of biological processes. However, owing to their branched structures and the presence of stereogenic centres at each glycosidic linkage between monomers, carbohydrates are harder to characterize than are peptides and oligonucleotides. Methods such as nuclear magnetic resonance spectroscopy can be used to characterize glycosidic linkages, but this technique requires milligram amounts of material and cannot detect small amounts of coexisting isomers. Mass spectrometry, on the other hand, can provide information on carbohydrate composition and connectivity for even small amounts of sample, but it cannot be used to distinguish between stereoisomers. Here, we demonstrate that ion mobility-mass spectrometry--a method that separates molecules according to their mass, charge, size, and shape--can unambiguously identify carbohydrate linkage-isomers and stereoisomers. We analysed six synthetic carbohydrate isomers that differ in composition, connectivity, or configuration. Our data show that coexisting carbohydrate isomers can be identified, and relative concentrations of the minor isomer as low as 0.1 per cent can be detected. In addition, the analysis is rapid, and requires no derivatization and only small amounts of sample. These results indicate that ion mobility-mass spectrometry is an effective tool for the analysis of complex carbohydrates. This method could have an impact on the field of carbohydrate synthesis similar to that of the advent of high-performance liquid chromatography on the field of peptide assembly in the late 1970s.

  16. New Types of Ionization Sources for Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)



    The purpose of this Cooperative Research and Development Agreement (CRADA) between UT-Battelle (Contractor) and MDS Sciex (Participant) and ESA, Inc. (Participant) is to research, develop and apply new types of ionization sources and sampling/inlet systems for analytical mass spectrometry making use of the Participants state-of-the-art atmospheric sampling mass spectrometry electrochemical cell technology instrumentation and ancillary equipment. The two overriding goals of this research project are: to understand the relationship among the various instrumental components and operational parameters of the various ion sources and inlet systems under study, the chemical nature of the gases, solvents, and analytes in use, and the nature and abundances of the ions ultimately observed in the mass spectrometer; and to develop new and better analytical and fundamental applications of these ion sources and inlet systems or alternative sources and inlets coupled with mass spectrometry on the basis of the fundamental understanding obtained in Goal 1. The end results of this work are expected to be: (1) an expanded utility for the ion sources and inlet systems under study (such as the analysis of new types of analytes) and the control or alteration of the ionic species observed in the gas-phase; (2) enhanced instrument performance as judged by operational figures-of-merit such as dynamic range, detection limits, susceptibility to matrix signal suppression and sensitivity; and (3) novel applications (such as surface sampling with electrospray) in both applied and fundamental studies. The research projects outlined herein build upon work initiated under the previous CRADA between the Contractor and MDS Sciex on ion sources and inlet systems for mass spectrometry. Specific ion source and inlet systems for exploration of the fundamental properties and practical implementation of these principles are given.

  17. Preliminary mass spectrometry characterization studies of galectin-3 samples, prior to carbohydrate-binding studies using Affinity mass spectrometry. (United States)

    Jovanović, Marko; Peter-Katalinić, Jasna


    Investigation of non-covalent complexes of proteins using Affinity Mass Spectrometry (AMS) represents a major challenge in modern biomedical research. However, many experimental obstacles can make AMS data analysis complex. Additionally, sample purity and size of the protein may still pose significant challenges. Matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) mass spectrometry (MS) was used for initial mapping of protein samples. nanoESI (electrospray ionization) quadrupole-time-of-flight (QTOF) MS was used for mapping of protein samples under native conditions and subsequent AMS studies. The human galectin-3 protein sample was expressed in E. coli. Full length galectin-3 was difficult to work with, due to several truncated forms observed after the purification procedures. On the other hand, galectin-3C produced excellent quality nanoESI-MS spectra. A covalent adduct of lactose was found to be located on residue Lys 176. Functional AMS control studies indicated that galectin-3 interactions with oligosaccharides may be dependent on its charge. Mass spectrometry represents a valuable tool that can be efficiently used for structural characterization of protein samples prior to functional analyses. By means of accurate mass measurements, many protein truncations can be identified based on mass alone. Analysis of covalent adducts is more challenging. Finally, for AMS studies, careful use of controls may reveal charge-dependence of protein-oligosaccharide interactions. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  18. Mass spectrometry for the determination of fission products 135Cs, 137Cs and 90Sr: A review of methodology and applications (United States)

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


    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

  19. Metabolism of halogenated compounds in the white rot fungus Bjerkandera adusta studied by membrane inlet mass spectrometry and tandem mass spectrometry

    DEFF Research Database (Denmark)

    Beck, Hans Christian; Lauritsen, F.R.; Patrick, J.S.


    Membrane inlet mass spectrometry has been used for the characterization of halogenated organic compounds produced by the fungus Bjerkandera adusta. Using this technique, electron impact-, chemical ionization-, electron capture negative chemical ionization-mass spectra and tandem mass spectra were...

  20. Characterisation of covalent copper and manganese organometallic complexes with Schiff bases by ionspray mass spectrometry

    NARCIS (Netherlands)

    Raffaelli, A.; Minutolo, F.; Feringa, B.L.; Salvadori, P.


    Copper and manganese complexes containing Schiff bases as ligands, having potential interest in homogeneous catalysis, have been characterised by mass spectrometry using ionspray ionisation. Single stage mass spectrometry allowed us to confirm the molecular weight of complexes in all cases,

  1. Fourier Transform Mass Spectrometry: The Transformation of Modern Environmental Analyses (United States)

    Lim, Lucy; Yan, Fangzhi; Bach, Stephen; Pihakari, Katianna; Klein, David


    Unknown compounds in environmental samples are difficult to identify using standard mass spectrometric methods. Fourier transform mass spectrometry (FTMS) has revolutionized how environmental analyses are performed. With its unsurpassed mass accuracy, high resolution and sensitivity, researchers now have a tool for difficult and complex environmental analyses. Two features of FTMS are responsible for changing the face of how complex analyses are accomplished. First is the ability to quickly and with high mass accuracy determine the presence of unknown chemical residues in samples. For years, the field has been limited by mass spectrometric methods that were based on knowing what compounds of interest were. Secondly, by utilizing the high resolution capabilities coupled with the low detection limits of FTMS, analysts also could dilute the sample sufficiently to minimize the ionization changes from varied matrices. PMID:26784175

  2. Establishing Drug Resistance in Microorganisms by Mass Spectrometry (United States)

    Demirev, Plamen A.; Hagan, Nathan S.; Antoine, Miquel D.; Lin, Jeffrey S.; Feldman, Andrew B.


    A rapid method to determine drug resistance in bacteria based on mass spectrometry is presented. In it, a mass spectrum of an intact microorganism grown in drug-containing stable isotope-labeled media is compared with a mass spectrum of the intact microorganism grown in non-labeled media without the drug present. Drug resistance is determined by predicting characteristic mass shifts of one or more microorganism biomarkers using bioinformatics algorithms. Observing such characteristic mass shifts indicates that the microorganism is viable even in the presence of the drug, thus incorporating the isotopic label into characteristic biomarker molecules. The performance of the method is illustrated on the example of intact E. coli, grown in control (unlabeled) and 13C-labeled media, and analyzed by MALDI TOF MS. Algorithms for data analysis are presented as well.

  3. Fourier Transform Mass Spectrometry: The Transformation of Modern Environmental Analyses

    Directory of Open Access Journals (Sweden)

    Lucy Lim


    Full Text Available Unknown compounds in environmental samples are difficult to identify using standard mass spectrometric methods. Fourier transform mass spectrometry (FTMS has revolutionized how environmental analyses are performed. With its unsurpassed mass accuracy, high resolution and sensitivity, researchers now have a tool for difficult and complex environmental analyses. Two features of FTMS are responsible for changing the face of how complex analyses are accomplished. First is the ability to quickly and with high mass accuracy determine the presence of unknown chemical residues in samples. For years, the field has been limited by mass spectrometric methods that were based on knowing what compounds of interest were. Secondly, by utilizing the high resolution capabilities coupled with the low detection limits of FTMS, analysts also could dilute the sample sufficiently to minimize the ionization changes from varied matrices.

  4. Recent directions of electrospray mass spectrometry for elemental speciation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Schaumloeffel, Dirk [Universite de Pau et des Pays de l' Adour/CNRS UMR 5254, Laboratoire de Chimie Analytique Bio-Inorganique et Environnement/IPREM, Pau (France); Tholey, Andreas [Christian-Albrechts-Universitaet, Institute for Experimental Medicine - Div. Systematic Proteome Research, Kiel (Germany)


    A brief survey is given of the last 2 years' literature on electrospray mass spectrometry (ESI-MS) for speciation analysis. As observed for many years, the main recent applications in this field concern arsenic and selenium species, especially in studies encompassing combined use of molecular and element mass spectrometry. A further application field is the stoichiometric characterization of metal complexes by ESI-MS, which in some studies was assisted by nuclear magnetic resonance spectroscopy. A few examples are presented to illustrate arsenic species involved in metabolic pathways, sulfur species in oils and bitumen, and aluminum complexes. On the basis of this review, we also give an outlook of expected future developments and trends in this research field. (orig.)

  5. Discovery based and targeted Mass Spectrometry in farm animal proteomics

    DEFF Research Database (Denmark)

    Bendixen, Emøke


    Technological advances in mass spectrometry have greatly improved accuracy and speed of analyses of proteins and biochemical pathways. These proteome technologies have transformed research and diagnostic methods in the biomedical fields, and in food and farm animal sciences proteomics can be used...... to investigate and monitor specific marker proteins and peptides within complex food matrices, as for example, for guaranteeing safety and quality of processed and stored foods like cheese and cured meat. Likewise, specific diagnostic markers associated with compromised welfare, or with early infections can...... for investigating farm animal biology. SRM is particularly important for validation biomarker candidates This talk will introduce the use of different mass spectrometry approaches through examples related to food quality and animal welfare, including studies of gut health in pigs, host pathogen interactions...

  6. Investigating quantitation of phosphorylation using MALDI-TOF mass spectrometry. (United States)

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


    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

  7. Statistical methods for quantitative mass spectrometry proteomic experiments with labeling

    Directory of Open Access Journals (Sweden)

    Oberg Ann L


    Full Text Available Abstract Mass Spectrometry utilizing labeling allows multiple specimens to be subjected to mass spectrometry simultaneously. As a result, between-experiment variability is reduced. Here we describe use of fundamental concepts of statistical experimental design in the labeling framework in order to minimize variability and avoid biases. We demonstrate how to export data in the format that is most efficient for statistical analysis. We demonstrate how to assess the need for normalization, perform normalization, and check whether it worked. We describe how to build a model explaining the observed values and test for differential protein abundance along with descriptive statistics and measures of reliability of the findings. Concepts are illustrated through the use of three case studies utilizing the iTRAQ 4-plex labeling protocol.

  8. Proteomics and Mass Spectrometry for Cancer Biomarker Discovery (United States)

    Lu, Ming; Faull, Kym F.; Whitelegge, Julian P.; He, Jianbo; Shen, Dejun; Saxton, Romaine E.; Chang, Helena R.


    Proteomics is a rapidly advancing field not only in the field of biology but also in translational cancer research. In recent years, mass spectrometry and associated technologies have been explored to identify proteins or a set of proteins specific to a given disease, for the purpose of disease detection and diagnosis. Such biomarkers are being investigated in samples including cells, tissues, serum/plasma, and other types of body fluids. When sufficiently refined, proteomic technologies may pave the way for early detection of cancer or individualized therapy for cancer. Mass spectrometry approaches coupled with bioinformatic tools are being developed for biomarker discovery and validation. Understanding basic concepts and application of such technology by investigators in the field may accelerate the clinical application of protein biomarkers in disease management. PMID:19662217

  9. Challenges ahead for mass spectrometry and proteomics applications in epigenetics. (United States)

    Kessler, Benedikt M


    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.

  10. Sharing and community curation of mass spectrometry data with GNPS (United States)

    Nguyen, Don Duy; Watrous, Jeramie; Kapono, Clifford A; Luzzatto-Knaan, Tal; Porto, Carla; Bouslimani, Amina; Melnik, Alexey V; Meehan, Michael J; Liu, Wei-Ting; Crüsemann, Max; Boudreau, Paul D; Esquenazi, Eduardo; Sandoval-Calderón, Mario; Kersten, Roland D; Pace, Laura A; Quinn, Robert A; Duncan, Katherine R; Hsu, Cheng-Chih; Floros, Dimitrios J; Gavilan, Ronnie G; Kleigrewe, Karin; Northen, Trent; Dutton, Rachel J; Parrot, Delphine; Carlson, Erin E; Aigle, Bertrand; Michelsen, Charlotte F; Jelsbak, Lars; Sohlenkamp, Christian; Pevzner, Pavel; Edlund, Anna; McLean, Jeffrey; Piel, Jörn; Murphy, Brian T; Gerwick, Lena; Liaw, Chih-Chuang; Yang, Yu-Liang; Humpf, Hans-Ulrich; Maansson, Maria; Keyzers, Robert A; Sims, Amy C; Johnson, Andrew R.; Sidebottom, Ashley M; Sedio, Brian E; Klitgaard, Andreas; Larson, Charles B; P., Cristopher A Boya; Torres-Mendoza, Daniel; Gonzalez, David J; Silva, Denise B; Marques, Lucas M; Demarque, Daniel P; Pociute, Egle; O'Neill, Ellis C; Briand, Enora; Helfrich, Eric J. N.; Granatosky, Eve A; Glukhov, Evgenia; Ryffel, Florian; Houson, Hailey; Mohimani, Hosein; Kharbush, Jenan J; Zeng, Yi; Vorholt, Julia A; Kurita, Kenji L; Charusanti, Pep; McPhail, Kerry L; Nielsen, Kristian Fog; Vuong, Lisa; Elfeki, Maryam; Traxler, Matthew F; Engene, Niclas; Koyama, Nobuhiro; Vining, Oliver B; Baric, Ralph; Silva, Ricardo R; Mascuch, Samantha J; Tomasi, Sophie; Jenkins, Stefan; Macherla, Venkat; Hoffman, Thomas; Agarwal, Vinayak; Williams, Philip G; Dai, Jingqui; Neupane, Ram; Gurr, Joshua; Rodríguez, Andrés M. C.; Lamsa, Anne; Zhang, Chen; Dorrestein, Kathleen; Duggan, Brendan M; Almaliti, Jehad; Allard, Pierre-Marie; Phapale, Prasad; Nothias, Louis-Felix; Alexandrov, Theodore; Litaudon, Marc; Wolfender, Jean-Luc; Kyle, Jennifer E; Metz, Thomas O; Peryea, Tyler; Nguyen, Dac-Trung; VanLeer, Danielle; Shinn, Paul; Jadhav, Ajit; Müller, Rolf; Waters, Katrina M; Shi, Wenyuan; Liu, Xueting; Zhang, Lixin; Knight, Rob; Jensen, Paul R; Palsson, Bernhard O; Pogliano, Kit; Linington, Roger G; Gutiérrez, Marcelino; Lopes, Norberto P; Gerwick, William H; Moore, Bradley S; Dorrestein, Pieter C; Bandeira, Nuno


    The potential of the diverse chemistries present in natural products (NP) for biotechnology and medicine remains untapped because NP databases are not searchable with raw data and the NP community has no way to share data other than in published papers. Although mass spectrometry techniques are well-suited to high-throughput characterization of natural products, there is a pressing need for an infrastructure to enable sharing and curation of data. We present Global Natural Products Social molecular networking (GNPS,, an open-access knowledge base for community wide organization and sharing of raw, processed or identified tandem mass (MS/MS) spectrometry data. In GNPS crowdsourced curation of freely available community-wide reference MS libraries will underpin improved annotations. Data-driven social-networking should facilitate identification of spectra and foster collaborations. We also introduce the concept of ‘living data’ through continuous reanalysis of deposited data. PMID:27504778

  11. Improved liquid chromatography-tandem mass spectrometry method for the analysis of eptifibatide in human plasma. (United States)

    Zhou, Zhi-Ling; Yu, Xi-Yong; Yang, Min; Mai, Li-Ping; Lin, Qiu-Xiong; Deng, Chun-Yu; Shan, Zhi-Xin; Kuang, Su-Juan; Zhu, Ping; Huang, Xiao-Zhong; Li, Xiao-Hong; Chen, Tie-Feng; Lin, Shu-Guang


    A rapid, selective and highly sensitive high performance liquid chromatography-tandem mass spectrometry method (LC-MS/MS) was developed and validated for the determination and pharmacokinetic investigation of eptifibatide in human plasma. Eptifibatide and the internal standard (IS), EPM-05, were extracted from plasma samples using solid phase extraction. Chromatographic separation was performed on a C(18) column at a flow rate of 0.5 mL/min. Detection of eptifibatide and the IS was achieved by tandem mass spectrometry with an electrospray ionization (ESI) interface in positive ion mode. Traditional multiple reaction monitoring (MRM) using the transition of m/z 832.6-->m/z 646.4 and m/z 931.6-->m/z 159.4 was performed to quantify eptifibatide and the IS, respectively. The calibration curves were linear over the range of 1-1000 ng/mL with the lower limit of quantitation validated at 1 ng/mL. The intra- and inter-day precisions were within 13.3%, while the accuracy was within +/-7.6% of nominal values. The validated LC-MS/MS method was successfully applied for the evaluation of pharmacokinetic parameters of eptifibatide after intravenous (i.v.) administration of a 45 microg/kg bolus of eptifibatide to 8 healthy volunteers. Copyright 2010 Elsevier B.V. All rights reserved.

  12. Proposal on dynamic correction method for resonance ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Noto, Takuma, E-mail:; Tomita, Hideki [Nagoya University, Department of Quantum Engineering (Japan); Richter, Sven; Schneider, Fabian; Wendt, Klaus [Johannes Gutenberg University Mainz, Institute of Physics (Germany); Iguchi, Tetsuo; Kawarabayashi, Jun [Nagoya University, Department of Quantum Engineering (Japan)


    For high precision and accuracy in isotopic ratio measurement of transuranic elements using laser ablation assisted resonance ionization mass spectrometry, a dynamic correction method based on correlation of ion signals with energy and timing of each laser pulse was proposed. The feasibility of this dynamic correction method was investigated through the use of a programmable electronics device for fast acquisition of the energy and timing of each laser pulse.

  13. Advances in characterizing ubiquitylation sites by mass spectrometry

    DEFF Research Database (Denmark)

    Sylvestersen, K.B.; Young, C.; Nielsen, M.L.


    The attachment of one or more ubiquitin moieties to proteins plays a central regulatory mechanism in eukaryotic cells. Protein ubiquitylation regulates numerous cellular processes, including protein degradation, signal transduction, DNA repair and cell division. The characterization...... of ubiquitylation is a two-fold challenge that involves the mapping of ubiquitylation sites and the determination of ubiquitin chain topology. This review focuses on the technical advances in the mass spectrometry-based characterization of ubiquitylation sites, which have recently involved the large...

  14. Accelerator mass spectrometry for quantitative in vivo tracing

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, J S


    Accelerator mass spectrometry (AMS) counts individual rare, usually radio-, isotopes such as radiocarbon at high efficiency and specificity in milligram-sized samples. AMS traces very low chemical doses ({micro}g) and radiative doses (100 Bq) of isotope labeled compounds in animal models and directly in humans for pharmaceutical, nutritional, or toxicological research. Absorption, metabolism, distribution, binding, and elimination are all quantifiable with high precision after appropriate sample definition.

  15. Stable Isotope Dilution Mass Spectrometry for Membrane Transporter Quantitation


    Farrokhi, Vahid; McShane, Adam J.; Nemati, Reza; Yao, Xudong


    This review provides an introduction to stable isotope dilution mass spectrometry (MS) and its emerging applications in the analysis of membrane transporter proteins. Various approaches and application examples, for the generation and use of quantitation reference standards—either stable isotope-labeled peptides or proteins—are discussed as they apply to the MS quantitation of membrane proteins. Technological considerations for the sample preparation of membrane transporter proteins are also ...

  16. Time of flight mass spectrometry of pharmaceutical systems


    Armitage Nolan, Jennifer Claire


    Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a widely used surface chemical analysis technique that is traditionally employed to characterise the first few molecular layers of a material interface. The ability of this technique to accurately reflect the surface chemistry of polymers, biomaterials and many other solid materials is well documented. However, the majority of research that utilises this technique is based upon a qualitative rather than quantitative assessment of th...

  17. Significant advancement of mass spectrometry imaging for food chemistry. (United States)

    Yoshimura, Yukihiro; Goto-Inoue, Naoko; Moriyama, Tatsuya; Zaima, Nobuhiro


    Food contains various compounds that have an impact on our daily lives. Many technologies have been established to analyze these molecules of interest in foods. However, the analysis of the spatial distribution of these compounds in foods using conventional technology, such as high-performance liquid chromatography-mass spectrometry or gas chromatography-mass spectrometry is difficult. Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) is considered an ideal complementary approach. MALDI-MSI is a two-dimensional MALDI-MS technology that can detect compounds in a tissue section without extraction, purification, separation, or labeling. MALDI-MSI can be used to visualize the spatial distribution of chemical compounds or biomolecules in foods. Although the methodology of MALDI-MSI in food science is not yet fully established, the versatility of MALDI-MSI is expected to open a new frontier in food science. Herein, we describe the principles and applications of MALDI-MSI in food science and related fields. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Computational quality control tools for mass spectrometry proteomics. (United States)

    Bittremieux, Wout; Valkenborg, Dirk; Martens, Lennart; Laukens, Kris


    As mass-spectrometry-based proteomics has matured during the past decade, a growing emphasis has been placed on quality control. For this purpose, multiple computational quality control tools have been introduced. These tools generate a set of metrics that can be used to assess the quality of a mass spectrometry experiment. Here we review which types of quality control metrics can be generated, and how they can be used to monitor both intra- and inter-experiment performances. We discuss the principal computational tools for quality control and list their main characteristics and applicability. As most of these tools have specific use cases, it is not straightforward to compare their performances. For this survey, we used different sets of quality control metrics derived from information at various stages in a mass spectrometry process and evaluated their effectiveness at capturing qualitative information about an experiment using a supervised learning approach. Furthermore, we discuss currently available algorithmic solutions that enable the usage of these quality control metrics for decision-making. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Biomarker Motif Discovery by Integrating Mass Spectrometry and PPI Network (United States)

    Zhou, Xiaobo; Wang, Yuan; Wang, Honghui; Pham, Tuan D.; Li, King


    Traditional mass spectrometry biomarker discovery studies which focus on single biomarkers or a panel of biomarkers have shown their limitations with low reproducibility. In this paper, we propose a novel biomarker motif discovery approach by integrating both mass spectrometry data and protein interaction network information together to identify biomarkers. A novel Bayesian score method is developed to score the protein subnetwork both from the expression of protein and from the protein interaction network structure. Compared with the previous biomarker discovery method, our biomarker motif identification method not only models the expression of each protein, but also the relationship of proteins affected by the protein-protein interaction network. The experiment results show that our proposed biomarker discovery method has a higher sensitivity and lower false discovery rates than previously used methods. When applying our biomarker motifs discovery approach to the real stroke mass spectrometry data, we can identify several biomarker motifs for ischemic stroke which can achieve a higher classification performance with high biological significance.

  20. Practical aspects of trapped ion mass spectrometry, 5 applications of ion trapping devices

    CERN Document Server

    March, Raymond E


    Examines ion/neutral and ion/ion reactions, ion spectroscopy, and the structural characterization of proteins and peptides using quadropole ion trap mass spectrometry, Fourier transform - ion cyclotron resonance (FT-ICR) mass spectrometry, and traveling wave ion mobility mass spectrometry.

  1. Characterization of individual particles in gaseous media by mass spectrometry (United States)

    Sinha, M. P.


    An introduction is given to a system for particle analysis by mass spectrometry (PAMS) which employs particle-beam techniques to measure mass spectra on a continuous real-time basis. The system is applied to particles of both organic and inorganic compounds, and the measurements give the chemical characteristics of particles in mixtures and indicate source apportionment. The PAMS system can be used for process control and studying heterogeneous/catalytic reactions in particles, and can be fitted to study the real-time attributes of PAMS.

  2. Temperature-programmed desorption for membrane inlet mass spectrometry

    DEFF Research Database (Denmark)

    Ketola, R.A.; Grøn, C.; Lauritsen, F.R.


    We present a novel technique for analyzing volatile organic compounds in air samples using a solid adsorbent together with temperature-programmed desorption and subsequent detection by membrane inlet mass spectrometry (TPD-MIMS). The new system has the advantage of a fast separation of compounds...... to diffuse through the membrane into the mass spectrometer in a few seconds. In this fashion we could completely separate many similar volatile compounds, for example toluene from xylene and trichloroethene from tetrachloroethene. Typical detection limits were at low or sub-nanogram levels, the dynamic range...

  3. Detection of methamphetamine and amphetamine in a single human hair by gas chromatography/chemical ionization mass spectrometry. (United States)

    Suzuki, O; Hattori, H; Asano, M


    A detailed procedure of an extremely sensitive method for quantitation of methamphetamine and amphetamine in human hair by gas chromatography (GC)/chemical ionization (CI) mass spectrometry (MS) is presented. N-methylbenzylamine was used as an internal standard. The samples, after extraction with an organic solvent, were derivatized with trifluoroacetic anhydride before the GC/MS analysis. Quantitation was made with quasi-molecular ions of the derivatives by selected ion monitoring in the CI mode. The detection limit was about 10 pg in an injected volume. The high sensitivity enabled us to measure both stimulants in a single human hair in actual cases.

  4. Coupling the Torpedo microplate-receptor binding assay with mass spectrometry to detect cyclic imine neurotoxins. (United States)

    Aráoz, Rómulo; Ramos, Suzanne; Pelissier, Franck; Guérineau, Vincent; Benoit, Evelyne; Vilariño, Natalia; Botana, Luis M; Zakarian, Armen; Molgó, Jordi


    Cyclic imine neurotoxins constitute an emergent family of neurotoxins of dinoflagellate origin that are potent antagonists of nicotinic acetylcholine receptors. We developed a target-directed functional method based on the mechanism of action of competitive agonists/antagonists of nicotinic acetylcholine receptors for the detection of marine cyclic imine neurotoxins. The key step for method development was the immobilization of Torpedo electrocyte membranes rich in nicotinic acetylcholine receptors on the surface of microplate wells and the use of biotinylated-α-bungarotoxin as tracer. Cyclic imine neurotoxins competitively inhibit biotinylated-α-bungarotoxin binding to Torpedo-nicotinic acetylcholine receptors in a concentration-dependent manner. The microplate-receptor binding assay allowed rapid detection of nanomolar concentrations of cyclic imine neurotoxins directly in shellfish samples. Although highly sensitive and specific for the detection of neurotoxins targeting nicotinic acetylcholine receptors as a class, the receptor binding assay cannot identify a given analyte. To address the low selectivity of the microplate-receptor binding assay, the cyclic imine neurotoxins tightly bound to the coated Torpedo nicotinic receptor were eluted with methanol, and the chemical nature of the eluted ligands was identified by mass spectrometry. The immobilization of Torpedo electrocyte membranes on the surface of microplate wells proved to be a high-throughput format for the survey of neurotoxins targeting nicotinic acetylcholine receptors directly in shellfish matrixes with high sensitivity and reproducibility.

  5. Elevated serum high-sensitivity C-reactive protein levels in fibromyalgia syndrome patients correlate with body mass index, interleukin-6, interleukin-8, erythrocyte sedimentation rate. (United States)

    Xiao, Yangming; Haynes, Wanda L; Michalek, Joel E; Russell, I Jon


    The levels of several inflammatory cytokines are abnormal in many patients with the fibromyalgia syndrome (FMS) and may play a role in its pathogenesis. The inflammatory marker C-reactive protein (CRP) is associated with the disease activity in patients with inflammatory rheumatic diseases, but its role in FMS is unknown. We undertook this study to determine whether high-sensitivity CRP (hsCRP) is elevated in FMS and whether its levels relate to key biologic or clinical measures. One hundred and five patients with FMS (1990 ACR criteria) and 61 healthy normal controls (HNC) at a ratio of 2:1 were recruited. The serum concentrations of hsCRP, interleukin-8 (IL-8), and interleukin-6 (IL-6) were assessed using enzyme-linked immunosorbent assays. The hsCRP levels were marginally higher in FMS than in HNC (p = 0.06) and its abnormality rate (>1.5 SD above the HNC mean) was significantly higher in FMS (25 %) compared with HNC (6.8 %) (p = 0.03). Serum IL-8 levels, IL-6 levels, and erythrocyte sedimentation rate (ESR) in FMS did not differ from those in HNC. Body mass index (BMI), ESR, IL-8, and IL-6 levels correlated with hsCRP levels in FMS. No associations were found between hsCRP and age, gender, ethnicity, or other clinical measures. Serum CRP levels were higher in FMS and significantly correlated with BMI, ESR, IL-8, and IL-6 levels, suggesting that inflammation may contribute to the symptoms in some FMS patients, particularly those who are obese. Weight loss and therapies directed against inflammation may be useful in the management of FMS patients with elevated hsCRP.

  6. Highly sensitive C-reactive protein, body mass index, and serum lipids in HIV-infected persons receiving antiretroviral therapy: a longitudinal study. (United States)

    Boger, Michael S; Shintani, Ayumi; Redhage, Leigh Anne; Mitchell, Valerie; Haas, David W; Morrow, Jason D; Hulgan, Todd


    Antiretroviral therapy (ART) affects cardiovascular disease (CVD) risk. In the general population, highly sensitive creactive protein (hsCRP) is an established predictor of future coronary events. Little is known about its utility in chronic inflammatory conditions such as HIV infection. We assessed relationships between hsCRP and metabolic parameters over time in HIV-infected patients on ART. Data are from a prospective cohort of HIV-infected adults enrolled June 2005 to July 2007. Participants were receiving ART, had HIV-1 RNA,10,000 copies per milliliter, and no diabetes or CVD. Nonlinear mixed-effect regression models assessed relationships between body mass index (BMI), lipids, and hsCRP over time adjusting for covariates. Ninety-four individuals had data from $1 study visit. Median age was 44 years, 27% were female, 57% white, and 54% were on protease inhibitors. Median CD4+ T cells, HIV-1 RNA, and hsCRP were 502 cells per cubic millimeter, 50 copies per milliliter, and 2.94 mg/dL, respectively. Median Framingham score was 3. Multivariate analysis identified associations between increased hsCRP and greater BMI (P = 0.001), higher non-high-density lipoprotein cholesterol (P = 0.013) and triglycerides (P = 0.017), and lower high-density lipoprotein cholesterol (P = 0.015). Among HIV-infected adults with low estimated CVD risk and virologic suppression on ART, hsCRP was elevated and independently associated with BMI and lipid changes. Future studies should assess associations between hsCRP and clinical outcomes.

  7. Structural analyses of sucrose laurate regioisomers by mass spectrometry techniques

    DEFF Research Database (Denmark)

    Lie, Aleksander; Stensballe, Allan; Pedersen, Lars Haastrup


    6- And 6′-O-lauroyl sucrose were isolated and analyzed by matrix-assisted laser desorption/ionisation (MALDI) time-of-flight (TOF) mass spectrometry (MS), Orbitrap high-resolution (HR) MS, and electrospray-ionization (ESI) tandem mass spectrometry (MS/MS). The analyses aimed to explore.......8, respectively, and Orbitrap HRMS confirmed the mass of [M+Na]+ (m/z 547.2712). ESI-MS/MS on the precursor ion [M+Na]+ resulted in product ion mass spectra showing two high-intensity signals for each sample. 6-O-Lauroyl sucrose produced signals located at m/z 547.27 and m/z 385.21, corresponding to the 6-O......-lauroyl glucose sodium adduct ions, while the signals for 6′-O-lauroyl sucrose were located at m/z 385.22 and 367.20, respectively corresponding to the sodium adduct ions with 6-O-lauroyl fructose and 6-O-lauroyl fructosyl. The mass spectra of the two regioisomers were clearly different, and the investigation...

  8. High-Sensitivity Spectrophotometry. (United States)

    Harris, T. D.


    Selected high-sensitivity spectrophotometric methods are examined, and comparisons are made of their relative strengths and weaknesses and the circumstances for which each can best be applied. Methods include long path cells, noise reduction, laser intracavity absorption, thermocouple calorimetry, photoacoustic methods, and thermo-optical methods.…

  9. Analysis of polar lipids in the serum from rats fed shiitake by liquid chromatography-mass spectrometry/mass spectrometry. (United States)

    Yu, Shanggong; Peng, Min; Ronis, Martin; Badger, Thomas; Fang, Nianbai


    Consumption of a shiitake mushroom diet has been reported to have effects on serum phospholipids. However, much less is known about the effect on serum polar lipids including lysophospholipids and free fatty acids. In the present study, the effects of a shiitake diet were evaluated on the basis of identification and quantification of individual polar lipid components in rat serum using liquid chromatography-mass spectrometry/mass spectrometry. By comparison with standards and published data, 50 lysophospholipids and 32 free fatty acids were identified, and the concentrations of 27 polar lipids in rat serum were determined. Shiitake diets decreased the levels of all individual polar lipid components in the serum of male rat. The total level of serum polar lipids in males fed 4% shiitake diets (1365.71 mol/L) was significantly lower than that of the control (2270.26 mol/L). However, shiitake diets did not significantly affect the levels of serum polar lipids in female rats.

  10. Neuropeptide Signaling in Crustaceans Probed by Mass Spectrometry (United States)

    Liang, Zhidan

    Neuropeptides are one of the most diverse classes of signaling molecules whose identities and functions are not yet fully understood. They have been implicated in the regulation of a wide range of physiological processes, including feeding-related and motivated behaviors, and also environmental adaptations. In this work, improved mass spectrometry-based analytical platforms were developed and applied to the crustacean systems to characterize signaling molecules. This dissertation begins with a review of mass spectrometry-based neuropeptide studies from both temporal- and spatial-domains. This review is then followed by several chapters detailing a few research projects related to the crustacean neuropeptidomic characterization and comparative analysis. The neuropeptidome of crayfish, Orconectes rusticus is characterized for the first time using mass spectrometry-based tools. In vivo microdialysis sampling technique offers the capability of direct sampling from extracellular space in a time-resolved manner. It is used to investigate the secreted neuropeptide and neurotransmitter content in Jonah crab, Cancer borealis, in this work. A new quantitation strategy using alternative mass spectrometry data acquisition approach is developed and applied for the first time to quantify neuropeptides. Coupling of this method with microdialysis enables the study of neuropeptide dynamics concurrent with different behaviors. Proof-of-principle experiments validating this approach have been carried out in Jonah crab, Cancer borealis to study feeding- and circadian rhythm-related neuropeptide changes using micoridialysis in a time-resolved manner. This permits a close correlation between behavioral and neurochemical changes, providing potential candidates for future validation of regulatory roles. In addition to providing spatial information, mass spectrometry imaging (MSI) technique enables the characterization of signaling molecules while preserving the temporal resolution. A

  11. Mass Spectrometry of Aliphatic Macrolides, Important Semiochemicals or Pheromones. (United States)

    Schulz, Stefan; Peram, Pardha Saradhi; Menke, Markus; Hötling, Susann; Röpke, Rene; Melnik, Kristina; Poth, Dennis; Mann, Florian; Henrichsen, Selma; Dreyer, Katja


    Macrolides are a relatively common structural motif prevalent in Nature. However, the structures of these large ring lactones have been relatively difficult to elucidate via NMR spectroscopy due to the minute amounts of compounds that are sometimes obtainable from natural sources. Thus, GC-MS analysis of individual macrolactones has become the method of choice for the structural identification of these compounds. Here we discuss the mass spectrometric behavior of aliphatic macrolides, evaluating spectra from numerous compounds of various ring size, including derivatives containing methyl branches as well as double bonds. The specific fragmentation of these macrolactones under electron impact conditions allows for the development of a general rule set aimed at the identification of similar compounds by mass spectrometry. In addition, the mass spectra of dimethyl disulfide adducts of unsaturated macrolides are discussed. The mass spectra of almost 50 macrolides are presented.

  12. Electron impact mass spectrometry of alkanes in supersonic molecular beams. (United States)

    Dagan, S; Amirav, A


    The electron impact mass spectrometry of straight chain alkanes C8H18-C40H82, squalane, methylstearate, 1-chlorohexadecane, 1-bromohexadecane, and dioctylphthalate was studied by sampling them with supersonic molecular beams. A fly-through Brink-type electron impact ion source was used, utilizing a vacuum background ion filtration technique based on differences between the kinetic energy of the supersonic beam species and that of thermal molecules. The 70-eV electron impact mass spectra of all the alkanes were characterized by a pronounced or dominant molecular weight peak together with all the fragment ions normally exhibited by the standard thermal 70-eV EI mass spectra. In contrast, the NIST library of most of these molecules did not show any molecular weight peak. By eliminating tile intramolecular thermal vibrational energy we gained control over the degree of molecular ion fragmentation by the electron energy. At an electron energy of 18 eV the molecular ion dissociation was further reduced considerably, with only a small absolute reduction in the peak height by less than a factor of 2. The effect of vibrational cooling increased with the molecular size and number of atoms. Pronounced differences were observed between the mass spectra of the straight chain triacontane and its branched isomer squalane. Similar mass spectra of octacosane (C28H58) achieved with 70-eV EI in a supersonic molecular beam were obtained with a magnetic sector mass spectrometer by using an electron energy of 14 eV and an ion source temperature of 150 °C. However, this ion source temperature precluded the gas chromatography-mass spectrometry (GC-MS) of octacosane. The GC-MS of alkanes was studied with an ion trap gas chromatograph-mass spectrometer at an ion source temperature of 230 °C. Thermal peak tailing was observed for C20H42 and heavier alkanes, whereas for C28H58 and heavier alkanes the severe peak tailing made quantitative GC-MS impractical. In contrast, no peak tailing

  13. Proton transfer reaction-mass spectrometry applications in medical research. (United States)

    Herbig, Jens; Amann, Anton


    Gathering information about a subject's physiological and pathophysiological condition from the `smell' of breath is an idea that dates back to antiquity. This intriguing concept of non-invasive diagnosis has been revitalized by `exhaled breath analysis' in recent decades. A main driving force was the development of sensitive and versatile gas-chromatographic and mass-spectrometric instruments for trace gas analysis. Ironically, only non-smelling constituents of breath, such as O(2), CO(2), H(2), and NO have so far been included in routine clinical breath analysis. The `smell' of human breath, on the other hand, arises through a combination of volatile organic compounds (VOCs) of which several hundred have been identified to date. Most of these volatiles are systemic and are released in the gas-exchange between blood and air in the alveoli. The concentration of these compounds in the alveolar breath is related to the respective concentrations in blood. Measuring VOCs in exhaled breath allows for screening of disease markers, studying the uptake and effect of medication (pharmacokinetics), or monitoring physiological processes. There is a range of requirements for instruments for the analysis of a complex matrix, such as human breath. Mass-spectrometric techniques are particularly well suited for this task since they offer the possibility of detecting a large variety of interesting compounds. A further requirement is the ability to measure accurately in the concentration range of breath VOCs, i.e. between parts-per-trillion (pptv) and parts-per-million (ppmv) range. In the mid 1990's proton transfer reaction-mass spectrometry (PTR-MS) was developed as a powerful and promising tool for the analysis of VOCs in gaseous media. Soon thereafter these instruments became commercially available to a still growing user community and have now become standard equipment in many fields including environmental research, food and flavour science, as well as life sciences. Their

  14. Quantitative and confirmative performance of liquid chromatography coupled to high-resolution mass spectrometry compared to tandem mass spectrometry. (United States)

    Kaufmann, Anton; Butcher, Patrick; Maden, Kathryn; Walker, Stephan; Widmer, Miryam


    The quantitative and confirmative performance of two different mass spectrometry (MS) techniques (high-resolution MS and tandem MS) was critically compared. Evaluated was a new extraction and clean-up protocol which was developed to cover more than 100 different veterinary drugs at trace levels in a number of animal tissues and honey matrices. Both detection techniques, high-resolution mass spectrometry (HRMS) (single-stage Orbitrap instrument operated at 50 000 full width at half maximum) and tandem mass spectrometry (MS/MS) (quadrupole technology) were used to validate the method according to the EU Commission Decision 2002/657/EEC. Equal or even a slightly better quantitative performance was observed for the HRMS-based approach. Sensitivity is higher for unit mass resolution MS/MS if only a subset of the 100 compounds has to be monitored. Confirmation of suspected positive findings can be done by evaluating the intensity ratio between different MS/MS transitions, or by accurate mass based product ion traces (no precursor selection applied). MS/MS relies on compound-specific optimized transitions; hence the second, confirmatory transition generally shows relatively high ion abundance (fragmentation efficacy). This is often not the case in single-stage HRMS, since a generic (not compound-optimized) collision energy is applied. Hence, confirmation of analytes present at low levels is superior when performed by MS/MS. Slightly better precision, but poorer accuracy (fortified matrix extracts versus pure standard solution) of ion ratios were observed when comparing data obtained by HRMS versus MS/MS. Copyright © 2011 John Wiley & Sons, Ltd.

  15. Advances in mass spectrometry-based clinical biomarker discovery. (United States)

    Crutchfield, Christopher A; Thomas, Stefani N; Sokoll, Lori J; Chan, Daniel W


    The greatest unmet needs in biomarker discovery are those discoveries that lead to the development of clinical diagnostic tests. These clinical diagnostic tests can provide early intervention when a patient would present otherwise healthy (e.g., cancer or cardiovascular disease) and aid clinical decision making with improved clinical outcomes. The past two decades have seen significant technological improvements in the analytical capabilities of mass spectrometers. Mass spectrometers are unique in that they can directly analyze any biological molecule susceptible to ionization. The biological studies of human metabolites and proteins using contemporary mass spectrometry technology (metabolomics and proteomics, respectively) has been ongoing for over a decade. Some of these studies have resulted in exciting insights into human biology. However, relatively few biomarkers have been translated into clinical tests. This review will discuss some key technological developments that have occurred over this time with an emphasis on technologies that will create new avenues for biomarker discovery.

  16. Inductively coupled plasma mass spectrometry: recent trends and developments. (United States)

    Engelhard, Carsten


    This year inductively coupled plasma mass spectrometry (ICP-MS) moves into the fourth decade of development. In this article, some recent trends and developments in ICP-MS are reviewed, with special focus on instrumental development and emerging applications. Some key trends include a novel mass spectrometer for elemental and speciation analysis in Mattauch-Herzog geometry with a focal-plane-camera array detector. The reason for this development is the possibility to record the full elemental mass range simultaneously and all the time. Monitoring fast transient signals in chromatography or laser ablation is now possible and will become an important asset in future studies, e.g., for isotope ratio analysis. In addition, there is a lot of new activity and interest in the area of nanosciences and medicine. Here, instrumental developments are reported that allow the direct analysis of microparticles and single cells.

  17. A nanostructure-initiator mass spectrometry-based enzyme activity assay

    Energy Technology Data Exchange (ETDEWEB)

    Siuzdak, Gary; Northen, Trent R.; Lee, Jinq-Chyi; Hoang, Linh; Raymond, Jason; Hwang, Der-Ren; Yannone, Steven M.; Wong, Chi-Huey; Siuzdak, Gary


    We describe a Nanostructure-Initiator Mass Spectrometry (NIMS) enzymatic (Nimzyme) assay in which enzyme substrates are immobilized on the mass spectrometry surface by using fluorous-phase interactions. This 'soft' immobilization allows efficient desorption/ionization while also enabling the use of surface-washing steps to reduce signal suppression from complex biological samples, which results from the preferential retention of the tagged products and reactants. The Nimzyme assay is sensitive to subpicogram levels of enzyme, detects both addition and cleavage reactions (sialyltransferase and galactosidase), is applicable over a wide range of pHs and temperatures, and can measure activity directly from crude cell lysates. The ability of the Nimzyme assay to analyze complex mixtures is illustrated by identifying and directly characterizing {beta}-1,4-galactosidase activity from a thermophilic microbial community lysate. The optimal enzyme temperature and pH were found to be 65 C and 5.5, respectively, and the activity was inhibited by both phenylethyl-{beta}-d-thiogalactopyranoside and deoxygalactonojirimycin. Metagenomic analysis of the community suggests that the activity is from an uncultured, unsequenced {gamma}-proteobacterium. In general, this assay provides an efficient method for detection and characterization of enzymatic activities in complex biological mixtures prior to sequencing or cloning efforts. More generally, this approach may have important applications for screening both enzymatic and inhibitor libraries, constructing and screening glycan microarrays, and complementing fluorous-phase organic synthesis. The interest in leveraging mass spectrometry for studying enzyme activities in complex biological samples derives from its high sensitivity and specificity; however, signal suppression and significant sample preparation requirements limit its overall utility (1). Here we describe a Nanostructure-Initiator Mass Spectrometry (NIMS

  18. Uncovering biologically significant lipid isomers with liquid chromatography, ion mobility spectrometry and mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Kyle, Jennifer E.; Zhang, Xing; Weitz, Karl K.; Monroe, Matthew E.; Ibrahim, Yehia M.; Moore, Ronald J.; Cha, Jeeyeon; Sun, Xiaofei; Lovelace, Erica S.; Wagoner, Jessica; Polyak, Steve; Metz, Thomas O.; Dey, Sudhansu K.; Smith, Richard D.; Burnum-Johnson, Kristin E.; Baker, Erin Shammel


    Understanding how biological molecules are generated, metabolized and eliminated in living systems is important for interpreting processes such as immune response and disease pathology. While genomic and proteomic studies have provided vast amounts of information over the last several decades, interest in lipidomics has also grown due to improved analytical technologies revealing altered lipid metabolism in type 2 diabetes, cancer, and lipid storage disease. Liquid chromatography and mass spectrometry (LC-MS) measurements are currently the dominant approach for characterizing the lipidome by providing detailed information on the spatial and temporal composition of lipids. However, interpreting lipids’ biological roles is challenging due to the existence of numerous structural and stereoisomers (i.e. distinct acyl chain and double-bond positions), which are unresolvable using present LC-MS approaches. Here we show that combining structurally-based ion mobility spectrometry (IMS) with LC-MS measurements distinguishes lipid isomers and allows insight into biological and disease processes.

  19. Uncovering Biologically Significant Lipid Isomers with Liquid Chromatography, Ion Mobility Spectrometry and Mass Spectrometry (United States)

    Kyle, Jennifer E.; Zhang, Xing; Weitz, Karl K.; Monroe, Matthew E.; Ibrahim, Yehia M.; Moore, Ronald J.; Cha, Jeeyeon; Sun, Xiaofei; Lovelace, Erica S.; Wagoner, Jessica; Polyak, Stephen J.; Metz, Thomas O.; Dey, Sudhansu K.; Smith, Richard D.; Burnum-Johnson, Kristin E.; Baker, Erin S.


    Understanding how biological molecules are generated, metabolized and eliminated in living systems is important for interpreting processes such as immune response and disease pathology. While genomic and proteomic studies have provided vast amounts of information over the last several decades, interest in lipidomics has also grown due to improved analytical technologies revealing altered lipid metabolism in type 2 diabetes, cancer, and lipid storage disease. Mass spectrometry (MS) measurements are currently the dominant approach for characterizing the lipidome by providing detailed information on the spatial and temporal composition of lipids. However, interpreting lipids’ biological roles is challenging due to the existence of numerous structural and stereoisomers (i.e. distinct acyl chain and double-bond positions), which are often unresolvable using present approaches. Here we show that combining liquid chromatography (LC) and structurally-based ion mobility spectrometry (IMS) measurement with MS analyses distinguishes lipid isomers and allows insight into biological and disease processes. PMID:26734689

  20. Mass Spectrometry Based Lipidomics: An Overview of Technological Platforms

    Directory of Open Access Journals (Sweden)

    Harald C. Köfeler


    Full Text Available One decade after the genomic and the proteomic life science revolution, new ‘omics’ fields are emerging. The metabolome encompasses the entity of small molecules—Most often end products of a catalytic process regulated by genes and proteins—with the lipidome being its fat soluble subdivision. Within recent years, lipids are more and more regarded not only as energy storage compounds but also as interactive players in various cellular regulation cycles and thus attain rising interest in the bio-medical community. The field of lipidomics is, on one hand, fuelled by analytical technology advances, particularly mass spectrometry and chromatography, but on the other hand new biological questions also drive analytical technology developments. Compared to fairly standardized genomic or proteomic high-throughput protocols, the high degree of molecular heterogeneity adds a special analytical challenge to lipidomic analysis. In this review, we will take a closer look at various mass spectrometric platforms for lipidomic analysis. We will focus on the advantages and limitations of various experimental setups like ‘shotgun lipidomics’, liquid chromatography—Mass spectrometry (LC-MS and matrix assisted laser desorption ionization-time of flight (MALDI-TOF based approaches. We will also examine available software packages for data analysis, which nowadays is in fact the rate limiting step for most ‘omics’ workflows.

  1. Towards airborne nanoparticle mass spectrometry with nanomechanical string resonators (United States)

    Schmid, Silvan; Kurek, Maksymilian; Boisen, Anja


    Airborne nanoparticles can cause severe harm when inhaled. Therefore, small and cheap portable airborne nanoparticle monitors are highly demanded by authorities and the nanoparticle producing industry. We propose to use nanomechanical resonators to build the next generation cheap and portable airborne nanoparticle sensors. Recently, nanomechanical mass spectrometry was established. One of the biggest challenges of nanomechanical sensors is the low efficiency of diffusion-based sampling. We developed an inertial-based sampling method that enables the efficient sampling of airborne nanoparticles on a nanomechanical sensor operating directly in air. We measured a sampling rate of over 1000 particles per second, for 28 nm silica nanoparticles with a concentration of 380000 #/cm3, collected on a 500 nm wide nanomechanical string resonator. We show that it is possible to reach a saturated sampling regime in which 100% of all nanoparticles are captured that are owing in the projection of the nanostring. We further show that it is possible to detect single airborne nanoparticles by detecting 50 nm Au particles with a 250 nm wide string resonator. Our resonators are currently operating in the first bending mode. Mass spectrometry of airborne nanoparticles requires the simultaneous operation in the first and second mode, which can be implemented in the transduction scheme of the resonator. The presented results lay the cornerstone for the realization of a portable airborne nanoparticle mass spectrometer.

  2. Improvements in Mass Spectrometry Assay Library Generation for Targeted Proteomics. (United States)

    Teleman, Johan; Hauri, Simon; Malmström, Johan


    In data-independent acquisition mass spectrometry (DIA-MS), targeted extraction of peptide signals in silico using mass spectrometry assay libraries is a successful method for the identification and quantification of proteins. However, it remains unclear if high quality assay libraries with more accurate peptide ion coordinates can improve peptide target identification rates in DIA analysis. In this study, we systematically improved and evaluated the common algorithmic steps for assay library generation and demonstrate that increased assay quality results in substantially higher identification rates of peptide targets from mouse organ protein lysates measured by DIA-MS. The introduced changes are (1) a new spectrum interpretation algorithm, (2) reapplication of segmented retention time normalization, (3) a ppm fragment mass error matching threshold, (4) usage of internal peptide fragments, and (5) a multilevel false discovery rate calculation. Taken together, these changes yielded 14-36% more identified peptide targets at 1% assay false discovery rate and are implemented in three new open source tools, Fraggle, Tramler, and Franklin, available at . The improved algorithms provide ways to better utilize discovery MS data, translating to substantially increased DIA performance and ultimately better foundations for drawing biological conclusions in DIA-based experiments.

  3. Deep Learning for Tumor Classification in Imaging Mass Spectrometry. (United States)

    Behrmann, Jens; Etmann, Christian; Boskamp, Tobias; Casadonte, Rita; Kriegsmann, Jörg; Maass, Peter


    Tumor classification using Imaging Mass Spectrometry (IMS) data has a high potential for future applications in pathology. Due to the complexity and size of the data, automated feature extraction and classification steps are required to fully process the data. Since mass spectra exhibit certain structural similarities to image data, deep learning may offer a promising strategy for classification of IMS data as it has been successfully applied to image classification. Methodologically, we propose an adapted architecture based on deep convolutional networks to handle the characteristics of mass spectrometry data, as well as a strategy to interpret the learned model in the spectral domain based on a sensitivity analysis. The proposed methods are evaluated on two algorithmically challenging tumor classification tasks and compared to a baseline approach. Competitiveness of the proposed methods are shown on both tasks by studying the performance via cross-validation. Moreover, the learned models are analyzed by the proposed sensitivity analysis revealing biologically plausible effects as well as confounding factors of the considered tasks. Thus, this study may serve as a starting point for further development of deep learning approaches in IMS classification tasks., Supplementary data are available at Bioinformatics online.

  4. Characterisation of the volatile profiles of infant formulas by proton transfer reaction-mass spectrometry and gas chromatography-mass spectrometry

    NARCIS (Netherlands)

    Ruth, van S.M.; Floris, V.; Fayoux, S.


    The volatile profiles of 13 infant formulas were evaluated by proton transfer reaction-mass spectrometry (PTR-MS) and gas chromatography¿mass spectrometry (GC¿MS). The infant formulas varied in brand (Aptamil, Cow & Gate, SMA), type (for different infant target groups) and physical form

  5. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.


    We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of d13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

  6. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, Tanja C. W.; Schierbeek, Henk; Houtekamer, Marco; van Engeland, Tom; Derrien, Delphine; Stal, Lucas J.; Boschker, Henricus T. S.


    We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ(13)C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

  7. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.


    Rationale: We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence,

  8. Atmospheric-Pressure Chemical Ionization Tandem Mass Spectrometry (APGC/MS/MS) an Alternative to High-Resolution Mass Spectrometry (HRGC/HRMS) for the Determination of Dioxins

    NARCIS (Netherlands)

    Bavel, Van Bert; Geng, Dawei; Cherta, Laura; Nácher-Mestre, Jaime; Portolés, Tania; Ábalos, Manuela; Sauló, Jordi; Abad, Esteban; Dunstan, Jody; Jones, Rhys; Kotz, Alexander; Winterhalter, Helmut; Malisch, Rainer; Traag, Wim; Hagberg, Jessika; Ericson Jogsten, Ingrid; Beltran, Joaquim; Hernández, Félix


    The use of a new atmospheric-pressure chemical ionization source for gas chromatography (APGC) coupled with a tandem quadrupole mass spectrometry (MS/MS) system, as an alternative to high-resolution mass spectrometry (HRMS), for the determination of PCDDs/PCDFs is described. The potential of

  9. Analysis of [U-13C6]glucose in human plasma using liquid chromatography/isotope ratio mass spectrometry compared with two other mass spectrometry techniques

    NARCIS (Netherlands)

    Schierbeek, H.; Moerdijk-Poortvliet, T.C.W.; van den Akker, C.H.P.; te Braake, F.W.J.; Boschker, H.T.S.; van Goudoever, J.B.


    The use of stable isotope labelled glucose provides insight into glucose metabolism. The 13C-isotopic enrichment of glucose is usually measured by gas chromatography/mass spectrometry (GC/MS) or gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). However, in both techniques

  10. Dehydrodimerization of pterostilbene during electrospray ionization mass spectrometry

    KAUST Repository

    Raji, Misjudeen


    RATIONALE Pterostilbene is a member of the hydroxystilbene family of compounds commonly found in plants such as blueberry and grapes. During the analysis of this compound by electrospray ionization mass spectrometry (ESI-MS), an ion was observed that corresponds to the dehydrodimer of pterostilbene in mass-to-charge ratio. Since such unexpected dimerization may lead to decreased monomer signal during quantitative analysis, it was of interest to identify the origin and structure of the observed pterostilbene dimer and examine the experimental conditions that influence its formation. METHODS Liquid Chromatography/Mass Spectrometry (LC/MS), Nuclear Magnetic Resonance (NMR), and High-Field Asymmetric Waveform Ion Mobility Spectrometry (FAIMS) were used to examine the origin of the dimerization products. The structure of the formed pterostilbene dimer was examined by performing MSn analysis on the dimer ion. Effects of solvent composition, analyte concentration, radical scavenger, and other experimental conditions on the dimerization were also studied. RESULTS LC/MS and NMR analyses clearly showed that the starting solution did not contain the pterostilbene dimer. Solvent type and radical scavenger concentration were found to have pronounced effects on the dimer formation. Particularly, presence of acetonitrile or ammonium acetate had favorable effects on the extent of dimerization during ESI-MS analysis whereas hydroquinone and butylated hydroquinone had negative effects. Dimer formation decreased at high flow rates and when fused-silica capillary was used as the spray needle. CONCLUSIONS The data indicate that this dimerization occurs as a result of solution-phase electrochemical reactions taking place during the electrospray process. A possible structure for this dimer was proposed based on the MSn analysis and was similar to that of the enzymatically derived pterostilbene dehydrodimer already reported in the literature. Copyright © 2013 John Wiley & Sons, Ltd

  11. Future Directions of Structural Mass Spectrometry using Hydroxyl Radical Footprinting

    Energy Technology Data Exchange (ETDEWEB)

    J Kiselar; M Chance


    Hydroxyl radical protein footprinting coupled to mass spectrometry has been developed over the last decade and has matured to a powerful method for analyzing protein structure and dynamics. It has been successfully applied in the analysis of protein structure, protein folding, protein dynamics, and protein-protein and protein-DNA interactions. Using synchrotron radiolysis, exposure of proteins to a 'white' X-ray beam for milliseconds provides sufficient oxidative modification to surface amino acid side chains, which can be easily detected and quantified by mass spectrometry. Thus, conformational changes in proteins or protein complexes can be examined using a time-resolved approach, which would be a valuable method for the study of macromolecular dynamics. In this review, we describe a new application of hydroxyl radical protein footprinting to probe the time evolution of the calcium-dependent conformational changes of gelsolin on the millisecond timescale. The data suggest a cooperative transition as multiple sites in different molecular subdomains have similar rates of conformational change. These findings demonstrate that time-resolved protein footprinting is suitable for studies of protein dynamics that occur over periods ranging from milliseconds to seconds. In this review, we also show how the structural resolution and sensitivity of the technology can be improved as well. The hydroxyl radical varies in its reactivity to different side chains by over two orders of magnitude, thus oxidation of amino acid side chains of lower reactivity are more rarely observed in such experiments. Here we demonstrate that the selected reaction monitoring (SRM)-based method can be utilized for quantification of oxidized species, improving the signal-to-noise ratio. This expansion of the set of oxidized residues of lower reactivity will improve the overall structural resolution of the technique. This approach is also suggested as a basis for developing hypothesis

  12. Measuring odour emission and biofilter efficiency in composting plants by proton transfer reaction-mass spectrometry. (United States)

    Biasioli, F; Aprea, E; Gasperi, F; Märk, T D


    PTR-MS (Proton Transfer Reaction-Mass Spectrometry) is an innovative technique that allows the rapid detection of most volatile organic compounds (VOCs) with high sensitivity (sub-ppb) and by direct injection. We describe here the possible use of PTR-MS in waste managements and composting plants both for the real time monitoring of volatile emissions and, after calibration with olfactometric assessments, for the instrumental determination of odour concentration. Beside a short description of the technique, we will report on the calibration of PTR-MS data with olfactometric assessment of odour concentration showing the possibility of a relatively good estimation of odour concentration by instrumental data. We will also show how the rapid PTR-MS fingerprint can be used to visualise the overall effect of a biofilter on the VOCs concentration and to calculate the reduction of the concentration of single masses and, finally, we will provide examples of the performances of a new implementation of this technique based on a time of flight (TOF) analyser. Instead of the usual quadrupole mass filter, the TOF provides an increase of analytical information and the possibility to separate important compounds that in the quadrupole version were not or only indirectly quantifiable. In conclusion we suggest that PTR-MS analysis can be a valuable tool for the rapid and on site monitoring of odour emission and plant operation.

  13. Characterization of the mouse bronchoalveolar lavage proteome by micro-capillary LC–FTICR mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Pounds, Joel G.; Flora, Jason W.; Adkins, Joshua N.; Lee, Kyeonghee M.; Rana, Gaurav S.J.B.; Sengupta, Tapas; Smith, Richard D.; McKinney, Willie J.


    Bronchoalveolar lavage fluid (BALF) contains proteins derived from various pulmonary cell types, secretions and blood. As the characterization of the BALF proteome will be instrumental in establishing potential biomarkers of pathophysiology in the lungs, the objective of this study was to contribute to the comprehensive collection of Mus musculus BALF proteins using high resolution and highly sensitive micro-capillary liquid chromatography (microLC) combined with state-of-the-art high resolution mass spectrometry (MS). BALF was collected from ICR and C57BL/6 male mice exposed to nose-only inhalation to either air or cigarette smoke. The tandem mass spectra were analyzed by SEQUEST for peptide identifications with the subsequent application of accurate mass and time tags resulting in the identification of 1797 peptides with high confidence by high resolution MS. These peptides covered 959 individual proteins constituting the largest collection of BALF proteins to date. High throughput monitoring profiles of this extensive collection of BALF proteins will facilitate the discovery and validation of biomarkers that would elucidate pathogenic or adaptive responses of the lungs upon toxic insults.

  14. Hydrolysis mechanism of methyl parathion evidenced by Q-Exactive mass spectrometry. (United States)

    Liu, Yuan; Zhang, Caixiang; Liao, Xiaoping; Luo, Yinwen; Wu, Sisi; Wang, Jianwei


    Organophosphorus pesticides (OPPs), a kind of widely used pesticides, are currently attracting great attention due to their adverse effects on human central nervous systems, particularly in children. Although the hydrolysis behavior of OPPs has been studied well, its hydrolysis mechanism remained controversial, especially at various pH conditions, partly due to their relatively complex structures and abundant moieties that were prone to be attacked by nucleophiles. The Q-Exactive mass spectrometer, part of those hybrid high-resolution mass spectrometers (HRMS), was used to determine hydrolysis products of methyl parathion (MP), a kind of OPPs in situ buffer aqueous solution with pH ranging from 1 to 13 in this study. Most of the complex hydrolysis products of MP were identified due to the high sensitivity and accuracy of HRMS. The results demonstrated that the hydrolysis rate and pathway of MP were strong pH dependent. With the increase of pH, the hydrolysis rate of MP increased, and two different reaction mechanisms were identified: SN (2)@P pathway dominated the hydrolysis process at high pH (e.g., pH ≥ 11) while SN (2)@C was the main behavior at low pH (e.g., pH ≤ 9). This study helps understand the hydrolysis mechanism of OPPs at various pH and extends the use of Q-Exactive mass spectrometry in identifying organic pollutants and their degradation products in environmental matrices.

  15. Vaporization Studies of Olivine via Knudsen Effusion Mass Spectrometry (United States)

    Costa, G. C. C.; Jacobson, N. S.


    Olivine is the major mineral in the Earth's upper mantle occurring predominantly in igneous rocks and has been identified in meteorites, asteroids, the Moon and Mars. Among many other important applications in planetary and materials sciences, the thermodynamic properties of vapor species from olivine are crucial as input parameters in computational modelling of the atmospheres of hot, rocky exoplanets (lava planets). There are several weight loss studies of olivine vaporization in the literature and one Knudsen Effusion Mass Spectrometry (KEMS) study. In this study, we examine a forsterite-rich olivine (93% forsterite and 7% fayalite, Fo93Fa7) with KEMS to further understand its vaporization and thermodynamic properties.

  16. Monitoring of wine aging process by electrospray ionization mass spectrometry

    Directory of Open Access Journals (Sweden)

    Alexandra Christine Helena Frankland Sawaya


    Full Text Available The characterization of wine samples by direct insertion electrospray ionization mass spectrometry (ESI-MS, without pre-treatment or chromatographic separation, in a process denominated fingerprinting, has been applied to several samples of wine produced with grapes of the Pinot noir, Merlot and Cabernet Sauvignon varieties from the state o Rio Grande do Sul, in Brazil. The ESI-MS fingerprints of the samples detected changes which occurred during the aging process in the three grape varieties. Principal Component Analysis (PCA of the negative ion mode fingerprints was used to group the samples, pinpoint the main changes in their composition, and indicate marker ions for each group of samples.

  17. Analytical strategies in mass spectrometry-based phosphoproteomics

    DEFF Research Database (Denmark)

    Rosenqvist, Heidi; Ye, Juanying; Jensen, Ole N


    to reveal key regulatory events and phosphorylation-mediated processes in the cell and in whole organisms. We present an overview of sensitive and robust analytical methods for phosphopeptide analysis, including calcium phosphate precipitation and affinity enrichment methods such as IMAC and TiO(2). We...... then discuss various tandem mass spectrometry approaches for phosphopeptide sequencing and quantification, and we consider aspects of phosphoproteome data analysis and interpretation. Efficient integration of these stages of phosphoproteome analysis is highly important to ensure a successful outcome of large...

  18. Uncertainty of relative sensitivity factors in glow discharge mass spectrometry (United States)

    Meija, Juris; Methven, Brad; Sturgeon, Ralph E.


    The concept of the relative sensitivity factors required for the correction of the measured ion beam ratios in pin-cell glow discharge mass spectrometry is examined in detail. We propose a data-driven model for predicting the relative response factors, which relies on a non-linear least squares adjustment and analyte/matrix interchangeability phenomena. The model provides a self-consistent set of response factors for any analyte/matrix combination of any element that appears as either an analyte or matrix in at least one known response factor.

  19. Application of accelerator mass spectrometry in aluminum metabolism studies (United States)

    Meirav, O.; Sutton, R. A. L.; Fink, D.; Middleton, R.; Klein, J.; Walker, V. R.; Halabe, A.; Vetterli, D.; Johnson, R. R.


    The recent recognition that aluminum causes toxicity in uremie patients and may be associated with Alzheimer's disease has stimulated many studies of its biochemical effects. However, such studies were hampered by the lack of a suitable tracer. In a novel experiment, we have applied the new technique of accelerator mass spectrometry to investigate aluminum kinetics in rats, using as a marker the long-lived isotope 26Al. We present the first aluminum kinetic model for a biological system. The results clearly demonstrate the advantage this technique holds for isotope tracer studies in animals as well as in humans.

  20. Imaging mass spectrometry tackles interfacial challenges in electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xiao-Ying


    Electrochemistry has played a significant role in many research fields. Owing to its sensitivity and selectivity, in situ electroanalysis has been widely used as a fast and economical means for achieving outstanding results. Although many spectroscopic techniques have been used in electrochemistry, the challenges to capture short-lived intermediate species as a result of electron transfer in the buried solid electrode and electrolyte solution interface remains a grand challenge. In situ imaging mass spectrometry (IMS) recently has been extended to capture transient species in electrochemistry. This review intends to summarize newest development of IMS and its applications in advancing fundamental electrochemistry.

  1. Solid support resins and affinity purification mass spectrometry. (United States)

    Havis, Spencer; Moree, Wilna J; Mali, Sujina; Bark, Steven J


    Co-affinity purification-mass spectrometry (CoAP-MS) is a primary technology for elucidating the protein-protein interactions that form the basis of all biological processes. A critical component of CoAP-MS is the affinity purification (AP) of the bait protein, usually by immobilization of an antibody to a solid-phase resin. This Minireview discusses common resins, reagents, tagging methods, and their consideration for successful AP of tagged proteins. We discuss our experiences with different solid supports, their impact in AP experiments, and propose areas where chemistry can advance this important technology.

  2. Multinozzle emitter arrays for ultrahigh-throughput nanoelectrospray mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Daojing; Mao, Pan; Wang, Hung-Ta; Yang, Peidong


    The present invention provides for a structure comprising a plurality of emitters, wherein a first nozzle of a first emitter and a second nozzle of a second emitter emit in two directions that are not or essentially not in the same direction; wherein the walls of the nozzles and the emitters form a monolithic whole. The present invention also provides for a structure comprising an emitter with a sharpened end from which the emitter emits; wherein the emitters forms a monolithic whole. The present invention also provides for a fully integrated separation of proteins and small molecules on a silicon chip before the electrospray mass spectrometry analysis.

  3. Hydrogen Exchange Mass Spectrometry: Are We Out of the Quicksand? (United States)

    Iacob, Roxana E.; Engen, John R.


    Although the use of hydrogen exchange (HX) mass spectrometry (MS) to study proteins and protein conformation is now over 20 years old, the perception lingers that it still has "issues." Is this method, in fact, still in the quicksand with many remaining obstacles to overcome? We do not think so. This critical insight addresses the "issues" and explores several broad questions including, have the limitations of HX MS been surmounted and has HX MS achieved "indispensable" status in the pantheon of protein structural analysis tools.

  4. Clusters of Monoisotopic Elements for Calibration in (TOF) Mass Spectrometry (United States)

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


    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.

  5. Clusters of Monoisotopic Elements for Calibration in (TOF) Mass Spectrometry. (United States)

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


    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. Graphical Abstract ᅟ.

  6. Tandem mass spectrometry data quality assessment by self-convolution

    Directory of Open Access Journals (Sweden)

    Tham Wai


    Full Text Available Abstract Background Many algorithms have been developed for deciphering the tandem mass spectrometry (MS data sets. They can be essentially clustered into two classes. The first performs searches on theoretical mass spectrum database, while the second based itself on de novo sequencing from raw mass spectrometry data. It was noted that the quality of mass spectra affects significantly the protein identification processes in both instances. This prompted the authors to explore ways to measure the quality of MS data sets before subjecting them to the protein identification algorithms, thus allowing for more meaningful searches and increased confidence level of proteins identified. Results The proposed method measures the qualities of MS data sets based on the symmetric property of b- and y-ion peaks present in a MS spectrum. Self-convolution on MS data and its time-reversal copy was employed. Due to the symmetric nature of b-ions and y-ions peaks, the self-convolution result of a good spectrum would produce a highest mid point intensity peak. To reduce processing time, self-convolution was achieved using Fast Fourier Transform and its inverse transform, followed by the removal of the "DC" (Direct Current component and the normalisation of the data set. The quality score was defined as the ratio of the intensity at the mid point to the remaining peaks of the convolution result. The method was validated using both theoretical mass spectra, with various permutations, and several real MS data sets. The results were encouraging, revealing a high percentage of positive prediction rates for spectra with good quality scores. Conclusion We have demonstrated in this work a method for determining the quality of tandem MS data set. By pre-determining the quality of tandem MS data before subjecting them to protein identification algorithms, spurious protein predictions due to poor tandem MS data are avoided, giving scientists greater confidence in the

  7. Evaluation of Mass Filtered, Time Dilated, Time-of-Flight Mass Spectrometry (United States)


    spectrometry and this thesis evaluates the utility of a Pretzel magnet as an improved mass analyzer. Skoog et al. (2007) present a more complete view of...isotopic systems and geochronology in mineral systems. Australian Journal of Earth Sciences 49: 601-611. SKOOG , D., F.J. HOLLER, AND S.R. CROUCH

  8. Combination of Selective Immunoassays and Mass Spectrometry to Characterize Preproghrelin-Derived Peptides in Mouse Tissues

    Directory of Open Access Journals (Sweden)

    Virginie Tolle


    Full Text Available Preproghrelin is a prohormone producing several preproghrelin-derived peptides with structural and functional heterogeneity: acyl ghrelin (AG, desacyl ghrelin (DAG, and obestatin. The absence of selective and reliable assays to measure these peptides simultaneously in biological samples has been a limitation to assess their real proportions in tissues and plasma in physiological and pathological conditions. We aimed at reliably measure the ratio between the different preproghrelin-derived peptides in murine tissues using selective immunoassays combined with a highly sensitive mass spectrometry method. AG-, DAG-, and obestatin-immunopositive fractions from the gastrointestinal tract of adult wild-type and ghrelin-deficient mice were processed for analysis by mass spectrometry (MS with a Triple Quadrupole mass spectrometer. We found that DAG was predominant in mouse plasma, however it only represented 50% of total ghrelin (AG+DAG production in the stomach and duodenum. Obestatin plasma levels accounted for about 30% of all circulating preproghrelin-derived peptides, however, it represented <1% of total preproghrelin-derived peptides production (AG+DAG+Obestatin in the stomach. Assays were validated in ghrelin-deficient mice since neither ghrelin nor obestatin immunoreactivities were detected in their stomach, duodenum nor plasma. MS analyses confirmed that obestatin-immunoreactivity in stomach corresponded to the C-terminal amidated form of the peptide but not to des(1–10-obestatin, nor to obestatin-Gly. In conclusion, specificity of ghrelin and obestatin immunoreactivities in gastrointestinal tissues using selective immunoassays was validated by MS. Obestatin was less abundant than AG or DAG in these tissues. Whether this is due to inefficient processing rate of preproghrelin into mature obestatin in gastrointestinal mouse tissues remains elusive.

  9. Theory and technique of spark source mass spectrometry; Theorie et technique de la spectrometrie de masse a etincelles

    Energy Technology Data Exchange (ETDEWEB)

    Stefani, R. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires


    Trace analysis in solids by spark source mass spectrometry involves complicated phenomena: element ionization in spark and blacking of sensitive emulsion by focused ion beam. However the principal risk of selectivity lies in analyser system, which realizes double focusing only for a part of the ions. Therefore, each analyst has to known ionic optics of his apparatus, for ensuring the transmission of mean energetic ions, which are representative of sample composition. By a careful photometry of mass spectrum, good reproducibility can be obtained. Thereafter accuracy depends on the knowledge of sensitivity coefficients proper to this apparatus. (author) [French] L'analyse de traces dans les solides par spectrometrie de masse a etincelles met en jeu des phenomenes complexes qui sont l'ionisation des elements dans l'etincelle, et le noircissement de l'emulsion sensible par les faisceaux ioniques focalises. Cependant, le risque majeur de selectivite provient de l'ensemble analyseur, qui realise la double focalisation sur une fraction seulement du faisceau d'ions. L'analyste doit donc connaitre en detail l'optique ionique de son appareil, pour assurer le passage de la bande d'energie moyenne des ions, qui seule caracterise quantitativement la composition chimique de l'echantillon. Une exploitation photometrique soignee du spectrogramme donne alors des resultats reproductibles, dont la justesse ne depend plus que des coefficients de sensibilite propres a ce type d'instrument. (auteur)

  10. Comparison of triple quadrupole mass spectrometry and Orbitrap high-resolution mass spectrometry in ultrahigh performance liquid chromatography for the determination of veterinary drugs in sewage: benefits and drawbacks. (United States)

    Herrero, P; Cortés-Francisco, N; Borrull, F; Caixach, J; Pocurull, E; Marcé, R M


    This paper presents a comparison of triple quadrupole tandem mass spectrometry (MS/MS) and Orbitrap high-resolution mass spectrometry (HRMS) combined to ultrahigh performance liquid chromatography for the determination of glucocorticoids and polyether ionophores in sewage, in order to show the major benefits and drawbacks for each mass spectrometry analyser. Overall, HRMS measurements have enhanced performance in terms of confirmatory capabilities than MS/MS measurements. Moreover, similar limits of quantification, limits of detection, linear range and repeatability for glucocorticoids with both the MS/MS and HRMS methods were compared, but in the case of polyether ionophores, slightly better limits of detection and limits of quantification were obtained with the HRMS method because of the high sensitivity obtained when diagnostic ions are used for quantification instead of selected reaction monitoring transitions for these compounds. The two methods have been applied to the analysis of several influent and effluent sewage samples from sewage treatment plants located in the Tarragona region (Catalonia, Spain), showing an excellent correlation between the two methods. Copyright © 2014 John Wiley & Sons, Ltd.

  11. Sequencing of Oligourea Foldamers by Tandem Mass Spectrometry (United States)

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


    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.

  12. Mass Spectrometry of Polymer Electrolyte Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Viktor Johánek


    Full Text Available The chemical analysis of processes inside fuel cells under operating conditions in either direct or inverted (electrolysis mode and their correlation with potentiostatic measurements is a crucial part of understanding fuel cell electrochemistry. We present a relatively simple yet powerful experimental setup for online monitoring of the fuel cell exhaust (of either cathode or anode side downstream by mass spectrometry. The influence of a variety of parameters (composition of the catalyst, fuel type or its concentration, cell temperature, level of humidification, mass flow rate, power load, cell potential, etc. on the fuel cell operation can be easily investigated separately or in a combined fashion. We demonstrate the application of this technique on a few examples of low-temperature (70°C herein polymer electrolyte membrane fuel cells (both alcohol- and hydrogen-fed subjected to a wide range of conditions.

  13. Use of mass spectrometry to study signaling pathways

    DEFF Research Database (Denmark)

    Pandey, A; Andersen, Jens S.; Mann, M


    Activation of cells by extracellular stimuli, such as growth factors, initiates a cascade of events involving posttranslational modifications, including phosphorylation, formation of protein complexes, and induction or repression of gene expression. Traditionally, genetic methods or specific...... biochemical assays have been used to identify molecules involved in signaling pathways. Lately, mass spectrometry, combined with elegant biochemical approaches, has become a powerful tool for identifying proteins and posttranslational modifications. With this protocol, we hope to bridge the gap between...... the biochemical and molecular aspects of signal transduction pathways and the mass spectrometric tools and techniques that are available to study them. We provide methods for large-scale cell culture and immunoprecipitation of tyrosine-phosphorylated proteins, silver staining of gels, trypsin digests, and protein...

  14. Differential Rapid Screening of Phytochemicals by Leaf Spray Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Thomas; Graham Cooks, R. [Univ. of Innsbruck, Innsbruck (Austria)


    Ambient ionization can be achieved by generating an electrospray directly from plant tissue ('leaf spray'). The resulting mass spectra are characteristic of ionizable phytochemicals in the plant material. By subtracting the leaf spray spectra recorded from the petals of two hibiscus species H. moscheutos and H. syriacus one gains rapid access to the metabolites that differ most in the two petals. One such compound was identified as the sambubioside of quercitin (or delphinidin) while others are known flavones. Major interest centered on a C{sub 19}H{sub 29}NO{sub 5} compound that occurs only in the large H. moscheutos bloom. Attempts were made to characterize this compound by mass spectrometry alone as a test of such an approach. This showed that the compound is an alkaloid, assigned to the polyhydroxylated pyrrolidine class, and bound via a C{sub 3} hydrocarbon unit to a monoterpene.

  15. High Resolution Mass Spectrometry of Polyfluorinated Polyether-Based Formulation

    DEFF Research Database (Denmark)

    Dimzon, Ian Ken; Trier, Xenia; Frömel, Tobias


    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...... 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......-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....

  16. Mass Spectrometry of Polymer Electrolyte Membrane Fuel Cells. (United States)

    Johánek, Viktor; Ostroverkh, Anna; Fiala, Roman; Rednyk, Andrii; Matolín, Vladimír


    The chemical analysis of processes inside fuel cells under operating conditions in either direct or inverted (electrolysis) mode and their correlation with potentiostatic measurements is a crucial part of understanding fuel cell electrochemistry. We present a relatively simple yet powerful experimental setup for online monitoring of the fuel cell exhaust (of either cathode or anode side) downstream by mass spectrometry. The influence of a variety of parameters (composition of the catalyst, fuel type or its concentration, cell temperature, level of humidification, mass flow rate, power load, cell potential, etc.) on the fuel cell operation can be easily investigated separately or in a combined fashion. We demonstrate the application of this technique on a few examples of low-temperature (70°C herein) polymer electrolyte membrane fuel cells (both alcohol- and hydrogen-fed) subjected to a wide range of conditions.

  17. Charge detection mass spectrometry: Instrumentation & applications to viruses (United States)

    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

  18. Improved quantitative analysis of mass spectrometry using quadratic equations. (United States)

    Yoon, Joo Young; Lim, Kyung Young; Lee, Sunho; Park, Kunsoo; Paek, Eunok; Kang, Un-Beom; Yeom, Jeonghun; Lee, Cheolju


    Protein quantification is one of the principal computational problems in mass spectrometry (MS) based proteomics. For robust and trustworthy protein quantification, accurate peptide quantification must be preceded. In recent years, stable isotope labeling has become the most popular method for relative quantification of peptides. However, some stable isotope labeling methods may carry a critical problem, which is an overlap of isotopic clusters. If the mass difference between the light- and heavy-labeled peptides is very small, the overlap of their isotopic clusters becomes larger as the mass of original peptide increases. Here we propose a new algorithm for peptide quantification that separates overlapping isotopic clusters using quadratic equations. It can be easily applied in Trans-Proteomic Pipeline (TPP) instead of XPRESS. For the mTRAQ-labeled peptides obtained by an Orbitrap mass spectrometer, it showed more accurate ratios and better standard deviations than XPRESS. Especially, for the peptides that do not contain lysine, the ratio difference between XPRESS and our algorithm became larger as the peptide masses increased. We expect that this algorithm can also be applied to other labeling methods such as (18)O labeling and acrylamide labeling.

  19. Validation of the Mass-Extraction-Window for Quantitative Methods Using Liquid Chromatography High Resolution Mass Spectrometry. (United States)

    Glauser, Gaétan; Grund, Baptiste; Gassner, Anne-Laure; Menin, Laure; Henry, Hugues; Bromirski, Maciej; Schütz, Frédéric; McMullen, Justin; Rochat, Bertrand


    A paradigm shift is underway in the field of quantitative liquid chromatography-mass spectrometry (LC-MS) analysis thanks to the arrival of recent high-resolution mass spectrometers (HRMS). The capability of HRMS to perform sensitive and reliable quantifications of a large variety of analytes in HR-full scan mode is showing that it is now realistic to perform quantitative and qualitative analysis with the same instrument. Moreover, HR-full scan acquisition offers a global view of sample extracts and allows retrospective investigations as virtually all ionized compounds are detected with a high sensitivity. In time, the versatility of HRMS together with the increasing need for relative quantification of hundreds of endogenous metabolites should promote a shift from triple-quadrupole MS to HRMS. However, a current "pitfall" in quantitative LC-HRMS analysis is the lack of HRMS-specific guidance for validated quantitative analyses. Indeed, false positive and false negative HRMS detections are rare, albeit possible, if inadequate parameters are used. Here, we investigated two key parameters for the validation of LC-HRMS quantitative analyses: the mass accuracy (MA) and the mass-extraction-window (MEW) that is used to construct the extracted-ion-chromatograms. We propose MA-parameters, graphs, and equations to calculate rational MEW width for the validation of quantitative LC-HRMS methods. MA measurements were performed on four different LC-HRMS platforms. Experimentally determined MEW values ranged between 5.6 and 16.5 ppm and depended on the HRMS platform, its working environment, the calibration procedure, and the analyte considered. The proposed procedure provides a fit-for-purpose MEW determination and prevents false detections.

  20. Bead Separation and MALDI-TOF Mass Spectrometry Analysis

    Directory of Open Access Journals (Sweden)

    Nai-Jun Fan


    Full Text Available Background. Colorectal cancer (CRC is one of the most common cancers in the world, identification of biomarkers for early detection of CRC represents a relevant target. The present study aims to determine serum peptidome patterns for CRC diagnosis. Methods. The present work focused on serum proteomic analysis of 32 health volunteers and 38 CRC by ClinProt Kit combined with mass spectrometry. This approach allowed the construction of a peptide patterns able to differentiate the studied populations. An independent group of serum (including 33 health volunteers, 34 CRC, 16 colorectal adenoma, 36 esophageal carcinoma, and 31 gastric carcinoma samples was used to verify the diagnostic and differential diagnostic capability of the peptidome patterns blindly. An immunoassay method was used to determine serum CEA of CRC and controls. Results. A quick classifier algorithm was used to construct the peptidome patterns for identification of CRC from controls. Two of the identified peaks at m/z 741 and 7772 were used to construct peptidome patterns, achieving an accuracy close to 100% (>CEA, P<0.05. Furthermore, the peptidome patterns could differentiate validation group with high accuracy. Conclusions. These results suggest that the ClinProt Kit combined with mass spectrometry yields significantly higher accuracy for the diagnosis and differential diagnosis of CRC.

  1. Analysis of hazardous biological material by MALDI mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    KL Wahl; KH Jarman; NB Valentine; MT Kingsley; CE Petersen; ST Cebula; AJ Saenz


    Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-MS) has become a valuable tool for analyzing microorganisms. The speed with which data can be obtained from MALDI-MS makes this a potentially important tool for biological health hazard monitoring and forensic applications. The excitement in the mass spectrometry community in this potential field of application is evident by the expanding list of research laboratories pursuing development of MALDI-MS for bacterial identification. Numerous research groups have demonstrated the ability to obtain unique MALDI-MS spectra from intact bacterial cells and bacterial cell extracts. The ability to differentiate strains of the same species has been investigated. Reproducibility of MALDI-MS spectra from bacterial species under carefully controlled experimental conditions has also been demonstrated. Wang et al. have reported on interlaboratory reproducibility of the MALDI-MS analysis of several bacterial species. However, there are still issues that need to be addressed, including the careful control of experimental parameters for reproducible spectra and selection of optimal experimental parameters such as solvent and matrix.

  2. Bio-Aerosol Detection Using Mass Spectrometry: Public Health Applications

    Energy Technology Data Exchange (ETDEWEB)

    Ludvigson, Laura D. [Univ. of California, Berkeley, CA (United States)


    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 prevention 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.

  3. Pesticide residues screening in wine by mass spectrometry

    Directory of Open Access Journals (Sweden)

    Machado Andrea F.


    Full Text Available Recently, a study (from PAN Europe covered 40 bottles of wine – 34 conventional and six organic ones – purchased inside the EU. According to the results, the 34 bottles of conventional wine together contained 148 pesticide residues. All 34 bottles contained from one to ten pesticides, bringing the average per bottle to more than four. Of the six bottles of organic wine tested, one sample contained a low concentration of a possibly carcinogenic pesticide. According to PAN Europe, the “contamination of wines is a direct result of over-reliance on pesticides in grape production”. This study, between others, to prove the importance of develop methods sensivity and confident for pesticide detection in wine. A multi-residue method was developed for the determination ca of 250 pesticide residues in wine using Quechers extraction, gas chromatography-tandem mass spectrometry (GC-MS-MS and liquid chromatography-tandem mass spectrometry (LC-MS-MS. The method was validated with the evaluation of follow parameters: Linearity, Precision, Accuracy, Matrix effect, Limit of detection and Limit of Quantification. The method was approved and was able to quantify pesticide residues in more than 60 samples of wine.

  4. Mass spectrometry-based proteomics: existing capabilities and future directions

    Energy Technology Data Exchange (ETDEWEB)

    Angel, Thomas E.; Aryal, Uma K.; Hengel, Shawna M.; Baker, Erin Shammel; Kelly, Ryan T.; Robinson, Errol W.; Smith, Richard D.


    Mass spectrometry-based proteomics provides a means for identification, characterization, and quantification of biomolecules that are integral components of the processes essential for life. Characterization of proteins present in a biological system at the proteome and sub-proteomes (e.g., the phosphoproteome, proteoglycome, or degradome/peptidome) levels provides a foundation for understanding fundamental aspects as well as potentially a range of translational applications. Emerging technologies such as ion mobility separations coupled with mass spectrometry and microchip-based - proteome measurements combined with continued enhancement of MS instrumentation and separation techniques, such as reversed phase liquid chromatography and potentially capillary electrophoresis, show great promise for both broad undirected as well as targeted measurements and will be critical for e.g., the proteome-wide characterization of post translational modifications and identification, or the verification, and validation of potential biomarkers of disease. MS-based proteomics is also increasingly demonstrating great potential for contributing to our understanding of the dynamics, reactions, and roles proteins and peptides play advancing our understanding of biology on a system wide level for a wide range of applications, from investigations of microbial communities, bioremediation, and human health and disease states alike.

  5. Secondary ionization mass spectrometry analysis in petrochronology: Chapter 7 (United States)

    Schmitt, Axel K.; Vazquez, Jorge A.


    The goal of petrochronology is to extract information about the rates and conditions at which rocks and magmas are transported through the Earth’s crust. Garnering this information from the rock record greatly benefits from integrating textural and compositional data with radiometric dating of accessory minerals. Length scales of crystal growth and diffusive transport in accessory minerals under realistic geologic conditions are typically in the range of 1–10’s of μm, and in some cases even substantially smaller, with zircon having among the lowest diffusion coefficients at a given temperature (e.g., Cherniak and Watson 2003). Intrinsic to the compartmentalization of geochemical and geochronologic information from intra-crystal domains is the requirement to determine accessory mineral compositions using techniques that sample at commensurate spatial scales so as to not convolute the geologic signals that are recorded within crystals, as may be the case with single grain or large grain fragment analysis by isotope dilution thermal ionization mass spectrometry (ID-TIMS; e.g., Schaltegger and Davies 2017, this volume; Schoene and Baxter 2017, this volume). Small crystals can also be difficult to extract by mineral separation techniques traditionally used in geochronology, which also lead to a loss of petrographic context. Secondary Ionization Mass Spectrometry, that is SIMS performed with an ion microprobe, is an analytical technique ideally suited to meet the high spatial resolution analysis requirements that are critical for petrochronology (Table 1).

  6. NMR and mass spectrometry of phosphorus in wetlands (United States)

    El-Rifai, H.; Heerboth, M.; Gedris, T.E.; Newman, S.; Orem, W.; Cooper, W.T.


    There is at present little information on the long-term stability of phosphorus sequestered in wetlands. Phosphorus sequestered during high loading periods may be relatively unstable and easily remobilized following changes in nutrient status or hydrological regime, but the chemical forms of sequestered phosphorus that do remobilize are largely unknown at this time. A lack of suitable analytical techniques has contributed to this dearth of knowledge regarding the stability of soil organic phosphorus. We analysed phosphorus in soils from the 'head' of Rescue Strand tree island and an adjacent marsh in the Florida Everglades by 31P nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry. Tree islands are important areas of biodiversity within the Everglades and offer a unique opportunity to study phosphorus sequestration because they are exposed to large phosphorus loads and appear to be natural nutrient sinks. The 31P NMR profiling of extracts from surface and sediment samples in the tree island indicates that phosphorus input to Rescue Strand tree island soils is mostly in the form of inorganic ortho-phosphate and is either refractory when deposited or rapidly recycled by the native vegetation into a stable phosphorus pool largely resistant to re-utilization by plants or microbes. Mass spectrometry revealed the presence of inositol hexakisphosphate, a common organic monophosphate ester not previously observed in Everglades' soils. ?? 2008 The Authors.

  7. Expanded newborn screening by mass spectrometry: New tests, future perspectives. (United States)

    Ombrone, Daniela; Giocaliere, Elisa; Forni, Giulia; Malvagia, Sabrina; la Marca, Giancarlo


    Tandem mass spectrometry (MS/MS) has become a leading technology used in clinical chemistry and has shown to be particularly sensitive and specific when used in newborn screening (NBS) tests. The success of tandem mass spectrometry is due to important advances in hardware, software and clinical applications during the last 25 years. MS/MS permits a very rapid measurement of many metabolites in different biological specimens by using filter paper spots or directly on biological fluids. Its use in NBS give us the chance to identify possible treatable metabolic disorders even when asymptomatic and the benefits gained by this type of screening is now recognized worldwide. Today the use of MS/MS for second-tier tests and confirmatory testing is promising especially in the early detection of new disorders such as some lysosomal storage disorders, ADA and PNP SCIDs, X-adrenoleucodistrophy (X-ALD), Wilson disease, guanidinoacetate methyltransferase deficiency (GAMT), and Duchenne muscular dystrophy. The new challenge for the future will be reducing the false positive rate by using second-tier tests, avoiding false negative results by using new specific biomarkers and introducing new treatable disorders in NBS programs. © 2015 Wiley Periodicals, Inc.

  8. Optimal selection of epitopes for TXP-immunoaffinity mass spectrometry

    Directory of Open Access Journals (Sweden)

    Joos Thomas


    Full Text Available Abstract Background Mass spectrometry (MS based protein profiling has become one of the key technologies in biomedical research and biomarker discovery. One bottleneck in MS-based protein analysis is sample preparation and an efficient fractionation step to reduce the complexity of the biological samples, which are too complex to be analyzed directly with MS. Sample preparation strategies that reduce the complexity of tryptic digests by using immunoaffinity based methods have shown to lead to a substantial increase in throughput and sensitivity in the proteomic mass spectrometry approach. The limitation of using such immunoaffinity-based approaches is the availability of the appropriate peptide specific capture antibodies. Recent developments in these approaches, where subsets of peptides with short identical terminal sequences can be enriched using antibodies directed against short terminal epitopes, promise a significant gain in efficiency. Results We show that the minimal set of terminal epitopes for the coverage of a target protein list can be found by the formulation as a set cover problem, preceded by a filtering pipeline for the exclusion of peptides and target epitopes with undesirable properties. Conclusions For small datasets (a few hundred proteins it is possible to solve the problem to optimality with moderate computational effort using commercial or free solvers. Larger datasets, like full proteomes require the use of heuristics.

  9. Use of Tritium Accelerator Mass Spectrometry for Tree Ring Analysis (United States)



    Public concerns over the health effects associated with low-level and long-term exposure to tritium released from industrial point sources have generated the demand for better methods to evaluate historical tritium exposure levels for these communities. The cellulose of trees accurately reflects the tritium concentration in the source water and may contain the only historical record of tritium exposure. The tritium activity in the annual rings of a tree was measured using accelerator mass spectrometry to reconstruct historical annual averages of tritium exposure. Milligram-sized samples of the annual tree rings from a Tamarix located at the Nevada Test Site are used for validation of this methodology. The salt cedar was chosen since it had a single source of tritiated water that was well-characterized as it varied over time. The decay-corrected tritium activity of the water in which the salt cedar grew closely agrees with the organically bound tritium activity in its annual rings. This demonstrates that the milligram-sized samples used in tritium accelerator mass spectrometry are suited for reconstructing anthropogenic tritium levels in the environment. PMID:12144257

  10. Isotope determination of sulfur by mass spectrometry in soil samples

    Directory of Open Access Journals (Sweden)

    Alexssandra Luiza Rodrigues Molina Rossete


    Full Text Available Sulphur plays an essential role in plants and is one of the main nutrients in several metabolic processes. It has four stable isotopes (32S, 33S, 34S, and 36S with a natural abundance of 95.00, 0.76, 4.22, and 0.014 in atom %, respectively. A method for isotopic determination of S by isotope-ratio mass spectrometry (IRMS in soil samples is proposed. The procedure involves the oxidation of organic S to sulphate (S-SO4(2-, which was determined by dry combustion with alkaline oxidizing agents. The total S-SO4(2- concentration was determined by turbidimetry and the results showed that the conversion process was adequate. To produce gaseous SO2 gas, BaSO4 was thermally decomposed in a vacuum system at 900 ºC in the presence of NaPO3. The isotope determination of S (atom % 34S atoms was carried out by isotope ratio mass spectrometry (IRMS. In this work, the labeled material (K2(34SO4 was used to validate the method of isotopic determination of S; the results were precise and accurate, showing the viability of the proposed method.

  11. Statistical analysis of proteomics, metabolomics, and lipidomics data using mass spectrometry

    CERN Document Server

    Mertens, Bart


    This book presents an overview of computational and statistical design and analysis of mass spectrometry-based proteomics, metabolomics, and lipidomics data. This contributed volume provides an introduction to the special aspects of statistical design and analysis with mass spectrometry data for the new omic sciences. The text discusses common aspects of design and analysis between and across all (or most) forms of mass spectrometry, while also providing special examples of application with the most common forms of mass spectrometry. Also covered are applications of computational mass spectrometry not only in clinical study but also in the interpretation of omics data in plant biology studies. Omics research fields are expected to revolutionize biomolecular research by the ability to simultaneously profile many compounds within either patient blood, urine, tissue, or other biological samples. Mass spectrometry is one of the key analytical techniques used in these new omic sciences. Liquid chromatography mass ...

  12. Elucidation of the mass fragmentation pathways of potato glycoalkaloids and aglycons using Orbitrap mass spectrometry. (United States)

    Cahill, Michael G; Caprioli, Giovanni; Vittori, Sauro; James, Kevin J


    The mass fragmentation of potato glycoalkaloids, α-solanine and α-chaconine, and the aglycons, demissidine and solasodine were studied using the Orbitrap Fourier transform (FT) mass spectrometer. Using the linear ion trap (LIT) mass spectrometry, multistage collisional-induced dissociation (CID) experiments (MS(n)) on the [M + H](+) precursor ions were performed to aid the elucidation of the mass fragmentation pathways. In addition, higher energy collisional-induced dissociation (HCD) mass spectra were generated for these toxins at a high resolution setting [100,000 FWHM (full width at half maximum)] using the Orbitrap. This hybrid mass spectrometry instrumentation was exploited to produce MS(3) spectra by selecting MS(2) product ions, generated using LIT MS, and fragmentation using HCD. The accurate mass data in the MS(3) spectra aided the confirmation of proposed product ion formulae. The precursor and product ions from glycoalkaloids lost up to four sugars from different regions during MS(n) experiments. Mass fragmentation of the six-ring aglycons were similar, generating major product ions that resulted from cleavages at the B-rings and E-rings. 2010 John Wiley & Sons, Ltd.

  13. Sensitive sandwich immunoassay based on single particle mode inductively coupled plasma mass spectrometry detection. (United States)

    Liu, Rui; Xing, Zhi; Lv, Yi; Zhang, Sichun; Zhang, Xinrong


    A sensitive sandwich type immunoassay has been proposed with the detection by inductively coupled plasma mass spectrometry (ICP-MS) in a single particle mode (time resolved analysis). The signal induced by the flash of ions ((197)Au(+)) due to the ionization of single Au-nanoparticle (Au-NP) label in the plasma torch can be measured by the mass spectrometer. The frequency of the transient signals is proportional to the concentration of Au-NPs labels. Characteristics of the signals obtained from Au-NPs of 20, 45 and 80 nm in diameters were discussed. The analytical figures for the determination of Au-labeled IgG using ICP-MS in conventional integral mode and single particle mode were compared in detail. Rabbit-anti-human IgG was used as a model analyte in the sandwich immunoassay. A detection limit (3 σ) of 0.1 ng mL(-1) was obtained for rabbit-anti-human IgG after immunoreactions, with a linear range of 0.3-10 ng mL(-1) and a RSD of 8.1% (2.0 ng mL(-1)). Finally, the proposed method was successfully applied to spiked rabbit-anti-human IgG samples and rabbit-anti-human serum samples. The method resulted to be a highly sensitive ICP-MS based sandwich type immunoassay. Copyright © 2010 Elsevier B.V. All rights reserved.

  14. Application of proton-transfer-reaction-mass-spectrometry for Indoor Air Quality research. (United States)

    Schripp, T; Etienne, S; Fauck, C; Fuhrmann, F; Märk, L; Salthammer, T


    In the field of Indoor Air Quality research, the measurement of volatile organic compounds (VOCs) demands instruments that are rapid, mobile, robust, highly sensitive and allow for simultaneous monitoring of multiple compounds. These instruments should also compensate for possible interferences from permanent gases and air humidity. Proton-transfer-reaction-mass-spectrometry (PTR-MS) has proved to be a valuable and promising technique that fits the mentioned requirements for a suitable online measuring device. In this study, five exemplary applications of PTR-MS are described: (i) release of paint additives during drying process, (ii) emission of VOCs from active hardcopy devices, (iii) reference material evaluation, (iv) diffusion studies, and (v) emission testing of building products. The examples are selected to illustrate possibilities and limitations of the PTR technique in this field of research. The quadruple-based PTR-QMS was able to determine the emission characteristics during the experiments, especially in case of depleting emission sources (e.g., reference material). This allows for chemometrical analysis of the measured release patterns and detection of underlying processes. However, PTR-QMS reaches a functional limit in case of compound identification. If identification of VOCs is necessary, the measurements need to be accompanied by GC/MS analytics or a PTR instrument with higher mass-resolution (e.g., PTR-TOF-MS). © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Intelligent Mixing of Proteomes for Elimination of False Positives in Affinity Purification-Mass Spectrometry. (United States)

    Eyckerman, Sven; Impens, Francis; Van Quickelberghe, Emmy; Samyn, Noortje; Vandemoortele, Giel; De Sutter, Delphine; Tavernier, Jan; Gevaert, Kris


    Protein complexes are essential in all organizational and functional aspects of the cell. Different strategies currently exist for analyzing such protein complexes by mass spectrometry, including affinity purification (AP-MS) and proximal labeling-based strategies. However, the high sensitivity of current mass spectrometers typically results in extensive protein lists mainly consisting of nonspecifically copurified proteins. Finding the true positive interactors in these lists remains highly challenging. Here, we report a powerful design based on differential labeling with stable isotopes combined with nonequal mixing of control and experimental samples to discover bona fide interaction partners in AP-MS experiments. We apply this intelligent mixing of proteomes (iMixPro) concept to overexpression experiments for RAF1, RNF41, and TANK and also to engineered cell lines expressing epitope-tagged endogenous PTPN14, JIP3, and IQGAP1. For all baits, we confirmed known interactions and found a number of novel interactions. The results for RNF41 and TANK were compared to a classical affinity purification experiment, which demonstrated the efficiency and specificity of the iMixPro approach.

  16. Ion Mobility Spectrometry - High Resolution LTQ-Orbitrap Mass Spectrometry for Analysis of Homemade Explosives (United States)

    Hagan, Nathan; Goldberg, Ilana; Graichen, Adam; St. Jean, Amanda; Wu, Ching; Lawrence, David; Demirev, Plamen


    The detailed chemical characterization of homemade explosives (HMEs) and other chemicals that can mimic or mask the presence of explosives is important for understanding and improving the performance of commercial instrumentation used for explosive detection. To that end, an atmospheric-pressure drift tube ion mobility spectrometry (IMS) instrument has been successfully coupled to a commercial tandem mass spectrometry (MS) system. The tandem MS system is comprised of a linear ion trap and a high resolution Orbitrap analyzer. This IMS-MS combination allows extensive characterization of threat chemical compounds, including HMEs, and complex real-world background chemicals that can interfere with detection. Here, the composition of ion species originating from a specific HME, erythritol tetranitrate, has been elucidated using accurate mass measurements, isotopic ratios, and tandem MS. Gated IMS-MS and high-resolution MS have been used to identify minor impurities that can be indicative of the HME source and/or synthesis route. Comparison between data obtained on the IMS/MS system and on commercial stand-alone IMS instruments used as explosive trace detectors (ETDs) has also been performed. Such analysis allows better signature assignments of threat compounds, modified detection algorithms, and improved overall ETD performance.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.


    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 spectrometry 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.

  18. Method for predicting peptide detection in mass spectrometry (United States)

    Kangas, Lars [West Richland, WA; Smith, Richard D [Richland, WA; Petritis, Konstantinos [Richland, WA


    A method of predicting whether a peptide present in a biological sample will be detected by analysis with a mass spectrometer. The method uses at least one mass spectrometer to perform repeated analysis of a sample containing peptides from proteins with known amino acids. The method then generates a data set of peptides identified as contained within the sample by the repeated analysis. The method then calculates the probability that a specific peptide in the data set was detected in the repeated analysis. The method then creates a plurality of vectors, where each vector has a plurality of dimensions, and each dimension represents a property of one or more of the amino acids present in each peptide and adjacent peptides in the data set. Using these vectors, the method then generates an algorithm from the plurality of vectors and the calculated probabilities that specific peptides in the data set were detected in the repeated analysis. The algorithm is thus capable of calculating the probability that a hypothetical peptide represented as a vector will be detected by a mass spectrometry based proteomic platform, given that the peptide is present in a sample introduced into a mass spectrometer.

  19. Time-of-flight mass spectrometry: Introduction to the basics. (United States)

    Boesl, Ulrich


    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.

  20. Mass spectrometry in the pharmacokinetic studies of anticancer natural products. (United States)

    Crotti, Sara; Posocco, Bianca; Marangon, Elena; Nitti, Donato; Toffoli, Giuseppe; Agostini, Marco


    In the history of medicine, nature has represented the main source of medical products. Indeed, the therapeutic use of plants certainly goes back to the Sumerian and Hippocrates and nowadays nature still represents the major source for new drugs discovery. Moreover, in the cancer treatment, drugs are either natural compounds or have been developed from naturally occurring parent compounds firstly isolated from plants and microbes from terrestrial and marine environment. A critical element of an anticancer drug is represented by its severe toxicities and, after administration, the drug concentrations have to remain in an appropriate range to be effective. Anyway, the drug dosage defined during the clinical studies could be inappropriate for an individual patient due to differences in drug absorption, metabolism and excretion. For this reason, personalized medicine, based on therapeutic drug monitoring (TDM), represents one of most important challenges in cancer therapy. Mass spectrometry sensitivity, specificity and fastness lead to elect this technique as the Golden Standard for pharmacokinetics and drug metabolism studies therefore for TDM. This review focuses on the mass spectrometry-based methods developed for pharmacokinetic quantification in human plasma of anticancer drugs derived from natural sources and already used in clinical practice. Particular emphasis was placed both on the pre-analytical and analytical steps, such as: sample preparation procedures, sample size required by the analysis and the limit of quantification of drugs and metabolites to give some insights on the clinical practice applicability. © 2015 Wiley Periodicals, Inc. Mass Spec Rev. 36:213-251, 2017. © 2015 Wiley Periodicals, Inc.

  1. Screening Non-colored Phenolics in Red Wines using Liquid Chromatography/Ultraviolet and Mass Spectrometry/Mass Spectrometry Libraries

    Directory of Open Access Journals (Sweden)

    Jianping Sun


    Full Text Available Liquid chromatography/ultraviolet (LC/UV and mass spectrometry/mass spectrometry (MS/MS libraries containing 39 phenolic compounds were established by coupling a LC and an ion trap MS with an electrospray ionization (ESI source, operated in negative ion mode. As a result, the deprotonated [M-H]- molecule was observed for all the analyzed compounds. Using MS/MS hydroxybenzoic acid and hydroxycinnamic acids showed a loss of CO2 and production of a [M-H-44] - fragment and as expected, the UV spectra of these two compounds were affected by their chemical structures. For flavonol and flavonol glycosides, the spectra of their glycosides and aglycones produced deprotonated [M-H]- and [A-H]- species, respectively, and their UV spectra each presented two major absorption peaks. The UV spectra and MS/MS data of flavan-3-ols and stilbenes were also investigated. Using the optimized LC/MS/MS analytical conditions, the phenolic extracts from six representative wine samples were analyzed and 31 phenolic compounds were detected, 26 of which were identified by searching the LC/UV and MS/MS libraries. Finally, the presence of phenolic compounds was confirmed in different wine samples using the LC/UV and LC/MS/MS libraries.

  2. Evaluation of nanoflow liquid chromatography high resolution mass spectrometry for pesticide residue analysis in food. (United States)

    Moreno-González, David; Pérez-Ortega, Patricia; Gilbert-López, Bienvenida; Molina-Díaz, Antonio; García-Reyes, Juan F; Fernández-Alba, Amadeo R


    This article reports on the evaluation of nanoflow liquid chromatography-mass spectrometry (LC-MS) for pesticide residue analysis in food. The approach is based on the use of reversed-phase C18nano columns with an integrated emitter, so that separation, ionization and detection are performed minimizing dead volumes. The use of nanoflow not only increases ionization efficiency and minimizes ionization suppression but also boost sensitivity compared to analytical-scale LC-MS methods. The nanoflow LC system was combined with full-scan high resolution mass spectrometry using a Q-Exactive Orbitrap instrument. The analytical performance was assessed for over 60 representative pesticides in five representative commodities (tomato, baby food, orange, fruit-based jam and olive oil). The sensitivity achieved with this configuration enables the implementation of high dilution factors (eg. 1:20, 1:50 or beyond) in pesticide residue workflows without compromising sensitivity, featuring limits of quantitation in the low ng kg-1 range. Using this dilution factors, signal suppression was found negligible in most cases (<10% in most cases, especially with 1:50 dilution), so that matrix-matched standards may be skipped, thus simplifying laboratory workflows. The robustness of the nanoflow LC system and its capability to withstand long analytical runs was also evaluated. Appropriate precision in terms of peak area and retention time was obtained at different concentration levels for over 125 injections without any instrument servicing. The main benefits of the nanoflow liquid chromatography approach are the high sensitivity gain and the outstanding reduction in matrix effects thanks to the high sample dilution factors that can be implemented, along with the substantial reduction in solvent usage. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Rapid quantification of ionophores in feeds by liquid chromatography-tandem mass spectrometry. (United States)

    Huang, Min; Rumbeiha, Wilson K; Braselton, W Emmett; Johnson, Margaret


    Ionophores are widely used in veterinary medicine as coccidiostats and for improving nutrient utilization in livestock production. Because of widespread use, ionophores sometimes cause poisoning in livestock. Quantifying concentration of these compounds in feeds for diagnostic purposes is needed. A method with a single step of solvent extraction was developed for rapid simultaneous quantification of monensin, lasalocid, salinomycin, and narasin in feeds by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The ionophores were extracted using methanol:water (90:10). With the high specificity and high sensitivity of tandem mass spectrometry, the extract was introduced for measurement without further processing. The effect of particle size of feeds on extraction efficiency was also investigated. It was found that feeds passing through a 1-mm filter or sieve show better quantitative extraction. Nigericin was used as internal standard for the measurement. The method was validated by fortification of the selected ionophore compounds in horse feed at different concentrations. The typical recovery rate was 69-122%. Meanwhile, various interlaboratory proficiency test samples of different matrices were also quantified as part of the procedure for method validation. A good agreement was found between results and the suggested values. The method is very sensitive, with detection limits between 0.018 µg/g and 0.056 µg/g for the compounds tested. Results showed that the lower limit of quantification was 0.2 µg/g for the ionophore compounds, which is much lower than the contents of the ionophores in medicated feeds, which is generally approximately 10-100 µg/g feed.

  4. Electrospray ionization tandem mass spectrometry for the simultaneous determination of opiates and cocaine in human hair. (United States)

    Míguez-Framil, Martha; Moreda-Piñeiro, Antonio; Bermejo-Barrera, Pilar; Cocho, José Ángel; Tabernero, María Jesús; Bermejo, Ana María


    A fast and highly sensitive electrospray ionization tandem mass spectrometry (ESI-MS/MS) method has been developed for the simultaneous determination of morphine, 6-methylacetylmorphine (6-MAM), codeine, cocaine and benzoylecgonine (BZE) in hair from drug abusers. Pulverized hair samples were subjected to an optimized matrix solid phase dispersion (MSPD) procedure with alumina, followed by diluted hydrochloric acid elution on column solid-phase extraction (SPE) clean-up/pre-concentration. Alternatively, samples were also subjected to an optimized ultrasound assisted enzymatic hydrolysis (USEH) with Pronase E, followed by an off-line SPE clean up/pre-concentration procedure. Positive electrospray ionization and multiple reaction monitoring (MRM) with one precursor ion/product ion transition were used for the identification and quantification (deuterated analogues of each target as internal standards) of each analyte. The chromatographic pump and the autosampler were used for injecting the standards and the hair extracts (20 μL) as a flow injection analysis mode. The highest sensitivity was achieved when delivering the targets with an acetonitrile/water/formic acid (80/19.875/0.125) mixture. The limits of detection of the method were 39.2, 4.4, 6.8, 7.0 and 7.4 ng g(-1) for morphine, 6-MAM, codeine, cocaine and BZE, respectively. Relative standard deviations of intra- and inter-day precision were lower than 9 and 12%, respectively; whereas, analytical recoveries ranged from 96±5 to 106±4%. The developed method (MSPD-ESI-MS/MS) was applied to different hair samples from polydrug abusers, and results were statistically compared to those obtained after a conventional gas chromatography-mass spectrometry (GC-MS) analysis and also after USEH and ESI-MS/MS or GC-MS determinations. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Direct Analysis in Real Time (DART of an Organothiophosphate at Ultrahigh Resolution by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry and Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Laszlo Prokai


    Full Text Available Direct analysis in real time (DART is a recently developed ambient ionization technique for mass spectrometry to enable rapid and sensitive analyses with little or no sample preparation. After swab-based field sampling, the organothiophosphate malathion was analyzed using DART-Fourier transform ion cyclotron resonance (FT-ICR mass spectrometry (MS and tandem mass spectrometry (MS/MS. Mass resolution was documented to be over 800,000 in full-scan MS mode and over 1,000,000 for an MS/MS product ion produced by collision-induced dissociation of the protonated analyte. Mass measurement accuracy below 1 ppm was obtained for all DART-generated ions that belonged to the test compound in the mass spectra acquired using only external mass calibration. This high mass measurement accuracy, achievable at present only through FTMS, was required for unequivocal identification of the corresponding molecular formulae.

  6. Comparing and combining capillary electrophoresis electrospray ionization mass spectrometry and nano-liquid chromatography electrospray ionization mass spectrometry for the characterization of post-translationally modified histones. (United States)

    Sarg, Bettina; Faserl, Klaus; Kremser, Leopold; Halfinger, Bernhard; Sebastiano, Roberto; Lindner, Herbert H


    We present the first comprehensive capillary electrophoresis electrospray ionization mass spectrometry (CESI-MS) analysis of post-translational modifications derived from H1 and core histones. Using a capillary electrophoresis system equipped with a sheathless high-sensitivity porous sprayer and nano-liquid chromatography electrospray ionization mass spectrometry (nano-LC-ESI-MS) as two complementary techniques, we characterized H1 histones isolated from rat testis. Without any pre-separation of the perchloric acid extraction, a total of 70 different modified peptides, including 50 phosphopeptides, were identified in the rat linker histones H1.0, H1a-H1e, and H1t. Out of the 70 modified H1 histone peptides, 27 peptides could be identified with CESI-MS only, and 11 solely with LC-ESI-MS. Immobilized metal-affinity chromatography enrichment prior to MS analysis yielded a total of 55 phosphopeptides; 22 of these peptides could be identified only by CESI-MS, and 19 only by LC-ESI-MS, showing the complementarity of the two techniques. We mapped 42 H1 modification sites, including 31 phosphorylation sites, of which 8 were novel sites. For the analysis of core histones, we chose a different strategy. In a first step, the sulfuric-acid-extracted core histones were pre-separated using reverse-phase high-performance liquid chromatography. Individual rat testis core histone fractions obtained in this way were digested and analyzed via bottom-up CESI-MS. This approach yielded the identification of 42 different modification sites including acetylation (lysine and N(α)-terminal); mono-, di-, and trimethylation; and phosphorylation. When we applied CESI-MS for the analysis of intact core histone subtypes from butyrate-treated mouse tumor cells, we were able to rapidly detect their degree of modification, and we found this method very useful for the separation of isobaric trimethyl and acetyl modifications. Taken together, our results highlight the need for additional techniques

  7. Transition of Iodine Analysis to Accelerator Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Watrous, Matthew George [Idaho National Lab. (INL), Idaho Falls, ID (United States); Adamic, Mary Louise [Idaho National Lab. (INL), Idaho Falls, ID (United States); Olson, John Eric [Idaho National Lab. (INL), Idaho Falls, ID (United States); Baeck, D. L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Fox, R. V. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hahn, P. A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Jenson, D. D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lister, T. E. [Idaho National Lab. (INL), Idaho Falls, ID (United States)


    The goal of the project, New Paradigms for Isotope Ratio Mass Spectrometry: Raising the Scientific Profile and Improved Performance for Accelerator Mass Spectrometry (AMS) and Thermal Ionization Mass Spectrometry (TIMS), is to ensure that the ongoing isotope ratio determination capability within the U.S. Department of Energy complex is the world’s best for application to nonproliferation. This report spells out the progress of Task 4, Transition of TIMS to AMS for Iodine Analysis, of the larger project. The subtasks under Task 4 and the accomplishments throughout the three year project life cycle are presented in this report. Progress was made in optimization of chemical extraction, determination of a detection limit for 127Iodine, production of standard materials for AMS analysis quality assurance, facilitation of knowledge exchange with respect to analyzing iodine on an AMS, cross comparison with a world-leading AMS laboratory, supercritical fluid extraction of iodine for AMS analysis and electrodeposition of seawater as a direct method of preparation for iodine analysis by AMS--all with the goal of minimizing the time required to stand up an AMS capability for iodine analysis of exposed air filters at INL. An effective extraction method has been developed and demonstrated for iodine analysis of exposed air filters. Innovative techniques to accomplish the cathode preparation for AMS analysis were developed and demonstrated and published. The known gap of a lack of available materials for reference standards in the analysis of iodine by AMS was filled by the preparation of homogenous materials that were calibrated against NIST materials. A minimum limit on the amount of abundant isotope in a sample was determined for AMS analysis. The knowledge exchange occurred with fantastic success. Scientists engaged the international AMS community at conferences, as well as in their laboratories for collaborative work. The supercritical fluid extraction work has positive

  8. Liquid extraction surface analysis field asymmetric waveform ion mobility spectrometry mass spectrometry for the analysis of dried blood spots. (United States)

    Griffiths, Rian L; Dexter, Alex; Creese, Andrew J; Cooper, Helen J


    Liquid extraction surface analysis (LESA) is a surface sampling technique that allows electrospray mass spectrometry analysis of a wide range of analytes directly from biological substrates. Here, we present LESA mass spectrometry coupled with high field asymmetric waveform ion mobility spectrometry (FAIMS) for the analysis of dried blood spots on filter paper. Incorporation of FAIMS in the workflow enables gas-phase separation of lipid and protein molecular classes, enabling analysis of both haemoglobin and a range of lipids (phosphatidylcholine or phosphatidylethanolamine, and sphingomyelin species) from a single extraction sample. The work has implications for multiplexed clinical assays of multiple analytes.

  9. Isotope effects in mass-spectrometry; Les effets isotopiques en spectrometrie de masse

    Energy Technology Data Exchange (ETDEWEB)

    Leicknam, J.P. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires. Departement de physico-chimie, service des isotopes stables, section de spectrometrie de masse


    In the first part, a review is made of the work concerning the influence of isotopic substitution on the stabilities of ionised molecules and the bond-breaking probabilities; metastable transitions are also affected by this substitution. A model based on the Franck-Condon principle accounts for the experimentally observed isotopic effects for diatomic molecules; to a certain extent it is possible to generalise the calculation for the case of isotopic molecules of carbon dioxide gas. For deuterated polyatomic molecules there exist a {pi} effect making it possible to compare the relative stabilities of the X-H and X-D bonds, and a {gamma} effect which characterizes the different behaviours of the X-H bond in a normal molecule and in its partially deuterated homologue. Usually there is a very marked {pi} effect (e.g. the C-D bonds are more difficult to break than the homologous C-H bonds) and a {gamma} effect, the partial deuteration of a molecule leading in general to an increase in the probability of breakage of a given bond. An interpretation of {pi} and {gamma} effects based on Rosenstock near-equilibrium theory accounts for the observed phenomena, qualitatively at least, in the case of propane and acetylene. In the second part are gathered together results concerning isotopic effects produced during the formation of rearranged ions. The existence of cyclic transition ions has made it possible for Mc Lafferty to explain the existence of these ions in the mass spectrum; isotopic substitution leads to a modification of the rearrangement mechanism, the bonding forces being no longer the same. (author) [French] Dans une premiere partie, on rassemble les travaux concernant l'influence de la substitution isotopique sur les stabilites des molecules ionisees et les probabilites de rupture des liaisons; les transitions metastables sont egalement modifiees par cette substitution. Un modele base sur le principe de Franck-Condon rend compte des effets isotopiques

  10. The use of mass spectrometry to analyze dried blood spots. (United States)

    Wagner, Michel; Tonoli, David; Varesio, Emmanuel; Hopfgartner, Gérard


    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

  11. Nanomaterial based affinity matrix-assisted laser desorption/ionization mass spectrometry for biomolecules and pathogenic bacteria. (United States)

    Chiu, Tai-Chia; Huang, Li-Shing; Lin, Po-Chiao; Chen, Yu-Chie; Chen, Yu-Ju; Lin, Chun-Cheng; Chang, Huan-Tsung


    This paper describes mass spectrometry (MS) using nanoparticles (NPs) for the analysis of biomolecules such as aminothiol compounds, drugs, peptides, proteins, and bacteria. Papers and patents dealing with preparation and use of several NPs in MS have been briefly reviewed, including carbon nanotubes, gold NPs, and magnetic NPs. The NPs or bioconjugated NPs were used for selective concentration and/or assisted matrices for desorption and ionization of analytes of interest. When compared to conventional organic matrixes, the NPs provide low MS background in low-mass region and low shot-to-shot variation. MS techniques using NPs and bioconjugated NPs for the analysis of disease-associated biomarkers and bacteria in real samples such as blood and urine are highlighted, showing the advantages of high sensitivity, reproducibility, and simplicity.

  12. Estimation of brassylic acid by gas chromatography-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed J. Nasrullah, Erica N. Pfarr, Pooja Thapliyal, Nicholas S. Dusek, Kristofer L. Schiele, Christy Gallagher-Lein, and James A. Bahr


    The main focus of this work is to estimate Brassylic Acid (BA) using gas chromatography-mass spectrometry (GC-MS). BA is a product obtained from the oxidative cleavage of Erucic Acid (EA). BA has various applications for making nylons and high performance polymers. BA is a 13 carbon compound with two carboxylic acid functional groups at the terminal end. BA has a long hydrocarbon chain that makes the molecule less sensitive to some of the characterization techniques. Although BA can be characterized by NMR, both the starting material (EA) and products BA and nonanoic acid (NA) have peaks at similar {delta}, ppm values. Hence it becomes difficult for the quick estimation of BA during its synthesis.

  13. Monitoring the synthesis of biomolecules using mass spectrometry. (United States)

    Miyagi, Masaru; Kasumov, Takhar


    The controlled and selective synthesis/clearance of biomolecules is critical for most cellular processes. In most high-throughput 'omics' studies, we measure the static quantities of only one class of biomolecules (e.g. DNA, mRNA, proteins or metabolites). It is, however, important to recognize that biological systems are highly dynamic in which biomolecules are continuously renewed and different classes of biomolecules interact and affect each other's production/clearance. Therefore, it is necessary to measure the turnover of diverse classes of biomolecules to understand the dynamic nature of biological systems. Herein, we explain why the kinetic analysis of a diverse range of biomolecules is important and how such an analysis can be done. We argue that heavy water ((2)H2O) could be a universal tracer for monitoring the synthesis of biomolecules on a global scale.This article is part of the themed issue 'Quantitative mass spectrometry'. © 2016 The Author(s).

  14. Evaluating plant immunity using mass spectrometry-based metabolomics workflows

    Directory of Open Access Journals (Sweden)

    Adam L Heuberger


    Full Text Available Metabolic processes in plants are key components of physiological and biochemical disease resistance. Metabolomics, the analysis of a broad range of small molecule compounds in a biological system, has been used to provide a systems-wide overview of plant metabolism associated with defense responses. Plant immunity has been examined using multiple metabolomics workflows that vary in methods of detection, annotation, and interpretation, and the choice of workflow can significantly impact the conclusions inferred from a metabolomics investigation. The broad range of metabolites involved in plant defense often supports the need for multiple chemical detection platforms and implementation of a non-targeted approach. A review of the current literature reveals a wide range of workflows that are currently used in plant metabolomics, and new methods for analyzing and reporting mass spectrometry data can improve the ability to translate investigative findings among different plant-pathogen systems.

  15. High-Throughput Mass Spectrometry Applied to Structural Genomics

    Directory of Open Access Journals (Sweden)

    Rod Chalk


    Full Text Available Mass spectrometry (MS remains under-utilized for the analysis of expressed proteins because it is inaccessible to the non-specialist, and sample-turnaround from service labs is slow. Here, we describe 3.5 min Liquid-Chromatography (LC-MS and 16 min LC-MSMS methods which are tailored to validation and characterization of recombinant proteins in a high throughput structural biology pipeline. We illustrate the type and scope of MS data typically obtained from a 96-well expression and purification test for both soluble and integral membrane proteins (IMPs, and describe their utility in the selection of constructs for scale-up structural work, leading to cost and efficiency savings. We propose that value of MS data lies in how quickly it becomes available and that this can fundamentally change the way in which it is used.

  16. Chemical reaction interface mass spectrometry with high efficiency nebulization. (United States)

    Jorabchi, Kaveh; Kahen, Kaveh; Lecchi, Paolo; Montaser, Akbar


    A high efficiency nebulizer (HEN) coupled to a heated spray chamber and a membrane desolvator is used for liquid sample introduction in chemical reaction interface mass spectrometry (CRIMS). Compared to the conventional thermospray nebulizer operated at solvent flow rate of 1 mL/min, the HEN provides small droplets at lower flow rates (10-100 microL/min), improving the desolvation and analyte transport efficiency. As a result, the sensitivity for carbon detection by CRIMS is improved by a factor of 4. The new arrangement offers an easy-to-use and robust interface, facilitating the availability of a variety of liquid chromatographic techniques to the CRIMS. Separation and detection of labeled peptides in a mixture of unlabeled biopolymers is illustrated at a solvent flow rate of 45 microL/min as an example of new possibilities offered by the improved liquid introduction interface.

  17. Centrosome isolation and analysis by mass spectrometry-based proteomics

    DEFF Research Database (Denmark)

    Jakobsen, Lis; Schrøder, Jacob Morville; Larsen, Katja M


    Centrioles are microtubule-based scaffolds that are essential for the formation of centrosomes, cilia, and flagella with important functions throughout the cell cycle, in physiology and during development. The ability to purify centriole-containing organelles on a large scale, combined with advan......Centrioles are microtubule-based scaffolds that are essential for the formation of centrosomes, cilia, and flagella with important functions throughout the cell cycle, in physiology and during development. The ability to purify centriole-containing organelles on a large scale, combined...... understood. Considering the complexity and dynamics of centriole-related proteomes and the first-pass analyses reported so far, it is likely that further insight might come from more thorough proteome analyses under various cellular and physiological conditions. To this end, we here describe methods...... to isolate centrosomes from human cells and strategies to selectively identify and study the properties of the associated proteins using quantitative mass spectrometry-based proteomics....

  18. Triacylglycerol profiling of marine microalgae by mass spectrometry. (United States)

    Danielewicz, Megan A; Anderson, Lisa A; Franz, Annaliese K


    We present a method for the determination of triacylglycerol (TAG) profiles of oleaginous saltwater microalgae relevant for the production of biofuels, bioactive lipids, and high-value lipid-based chemical precursors. We describe a technique to remove chlorophyll using quick, simple solid phase extraction (SPE) and directly compare the intact TAG composition of four microalgae species (Phaeodactylum tricornutum, Nannochloropsis salina, Nannochloropsis oculata, and Tetraselmis suecica) using MALDI time-of-flight (TOF) mass spectrometry (MS), ESI linear ion trap-orbitrap (LTQ Orbitrap) MS, and ¹H NMR spectroscopy. Direct MS analysis is particularly effective to compare the polyunsaturated fatty acid (PUFA) composition for triacylglycerols because oxidation can often degrade samples upon derivatization. Using these methods, we observed that T. suecica contains significant PUFA levels with respect to other microalgae. This method is applicable for high-throughput MS screening of microalgae TAG profiles and may aid in the commercial development of biofuels.

  19. Dating Studies of Elephant Tusks Using Accelerator Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Sideras-Haddad, E; Brown, T A


    A new method for determining the year of birth, the year of death, and hence, the age at death, of post-bomb and recently deceased elephants has been developed. The technique is based on Accelerator Mass Spectrometry radiocarbon analyses of small-sized samples extracted from along the length of a ge-line of an elephant tusk. The measured radiocarbon concentrations in the samples from a tusk can be compared to the {sup 14}C atmospheric bomb-pulse curve to derive the growth years of the initial and final samples from the tusk. Initial data from the application of this method to two tusks will be presented. Potentially, the method may play a significant role in wildlife management practices of African national parks. Additionally, the method may contribute to the underpinnings of efforts to define new international trade regulations, which could, in effect, decrease poaching and the killing of very young animals.

  20. Metriculator: quality assessment for mass spectrometry-based proteomics. (United States)

    Taylor, Ryan M; Dance, Jamison; Taylor, Russ J; Prince, John T


    Quality control in mass spectrometry-based proteomics remains subjective, labor-intensive and inconsistent between laboratories. We introduce Metriculator, a software designed to facilitate long-term storage of extensive performance metrics as introduced by NIST in 2010. Metriculator features a web interface that generates interactive comparison plots for contextual understanding of metric values and an automated metric generation toolkit. The comparison plots are designed for at-a-glance determination of outliers and trends in the datasets, together with relevant statistical comparisons. Easy-to-use quantitative comparisons and a framework for integration plugins will encourage a culture of quality assurance within the proteomics community. Available under the MIT license at

  1. MALDI imaging mass spectrometry and analysis of endogenous peptides. (United States)

    Chatterji, Bijon; Pich, Andreas


    In recent years, MALDI imaging mass spectrometry (MALDI-IMS) has developed as a promising tool to investigate the spatial distribution of biomolecules in intact tissue specimens. Ion densities of various molecules can be displayed as heat maps while preserving anatomical structures. In this short review, an overview of different biomolecules that can be analyzed by MALDI-IMS is given. Many reviews have covered imaging of lipids, small metabolites, whole proteins and enzymatically digested proteins in the past. However, little is known about imaging of endogenous peptides, for example, in the rat brain, and this will therefore be highlighted in this review. Furthermore, sample preparation of frozen or formalin-fixed, paraffin-embedded (FFPE) tissue is crucial for imaging experiments. Therefore, some aspects of sample preparation will be addressed, including washing and desalting, the choice of MALDI matrix and its deposition. Apart from mapping endogenous peptides, their reliable identification in situ still remains challenging and will be discussed as well.

  2. Biomarker discovery for kidney diseases by mass spectrometry. (United States)

    Niwa, Toshimitsu


    By the development of soft ionization such as matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI), mass spectrometry (MS) has become an indispensable technique to analyze proteins. The combination of protein separation and identification such as two-dimensional gel electrophoresis and MS, surface-enhanced laser desorption/ionization-MS, liquid chromatography/MS, and capillary electrophoresis/MS has been successfully applied for proteome analysis of urine and plasma to discover biomarkers of kidney diseases. Some urinary proteins and their proteolytic fragments have been identified as biomarker candidates for kidney diseases. This article reviews recent advances in the application of proteomics using MS to discover biomarkers for kidney diseases.

  3. Acetonitrile Ion Suppression in Atmospheric Pressure Ionization Mass Spectrometry. (United States)

    Colizza, Kevin; Mahoney, Keira E; Yevdokimov, Alexander V; Smith, James L; Oxley, Jimmie C


    Efforts to analyze trace levels of cyclic peroxides by liquid chromatography/mass spectrometry gave evidence that acetonitrile suppressed ion formation. Further investigations extended this discovery to ketones, linear peroxides, esters, and possibly many other types of compounds, including triazole and menadione. Direct ionization suppression caused by acetonitrile was observed for multiple adduct types in both electrospray ionization and atmospheric pressure chemical ionization. The addition of only 2% acetonitrile significantly decreased the sensitivity of analyte response. Efforts to identify the mechanism were made using various nitriles. The ion suppression was reduced by substitution of an acetonitrile hydrogen with an electron-withdrawing group, but was exacerbated by electron-donating or steric groups adjacent to the nitrile. Although current theory does not explain this phenomenon, we propose that polar interactions between the various functionalities and the nitrile may be forming neutral aggregates that manifest as ionization suppression. Graphical Abstract ᅟ.

  4. Plant Phosphoproteomics: Analysis of Plasma Membrane Transporters by Mass Spectrometry

    DEFF Research Database (Denmark)

    Ye, Juanying; Rudashevskaya, Elena; Young, Clifford

    the phosphopeptides with optimized TiO2 and IMAC enrichment methods prior to MS analysis. We further investigated the global phosphorylation profile of the whole plant plasma membrane proteins using the combination of our recently established phosphopeptide enrichment method, Calcium phosphate precipitation...... phosphorylation. Due to the low abundance of phosphoprotein, the specific enrichment prior to MS analysis is necessary. Plant proton pump (H+-ATPase) is an enzyme controls the major transport processes in the plant, such as root nutrient uptake. Moreover, this pump has been proposed to be involved in other......  Phosphorylation is a key regulatory factor in all aspects of eukaryotic biology including the regulation of plant membrane-bound transport proteins. To date, mass spectrometry (MS) has been introduced as powerful technology for study of post translational modifications (PTMs), including protein...

  5. Electrospray Ionisation Mass Spectrometry: Principles and Clinical Applications (United States)

    Ho, CS; Lam, CWK; Chan, MHM; Cheung, RCK; Law, LK; Lit, LCW; Ng, KF; Suen, MWM; Tai, HL


    This mini-review provides a general understanding of electrospray ionisation mass spectrometry (ESI-MS) which has become an increasingly important technique in the clinical laboratory for structural study or quantitative measurement of metabolites in a complex biological sample. The first part of the review explains the electrospray ionisation process, design of mass spectrometers with separation capability, characteristics of the mass spectrum, and practical considerations in quantitative analysis. The second part then focuses on some clinical applications. The capability of ESI-tandem-MS in measuring bio-molecules sharing similar molecular structures makes it particularly useful in screening for inborn errors of amino acid, fatty acid, purine, pyrimidine metabolism and diagnosis of galactosaemia and peroxisomal disorders. Electrospray ionisation is also efficient in generating cluster ions for structural elucidation of macromolecules. This has fostered a new and improved approach (vs electrophoresis) for identification and quantification of haemoglobin variants. With the understanding of glycohaemoglobin structure, an IFCC reference method for glycohaemoglobin assay has been established using ESI-MS. It represents a significant advancement for the standardisation of HbA1c in diabetic monitoring. With its other applications such as in therapeutic drug monitoring, ESI-MS will continue to exert an important influence in the future development and organisation of the clinical laboratory service. PMID:18568044

  6. Detection of bio-signature by microscopy and mass spectrometry (United States)

    Tulej, M.; Wiesendanger, R.; Neuland, M., B.; Meyer, S.; Wurz, P.; Neubeck, A.; Ivarsson, M.; Riedo, V.; Moreno-Garcia, P.; Riedo, A.; Knopp, G.


    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.

  7. Fast atom bombardment tandem mass spectrometry of carotenoids

    Energy Technology Data Exchange (ETDEWEB)

    van Breeman, R.B. [Univ. of Illinois, Chicago, IL (United States); Schmitz, H.H.; Schwartz, S.J. [North Carolina State Univ., Raleigh, NC (United States)


    Positive ion fast atom bombardment (FAB) tandem mass spectrometry (MS-MS) using a double-focusing mass spectrometer with linked scanning at constant B/E and high-energy collisionally activated dissociation (CAD) was used to differentiate 17 different cartenoids, including {beta}-apo-8{prime}- carotenal, astaxanthin, {alpha}-carotene, {beta}-carotene, {gamma}-carotene, {zeta}-carotene, canthaxanthin, {beta}-cryptoxanthin, isozeaxanthin bis (pelargonate), neoxanthin, neurosporene, nonaprene, lutein, lycopene, phytoene, phytofluene, and zeaxanthin. The carotenoids were either synthetic or isolated from plant tissues. The use of FAB ionization minimized degradation or rearrangement of the carotenoid structures due to the inherent thermal instability generally ascribed to these compounds. Instead of protonated molecules, both polar xanthophylls and nonpolar carotenes formed molecular ions, M{sup {center_dot}+}, during FAB ionization. Following collisionally activated dissociation, fragment ions of selected molecular ion precursors showed structural features indicative of the presence of hydroxyl groups, ring systems, ester groups, and aldehyde groups and the extent of aliphatic polyene conjugation. The fragmentation patterns observed in the mass spectra herein may be used as a reference for the structural determination of carotenoids isolated from plant and animal tissues. 18 refs., 4 figs.

  8. DNA sequencing using biotinylated dideoxynucleotides and mass spectrometry (United States)

    Edwards, John R.; Itagaki, Yasuhiro; Ju, Jingyue


    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MS) has been explored widely for DNA sequencing. The major requirement for this method is that the DNA sequencing fragments must be free from alkaline and alkaline earth salts as well as other contaminants for accurately measuring the masses of the DNA fragments. We report here the development of a novel MS DNA sequencing method that generates Sanger-sequencing fragments in one tube using biotinylated dideoxynucleotides. The DNA sequencing fragments that carry a biotin at the 3′-end are made free from salts and other components in the sequencing reaction by capture with streptavidin-coated magnetic beads. Only correctly terminated biotinylated DNA fragments are subsequently released and loaded onto a mass spectrometer to obtain accurate DNA sequencing data. Compared with gel electrophoresis-based sequencing systems, MS produces a very high resolution of DNA-sequencing fragments, fast separation on microsecond time scales, and completely eliminates the compressions associated with gel electrophoresis. The high resolution of MS allows accurate mutation and heterozygote detection. This optimized solid-phase DNA-sequencing chemistry plus future improvements in detector sensitivity for large DNA fragments in MS instrumentation will further improve MS for DNA sequencing. PMID:11691941

  9. Cloud parallel processing of tandem mass spectrometry based proteomics data. (United States)

    Mohammed, Yassene; Mostovenko, Ekaterina; Henneman, Alex A; Marissen, Rob J; Deelder, André M; Palmblad, Magnus


    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.

  10. Combinatorial Labeling Method for Improving Peptide Fragmentation in Mass Spectrometry (United States)

    Kuchibhotla, Bhanuramanand; Kola, Sankara Rao; Medicherla, Jagannadham V.; Cherukuvada, Swamy V.; Dhople, Vishnu M.; Nalam, Madhusudhana Rao


    Annotation of peptide sequence from tandem mass spectra constitutes the central step of mass spectrometry-based proteomics. Peptide mass spectra are obtained upon gas-phase fragmentation. Identification of the protein from a set of experimental peptide spectral matches is usually referred as protein inference. Occurrence and intensity of these fragment ions in the MS/MS spectra are dependent on many factors such as amino acid composition, peptide basicity, activation mode, protease, etc. Particularly, chemical derivatizations of peptides were known to alter their fragmentation. In this study, the influence of acetylation, guanidinylation, and their combination on peptide fragmentation was assessed initially on a lipase (LipA) from Bacillus subtilis followed by a bovine six protein mix digest. The dual modification resulted in improved fragment ion occurrence and intensity changes, and this resulted in the equivalent representation of b- and y-type fragment ions in an ion trap MS/MS spectrum. The improved representation has allowed us to accurately annotate the peptide sequences de novo. Dual labeling has significantly reduced the false positive protein identifications in standard bovine six peptide digest. Our study suggests that the combinatorial labeling of peptides is a useful method to validate protein identifications for high confidence protein inference. [Figure not available: see fulltext.

  11. Silver Coating for High-Mass-Accuracy Imaging Mass Spectrometry of Fingerprints on Nanostructured Silicon. (United States)

    Guinan, Taryn M; Gustafsson, Ove J R; McPhee, Gordon; Kobus, Hilton; Voelcker, Nicolas H


    Nanostructure imaging mass spectrometry (NIMS) using porous silicon (pSi) is a key technique for molecular imaging of exogenous and endogenous low molecular weight compounds from fingerprints. However, high-mass-accuracy NIMS can be difficult to achieve as time-of-flight (ToF) mass analyzers, which dominate the field, cannot sufficiently compensate for shifts in measured m/z values. Here, we show internal recalibration using a thin layer of silver (Ag) sputter-coated onto functionalized pSi substrates. NIMS peaks for several previously reported fingerprint components were selected and mass accuracy was compared to theoretical values. Mass accuracy was improved by more than an order of magnitude in several cases. This straightforward method should form part of the standard guidelines for NIMS studies for spatial characterization of small molecules.

  12. Paper-Based Electrochemical Cell Coupled to Mass Spectrometry. (United States)

    Liu, Yao-Min; Perry, Richard H


    On-line coupling of electrochemistry (EC) to mass spectrometry (MS) is a powerful approach for identifying intermediates and products of EC reactions in situ. In addition, EC transformations have been used to increase ionization efficiency and derivatize analytes prior to MS, improving sensitivity and chemical specificity. Recently, there has been significant interest in developing paper-based electroanalytical devices as they offer convenience, low cost, versatility, and simplicity. This report describes the development of tubular and planar paper-based electrochemical cells (P-EC) coupled to sonic spray ionization (SSI) mass spectrometry (P-EC/SSI-MS). The EC cells are composed of paper sandwiched between two mesh stainless steel electrodes. Analytes and reagents can be added directly to the paper substrate along with electrolyte, or delivered via the SSI microdroplet spray. The EC cells are decoupled from the SSI source, allowing independent control of electrical and chemical parameters. We utilized P-EC/SSI-MS to characterize various EC reactions such as oxidations of cysteine, dopamine, polycyclic aromatic hydrocarbons, and diphenyl sulfide. Our results show that P-EC/SSI-MS has the ability to increase ionization efficiency, to perform online EC transformations, and to capture intermediates of EC reactions with a response time on the order of hundreds of milliseconds. The short response time allowed detection of a deprotonated diphenyl sulfide intermediate, which experimentally confirms a previously proposed mechanism for EC oxidation of diphenyl sulfide to pseudodimer sulfonium ion. This report introduces paper-based EC/MS via development of two device configurations (tubular and planar electrodes), as well as discusses the capabilities, performance, and limitations of the technique.

  13. ELISA reagent coverage evaluation by affinity purification tandem mass spectrometry. (United States)

    Henry, Scott M; Sutlief, Elissa; Salas-Solano, Oscar; Valliere-Douglass, John


    Host cell proteins (HCPs) must be adequately removed from recombinant therapeutics by downstream processing to ensure patient safety, product quality, and regulatory compliance. HCP process clearance is typically monitored by enzyme-linked immunosorbent assay (ELISA) using a polyclonal reagent. Recently, mass spectrometry (MS) has been used to identify specific HCP process impurities and monitor their clearance. Despite this capability, ELISA remains the preferred analytical approach due to its simplicity and throughput. There are, however, inherent difficulties reconciling the protein-centric results of MS characterization with ELISA, or providing assurance that ELISA has acceptable coverage against all process-specific HCP impurities that could pose safety or efficacy risks. Here, we describe efficient determination of ELISA reagent coverage by proteomic analysis following affinity purification with a polyclonal anti-HCP reagent (AP-MS). The resulting HCP identifications can be compared with the actual downstream process impurities for a given process to enable a highly focused assessment of ELISA reagent suitability. We illustrate the utility of this approach by performing coverage evaluation of an anti-HCP polyclonal against both an HCP immunogen and the downstream HCP impurities identified in a therapeutic monoclonal antibody after Protein A purification. The overall goal is to strategically implement affinity-based mass spectrometry as part of a holistic framework for evaluating HCP process clearance, ELISA reagent coverage, and process clearance risks. We envision coverage analysis by AP-MS will further enable a framework for HCP impurity analysis driven by characterization of actual product-specific process impurities, complimenting analytical methods centered on consideration of the total host cell proteome.

  14. Determination of mercury in hair: Comparison between gold amalgamation-atomic absorption spectrometry and mass spectrometry. (United States)

    Domanico, Francesco; Forte, Giovanni; Majorani, Costanza; Senofonte, Oreste; Petrucci, Francesco; Pezzi, Vincenzo; Alimonti, Alessandro


    Mercury is a heavy metal that causes serious health problems in exposed subjects. The most toxic form, i.e., methylmercury (MeHg), is mostly excreted through human hair. Numerous analytical methods are available for total Hg analysis in human hair, including cold vapour atomic fluorescence spectrometry (CV-AFS), inductively coupled plasma mass spectrometry (ICP-MS) and thermal decomposition amalgamation atomic absorption spectrometry (TDA-AAS). The aim of the study was to compare the TDA-AAS with the ICP-MS in the Hg quantification in human hair. After the washing procedure to minimize the external contamination, from each hair sample two aliquots were taken; the first was used for direct analysis of Hg by TDA-AAS and the second was digested for Hg determination by the ICP-MS. Results indicated that the two data sets were fully comparable (median; TDA-AAS, 475ngg -1 ; ICP-MS, 437ngg -1 ) and were not statistically different (Mann-Whitney test; p=0.44). The two techniques presented results with a good coefficient of correlation (r=0.94) despite different operative ranges and method limits. Both techniques satisfied internal performance requirements and the parameters for method validation resulting sensitive, precise and reliable. Finally, the use of the TDA-AAS can be considered instead of the ICP-MS in hair analysis in order to reduce sample manipulation with minor risk of contamination, less time consuming due to the absence of the digestion step and cheaper analyses. Copyright © 2016 Elsevier GmbH. All rights reserved.

  15. Calculation of partial isotope incorporation into peptides measured by mass spectrometry

    Directory of Open Access Journals (Sweden)

    Harms Hauke


    Full Text Available Abstract Background Stable isotope probing (SIP technique was developed to link function, structure and activity of microbial cultures metabolizing carbon and nitrogen containing substrates to synthesize their biomass. Currently, available methods are restricted solely to the estimation of fully saturated heavy stable isotope incorporation and convenient methods with sufficient accuracy are still missing. However in order to track carbon fluxes in microbial communities new methods are required that allow the calculation of partial incorporation into biomolecules. Results In this study, we use the characteristics of the so-called 'half decimal place rule' (HDPR in order to accurately calculate the partial13C incorporation in peptides from enzymatic digested proteins. Due to the clade-crossing universality of proteins within bacteria, any available high-resolution mass spectrometry generated dataset consisting of tryptically-digested peptides can be used as reference. We used a freely available peptide mass dataset from Mycobacterium tuberculosis consisting of 315,579 entries. From this the error of estimated versus known heavy stable isotope incorporation from an increasing number of randomly drawn peptide sub-samples (100 times each; no repetition was calculated. To acquire an estimated incorporation error of less than 5 atom %, about 100 peptide masses were needed. Finally, for testing the general applicability of our method, peptide masses of tryptically digested proteins from Pseudomonas putida ML2 grown on labeled substrate of various known concentrations were used and13C isotopic incorporation was successfully predicted. An easy-to-use script 1 was further developed to guide users through the calculation procedure for their own data series. Conclusion Our method is valuable for estimating13C incorporation into peptides/proteins accurately and with high sensitivity. Generally, our method holds promise for wider applications in qualitative

  16. Examining the Influence of Phosphorylation on Peptide Ion Structure by Ion Mobility Spectrometry-Mass Spectrometry (United States)

    Glover, Matthew S.; Dilger, Jonathan M.; Acton, Matthew D.; Arnold, Randy J.; Radivojac, Predrag; Clemmer, David E.


    Ion mobility spectrometry-mass spectrometry (IMS-MS) techniques are used to study the general effects of phosphorylation on peptide structure. Cross sections for a library of 66 singly phosphorylated peptide ions from 33 pairs of positional isomers, and unmodified analogues were measured. Intrinsic size parameters (ISPs) derived from these measurements yield calculated collision cross sections for 85% of these phosphopeptide sequences that are within ±2.5% of experimental values. The average ISP for the phosphoryl group (0.64 ± 0.05) suggests that in general this moiety forms intramolecular interactions with the neighboring residues and peptide backbone, resulting in relatively compact structures. We assess the capability of ion mobility to separate positional isomers (i.e., peptide sequences that differ only in the location of the modification) and find that more than half of the isomeric pairs have >1% difference in collision cross section. Phosphorylation is also found to influence populations of structures that differ in the cis/ trans orientation of Xaa-Pro peptide bonds. Several sequences with phosphorylated Ser or Thr residues located N-terminally adjacent to Pro residues show fewer conformations compared to the unmodified sequences.

  17. Online deuterium hydrogen exchange and protein digestion coupled with ion mobility spectrometry and tandem mass spectrometry. (United States)

    Donohoe, Gregory C; Arndt, James R; Valentine, Stephen J


    Online deuterium hydrogen exchange (DHX) and pepsin digestion (PD) is demonstrated using drift tube ion mobility spectrometry (DTIMS) coupled with linear ion trap (LTQ) mass spectrometry (MS) with electron transfer dissociation (ETD) capabilities. DHX of deuterated ubiquitin, followed by subsequent quenching and digestion, is performed within ∼60 s, yielding 100% peptide sequence coverage. The high reproducibility of the IMS separation allows spectral feature matching between two-dimensional IMS-MS datasets (undeuterated and deuterated) without the need for dataset alignment. Extracted ion drift time distributions (XIDTDs) of deuterated peptic peptides are mobility-matched to corresponding XIDTDs of undeuterated peptic peptides that were identified using collision-induced dissociation (CID). Matching XIDTDs allows a straightforward identification and deuterium retention evaluation for labeled peptides. Aside from the mobility separation, the ion trapping capabilities of the LTQ, combined with ETD, are demonstrated to provide single-residue resolution. Deuterium retention for the c- series ions across residues M(1)-L(15) and N(25)-R(42) are in good agreement with the known secondary structural elements within ubiquitin.

  18. Oligosaccharide sequence determination using B/E linked field scanning or tandem mass spectrometry of phosphatidylethanolamine derivatives. (United States)

    Chai, W; Cashmore, G C; Stoll, M S; Gaskell, S J; Orkiszewski, R S; Lawson, A M


    Product ion mass spectral data of [M + H]+ ions of oligosaccharides, mainly tetra- and pentasaccharides, as their dipalmitoyl phosphatidylethanolamine derivatives were obtained using both liquid secondary ion mass spectrometry with B/E linked scanning and fast atom bombardment ionization with collision-induced dissociation/tandem mass spectrometry. Both methods give similar positive product ion spectra of equivalent high sensitivity (detection limits of approximately 50 pmol) that principally contain glycosidic cleavage ions retaining the reducing end of the molecule from which monosaccharide sequence can be deduced. A series of ions from fission of the phosphate ester bond together with glycosidic cleavage are present in the tandem mass spectra and B/E linked scan spectra when helium collision gas is used. Monosaccharide linkage position of isomeric molecules is reflected in the intensity of glycosidic fragmentation, without retention of the oxygen atom, with decreasing cleavage in the order 1-3 greater than 1-4 greater than 1-6 linkage. Fucose and N-acetylhexosamines show an increased degree of fragmentation over hexose sugars. The application of product ion spectra of derivatized oligosaccharides is demonstrated for characterizing mixed samples and also the acquisition of spectra directly from the silica surface of high-performance thin-layer chromatography plates.

  19. Understanding ligand effects in gold clusters using mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Grant E.; Laskin, Julia


    This review summarizes recent research on the influence of phosphine ligands on the size, stability, and reactivity of gold clusters synthesized in solution. Sub-nanometer clusters exhibit size- and composition-dependent properties that are unique from those of larger nanoparticles. The highly tunable properties of clusters and their high surface-to-volume ratio make them promising candidates for a variety of technological applications. However, because “each-atom-counts” toward defining cluster properties it is critically important to develop robust synthesis methods to efficiently prepare clusters of predetermined size. For decades phosphines have been known to direct the size-selected synthesis of gold clusters. Despite the preparation of numerous species it is still not understood how different functional groups at phosphine centers affect the size and properties of gold clusters. Using electrospray ionization mass spectrometry (ESI-MS) it is possible to characterize the effect of ligand substitution on the distribution of clusters formed in solution at defined reaction conditions. In addition, ligand exchange reactions on preformed clusters may be monitored using ESI-MS. Collision induced dissociation (CID) may also be employed to obtain qualitative insight into the fragmentation of mixed ligand clusters and the relative binding energies of differently substituted phosphines. Quantitative ligand binding energies and cluster stability may be determined employing surface induced dissociation (SID) in a custom-built Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR-MS). Rice-Ramsperger-Kassel-Marcus (RRKM) based modeling of the SID data allows dissociation energies and entropy values to be extracted that may be compared with the results of high-level theoretical calculations. The charge reduction and reactivity of atomically precise gold clusters, including partially ligated species generated in the gas-phase by in source CID, on well

  20. Understanding ligand effects in gold clusters using mass spectrometry. (United States)

    Johnson, Grant E; Laskin, Julia


    This review summarizes recent research on the influence of phosphine ligands on the size, stability, and reactivity of gold clusters synthesized in solution. Sub-nanometer clusters exhibit size- and composition-dependent properties that are unique from those of larger nanoparticles. The highly tunable properties of clusters and their high surface-to-volume ratio make them promising candidates for a variety of technological applications. However, because "each-atom-counts" toward defining cluster properties it is critically important to develop robust synthesis methods to efficiently prepare clusters of predetermined size. For decades phosphines have been known to direct the size-selected synthesis of gold clusters. Despite the preparation of numerous species it is still not understood how different functional groups at phosphine centers affect the size and properties of gold clusters. Using electrospray ionization mass spectrometry (ESI-MS) it is possible to characterize the effect of ligand substitution on the distribution of clusters formed in solution at defined reaction conditions. In addition, ligand exchange reactions on preformed clusters may be monitored using ESI-MS. Collision induced dissociation (CID) may also be employed to obtain qualitative insight into the fragmentation of mixed ligand clusters and the relative binding energies of differently substituted phosphines. Quantitative ligand binding energies and cluster stability may be determined employing surface induced dissociation (SID) in a custom-built Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR-MS). Rice-Ramsperger-Kassel-Marcus (RRKM) based modeling of the SID data allows dissociation energies and entropy values to be extracted. The charge reduction and reactivity of atomically precise gold clusters, including partially ligated species generated in the gas-phase by in source CID, on well-defined surfaces may be explored using ion soft landing (SL) in a custom

  1. Preparation of Single Cells for Imaging Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Berman, E S; Fortson, S L; Kulp, K S; Checchi, K D; Wu, L; Felton, J S; Wu, K J


    Characterizing chemical changes within single cells is important for determining fundamental mechanisms of biological processes that will lead to new biological insights and improved disease understanding. Imaging biological systems with mass spectrometry (MS) has gained popularity in recent years as a method for creating precise chemical maps of biological samples. In order to obtain high-quality mass spectral images that provide relevant molecular information about individual cells, samples must be prepared so that salts and other cell-culture components are removed from the cell surface and the cell contents are rendered accessible to the desorption beam. We have designed a cellular preparation protocol for imaging MS that preserves the cellular contents for investigation and removes the majority of the interfering species from the extracellular matrix. Using this method, we obtain excellent imaging results and reproducibility in three diverse cell types: MCF7 human breast cancer cells, Madin-Darby canine kidney (MDCK) cells, and NIH/3T3 mouse fibroblasts. This preparation technique allows routine imaging MS analysis of cultured cells, allowing for any number of experiments aimed at furthering scientific understanding of molecular processes within individual cells.

  2. Mass spectrometry for the discovery of biomarkers of sepsis. (United States)

    Ludwig, Katelyn R; Hummon, Amanda B


    Sepsis is a serious medical condition that occurs in 30% of patients in intensive care units (ICUs). Early detection of sepsis is key to prevent its progression to severe sepsis and septic shock, which can cause organ failure and death. Diagnostic criteria for sepsis are nonspecific and hinder a timely diagnosis in patients. Therefore, there is currently a large effort to detect biomarkers that can aid physicians in the diagnosis and prognosis of sepsis. Mass spectrometry is often the method of choice to detect metabolomic and proteomic changes that occur during sepsis progression. These "omics" strategies allow for untargeted profiling of thousands of metabolites and proteins from human biological samples obtained from septic patients. Differential expression of or modifications to these metabolites and proteins can provide a more reliable source of diagnostic biomarkers for sepsis. Here, we focus on the current knowledge of biomarkers of sepsis and discuss the various mass spectrometric technologies used in their detection. We consider studies of the metabolome and proteome and summarize information regarding potential biomarkers in both general and neonatal sepsis.

  3. Geoporphyrin analysis using electrospray ionization-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Van Berkel, G.J.; Quinones, M.A.; Quirke, J.M.E. (Oak Ridge National Laboratory, Oak Ridge, TN (USA). Analytical Chemistry Division)

    The utility of electrospray ionization combined with mass spectrometry (ES-MS) for the analysis of free-base, nickel and vanadyl geoporphyrins is demonstrated. In positive ion mode, free-base alkyl-substituted porphyrins are detected as the protonated molecule, (M + H)[sup +], while the nickel and vanadyl chelates of these same porphyrins are observed as their radical cations, M[sup .+], as is chlorophyll a. Detection of free-base octaethylporphyrin (OEP) using continuous infusion at 1-5 [mu]L/min required sampling as little as 1 fmol of material, while at these same flow rates 18 fmol of OEP could be detected via flow injection. Detection of 500 fmol of mesoporphyrin IX dimethyl ester injected is demonstrated using on-line reverse-phase microbore-HPLC at a solvent flow rate of 40 [mu]L/min. ES-MS is shown to be well-suited for geoporphyrin molecular weight and carbon number determination since no fragment ions are produced by this ionization process. Accuracy in determining the relative abundances of porphyrins within geoporphyrin mixtures is demonstrated using standard solutions containing known molar ratios of OEP and free-base etioporphyrin-III (etio-III) and a total free-base porphyrin mixture isolated from Gilsonite bitumen. On-line separation/mass spectrometric detection of free-base and nickel geoporphyrin mixtures using reverse-phase microbore-HPLC/ES/MS is demonstrated with Gilsonite porphyrins. 51 refs., 11 figs.

  4. Coupling of ultrafast LC with mass spectrometry by DESI. (United States)

    Cai, Yi; Liu, Yong; Helmy, Roy; Chen, Hao


    Recently we reported a desorption electrospray ionization (DESI) interface to combine liquid chromatography (LC) with mass spectrometry (MS) using a new LC eluent splitting strategy through a tiny orifice on LC capillary tube [J. Am. Soc. Mass Spectrom. 25, 286 (2014)]. The interface introduces negligible dead volume and back pressure, thereby allowing "near real-time" MS detection, fast LC elution, and online MS-directed purification. This study further evaluates the LC/DESI-MS performance with focus of using ultra-fast LC. Using a monolithic C18 column, metabolites in urine can be separated within 1.6 min and can be online collected for subsequent structure elucidation (e.g., by NMR, UV, IR) in a recovery yield up to 99%. Using a spray solvent with alkaline pH, negative ions could be directly generated for acidic analytes (e.g., ibuprofen) in acidic LC eluent by DESI, offering a novel protocol to realize "wrong-way around" ionization for LC/MS analysis. In addition, DESI-MS is found to be compatible with ultra-performance liquid chromatography (UPLC) for the first time.

  5. Mass spectrometry in the characterization of reactive metal alkoxides. (United States)

    Peruzzo, Valentina; Chiurato, Matteo Andrea; Favaro, Monica; Tomasin, Patrizia


    Metal alkoxides are metal-organic compounds characterized by the presence of MOC bonds (M = metal). Their chemistry seems to be, in principle, relatively simple but the number of possible reactant species arising as a consequence of their behavior is very remarkable. The physico-chemical properties of metal alkoxides are determined by many different parameters, the most important ones being the electronegativity of the metal, the ramification of the ligand, and the acidity of the corresponding alcohol. Their reactivity makes them suitable and versatile candidates for many applications, including homogeneous catalysis, synthesis of new ceramic materials through the sol-gel process and, recently, also for Cultural Heritage. Metal alkoxides are characterized by a strong tendency to give clusters and/or oligomers through oxo-bridges. Mass spectrometry has been successfully employed for the characterization of metal alkoxides in the gas-phase. Electron ionization (EI) allowed the assessment of the molecular weight and of the most relevant decomposition pathways giving information on the relative bond strength of differently substituted molecules. On the other hand, information on the reactivity in solution of these molecules have been obtained by electrospray ionization (ESI)-matrix assisted laser desorption ionization (MALDI) experiments performed on their reaction products. These data were relevant to investigate the sol-gel process. In this review, these aspects are described and the results obtained are critically evaluated. © 2016 Wiley Periodicals, Inc. Mass Spec Rev. © 2016 Wiley Periodicals, Inc.

  6. Applications of MALDI Mass Spectrometry in Clinical Chemistry. (United States)

    Duncan, Mark W; Nedelkov, Dobrin; Walsh, Ryan; Hattan, Stephen J


    MALDI-TOF mass spectrometry (MS) is set to make inroads into clinical chemistry because it offers advantages over other analytical platforms. These advantages include low acquisition and operating costs, ease of use, ruggedness, and high throughput. When coupled with innovative front-end strategies and applied to important clinical problems, it can deliver rapid, sensitive, and cost-effective assays. This review describes the general principles of MALDI-TOF MS, highlights the unique features of the platform, and discusses some practical methods based upon it. There is substantial potential for MALDI-TOF MS to make further inroads into clinical chemistry because of the selectivity of mass detection and its ability to independently quantify proteoforms. MALDI-TOF MS has already transformed the practice of clinical microbiology and this review illustrates how and why it is now set to play an increasingly important role in in vitro diagnostics in particular, and clinical chemistry in general. © 2015 American Association for Clinical Chemistry.

  7. Infrared laser ablation atmospheric pressure photoionization mass spectrometry. (United States)

    Vaikkinen, Anu; Shrestha, Bindesh; Kauppila, Tiina J; Vertes, Akos; Kostiainen, Risto


    In this paper we introduce laser ablation atmospheric pressure photoionization (LAAPPI), a novel atmospheric pressure ion source for mass spectrometry. In LAAPPI the analytes are ablated from water-rich solid samples or from aqueous solutions with an infrared (IR) laser running at 2.94 μm wavelength. Approximately 12 mm above the sample surface, the ablation plume is intercepted with an orthogonal hot solvent (e.g., toluene or anisole) jet, which is generated by a heated nebulizer microchip and directed toward the mass spectrometer inlet. The ablated analytes are desolvated and ionized in the gas-phase by atmospheric pressure photoionization using a 10 eV vacuum ultraviolet krypton discharge lamp. The effect of operational parameters and spray solvent on the performance of LAAPPI is studied. LAAPPI offers ~300 μm lateral resolution comparable to, e.g., matrix-assisted laser desorption ionization. In addition to polar compounds, LAAPPI efficiently ionizes neutral and nonpolar compounds. The bioanalytical application of the method is demonstrated by the direct LAAPPI analysis of rat brain tissue sections and sour orange (Citrus aurantium) leaves. © 2012 American Chemical Society

  8. Direct Detection of Biotinylated Proteins by Mass Spectrometry (United States)


    Mass spectrometric strategies to identify protein subpopulations involved in specific biological functions rely on covalently tagging biotin to proteins using various chemical modification methods. The biotin tag is primarily used for enrichment of the targeted subpopulation for subsequent mass spectrometry (MS) analysis. A limitation of these strategies is that MS analysis does not easily discriminate unlabeled contaminants from the labeled protein subpopulation under study. To solve this problem, we developed a flexible method that only relies on direct MS detection of biotin-tagged proteins called “Direct Detection of Biotin-containing Tags” (DiDBiT). Compared with conventional targeted proteomic strategies, DiDBiT improves direct detection of biotinylated proteins ∼200 fold. We show that DiDBiT is applicable to several protein labeling protocols in cell culture and in vivo using cell permeable NHS-biotin and incorporation of the noncanonical amino acid, azidohomoalanine (AHA), into newly synthesized proteins, followed by click chemistry tagging with biotin. We demonstrate that DiDBiT improves the direct detection of biotin-tagged newly synthesized peptides more than 20-fold compared to conventional methods. With the increased sensitivity afforded by DiDBiT, we demonstrate the MS detection of newly synthesized proteins labeled in vivo in the rodent nervous system with unprecedented temporal resolution as short as 3 h. PMID:25117199

  9. Screening of carnitine and biotin deficiencies on tandem mass spectrometry. (United States)

    Hagiwara, Shin-Ichiro; Kubota, Mitsuru; Nambu, Ryusuke; Kagimoto, Seiichi


    It is important to assess pediatric patients for nutritional deficiency when they are receiving specific interventions, such as enteral feeding. We focused on measurement of C0 and 3-hydroxyisovalerylcarnitine (C5-OH) with tandem mass spectrometry (MS/MS), which is performed as part of the newborn mass screening. The purpose of this study was to investigate the usefulness of MS/MS for screening carnitine and biotin deficiencies. Forty-two children (24 boys, 18 girls) were enrolled between December 2013 and December 2015. Blood tests, including measurement of serum free carnitine via the enzyme cycling method, and acylcarnitine analysis on MS/MS of dried blood spot (DBS), were performed for the evaluation of nutrition status. Median patient age was 2 years (range, 2 months-14 years). Mean serum free carnitine was 41.8 ± 19.2 μmol/L. In six of the 42 patients, serum free carnitine was 1.00 nmol/L. Therapy-resistant eczema was improved by treatment with additional biotin and a non-hydrolyzed formula. C0 and C5-OH, measured on MS/MS of DBS, were useful for screening carnitine and biotin deficiencies. © 2016 Japan Pediatric Society.

  10. Protein Glycation in Diabetes as Determined by Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Annunziata Lapolla


    Full Text Available Diabetes is a common endocrine disorder characterized by hyperglycemia leading to nonenzymatic glycation of proteins, responsible for chronic complications. The development of mass spectrometric techniques able to give highly specific and reliable results in proteome field is of wide interest for physicians, giving them new tools to monitor the disease progression and the possible complications related to diabetes, as well as the effectiveness of therapeutic treatments. This paper reports and discusses some of the data pertaining protein glycation in diabetic subjects obtained by matrix-assisted laser desorption ionization (MALDI mass spectrometry (MS. The preliminary studies carried out by in vitro protein glycation experiments show clear differences in molecular weight of glycated and unglycated proteins. Then, the attention was focused on plasma proteins human serum albumin (HSA and immunoglobulin G (IgG. Enzymatic degradation products of in vitro glycated HSA were studied in order to simulate the in vivo enzymatic digestion of glycated species by the immunological system leading to the highly reactive advanced glycation end-products (AGEs peptides. Further studies led to the evaluation of glycated Apo A-I and glycated haemoglobin levels. A different MALDI approach was employed for the identification of markers of disease in urine samples of healthy, diabetic, nephropathic, and diabetic-nephropathic subjects.

  11. Pharmacokinetic analysis of 14C-ursodiol in newborn infants using accelerator mass spectrometry. (United States)

    Gordi, Toufigh; Baillie, Rebecca; Vuong, Le T; Abidi, Saira; Dueker, Stephen; Vasquez, Herbert; Pegis, Priscilla; Hopper, Andrew O; Power, Gordon G; Blood, Arlin B


    Pharmacokinetic studies in the neonatal population are often limited by the small volume of blood that can be collected. The high sensitivity of (14) C-accelerator mass spectrometry (AMS) enables pharmacokinetic studies to be conducted with greatly reduced sample volumes. We demonstrated the utility of AMS in infants by studying the plasma pharmacokinetic behavior of nanogram doses of (14) C-ursodiol administered as a non-perturbing microdose or as a microtracer with therapeutic doses of non-labeled ursodiol in infants. Five non-cholestatic infants were administered 3 consecutive oral microdoses of (14) C-ursodiol: 8 ng (1.0 nCi), 26 ng (3.3 nCi), and 80 ng (10 nCi) 48 hours apart. Three additional infants with cholestasis were administered a single 80 ng (10.0 nCi) oral dose of (14) C-ursodiol together with a therapeutic dose of 40 mg/kg of non-labeled ursodiol. A pharmacokinetic model describing ursodiol concentrations was developed using nonlinear mixed-effects modeling. The pharmacokinetics of ursodiol in this pilot study were best described by a two-compartment model with first-order elimination. This study demonstrates the feasibility and utility of microdose and microtrace methodology in pediatric research. © 2014, The American College of Clinical Pharmacology.

  12. Preparation of Plant 41Ca Tracer Samples for Accelerator Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    ZHAO Qing-zhang1;JANG Ping-ping3;LIN De-yu4;YANG Xian-lin1;DOU Liang1;PANG Yi-jun1;WANG Xiao-ming1;ZHANG Hui1,5;YANG Xu-ran1;WU Shao-yong1;GAO Dong-sheng2;LI Ling2;WANG Lei2;SUN Ke-peng2;ZHOU Jun2;DONG Ke-jun1;HE Ming1


    Full Text Available Calcium plays an important role in the metabolism of plants and animals. In this paper, the preparation method of plant 41Ca for accelerator mass spectrometry (AMS measurement was developed for the first time in China. AMS, with its advantages of high sensitivity, small dose of radioactivity, high accuracy, large measuring range, and long tracer cycle, can be used to measure cosmogenic nuclide 41Ca , which has long half-life. The intensity of the beam in ion source is an important parameter for the sensitivity of AMS measurement. The high beam current can improve the sensitivity of AMS. The preparation methods of plant samples of 41Ca tracer were systematically studied to obtain high beam current using wet, dry and a combining method with wet and dry re-fluoride. A reliable preparation procedure of plant samples for 41Ca tracer and its optimization parameters were determined by testing beam currents of various samples and lay a foundation for the 41Ca-AMS technology at plant tracer applications.

  13. [Determination of gossypol in edible vegetable oil with high performance liquid chromatography-tandem mass spectrometry]. (United States)

    Zhang, Wenhua; Huang, Chaoqun; Xie, Wen; Shen, Li


    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of gossypol in edible vegetable oil. The sample was extracted with ethyl alcohol by vortex-excited oscillation. The extract was cleaned up by 0.22 microm filter membrane and centrifuged for 5 min at 4 000 r/min after standing in a fridge at 4 degrees C for 30 min. The compound was separated on a C18 column (100 mm x 2.1 mm, 3.5 microm) with acetonitrile and 1% (v/v) formic acid aqueous solution as mobile phase. The detection of gossypol was carried out by LC-MS/MS with positive electrospray ionization under multiple reaction monitoring (MRM) mode using external standard method. The limits of quantification (S/N > 10) of gossypol in edible vegetable oil was 1 mg/kg. The recoveries were from 87.4% to 100% at the spiked levels of 1, 2, 200 mg/kg of gossypol in edible vegetable oil with the relative standard deviations (RSDs) between 3.9% and 12.2%. The method, with high sensitivity, good precision and high recovery, was suitable for the confirmation and quantification of gossypol residue in edible vegetable oil.

  14. Quantitation of retinaldehyde in small biological samples using ultrahigh-performance liquid chromatography tandem mass spectrometry. (United States)

    Wang, Jinshan; Yoo, Hong Sik; Obrochta, Kristin M; Huang, Priscilla; Napoli, Joseph L


    We report an ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method to quantify all-trans-retinal in biological samples of limited size (15-35mg), which is especially advantageous for use with adipose. To facilitate recovery, retinal and the internal standard 3,4-didehydroretinal were derivatized in situ into their O-ethyloximes. UHPLC resolution combined with high sensitivity and specificity of MS/MS allowed quantification of retinal-O-ethyloximes with a 5-fmol lower limit of detection and a linear range from 5fmol to 1pmol. This assay revealed that extraocular concentrations of retinal range from approximately 2 to 40pmol/g in multiple tissues-the same range as all-trans-retinoic acid. All-trans-retinoic acid has high affinity (kd⩽0.4nM) for its nuclear receptors (RARα, -β, and -γ), whereas retinal has low (if any) affinity for these receptors, making it unlikely that these retinal concentrations would activate RAR. We also show that the copious amount of vitamin A used in chow diets increases retinal in adipose depots 2- to 5-fold relative to levels in adipose of mice fed a vitamin A-sufficient diet, as recommended for laboratory rodents. This assay also is proficient for quantifying conversion of retinol into retinal in vitro and, therefore, provides an efficient method to study metabolism of retinol in vivo and in vitro. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Food allergen detection by mass spectrometry: the role of systems biology. (United States)

    Croote, Derek; Quake, Stephen R


    Food allergy prevalence is rising worldwide, motivating the development of assays that can sensitively and reliably detect trace amounts of allergens in manufactured food. Mass spectrometry (MS) is a promising alternative to commonly employed antibody-based assays owing to its ability to quantify multiple proteins in complex matrices with high sensitivity. In this review, we discuss a targeted MS workflow for the quantitation of allergenic protein in food products that employs selected reaction monitoring (SRM). We highlight the aspects of SRM method development unique to allergen quantitation and identify opportunities for simplifying the process. One promising avenue identified through a comprehensive survey of published MS literature is the use of proteotypic peptides, which are peptides whose presence appears robust to variations in food matrix, sample preparation protocol, and MS instrumentation. We conclude that proteotypic peptides exist for a subset of allergenic milk, egg, and peanut proteins. For less studied allergens such as soy, wheat, fish, shellfish, and tree nuts, we offer guidance and tools for peptide selection and specificity verification as part of an interactive web database, the Allergen Peptide Browser ( With ongoing improvements in MS instrumentation, analysis software, and strategies for targeted quantitation, we expect an increasing role of MS as an analytical tool for ensuring regulatory compliance.

  16. Imaging Nicotine in Rat Brain Tissue by Use of Nanospray Desorption Electrospray Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lanekoff, Ingela T.; Thomas, Mathew; Carson, James P.; Smith, Jordan N.; Timchalk, Charles; Laskin, Julia


    Imaging mass spectrometry offers simultaneous detection of drugs, drug metabolites and endogenous substances in a single experiment. This is important when evaluating effects of a drug on a complex organ system such as the brain, where there is a need to understand how regional drug distribution impacts function. Nicotine is an addictive drug and its action in the brain is of high interest. Here we use nanospray desorption electrospray ionization, nano-DESI, imaging to discover the localization of nicotine in rat brain tissue after in vivo administration of nicotine. Nano-DESI is a new ambient technique that enables spatially-resolved analysis of tissue samples without special sample pretreatment. We demonstrate high sensitivity of nano-DESI imaging that enables detection of only 0.7 fmole nicotine per pixel in the complex brain matrix. Furthermore, by adding deuterated nicotine to the solvent, we examined how matrix effects, ion suppression, and normalization affect the observed nicotine distribution. Finally, we provide preliminary results suggesting that nicotine localizes to the hippocampal substructure called dentate gyrus.

  17. Changes of murine sperm phospholipid composition during epididymal maturation determined by MALDI-TOF mass spectrometry. (United States)

    Pyttel, S; Nimptsch, A; Böttger, J; Zschörnig, K; Jakop, U; Wegener, J; Müller, K; Paasch, U; Schiller, J


    After leaving the testis, spermatozoa undergo several important steps of biochemical maturation during the passage through the epididymis, increasing their motility and fertilizing ability. These changes comprise (among others) the modification of the phospholipid composition of the sperm membrane. This process is thought to be important for the achievement of motility and fertilizing capacity. The lipids of the sperm membrane are characterized by a significant content of unsaturated fatty acyl residues, resulting in a high sensitivity against oxidative stress. This is evidenced by the appearance of lysolipids, for example, lysophosphatidylcholine, which acts like a detergent and is normally present in only very small amounts in biological membranes. The epididymis represents a tubular system comprising three main parts (caput, corpus, and cauda), through which the spermatozoa are consecutively transported undergoing distinct maturation stages. Using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, we established three striking differences in the lipid composition of murine spermatozoa from the different epididymal regions: in comparison to the caput sperm, sperm from the cauda are characterized by (1) a higher degree of unsaturation (PC 18:0/22:5 and 18:0/22:6 vs. 18:0/20:4 and 18:0/18:1), (2) an enhanced plasmalogen content, and (3) an enhanced content of lysolipids. These changes are likely to be of physiological relevance and potentially useful as diagnostic markers of sperm maturation and acquisition of motility. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Mass Spectrometry of Synthetic Polysiloxanes: From Linear Models to Plasma Polymer Networks

    National Research Council Canada - National Science Library

    Fouquet, Thierry


    ...) for their mass analysis. Application of the fragmentation routes defined for polysiloxane standards turned the tandem mass spectrometry behavior of these newly soluble plasma oligomers into pieces of information to further...

  19. Integrative Mass Spectrometry Approaches to Monitor Protein Structures, Modifications, and Interactions

    NARCIS (Netherlands)

    Lössl, P.


    This thesis illustrates the current standing of mass spectrometry (MS) in molecular and structural biology. The primary aim of the herein described research is to facilitate protein characterization by combining mass spectrometric methods among each other and with complementary analytical

  20. Routine identification of Nocardia species by MALDI-TOF mass spectrometry

    NARCIS (Netherlands)

    Girard, V.; Mailler, S.; Polsinelli, S.; Jacob, D.; Saccomani, M.C.; Celliere, B.; Monnin, V.; Belkum, A. van; Hagen, F.; Meis, J.F.G.M.; Durand, G.


    We here show adequate species identification for bacterial isolates of the genus Nocardia spp. through VITEK mass spectrometry. Application of a specific sample preparation method in combination with a robust matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)

  1. Multidimensional chromatography coupled to mass spectrometry in analysing complex proteomics samples

    NARCIS (Netherlands)

    Horvatovich, Peter; Hoekman, Berend; Govorukhina, Natalia; Bischoff, Rainer

    Multidimensional chromatography coupled to mass spectrometry (LC(n)-MS) provides more separation power and an extended measured dynamic concentration range to analyse complex proteomics samples than one dimensional liquid chromatography coupled to mass spectrometry (1D-LC-MS). This review gives an

  2. Analysis of Chaperone Complexes by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

    NARCIS (Netherlands)

    Geels, R.B.J.


    Investigation of methodologies for analyses of noncovalently bound protein assemblies using Fourier transformation ion cyclotron resonance mass spectrometry (FT-ICR-MS) and quadrupole Time-of-Flight (qToF) mass spectrometry. Specifically, the co-chaperonins GroEL and gp31 are used to perform

  3. On-line microseparations with Fourier transform ion cyclotron resonance mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, J.H.; Hofstadler, S.A.; Zhao, Zhongxi; Gale, D.C.; Smith, R.D. [Pacific Northwest Lab., Richland, WA (United States)


    The combination of capillary electrophoresis (CE) with electrospray ionization mass spectrometry (ESI/MS) is a powerful bioanalytical tool. Accurate charge states are readily obtained through high resolution MS techniques such as Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. In this study, the authors examine the practical considerations that were necessary for successful on-line CE-ESI/FTICR MS.

  4. Test Sample for the Spatially Resolved Quantification of Illicit Drugs on Fingerprints Using Imaging Mass Spectrometry

    NARCIS (Netherlands)

    Muramoto, S.; Forbes, T.P.; van Asten, A.C.; Gillen, G.


    A novel test sample for the spatially resolved quantification of illicit drugs on the surface of a fingerprint using time-of-flight secondary ion mass spectrometry (ToF-SIMS) and desorption electrospray ionization mass spectrometry (DESI-MS) was demonstrated. Calibration curves relating the signal

  5. Following the Biochemical and Morphological Changes of Bacillus atrophaeus during Sporulation using Bioaerosol Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tobias, H J; Pitesky, M E; Fergenson, D P; Horn, J; Frank, M; Gard, E E


    The overall objective of this report is to develop a real-time single-particle mass spectrometry technique called Bio-Aerosol Mass Spectrometry (BAMS) in order to efficiently screen and identify bioaerosols and single cells of national security and public health concern.

  6. Low-Temperature Positive Secondary Ion Mass Spectrometry of Neat and Argon-Diluted Organic Solids

    NARCIS (Netherlands)

    Jonkman, Harry T.; Michl, Josef; King, Robert N.; Andrade, Joseph D.


    Secondary ion mass spectrometry of neat solid propane, n-pentane, benzene, toluene, and of propane imbedded in an argon matrix were observed at temperatures varying from 10 to 110 K and show fragmentation patterns similar to those known from ordinary electron impact mass spectrometry. The effects of

  7. Quantitation of Acrylamide in Foods by High-Resolution Mass Spectrometry

    NARCIS (Netherlands)

    Troise, A.D.; Fogliano, Vincenzo


    The use of liquid chromatography high-resolution mass spectrometry (LC-HRMS) and direct analysis real-time high-resolution mass spectrometry (DART-HRMS) defines a new scenario in the analysis of thermal-induced toxicants, such as acrylamide. Several factors contribute to the definition of the

  8. Simulation of Two Dimensional Electrophoresis and Tandem Mass Spectrometry for Teaching Proteomics (United States)

    Fisher, Amanda; Sekera, Emily; Payne, Jill; Craig, Paul


    In proteomics, complex mixtures of proteins are separated (usually by chromatography or electrophoresis) and identified by mass spectrometry. We have created 2DE Tandem MS, a computer program designed for use in the biochemistry, proteomics, or bioinformatics classroom. It contains two simulations--2D electrophoresis and tandem mass spectrometry.…

  9. Variability in Mass Spectrometry-based Quantification of Clinically Relevant Drug Transporters and Drug Metabolizing Enzymes

    NARCIS (Netherlands)

    Wegler, C.; Gaugaz, F.Z.; Andersson, T.B.; Wiśniewski, J.R.; Busch, D.; Gröer, C.; Oswald, S.; Norén, A.; Weiss, F.; Hammer, H.S.; Joos, T.O.; Poetz, O.; Achour, B.; Rostami-Hodjegan, A.; Steeg, E. van de; Wortelboer, H.M.; Artursson, P.


    Many different methods are used for mass-spectrometry-based protein quantification in pharmacokinetics and systems pharmacology. It has not been established to what extent the results from these various methods are comparable. Here, we compared six different mass spectrometry-based proteomics

  10. Quantitation of mycotoxins using direct analysis in real time (DART)-mass spectrometry (MS) (United States)

    Ambient ionization represents a new generation of mass spectrometry ion sources which is used for rapid ionization of small molecules under ambient conditions. The combination of ambient ionization and mass spectrometry allows analyzing multiple food samples with simple or no sample treatment, or in...


    NARCIS (Netherlands)


    Liquid chromatography-ionspray mass spectrometry was used to elucidate the structures of the decomposition products of salbutamol. The best sensitivity in mass spectrometry was achieved by using a mixture of acetonitrile and ammonium formate (10 mM, pH 3.3) as the mobile phase in liquid

  12. Advanced mass calibration and visualization for FT-ICR mass spectrometry imaging. (United States)

    Smith, Donald F; Kharchenko, Andriy; Konijnenburg, Marco; Klinkert, Ivo; Paša-Tolić, Ljiljana; Heeren, Ron M A


    Mass spectrometry imaging by Fourier transform ion cyclotron resonance (FT-ICR) yields hundreds of unique peaks, many of which cannot be resolved by lower performance mass spectrometers. The high mass accuracy and high mass resolving power allow confident identification of small molecules and lipids directly from biological tissue sections. Here, calibration strategies for FT-ICR MS imaging were investigated. Sub-parts-per-million mass accuracy is demonstrated over an entire tissue section. Ion abundance fluctuations are corrected by addition of total and relative ion abundances for a root-mean-square error of 0.158 ppm on 16,764 peaks. A new approach for visualization of FT-ICR MS imaging data at high resolution is presented. The "Mosaic Datacube" provides a flexible means to visualize the entire mass range at a mass spectral bin width of 0.001 Da. The high resolution Mosaic Datacube resolves spectral features not visible at lower bin widths, while retaining the high mass accuracy from the calibration methods discussed.

  13. Plasma Desorption Mass Spectrometry analysis of HCOOH ice

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, D.P.P.; Rocco, M.L.M. [Departamento de Fisico-Quimica, Instituto de Quimica, Universidade Federal do Rio de Janeiro, Cidade Universitaria, Ilha do Fundao, 21949-900 Rio de Janeiro, RJ (Brazil); Boechat-Roberty, H.M. [Observatorio do Valongo, Universidade Federal do Rio de Janeiro, Ladeira Pedro Antonio, 43, Centro, Rio de Janeiro, RJ (Brazil); Iza, P.; Martinez, R. [Departamento de Fisica, Pontificia Universidade Catolica do Rio de Janeiro, 22543-900 Rio de Janeiro (Brazil); Homem, M.G.P. [Laboratorio Nacional de Luz Sincrotron (LNLS), Box 6192, 13084-971 Campinas, SP (Brazil); Silveira, E.F. da [Departamento de Fisica, Pontificia Universidade Catolica do Rio de Janeiro, 22543-900 Rio de Janeiro (Brazil)], E-mail:


    Planetary magnetospheres, in which outer planet satellites orbit, are bombarded by energetic particles inducing chemical and physical changes in their icy surfaces. The existing condensed gases react to form new products, which then undergo thermal evolution from the natural day/night cycles of these satellites. Plasma irradiation of ice causes phase changes, e.g., water ice from crystalline to amorphous over short timescales. When ice is recrystallized by heating, the surface layers retain some disorder, which promote reactions among adsorbed molecules such as H{sub 2}O, CO{sub 2}, CH{sub 2}CO, HCOOH and theirs radiolysis products. In this work, chemical reactions involving formic acid condensed at 56 K are analyzed by using Plasma Desorption Mass Spectrometry-time-of-flight ({sup 252}Cf-PDMS-TOF). Mass spectra of positive and negative desorbed ions were obtained, giving information on the structure and abundance of the molecules on the ice; the expected cations and anions generated by the HCOOH dissociation have been observed. Furthermore, several series of cluster ions were also detected, all exhibiting the structure X{sub n}Y{sub m}R{sup {+-}}, where X and Y are the neutral ice molecules, such as HCOOH or H{sub 2}O, and R{sup {+-}} is either an atomic or a molecular ion, such as H{sup +}, H{sub 3}O{sup +} or COOH{sup -}. In general, the desorption yields of the observed positive and negative ions are characterized by a decreasing exponential function as the emitted ion mass increases; however, the (HCOOH){sub n}OH{sup -} series presents its maximum at n = 8.

  14. U-series dating using thermal ionisation mass spectrometry (TIMS)

    Energy Technology Data Exchange (ETDEWEB)

    McCulloch, M.T. [Australian National University, Canberra, ACT (Australia). Research School of Earth Science


    U-series dating is based on the decay of the two long-lived isotopes{sup 238}U({tau}{sub 1/2}=4.47 x 10{sup 9} years) and {sup 235}U ({tau}{sub 1/2} 0.7 x 10{sup 9} years). {sup 238}U and its intermediate daughter isotopes {sup 234}U ({tau}{sub 1/2} = 245.4 ka) and {sup 230}Th ({tau}{sub 1/2} = 75.4 ka) have been the main focus of recently developed mass spectrometric techniques (Edwards et al., 1987) while the other less frequently used decay chain is based on the decay {sup 235}U to {sup 231}Pa ({tau}{sub 1/2} = 32.8 ka). Both the {sup 238}U and {sup 235}U decay chains terminate at the stable isotopes {sup 206}Pb and {sup 207}Pb respectively. Thermal ionization mass spectrometry (TIMS) has a number of inherent advantages, mainly the ability to measure isotopic ratios at high precision on relatively small samples. In spite of these now obvious advantages, it is only since the mid-1980`s when Chen et al., (1986) made the first precise measurements of {sup 234}U and {sup 232}Th in seawater followed by Edwards et al., (1987) who made combined {sup 234}U-{sup 230}Th measurements, was the full potential of mass spectrometric methods first realised. Several examples are given to illustrate various aspects of TIMS U-series 9 refs., 3 figs.

  15. Fluconazole bioequivalence study: quantification by tandem mass spectrometry. (United States)

    Moraes, L A; Lerner, F E; Moraes, M E; Moraes, M O; Corso, G; De Nucci, G


    To develop a new method for quantifying fluoconazole in human plasma and to compare the bioavailability of two fluconazole capsule formulations, an open, randomized, two-period crossover study with a one-week washout interval was conducted in 24 healthy volunteers. Plasma samples were obtained up to 168 hours after drug administration and the serum fluconazole concentrations were analyzed using electrospray tandem mass spectrometry coupled to liquid chromatography using multiple reaction monitoring mode. The pharmacokinetic parameters obtained for fluconazole after the administration of each formulation included the Area under the curve (AUC)(0-168h), AUC(0-infinity), Cmax, Cmax/AUC(0-168h), Tmax, elimination rate constant (Ke), and half-life (T1/2). Within- and between-run imprecision was less than 2.3% and 8.2%, respectively. Inaccuracy within and between runs was -1.5% and -9.7%, respectively. The pharmacokinetic parameters for bioequivalence showed a normal distribution, and the variance of AUC(0-168h), AUC(0-infinity), and Cmax were homoscedastic. The geometric mean for the Fluconal/Zoltec (Fluconal; Libbs Farmacêutica Ltda, São Paulo, Brazil; Zoltec; Laboratórios Pfizer Ltda., São Paulo, Brazil) individual percent ratio was 94.9% for AUC(0-168h), 94.7% for AUC(0-infinity), 80.1% for Cmax, 102.6% for Ke, 97.5% for T1/2, and 0.93 for Tmax (arithmetic mean of individual differences). We have developed a method in which liquid chromatography is coupled with electrospray tandem mass spectrometry to improve the pharmacokinetic analysis of fluconazole. Because the 90% CI AUC is within the interval proposed for the Food and Drug Administration, we concluded that Fluconal is bioequivalent to Zoltec in terms of absorption. The CV was 27.5% for the Cmax parameter, indicating that fluconazole's absorption rate is highly variable. The European Union Regulatory Agency accepts an interval of 70-143%, and because the 90% CI for Cmax is within the interval proposed for

  16. Transition of Iodine Analysis to Accelerator Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    J. E. Delmore


    Funding was received from NA-22 to investigate transitioning iodine isotopic analyses to an accelerator mass spectrometry (AMS) system. The present method uses gas-phase chemistry followed by thermal ionization mass spectrometry (TIMS). It was anticipated that the AMS approach could provide comparable data, with improved background levels and superior sample throughput. An aqueous extraction method was developed for removal of iodine species from high-volume air filters. Ethanol and sodium hydroxide, plus heating and ultrasonic treatment, were used to successfully extract iodine from loaded high-volume air filters. Portions of the same filters were also processed in the traditional method and analyzed by TIMS for comparison. Aliquot parts of the aqueous extracts were analyzed by AMS at the Swiss Federal Institute of Technology. Idaho National Laboratory (INL) personnel visited several AMS laboratories in the US, Spain, and Switzerland. Experience with AMS systems from several manufacturers was gained, and relationships were developed with key personnel at the laboratories. Three batches of samples were analyzed in Switzerland, and one in Spain. Results show that the INL extraction method successfully extracted enough iodine from high-volume air filters to allow AMS analysis. Comparison of the AMS and TIMS data is very encouraging; while the TIMS showed about forty percent more atoms of 129I, the 129/127 ratios tracked each other very well between the two methods. The time required for analysis is greatly reduced for the aqueous extraction/AMS approach. For a hypothetical batch of thirty samples, the AMS methodology is about five times faster than the traditional gas-phase chemistry and TIMS analysis. As an additional benefit, background levels for the AMS method are about 1000 times lower than for TIMS. This results from the fundamental mechanisms of ionization in the AMS system and cleanup of molecular interferences. We showed that an aqueous extraction of high

  17. The relationship of high sensitivity C-reactive protein to percent body fat mass, body mass index, waist-to-hip ratio, and waist circumference in a Taiwanese population

    Directory of Open Access Journals (Sweden)

    Lin Wen-Yuan


    Full Text Available Abstract Background High-sensitivity C-reactive protein (hs-CRP is an easily measured inflammatory biomarker. This study compared the association of percent body fat mass (%FM, body mass index (BMI, waist circumference (WC, and waist-to-hip ratio (WHR with hs-CRP in a Taiwanese population. Methods A total of 1669 subjects aged 40-88 years were recruited in 2004 in a metropolitan city in Taiwan. The relationships between obesity indicators and a high level of hs-CRP were examined using multivariate logistic regression analysis. The upper quartile of the hs-CRP distributions was defined as the high category group. The areas under the curve (AUCs of the receiver operating characteristic curves were calculated for all obesity indicators to compare their relative ability to correctly classify subjects with a high level of hs-CRP. Results After multivariate adjustment, the odds ratio for %FM was the only significant indicator that was associated with a high level of hs-CRP in men (1.55, 95% CI: 1.07-2.25. All indicators were associated with a high level of hs-CRP in women. In men, the AUCs for %FM were significantly higher than those for BMI, WHR, and WC, when demographic and lifestyle behaviors were considered (p Conclusions Our study demonstrates that %FM is the only obesity indicator that is strongly associated with a high level of hs-CRP after adjusting for sociodemographic factors, lifestyle behaviors and components of metabolic syndrome in both genders in a Taiwanese population aged forty years and over. In men, %FM had the greatest ability to classify subjects with a high level of hs-CRP when only demographic and lifestyle behaviors were considered. Our study finding has important implications for the screening of obesity in community settings.

  18. A new approach to untargeted integration of high resolution liquid chromatography-mass spectrometry data. (United States)

    van der Kloet, Frans M; Hendriks, Margriet; Hankemeier, Thomas; Reijmers, Theo


    Because of its high sensitivity and specificity, hyphenated mass spectrometry has become the predominant method to detect and quantify metabolites present in bio-samples relevant for all sorts of life science studies being executed. In contrast to targeted methods that are dedicated to specific features, global profiling acquisition methods allow new unspecific metabolites to be analyzed. The challenge with these so-called untargeted methods is the proper and automated extraction and integration of features that could be of relevance. We propose a new algorithm that enables untargeted integration of samples that are measured with high resolution liquid chromatography-mass spectrometry (LC-MS). In contrast to other approaches limited user interaction is needed allowing also less experienced users to integrate their data. The large amount of single features that are found within a sample is combined to a smaller list of, compound-related, grouped feature-sets representative for that sample. These feature-sets allow for easier interpretation and identification and as important, easier matching over samples. We show that the automatic obtained integration results for a set of known target metabolites match those generated with vendor software but that at least 10 times more feature-sets are extracted as well. We demonstrate our approach using high resolution LC-MS data acquired for 128 samples on a lipidomics platform. The data was also processed in a targeted manner (with a combination of automatic and manual integration) using vendor software for a set of 174 targets. As our untargeted extraction procedure is run per sample and per mass trace the implementation of it is scalable. Because of the generic approach, we envision that this data extraction lipids method will be used in a targeted as well as untargeted analysis of many different kinds of TOF-MS data, even CE- and GC-MS data or MRM. The Matlab package is available for download on request and efforts are

  19. Ion source memory in {sup 36}Cl accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Pavetich, Stefan; Akhmadaliev, Shavkat; Merchel, Silke; Rugel, Georg [HZDR, Dresden (Germany); Arnold, Maurice; Aumaitre, Georges; Bourles, Didier; Martschini, Martin [ASTER, Aix-en-Provence (France); Buchriegler, Josef; Golser, Robin; Keddadouche, Karim; Steier, Peter [VERA, Vienna (Austria)


    Since the DREAMS (Dresden Accelerator Mass Spectrometry) facility went operational in 2011, constant effort was put into enabling routine measurements of long-lived radionuclides as {sup 10}Be, {sup 26}Al and {sup 41}Ca. For precise AMS-measurements of the volatile element Cl the key issue is the minimization of the long term memory effect. For this purpose one of the two original HVE sources was mechanically modified, allowing the usage of bigger cathodes with individual target apertures. Additionally a more open geometry was used to improve the vacuum level. To evaluate this improvement in comparison to other up-to-date ion sources, a small inter-laboratory comparison had been initiated. The long-term memory effect in the Cs sputter ion sources of the AMS facilities VERA, ASTER and DREAMS had been investigated by running samples of natural {sup 35}Cl/{sup 37}Cl-ratio and samples containing highly enriched {sup 35}Cl({sup 35}Cl/{sup 37}Cl > 500). Primary goals of the research are the time constants of the recovery from the contaminated sample ratio to the initial ratio of the sample and the level of the long-term memory effect in the sources.

  20. Integrated liquid chromatography-heated nebulizer microchip for mass spectrometry. (United States)

    Haapala, Markus; Saarela, Ville; Pól, Jaroslav; Kolari, Kai; Kotiaho, Tapio; Franssila, Sami; Kostiainen, Risto


    A new integrated microchip for liquid chromatography-mass spectrometry (LC-MS) is presented. The chip is made from bonded silicon and glass wafers with structures for a packed LC column channel, a micropillar frit, a channel for optional optical detection, and a heated vaporizer section etched in silicon and platinum heater elements on the glass cover. LC eluent is vaporized and mixed with nebulizer gas in the vaporizer section and the vapor is sprayed out from the chip. Nonpolar and polar analytes can be efficiently ionized in the gas phase by atmospheric pressure photoionization (APPI) as demonstrated with polycyclic aromatic hydrocarbons (PAHs) and selective androgen receptor modulators (SARMs). This is not achievable with present LC-MS chips, since they are based on electrospray ionization, which is not able to ionize nonpolar compounds efficiently. The preliminary quantitative performance of the new chip was evaluated in terms of limit of detection (down to 5 ng mL(-1)), linearity (r>0.999), and repeatability of signal response (RSD=2.6-4.0%) and retention time (RSD=0.3-0.5%) using APPI for ionization and PAHs as standard compounds. Determination of fluorescent compounds is demonstrated by using laser-induced fluorescence (LIF) for detection in the optical detection channel before the vaporizer section. 2010 Elsevier B.V. All rights reserved.

  1. Matrix Effects in Biological Mass Spectrometry Imaging: Identification and Compensation

    Energy Technology Data Exchange (ETDEWEB)

    Lanekoff, Ingela T.; Stevens, Susan; Stenzel-Poore, Mary; Laskin, Julia


    Matrix effects in mass spectrometry imaging (MSI) may affect the observed molecular distribution in chemical and biological systems. In this study, we introduce an experimental approach that efficiently compensates for matrix effects in nanospray desorption electrospray ionization (nano-DESI) MSI without introducing any complexity into the experimental protocol. We demonstrate compensation for matrix effects in nano-DESI MSI of phosphatidylcholine (PC) in normal and ischemic mouse brain tissue by doping the nano-DESI solvent with PC standards. Specifically, we use mouse brain tissue of a middle cerebral artery occlusion (MCAO) stroke model with an ischemic region localized to one hemisphere of the brain. Due to similar suppression in ionization of endogenous PC molecules extracted from the tissue and PC standards added to the solvent, matrix effects are eliminated by normalizing the intensity of the sodium and potassium adducts of endogenous PC to the intensity of the corresponding adduct of the PC standard. This approach efficiently compensates for signal variations resulting from differences in the local concentrations of sodium and potassium in tissue sections and from the complexity of the extracted analyte mixture derived from local variations in molecular composition.

  2. Uranium quantification in semen by inductively coupled plasma mass spectrometry. (United States)

    Todorov, Todor I; Ejnik, John W; Guandalini, Gustavo; Xu, Hanna; Hoover, Dennis; Anderson, Larry; Squibb, Katherine; McDiarmid, Melissa A; Centeno, Jose A


    In this study we report uranium analysis for human semen samples. Uranium quantification was performed by inductively coupled plasma mass spectrometry. No additives, such as chymotrypsin or bovine serum albumin, were used for semen liquefaction, as they showed significant uranium content. For method validation we spiked 2g aliquots of pooled control semen at three different levels of uranium: low at 5 pg/g, medium at 50 pg/g, and high at 1000 pg/g. The detection limit was determined to be 0.8 pg/g uranium in human semen. The data reproduced within 1.4-7% RSD and spike recoveries were 97-100%. The uranium level of the unspiked, pooled control semen was 2.9 pg/g of semen (n=10). In addition six semen samples from a cohort of Veterans exposed to depleted uranium (DU) in the 1991 Gulf War were analyzed with no knowledge of their exposure history. Uranium levels in the Veterans' semen samples ranged from undetectable (<0.8 pg/g) to 3350 pg/g. This wide concentration range for uranium in semen is consistent with known differences in current DU body burdens in these individuals, some of whom have retained embedded DU fragments. Published by Elsevier GmbH.

  3. Serum Biomarker Identification by Mass Spectrometry in Acute Aortic Dissection

    Directory of Open Access Journals (Sweden)

    Yong Ren


    Full Text Available Background/Aims: Aortic dissection (AD is also known as intramural hematoma. This study aimed to screen peripheral blood biomarkers of small molecule metabolites for AD using high-performance liquid chromatography-mass spectrometry (HPLC-MS. Methods: Sera from 25 healthy subjects, 25 patients with well-established AD, and 25 patients with well-established hypertension were investigated by HPLC-MS to detect metabolites, screen differentially expressed metabolites, and analyze metabolic pathways. Results: Twenty-six and four metabolites were significantly up- and down-regulated in the hypertensive patients compared with the healthy subjects; 165 metabolites were significantly up-regulated and 109 significantly down-regulated in the AD patients compared with the hypertensive patients. Of these metabolites, 35 were up-regulated and 105 down-regulated only in AD patients. The metabolites that were differentially expressed in AD are mainly involved in tryptophan, histidine, glycerophospholipid, ether lipid, and choline metabolic pathways. As AD alters the peripheral blood metabolome, analysis of peripheral blood metabolites can be used in auxiliary diagnosis of AD. Conclusion: Eight metabolites are potential biomarkers for AD, 3 of which were differentially expressed and can be used for auxiliary diagnosis of AD and evaluation of treatment effectiveness.

  4. Electrochemistry combined on-line with electrospray mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, F.; Berkel, G.J.V. [Oak Ridge National Lab., TN (United States)


    In this paper a variety of methods to couple electrochemistry on-line with electrospray mass spectrometry (EC/ES-MS) are presented, and the fundamental and analytical utility of this hybrid technique is illustrated. The major problems encountered in coupling EC and ES-MS are discussed, and means to overcome them are presented. Three types of electrochemical flow cells, viz., a thin-layer electrode flow-by cell, a tubular electrode flow-through cell, and a porous electrode flow-through cell, are discussed in regard to their suitability for this coupling. Methods for coupling each of these electrochemical cells on-line with ES-MS, either floated at or decoupled from the ES high voltage and controlled by a constant current supply, a constant potential supply, or a potentiostat are presented. Three applications are used to illustrate the utility and versatility of the EC/ES-MS combination: (1) the ionization of neutral analytes (i.e., perylene) for detection by ES-MS, (2) the study of the products of electrode reactions (i.e., nickel(II) octaethylporphyrin oxidation products), including relatively short-lived products (i.e., {Beta}-carotene oxidation products), and (3) the enhanced determination of metals (i.e., elemental silver) achieved by coupling anodic stripping voltammetry on-line with ES-MS. 52 refs., 6 figs.

  5. COPD Exacerbation Biomarkers Validated Using Multiple Reaction Monitoring Mass Spectrometry.

    Directory of Open Access Journals (Sweden)

    Janice M Leung

    Full Text Available Acute exacerbations of chronic obstructive pulmonary disease (AECOPD result in considerable morbidity and mortality. However, there are no objective biomarkers to diagnose AECOPD.We used multiple reaction monitoring mass spectrometry to quantify 129 distinct proteins in plasma samples from patients with COPD. This analytical approach was first performed in a biomarker cohort of patients hospitalized with AECOPD (Cohort A, n = 72. Proteins differentially expressed between AECOPD and convalescent states were chosen using a false discovery rate 1.2. Protein selection and classifier building were performed using an elastic net logistic regression model. The performance of the biomarker panel was then tested in two independent AECOPD cohorts (Cohort B, n = 37, and Cohort C, n = 109 using leave-pair-out cross-validation methods.Five proteins were identified distinguishing AECOPD and convalescent states in Cohort A. Biomarker scores derived from this model were significantly higher during AECOPD than in the convalescent state in the discovery cohort (p<0.001. The receiver operating characteristic cross-validation area under the curve (CV-AUC statistic was 0.73 in Cohort A, while in the replication cohorts the CV-AUC was 0.77 for Cohort B and 0.79 for Cohort C.A panel of five biomarkers shows promise in distinguishing AECOPD from convalescence and may provide the basis for a clinical blood test to diagnose AECOPD. Further validation in larger cohorts is necessary for future clinical translation.

  6. Improving Tritium Exposure Reconstructions Using Accelerator Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Love, A; Hunt, J; Knezovich, J


    Exposure reconstructions for radionuclides are inherently difficult. As a result, most reconstructions are based primarily on mathematical models of environmental fate and transport. These models can have large uncertainties, as important site-specific information is unknown, missing, or crudely estimated. Alternatively, surrogate environmental measurements of exposure can be used for site-specific reconstructions. In cases where environmental transport processes are complex, well-chosen environmental surrogates can have smaller exposure uncertainty than mathematical models. Because existing methodologies have significant limitations, the development or improvement of methodologies for reconstructing exposure from environmental measurements would provide important additional tools in assessing the health effects of chronic exposure. As an example, the direct measurement of tritium atoms by accelerator mass spectrometry (AMS) enables rapid low-activity tritium measurements from milligram-sized samples, which permit greater ease of sample collection, faster throughput, and increased spatial and/or temporal resolution. Tritium AMS was previously demonstrated for a tree growing on known levels of tritiated water and for trees exposed to atmospheric releases of tritiated water vapor. In these analyses, tritium levels were measured from milligram-sized samples with sample preparation times of a few days. Hundreds of samples were analyzed within a few months of sample collection and resulted in the reconstruction of spatial and temporal exposure from tritium releases.

  7. Computing fragmentation trees from metabolite multiple mass spectrometry data. (United States)

    Scheubert, Kerstin; Hufsky, Franziska; Rasche, Florian; Böcker, Sebastian


    Since metabolites cannot be predicted from the genome sequence, high-throughput de novo identification of small molecules is highly sought. Mass spectrometry (MS) in combination with a fragmentation technique is commonly used for this task. Unfortunately, automated analysis of such data is in its infancy. Recently, fragmentation trees have been proposed as an analysis tool for such data. Additional fragmentation steps (MS(n)) reveal more information about the molecule. We propose to use MS(n) data for the computation of fragmentation trees, and present the Colorful Subtree Closure problem to formalize this task: There, we search for a colorful subtree inside a vertex-colored graph, such that the weight of the transitive closure of the subtree is maximal. We give several negative results regarding the tractability and approximability of this and related problems. We then present an exact dynamic programming algorithm, which is parameterized by the number of colors in the graph and is swift in practice. Evaluation of our method on a dataset of 45 reference compounds showed that the quality of constructed fragmentation trees is improved by using MS(n) instead of MS² measurements.

  8. Laser desorption mass spectrometry for fast DNA analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.H.; Ch`ang, L.Y.; Taranenko, N.I.; Allman, S.L.; Tang, K.; Matteson, K.J.


    During the past few years, major effort has been directed toward developing mass spectrometry to measure biopolymers because of the great potential benefit to biomedical research. Hellenkamp and his co-workers were the first to report that large polypeptide molecules can be ionized and detected without significant fragmentation when a greater number of nicotinic acid molecules are used as a matrix. This method is now well known as matrix-assisted laser desorption/ionization (MALDI). Since then, various groups have reported measurements of very large proteins by MALDI. Reliable protein analysis by MALDI is more or less well established. However, the application of MALDI to nucleic acids analysis has been found to be much more difficult. Most research on the measurement of nucleic acid by MALDI were stimulated by the Human Genome Project. Up to now, the only method for reliable routine analysis of nucleic acid is gel electrophoresis. Different sizes of nucleic acids can be separated in gel medium when a high electric field is applied to the gel. However, the time needed to separate different sizes of DNA segments usually takes from several minutes to several hours. If MALDI can be successfully used for nucleic acids analysis, the analysis time can be reduced to less than I millisecond. In addition, no tagging with radioactive materials or chemical dyes is needed. In this work, we will review recent progress related to MALDI for DNA analysis.

  9. Laser mass spectrometry for DNA fingerprinting for forensic applications

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.H.; Tang, K.; Taranenko, N.I.; Allman, S.L.; Chang, L.Y.


    The application of DNA fingerprinting has become very broad in forensic analysis, patient identification, diagnostic medicine, and wildlife poaching, since every individual`s DNA structure is identical within all tissues of their body. DNA fingerprinting was initiated by the use of restriction fragment length polymorphisms (RFLP). In 1987, Nakamura et al. found that a variable number of tandem repeats (VNTR) often occurred in the alleles. The probability of different individuals having the same number of tandem repeats in several different alleles is very low. Thus, the identification of VNTR from genomic DNA became a very reliable method for identification of individuals. DNA fingerprinting is a reliable tool for forensic analysis. In DNA fingerprinting, knowledge of the sequence of tandem repeats and restriction endonuclease sites can provide the basis for identification. The major steps for conventional DNA fingerprinting include (1) specimen processing (2) amplification of selected DNA segments by PCR, and (3) gel electrophoresis to do the final DNA analysis. In this work we propose to use laser desorption mass spectrometry for fast DNA fingerprinting. The process and advantages are discussed.

  10. Mass spectrometry in clinical chemistry: the case of newborn screening. (United States)

    la Marca, Giancarlo


    Newborn screening (NBS) program is a complex and organized system consisting of family and personnel education, biochemical tests, confirmatory biochemical and genetic tests, diagnosis, therapy, and patient follow up. The program identifies treatable metabolic disorders possibly when asymptomatic by using dried blood spot (DBS). During the last 20 years tandem mass spectrometry (TMS) has become the leading technology in NBS programs demonstrating to be versatile, sensitive and specific. There is consistent evidence of benefits from NBS for many disorders detected by TMS as well as for congenital hypothyroidism, cystic fibrosis, congenital adrenal hyperplasia by immune-enzymatic methods. Real time PCR tests have more recently been proposed for the detection of some severe combined immunodeficiences (SCID) along with the use of TMS for ADA and PNP SCID; a first evaluation of their cost-benefit ratio is still ongoing. Avoiding false negative results by using specific biomarkers and reducing the false positive rate by using second tier tests, is fundamental for a successful NBS program. The fully integration of NBS and diagnostic laboratories with clinical service is crucial to have the best effectiveness in a comprehensive NBS system. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Improving tritium exposure reconstructions using accelerator mass spectrometry (United States)

    Hunt, J. R.; Vogel, J. S.; Knezovich, J. P.


    Direct measurement of tritium atoms by accelerator mass spectrometry (AMS) enables rapid low-activity tritium measurements from milligram-sized samples and permits greater ease of sample collection, faster throughput, and increased spatial and/or temporal resolution. Because existing methodologies for quantifying tritium have some significant limitations, the development of tritium AMS has allowed improvements in reconstructing tritium exposure concentrations from environmental measurements and provides an important additional tool in assessing the temporal and spatial distribution of chronic exposure. Tritium exposure reconstructions using AMS were previously demonstrated for a tree growing on known levels of tritiated water and for trees exposed to atmospheric releases of tritiated water vapor. In these analyses, tritium levels were measured from milligram-sized samples with sample preparation times of a few days. Hundreds of samples were analyzed within a few months of sample collection and resulted in the reconstruction of spatial and temporal exposure from tritium releases. Although the current quantification limit of tritium AMS is not adequate to determine natural environmental variations in tritium concentrations, it is expected to be sufficient for studies assessing possible health effects from chronic environmental tritium exposure. PMID:14735274

  12. 'Moringa oleifera: study of phenolics and glucosinolates by mass spectrometry'. (United States)

    Maldini, Mariateresa; Maksoud, Salwa A; Natella, Fausta; Montoro, Paola; Petretto, Giacomo Luigi; Foddai, Marzia; De Nicola, Gina Rosalinda; Chessa, Mario; Pintore, Giorgio


    Moringa oleifera is a medicinal plant and an excellent dietary source of micronutrients (vitamins and minerals) and health-promoting phytochemicals (phenolic compounds, glucosinolates and isothiocyanates). Glucosinolates and isothiocyanates are known to possess anti-carcinogenic and antioxidant effects and have attracted great interest from both toxicological and pharmacological points of view, as they are able to induce phase 2 detoxification enzymes and to inhibit phase 1 activation enzymes. Phenolic compounds possess antioxidant properties and may exert a preventative effect in regards to the development of chronic degenerative diseases. The aim of this work was to assess the profile and the level of bioactive compounds in all parts of M. oleifera seedlings, by using different MS approaches. First, flow injection electrospray ionization mass spectrometry (FI-ESI-MS) fingerprinting techniques and chemometrics (PCA) were used to achieve the characterization of the different plant's organs in terms of profile of phenolic compounds and glucosinolates. Second, LC-MS and LC-MS/MS qualitative and quantitative methods were used for the identification and/or determination of phenolics and glucosinolates in M. oleifera. Copyright © 2014 John Wiley & Sons, Ltd.

  13. Microstructure synthesis control of biological polyhydroxyalkanoates with mass spectrometry (United States)

    Pederson, Erik Norman

    Polyhydroxyalkanoates (PHA's) are a class of biologically produced polymers, or plastic, that is synthesized by various microorganisms. PHA's are made from biorenewable resources and are fully biodegradable and biocompatible, making them an environmentally friendly green polymer. A method of incorporating polymer microstructure into the PHA synthesized in Ralstonia eutropha was developed. These microstructures were synthesized with polyhydroxybutyrate (PHB) and poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) as the polymer domains. To synthesize the PHB V copolymer, the additional presence of valerate was required. To control valerate substrate additions to the bioreactor, an off-gas mass spectrometry (MS) feedback control system was developed. Important process information including the cell physiology, growth kinetics, and product formation kinetics in the bioreactor was obtained with MS and used to control microstructure synthesis. The two polymer microstructures synthesized were core-shell granules and block copolymers. Block copolymers control the structure of the individual polymer chains while core-shell granules control the organization of many polymer chains. Both these microstructures result in properties unattainable by blending the two polymers together. The core-shell structures were synthesized with controlled domain thickness based on a developed model. Different block copolymers compositions were synthesized by varying the switching time of the substrate pulses responsible for block copolymer synthesis. The block copolymers were tested to determine their chemical properties and cast into films to determine the materials properties. These block copolymer films possessed new properties not achieved by copolymers or blends of the two polymers.

  14. Model for Quality Control of Allergen Products with Mass Spectrometry. (United States)

    Spiric, Jelena; Schulenborg, Thomas; Schwaben, Luisa; Engin, Anna M; Karas, Michael; Reuter, Andreas


    Birch pollen allergy is diagnosed and treated with aqueous extracts from birch pollen, which contain a mixture of allergens and nonallergenic proteins, including large numbers of closely related sequence variants, so-called iso-allergens of the major allergen, Bet v 1. The quality of therapeutic and diagnostic allergen products largely depends on the allergen and iso-allergen composition. Several biochemical methods are currently applied to detect and quantify allergens and to record protein profiles without differentiating between iso-allergens. Mass spectrometry (MS) may entirely replace these technologies, as it allows sequence specific identification and quantification of proteins and protein profiles including sequence variants in one run. However, the protein inference problem still hampers the automatic assignment of peptide sequences to proteins, consequently impeding the quantification of sequence variants. Therefore, the aim of the study was to set up semitargeted analyses of label-free MS data that allow unambiguous identification and quantification of birch pollen allergens and nonallergenic proteins. We combined data independent acquisition with manual assignment of predefined target sequences for quantification of iso-allergens and automatic quantification of other allergens and nonallergenic proteins. The quantitative data for birch pollen allergens and sequence variants of Bet v 1 were further confirmed by multiple reaction monitoring.

  15. Fast multi-blind modification search through tandem mass spectrometry. (United States)

    Na, Seungjin; Bandeira, Nuno; Paek, Eunok


    With great biological interest in post-translational modifications (PTMs), various approaches have been introduced to identify PTMs using MS/MS. Recent developments for PTM identification have focused on an unrestrictive approach that searches MS/MS spectra for all known and possibly even unknown types of PTMs at once. However, the resulting expanded search space requires much longer search time and also increases the number of false positives (incorrect identifications) and false negatives (missed true identifications), thus creating a bottleneck in high throughput analysis. Here we introduce MODa, a novel "multi-blind" spectral alignment algorithm that allows for fast unrestrictive PTM searches with no limitation on the number of modifications per peptide while featuring over an order of magnitude speedup in relation to existing approaches. We demonstrate the sensitivity of MODa on human shotgun proteomics data where it reveals multiple mutations, a wide range of modifications (including glycosylation), and evidence for several putative novel modifications. Based on the reported findings, we argue that the efficiency and sensitivity of MODa make it the first unrestrictive search tool with the potential to fully replace conventional restrictive identification of proteomics mass spectrometry data.

  16. Uranium quantification in semen by inductively coupled plasma mass spectrometry (United States)

    Todorov, Todor; Ejnik, John W.; Guandalini, Gustavo S.; Xu, Hanna; Hoover, Dennis; Anderson, Larry W.; Squibb, Katherine; McDiarmid, Melissa A.; Centeno, Jose A.


    In this study we report uranium analysis for human semen samples. Uranium quantification was performed by inductively coupled plasma mass spectrometry. No additives, such as chymotrypsin or bovine serum albumin, were used for semen liquefaction, as they showed significant uranium content. For method validation we spiked 2 g aliquots of pooled control semen at three different levels of uranium: low at 5 pg/g, medium at 50 pg/g, and high at 1000 pg/g. The detection limit was determined to be 0.8 pg/g uranium in human semen. The data reproduced within 1.4–7% RSD and spike recoveries were 97–100%. The uranium level of the unspiked, pooled control semen was 2.9 pg/g of semen (n = 10). In addition six semen samples from a cohort of Veterans exposed to depleted uranium (DU) in the 1991 Gulf War were analyzed with no knowledge of their exposure history. Uranium levels in the Veterans’ semen samples ranged from undetectable (<0.8 pg/g) to 3350 pg/g. This wide concentration range for uranium in semen is consistent with known differences in current DU body burdens in these individuals, some of whom have retained embedded DU fragments.

  17. Analytical Properties of Solid-substrate Electrospray Ionization Mass Spectrometry (United States)

    Hu, Bin; So, Pui-Kin; Yao, Zhong-Ping


    Conventional electrospray ionization mass spectrometry (ESI-MS) uses a capillary for sample loading and ionization. Along with the development of ambient ionization techniques, ESI-MS using noncapillary emitters has attracted more interest in recent years. Following our recent report on ESI-MS using wooden tips ( Anal. Chem. 83, 8201-8207 (2011)), the technique was further investigated and extended in this study. Our results revealed that the wooden tips could serve as a chromatographic column for separation of sample components. Sequential and exhaustive ionization was observed for proteins and salts on wooden tips with salts ionized sooner and proteins later. Nonconductive materials that contain microchannels/pores could be used as tips for ESI-MS analysis with sample solutions loaded to the sharp-ends only, since rapid diffusion of sample solutions by capillary action would enable the tips to become conductive. Tips of inert materials such as bamboo, fabrics, and sponge could be used for sample loading and ionization, while samples such as tissue, mushroom, and bone could form tips to induce ionization for direct analysis with application of a high voltage. [Figure not available: see fulltext.

  18. Supercharging with Trivalent Metal Ions in Native Mass Spectrometry (United States)

    Flick, Tawnya G.; Williams, Evan R.


    Addition of 1.0 mM LaCl3 to aqueous ammonium acetate solutions containing proteins in their folded native forms can result in a significant increase in the molecular ion charging obtained with electrospray ionization as a result of cation adduction. In combination with m-nitrobenzyl alcohol, molecular ion charge states that are greater than the number of basic sites in the protein can be produced from these native solutions, even for lysozyme, which is conformationally constrained by four intramolecular disulfide bonds. Circular dichroism spectroscopy indicates that the conformation of ubiquitin is not measurably affected with up to 1.0 M LaCl3, but ion mobility data indicate that the high charge states that are formed when 1.0 mM LaCl3 is present are more unfolded than the low charge states formed without this reagent. These and other results indicate that the increased charging is a result of La3+ preferentially adducting onto compact or more native-like conformers during ESI and the gas-phase ions subsequently unfolding as a result of increased Coulomb repulsion. Electron capture dissociation of these high charge-state ions formed from these native solutions results in comparable sequence coverage to that obtained for ions formed from denaturing solutions without supercharging reagents, making this method a potentially powerful tool for obtaining structural information in native mass spectrometry.

  19. Fast Multi-blind Modification Search through Tandem Mass Spectrometry* (United States)

    Na, Seungjin; Bandeira, Nuno; Paek, Eunok


    With great biological interest in post-translational modifications (PTMs), various approaches have been introduced to identify PTMs using MS/MS. Recent developments for PTM identification have focused on an unrestrictive approach that searches MS/MS spectra for all known and possibly even unknown types of PTMs at once. However, the resulting expanded search space requires much longer search time and also increases the number of false positives (incorrect identifications) and false negatives (missed true identifications), thus creating a bottleneck in high throughput analysis. Here we introduce MODa, a novel “multi-blind” spectral alignment algorithm that allows for fast unrestrictive PTM searches with no limitation on the number of modifications per peptide while featuring over an order of magnitude speedup in relation to existing approaches. We demonstrate the sensitivity of MODa on human shotgun proteomics data where it reveals multiple mutations, a wide range of modifications (including glycosylation), and evidence for several putative novel modifications. Based on the reported findings, we argue that the efficiency and sensitivity of MODa make it the first unrestrictive search tool with the potential to fully replace conventional restrictive identification of proteomics mass spectrometry data. PMID:22186716

  20. Detection of {sup 59}Ni by accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Persson, Per; Erlandsson, Bengt; Freimann, K.; Hellborg, R.; Stenstroem, K. [Lund Univ. (Sweden). Dept. of Nuclear Physics; Larsson, Ragnar [Lund Univ. (Sweden). Chemical Engineering II; Skog, G. [Lund Univ. (Sweden). Dept. of Quaternary Geology


    The aims of this project were to develop a method to measure the amount of {sup 59}Ni in stainless steel and to determine the detection limit for this method. {sup 59}Ni is produced by neutron activation in the construction material close to the core in a nuclear reactor and it is important to know the amount of {sup 59}Ni present as it governs the classification of the waste. If the amount of {sup 59}Ni is known at different locations in relation to the core, it is also possible to refine the calculation models of the neutron flux in the reactor. Accelerator mass spectrometry, an ultra-sensitive method for measuring small concentrations of radionuclides as well as stable nuclides, has been used in this investigation to determine the concentration of {sup 59}Ni (and thereby the activity) in stainless steel. As the cobalt content in stainless steel is the main contributor to the background in a measurement of {sup 59}Ni, a method for the chemical extraction of nickel from stainless steel, including a purification step to reduce the cobalt content in the sample, has been developed. The detection limit for {sup 59}Ni has been determined to 100{+-}30 Bq per gram nickel (100{+-}30 Bq/g) with the present status of the system 14 refs, 6 figs, 3 tabs

  1. Neurological analyses: focus on gangliosides and mass spectrometry. (United States)

    Zamfir, Alina D


    Gangliosides, sialylated glycosphingolipids, are particularly enriched in mammalian central nervous system where their expression is cell type-specific and changes particularly during brain development, maturation, aging, and diseases. For this reason, gangliosides are important diagnostic markers for various brain ailments, including primary and secondary brain tumors and neurodegenerative diseases. Among all biochemical and biophysical methods employed so far for ganglioside analysis, mass spectrometry (MS) emerged as one of the most reliable due to the sensitivity, accuracy, and speed of analysis as well as the possibility to characterize in details the molecular structure of the identified biomarkers.This chapter presents significant achievements of MS with either electrospray (ESI), chip-based ESI, or matrix-assisted laser desorption/ionization (MALDI) in the analysis of gangliosides in normal and diseased human brain. Specifically, the chapter assesses the MS contribution in determination of topospecificity, filogenetic, and brain development stage dependence of ganglioside composition and structure as well as in discovery of ganglioside markers in neurodegenerative/neurodevelopmental conditions, primary and secondary brain tumors. The highlighted accomplishments in characterization of novel structures associated to severe brain pathologies show that MS has real perspectives to become a routine method for early diagnosis and therapy based on this biomolecule class.

  2. Capillary electrophoresis-mass spectrometry for glycoscreening in biomedical research. (United States)

    Zamfir, Alina; Peter-Katalinić, Jasna


    Application of capillary electrophoresis (CE) in combination with mass spectrometry (MS) and tandem MS to glycoscreening in biomedical projects is highlighted. In the first part recent CE-MS experiments by sheath liquid CE and multiple stage MS are reported. Neutral and negatively charged N-glycan mixtures from ribonuclease B and fetuin, high-mannose type N-glycoforms, oligosaccharides from lipopolysaccharides (LPS) of Haemophilus influenzae, polysaccharides of Pseudomonas aeruginosa and Staphylococcus aureus were analyzed. A particular emphasis is devoted to the applicability of novel off- and on-line CE-MS and tandem MS methods for screening of proteoglycan-derived oligosaccharides, glycosaminoglycans (GAGs), such as hyaluronates from Streptococcus agalactiae, chondroitin/dermatan sulfates (CS/DS) from bovine aorta and human skin fibroblast decorin, and heparin/heparan sulfate (HS) from porcine and bovine mucosa. The performance of CE-MS/MS for identification of glycoforms in glycopeptides and glycoproteins is illustrated by experiments performed on complex mixtures from urine of patients suffering from a hereditary N-acetylhexosaminidase deficiency (Schindler's disease) and urine of patients suffering from cancer cachexia. For determination of glycosylation patterns in glycoproteins like enzymes and antibodies by CE/MS, both CE-matrix assisted laser desorption/ionization (MALDI) and CE-electrospray ionization (ESI)-MS were functional. Finally, the potential of CE-ESI-MS strategy in glycolipid analysis is demonstrated for gangliosides from bovine brain for which particular CE buffer conditions are required.

  3. Cold-spray ionization mass spectrometry: principle and applications. (United States)

    Yamaguchi, Kentaro


    A direct solution analysis method, cold-spray ionization (CSI) mass spectrometry (MS), a variant of electrospray (ESI) MS operating at low temperature (ca -80 to 10 degrees C), allows the facile and precise characterization of labile organic species, especially those in which non-covalent bonding interactions are prominent. We applied this method to investigations of the solution structures of many labile organic species, including unstable reagents and reaction intermediates, asymmetric catalysts, supramolecules and even primary biomolecules. Remarkable analytical results were obtained for highly ordered supramolecules using the CSI method. Whereas conventional ESI is not applicable to these compounds because of their instability to heat and/or air, CSI affords multiply charged molecular ions with many solvent molecules attached. Investigation of the constitution of Grignard reagents in solution is extremely challenging, but CSI-MS allowed us to identify one of the key structures in THF solution. Recently, this method was adopted for investigations of the solution structures of primary biomolecules such as nucleosides, amino acids, sugars and lipids, revealing singly charged Na(+) adducts of large clusters (chain structures), presumably linked by non-covalent interactions, including hydrogen bonding and/or hydrophobic interactions. The principle of the CSI method and applications of the method to a wide variety of labile organic species and primary biomolecules in solution are described. Copyright 2003 John Wiley & Sons, Ltd.

  4. Mapping the Small Molecule Interactome by Mass Spectrometry. (United States)

    Flaxman, Hope A; Woo, Christina M


    Mapping small molecule interactions throughout the proteome provides the critical structural basis for functional analysis of their impact on biochemistry. However, translation of mass spectrometry-based proteomics methods to directly profile the interaction between a small molecule and the whole proteome is challenging because of the substoichiometric nature of many interactions, the diversity of covalent and noncovalent interactions involved, and the subsequent computational complexity associated with their spectral assignment. Recent advances in chemical proteomics have begun fill this gap to provide a structural basis for the breadth of small molecule-protein interactions in the whole proteome. Innovations enabling direct characterization of the small molecule interactome include faster, more sensitive instrumentation coupled to chemical conjugation, enrichment, and labeling methods that facilitate detection and assignment. These methods have started to measure molecular interaction hotspots due to inherent differences in local amino acid reactivity and binding affinity throughout the proteome. Measurement of the small molecule interactome is producing structural insights and methods for probing and engineering protein biochemistry. Direct structural characterization of the small molecule interactome is a rapidly emerging area pushing new frontiers in biochemistry at the interface of small molecules and the proteome.

  5. Quantitation of soybean allergens using tandem mass spectrometry. (United States)

    Houston, Norma L; Lee, Dong-Gi; Stevenson, Severin E; Ladics, Gregory S; Bannon, Gary A; McClain, Scott; Privalle, Laura; Stagg, Nicola; Herouet-Guicheney, Corinne; MacIntosh, Susan C; Thelen, Jay J


    Soybean (Glycine max) seed contain some proteins that are allergenic to humans and animals. However, the concentration of these allergens and their expression variability among germplasms is presently unknown. To address this problem, 10 allergens were quantified from 20 nongenetically modified commercial soybean varieties using parallel, label-free mass spectrometry approaches. Relative quantitation was performed by spectral counting and absolute quantitation was performed using multiple reaction monitoring (MRM) with synthetic, isotope-labeled peptides as internal standards. During relative quantitation analysis, 10 target allergens were identified, and five of these allergens showed expression levels higher than technical variation observed for bovine serum albumin (BSA) internal standard (∼11%), suggesting expression differences among the varieties. To confirm this observation, absolute quantitation of these allergens from each variety was performed using MRM. Eight of the 10 allergens were quantified for their concentration in seed and ranged from approximately 0.5 to 5.7 μg/mg of soy protein. MRM analysis reduced technical variance of BSA internal standards to approximately 7%, and confirmed differential expression for four allergens across the 20 varieties. This is the first quantitative assessment of all major soybean allergens. The results show the total quantity of allergens measured among the 20 soy varieties was mostly similar.

  6. Inductively coupled plasma - mass spectrometry - status, usability and regulatory acceptance

    Energy Technology Data Exchange (ETDEWEB)

    Wyrick, S.B. [SAIC, Gaithersburg, MD (United States)


    Analytical methods utilizing Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) are still relatively new to the regulatory community. The scientific community continues to utilize ICP-MS methods and to develop innovative upgrades to in the areas of on-line column separations and preconcentration, enhanced nebulization and sample introduction techniques, and improved collector hardware for improved resolution, sensitivity and matrix effect corrections. The U.S. Environmental Protection Agency (EPA) and American Society for Testing and Materials (ASTM) have produced draft methods for ICP-MS operations. The methods are generally nonspecific and may not apply to actinide determinations. The Analytical Services Division (EM- 263) of Department of Energy (DOE) Office of Environmental Management (EM) has developed a compendium of analytical methods titled, DOE Methods for Evaluating Environmental and Waste Management Samples. The purpose of this compendium is to provide and up-to-date reference for analytical procedures for DOE Nuclear Weapons Complex (NWC) applications, and to provide a placeholder for SOPs prior to inclusion in other national standards.

  7. Cationic Xylene Tag for Increasing Sensitivity in Mass Spectrometry (United States)

    Wang, Poguang; Zhang, Qi; Yao, Yuanyuan; Giese, Roger W.


    N-(2-(Bromomethyl)benzyl)-N,N-diethylethanaminium bromide, that we designate as CAX-B (cationic xylyl-bromide), is presented as a derivatization reagent for increasing sensitivity in mass spectrometry. Because of its aryl bromomethyl moiety, CAX-B readily labels compounds having an active hydrogen. In part, a CAX-tagged analyte (CAX-analyte) can be very sensitive especially in a tandem mass spectrometer (both ESI and MALDI). This is because of facile formation of an analyte-characteristic first product ion (as a xylyl-based cation) from favorable loss of triethylamine as a neutral from the precursor ion. This loss is enhanced both by resonance stabilization of the xylyl cation, and by anchimeric assistance from the ortho hetero atom of the attached analyte. High intensity of a first product ion opens up the opportunity for a CAX-analyte to be additionally sensitive when it is prone to a secondary neutral loss from the analyte part. For example, we have derivatized and detected 160 amol of thymidine by CAX-tagging/LC-MALDI-TOF/TOF-MS in this way, where the two neutral losses are triethylamine and deoxyribose. Other analytes detected at the amol level as CAX derivatives (as diluted standards) include estradiol and some nucleobases. The tendency for analytes with multiple active hydrogens to label just once with CAX (an advantage) is illustrated by the conversion of bisphenol A to a single product even when excess CAX-B is present. A family of analogous reagents with a variety of reactivity groups is anticipated as a consequence of replacing the bromine atom of CAX-B with various functional groups.

  8. Mass Spectrometry Imaging for the Investigation of Intratumor Heterogeneity. (United States)

    Balluff, B; Hanselmann, M; Heeren, R M A


    One of the big clinical challenges in the treatment of cancer is the different behavior of cancer patients under guideline therapy. An important determinant for this phenomenon has been identified as inter- and intratumor heterogeneity. While intertumor heterogeneity refers to the differences in cancer characteristics between patients, intratumor heterogeneity refers to the clonal and nongenetic molecular diversity within a patient. The deciphering of intratumor heterogeneity is recognized as key to the development of novel therapeutics or treatment regimens. The investigation of intratumor heterogeneity is challenging since it requires an untargeted molecular analysis technique that accounts for the spatial and temporal dynamics of the tumor. So far, next-generation sequencing has contributed most to the understanding of clonal evolution within a cancer patient. However, it falls short in accounting for the spatial dimension. Mass spectrometry imaging (MSI) is a powerful tool for the untargeted but spatially resolved molecular analysis of biological tissues such as solid tumors. As it provides multidimensional datasets by the parallel acquisition of hundreds of mass channels, multivariate data analysis methods can be applied for the automated annotation of tissues. Moreover, it integrates the histology of the sample, which enables studying the molecular information in a histopathological context. This chapter will illustrate how MSI in combination with statistical methods and histology has been used for the description and discovery of intratumor heterogeneity in different cancers. This will give evidence that MSI constitutes a unique tool for the investigation of intratumor heterogeneity, and could hence become a key technology in cancer research. © 2017 Elsevier Inc. All rights reserved.

  9. Mass spectrometry-based proteomic analyses of contact lens deposition. (United States)

    Green-Church, Kari B; Nichols, Jason J


    The purpose of this report is to describe the contact lens deposition proteome associated with two silicone hydrogel contact lenses and care solutions using a mass spectrometric-based approach. This was a randomized, controlled, examiner-masked crossover clinical trial that included 48 participants. Lenses and no-rub care solutions evaluated included galyfilcon A (Acuvue Advance, Vistakon Inc., Jacksonville, FL), lotrafilcon B (O2 Optix, CIBA Vision Inc., Duluth, GA), AQuify (CIBA Vision Inc.), and ReNu MoistureLoc (Bausch and Lomb Inc., Rochester, NY). After two weeks of daily wear in each lens-solution combination, the left lens was removed by the examiner (using gloves and forceps) and placed in a protein precipitation buffer (acetone). The precipitate was quantitated for total protein concentration (per lens), and proteins were then identified using liquid chromatography tandem mass spectrometry (nano-LC-MS/MS) and peptide sequencing. Between 7.32 and 9.76 microg/lens of protein was observed on average from each lens-solution combination. There were 19 total unique proteins identified across the two lens materials, and six proteins were identified in all four lens-solution combinations including lipocalin, lysozyme, lacritin, lactoferrin, proline rich 4, and Ig Alpha. Lotrafilcon B was associated with 15 individual proteins (across both care solutions), and 53% of these proteins were observed in at least 50% of the analyses. Galyfilcon A was associated with 13 individual proteins, and 38.5% of these proteins were observed in at least 50% of the analyses. There were three unique proteins identified from galyfilcon A and four unique proteins identified from lotrafilcon B. The total amount of proteins identified from silicone hydrogel materials is much less than the amount from traditional soft lens materials. For the most part, the deposition proteome across these lenses is similar, although the different polymer characteristics might be associated with some

  10. The association of fruits, vegetables, antioxidant vitamins and fibre intake with high-sensitivity C-reactive protein: sex and body mass index interactions. (United States)

    Oliveira, A; Rodríguez-Artalejo, F; Lopes, C


    To study the associations of fruits, vegetables, antioxidant vitamins and fibre intake with high-sensitivity C-reactive protein (hs-CRP). Existing literature on these associations is scarce and has rendered conflicting results. Cross-sectional study of 1060 individuals (675 women, 385 men), representative of the non-institutionalized population, aged >or=18 years, in Porto, Portugal (70% participation rate). Diet over the previous year was assessed with a validated food frequency questionnaire. Associations between diet and hs-CRP (categorized into 3 to intake, there was 30% less probability of changing of hs-CRP category (no risk to moderate risk, or moderate to high risk). Protective associations were also observed between hs-CRP and fruits (OR=0.73, 95% CI 0.56-0.96 per 100 g/day), vegetables (OR=0.55, 95% CI 0.35-0.86 per 100 g/day), vitamin C (OR=0.34, 95% CI 0.14-0.80 per 10 mg/day) and vitamin E (OR=0.14, 95% CI 0.02-0.88 per 1000 retinol equivalents per day). Overall, associations tended to be weaker in overweight participants. In men (BMI >or=25.0 kg/m(2)), fibre was also negatively associated with hs-CRP. In women, no significant associations were found between dietary variables and hs-CRP. A significant modification effect of the evaluated associations was found by sex for fruits and vegetables, vitamin C and fibre, but not by BMI. Intake of fruits and vegetables, vitamin C, E and fibre were negatively associated with hs-CRP in men.

  11. Liquid chromatography-tandem mass spectrometry determination of synthetic cathinones and phenethylamines in influent wastewater of eight European cities

    DEFF Research Database (Denmark)

    Bade, Richard; Bijlsma, Lubertus; Sancho, Juan V.


    (SPE) with Oasis MCX cartridges. Isotopically labelled internal standards were used to correct for matrix effects and potential SPE losses. Following chromatographic separation on a C18 column within 6 min, the compounds were measured by tandem mass spectrometry in positive ionization mode. The method...... relatively stable for up to 7 days. The method was then applied to influent wastewater samples from eight European countries, in which mephedrone, methylone and MDPV were detected. This work reveals that although NPS use is not as extensive as for classic illicit drugs, the application of a highly sensitive...... analytical procedure makes their detection in wastewater possible. The developed analytical methodology forms the basis of a subsequent model-based back-calculation of abuse rate in urban areas (i.e. wastewater-based epidemiology)....

  12. Analysis of triazines and associated metabolites with electrospray ionization field-asymmetric ion mobility spectrometry/mass spectrometry

    DEFF Research Database (Denmark)

    Mie, Axel; Sandulescu, Madaline; Mathiasson, Lennart


    Triazines comprise an important pollutant class owing to continued use in certain countries, and owing to strong environmental persistence that leads to problems even in countries like Sweden where the use of triazines has been prohibited for some years. We investigated mass-selective detection...... for analysis of triazines. More specifically, we studied the background reduction and sensitivity enhancement that result from the use of a new interface technique, field-asymmetric ion mobility spectrometry (FAIMS), in conjunction with electrospray ionization ion-trap mass spectrometry. This technique allows...

  13. Differentiating Fragmentation Pathways of Cholesterol by Two-Dimensional Fourier Transform Ion Cyclotron Resonance Mass Spectrometry. (United States)

    van Agthoven, Maria A; Barrow, Mark P; Chiron, Lionel; Coutouly, Marie-Aude; Kilgour, David; Wootton, Christopher A; Wei, Juan; Soulby, Andrew; Delsuc, Marc-André; Rolando, Christian; O'Connor, Peter B


    Two-dimensional Fourier transform ion cyclotron resonance mass spectrometry is a data-independent analytical method that records the fragmentation patterns of all the compounds in a sample. This study shows the implementation of atmospheric pressure photoionization with two-dimensional (2D) Fourier transform ion cyclotron resonance mass spectrometry. In the resulting 2D mass spectrum, the fragmentation patterns of the radical and protonated species from cholesterol are differentiated. This study shows the use of fragment ion lines, precursor ion lines, and neutral loss lines in the 2D mass spectrum to determine fragmentation mechanisms of known compounds and to gain information on unknown ion species in the spectrum. In concert with high resolution mass spectrometry, 2D Fourier transform ion cyclotron resonance mass spectrometry can be a useful tool for the structural analysis of small molecules. Graphical Abstract ᅟ.

  14. Application of MALDI-triple quadrupole mass spectrometry for the quantification of small molecules in biomedical research

    NARCIS (Netherlands)

    R.J.W. Meesters (Roland)


    textabstractA century after its introduction, mass spectrometry is still an innovative technology, which, due to continuous instrumental developments and improvements, has provided important scientific insights in biochemistry, molecular biology and medicine. Now, in 2011, mass spectrometry is used

  15. Characterization of Nitrated Sugar Alcohols by Atmospheric-Pressure Chemical-Ionization Mass Spectrometry (United States)


    mass spectrometry (APCI-MS) was used to detect ions characteristic of nitrated sugar alcohols. Time-of- flight APCI mass spectrometry (TOF APCI-MS...disclosed here will benefit the area of explosives trace detection for counterterrorism and forensics. INTRODUCTION The military-grade...with an Agilent 6520 QTOF quadrupole time-of- flight (TOF) mass spectrometer (Agilent technologies, Santa Clara, CA, USA) equipped with an APCI source

  16. Inductively Coupled Plasma Mass Spectrometry: Sample Analysis of Zirconium and Ruthenium in Metal Organic Frameworks (United States)


    INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY: SAMPLE ANALYSIS OF ZIRCONIUM AND RUTHENIUM IN METAL ORGANIC...MM-YYYY) XX-02-2018 2. REPORT TYPE Final 3. DATES COVERED (From - To) Aug 2016–Aug 2017 4. TITLE AND SUBTITLE Inductively Coupled Plasma Mass...MOFs) using inductively coupled plasma mass spectrometry (ICP–MS). Specifically, the MOFs were analyzed for the zirconium-to-ruthenium ratios. The

  17. Structural Characterization of Anticancer Drug Paclitaxel and Its Metabolites Using Ion Mobility Mass Spectrometry and Tandem Mass Spectrometry (United States)

    Lee, Hong Hee; Hong, Areum; Cho, Yunju; Kim, Sunghwan; Kim, Won Jong; Kim, Hugh I.


    Paclitaxel (PTX) is a popular anticancer drug used in the treatment of various types of cancers. PTX is metabolized in the human liver by cytochrome P450 to two structural isomers, 3'- p-hydroxypaclitaxel (3 p-OHP) and 6α-hydroxypaclitaxel (6α-OHP). Analyzing PTX and its two metabolites, 3 p-OHP and 6α-OHP, is crucial for understanding general pharmacokinetics, drug activity, and drug resistance. In this study, electrospray ionization ion mobility mass spectrometry (ESI-IM-MS) and collision induced dissociation (CID) are utilized for the identification and characterization of PTX and its metabolites. Ion mobility distributions of 3 p-OHP and 6α-OHP indicate that hydroxylation of PTX at different sites yields distinct gas phase structures. Addition of monovalent alkali metal and silver metal cations enhances the distinct dissociation patterns of these structural isomers. The differences observed in the CID patterns of metalated PTX and its two metabolites are investigated further by evaluating their gas-phase structures. Density functional theory calculations suggest that the observed structural changes and dissociation pathways are the result of the interactions between the metal cation and the hydroxyl substituents in PTX metabolites.

  18. Multi-laboratory assessment of reproducibility, qualitative and quantitative performance of SWATH-mass spectrometry. (United States)

    Collins, Ben C; Hunter, Christie L; Liu, Yansheng; Schilling, Birgit; Rosenberger, George; Bader, Samuel L; Chan, Daniel W; Gibson, Bradford W; Gingras, Anne-Claude; Held, Jason M; Hirayama-Kurogi, Mio; Hou, Guixue; Krisp, Christoph; Larsen, Brett; Lin, Liang; Liu, Siqi; Molloy, Mark P; Moritz, Robert L; Ohtsuki, Sumio; Schlapbach, Ralph; Selevsek, Nathalie; Thomas, Stefani N; Tzeng, Shin-Cheng; Zhang, Hui; Aebersold, Ruedi


    Quantitative proteomics employing mass spectrometry is an indispensable tool in life science research. Targeted proteomics has emerged as a powerful approach for reproducible quantification but is limited in the number of proteins quantified. SWATH-mass spectrometry consists of data-independent acquisition and a targeted data analysis strategy that aims to maintain the favorable quantitative characteristics (accuracy, sensitivity, and selectivity) of targeted proteomics at large scale. While previous SWATH-mass spectrometry studies have shown high intra-lab reproducibility, this has not been evaluated between labs. In this multi-laboratory evaluation study including 11 sites worldwide, we demonstrate that using SWATH-mass spectrometry data acquisition we can consistently detect and reproducibly quantify >4000 proteins from HEK293 cells. Using synthetic peptide dilution series, we show that the sensitivity, dynamic range and reproducibility established with SWATH-mass spectrometry are uniformly achieved. This study demonstrates that the acquisition of reproducible quantitative proteomics data by multiple labs is achievable, and broadly serves to increase confidence in SWATH-mass spectrometry data acquisition as a reproducible method for large-scale protein quantification.SWATH-mass spectrometry consists of a data-independent acquisition and a targeted data analysis strategy that aims to maintain the favorable quantitative characteristics on the scale of thousands of proteins. Here, using data generated by eleven groups worldwide, the authors show that SWATH-MS is capable of generating highly reproducible data across different laboratories.

  19. Highly sensitive protein detection by biospecific AFM-based fishing with pulsed electrical stimulation. (United States)

    Pleshakova, Tatyana O; Malsagova, Kristina A; Kaysheva, Anna L; Kopylov, Arthur T; Tatur, Vadim Yu; Ziborov, Vadim S; Kanashenko, Sergey L; Galiullin, Rafael A; Ivanov, Yuri D


    We report here the highly sensitive detection of protein in solution at concentrations from 10-15 to 10-18 m using the combination of atomic force microscopy (AFM) and mass spectrometry. Biospecific detection of biotinylated bovine serum albumin was carried out by fishing out the protein onto the surface of AFM chips with immobilized avidin, which determined the specificity of the analysis. Electrical stimulation was applied to enhance the fishing efficiency. A high sensitivity of detection was achieved by application of nanosecond electric pulses to highly oriented pyrolytic graphite placed under the AFM chip. A peristaltic pump-based flow system, which is widely used in routine bioanalytical assays, was employed throughout the analysis. These results hold promise for the development of highly sensitive protein detection methods using nanosensor devices.

  20. Determination of Cystatin C in human serum by isotope dilution mass spectrometry using mass overlapping peptides. (United States)

    González-Antuña, Ana; Rodríguez-González, Pablo; Ohlendorf, Rudiger; Henrion, André; Delatour, Vincent; García Alonso, J Ignacio


    We propose a peptide-based isotope dilution mass spectrometry approach for Cystatin C determination in human serum samples, a clinical marker for renal status for which backup by a mass spectrometry based primary method has been missing so far. In contrast to common protocols, the isotope labelled version of the proteotypic signature peptide is designed such as keeping the isotopic difference as little as possible with respect to the peptide released from the protein. Peptides labelled in two (13)C atoms are added to the serum samples just before proteolysis. After two steps of chromatographic purification the sample is measured by selected reaction monitoring using a LC-MS/MS. Resolution of the first quadrupole is reduced to transmit the whole parent ion cluster to the collision cell for monitoring accurate isotopic distributions of the molecular fragments. Molar fractions of labelled and natural abundance peptides are directly obtained from the experimental mass spectra of the in-cell fragment ions. Thus, the natural abundance protein concentration is obtained from the fragment-ion spectrum of the sample without resorting to extra calibration runs. Applicability of the approach is demonstrated by the measurement of the serum concentration of Cystatin C in Reference Material ERM R-DA471/IFCC and real samples. Cystatin C is used as an alternative marker instead of, or in combination with creatinine for non-invasive determination of glomerular filtration rates. Advantages advocating in favour of Cystatin C in diagnosis of chronic kidney diseases are the lower variability of its serum level and, particularly, virtual independence on sex, age and muscle mass. However, in order to capitalize, accuracy of measurement has to be in proportion with the predictive power of the marker. Though there are label-free methods available for screening purposes or high-throughput analysis, achieving high levels of reliability and accuracy in quantitative proteomics takes reference

  1. Identification of di(ethylhexyl) phthalate as impurity in the analysis by using chromatography gas tandem mass spectrometry (United States)

    Pusfitasari, Eka Dian; Hendarsyah, Hendris; Salahuddin, Ariani, Novita


    Di(ethylhexyl) phthalate (DEHP) is a plasticizer commonly used in plastics. Physically DEHP has a low vapor pressure. DEHP can seep into the liquid in direct contact with the plastic wrapping materials, and typically can occur rapidly if extractable into food or non-polar solvents, such as oil, once the food is packaged in PVC packaging materials. DEHP has been analyzed by using gas chromatography which has a high sensitivity level. If the equipment used for the analysis is made from plastic containing DEHP, then it may be possible that DEHP can be extracted and appear on the outcome of the injection. It can interfere with the process of analysis, especially for the analysis of food samples. This study has identified the present of DEHP in the blank injection performed by Gas Chromatography tandem Mass Spectrometry with Selected Ion Monitoring mode (SIM). Researchers are required to verify whether the gas chromatographic system used is ready for the analysis process. In addition, the comparison and calculation of the intensity of the ion fragmentation spectra generated by mass spectrometry detector can be used for the qualitative determination to ensure the presence of the target compound. In this study is also discussed the differences between the high-intensity fragmentation of DEHP and dioctyl phthalate (DOP).

  2. Quantitative analysis of cytokinins in plants by high performance liquid chromatography: electronspray ionization ion trap mass spectrometry. (United States)

    Chen, Weiqi; Gai, Ying; Liu, Shichang; Wang, Renxiao; Jiang, Xiangning


    The present paper introduces a highly sensitive and selective method for simultaneous quantification of 12 cytokinins (free form and their conjugates). The method includes a protocol of extraction with methanol/water/formic acid (15/4/1, v/v/v) to the micro-scale samples, pre-purification with solid phase extraction (SPE) cartridges of the extracts, separation with a high performance liquid chromatography (HPLC) and detection by an electrospray ionization ion trap mass spectrometry (ESI-Ion trap-MS) system in a consecutive ion monitoring (CRM) mode at the three stage fragmentation of mass spectrometry (MS(3) ). The lowest detection level of the cytokinins of the method reaches 0.1-2.0 pg with a very wide range of linear regression from 1-512 pg, at the coefficient factors of 0.98-0.99. The feasibility of this method has been proven in the application of the method to the analysis of the trace-amount contents of cytokinins in the micro-scale samples of various types of plant materials, such as aerial parts of rice and poplar leaves etc. 12 endogenous cytokinins had been identified and quantified in the plant tissues, with an acceptable relatively higher recovery rate from 40% to 70%. © 2010 Institute of Botany, Chinese Academy of Sciences.

  3. Extension of the focusable mass range in distance-of-flight mass spectrometry with multiple detectors. (United States)

    Gundlach-Graham, Alexander W; Dennis, Elise A; Ray, Steven J; Enke, Christie G; Carado, Anthony J; Barinaga, Charles J; Koppenaal, David W; Hieftje, Gary M


    Distance-of-flight mass spectrometry (DOFMS) is a velocity-based mass separation technique in which ions are spread across a spatially selective detector according to m/z. In this work, we investigate the practical mass range available for DOFMS with a finite-length detector. A glow-discharge DOFMS instrument has been constructed for the analysis of atomic ions. This instrument was modified to accommodate two spatially selective ion detectors, arranged co-linearly, along the mass-separation axis of the analyzer. With this geometry, each detector covers a different portion of the distance-of-flight spectrum and ions are detected simultaneously at the two detectors. The total flight distance covered by the two detectors is 106 mm and simulates DOF detection across a broad mass range. DOFMS theory predicts that ions of all m/z values are focused at a single flight time, but at m/z-dependent flight distances. Therefore, ions that are detected across a wide portion of the DOF axis should all yield the same peak widths. With a focal-plane camera detector and a micro-channel plate/phosphor-screen detection assembly, we found simultaneous, uniform focus of (40)Ar(2)(+) and of (65)Cu(+) and (63)Cu(+) with the ions spread 82 mm across the DOF axis. This detection length, combined with the current instrument geometry, allows for a simultaneously detectable m/z value of 4:3 (high mass-to-low mass). These results are the first experimental verification that constant-momentum acceleration (CMA)-DOFMS provides energy focus across an extended detection length. Evidence presented demonstrates that DOFMS is amenable to detection with (at least) a 100-mm detector surface. These results indicate that DOFMS is well suited for detection of broader mass ranges. Copyright © 2012 John Wiley & Sons, Ltd.

  4. Fundamentals of ambient metastable-induced chemical ionization mass spectrometry and atmospheric pressure ion mobility spectrometry (United States)

    Harris, Glenn A.

    Molecular ionization is owed much of its development from the early implementation of electron ionization (EI). Although dramatically increasing the library of compounds discovered, an inherent problem with EI was the low abundance of molecular ions detected due to high fragmentation leading to the difficult task of the correct chemical identification after mass spectrometry (MS). These problems stimulated the research into new ionization methods which sought to "soften" the ionization process. In the late 1980s the advancements of ionization techniques was thought to have reached its pinnacle with both electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI). Both ionization techniques allowed for "soft" ionization of large molecular weight and/or labile compounds for intact characterization by MS. Albeit pervasive, neither ESI nor MALDI can be viewed as "magic bullet" ionization techniques. Both techniques require sample preparation which often included native sample destruction, and operation of these techniques took place in sealed enclosures and often, reduced pressure conditions. New open-air ionization techniques termed "ambient MS" enable direct analysis of samples of various physical states, sizes and shapes. One particular technique named Direct Analysis In Real Time (DART) has been steadily growing as one of the ambient tools of choice to ionize small molecular weight (applications using DART as an ionization source, there have not been many studies investigating the fundamental properties of DART desorption and ionization mechanisms. The work presented in this thesis is aimed to provide in depth findings on the physicochemical phenomena during open-air DART desorption and ionization MS and current application developments. A review of recent ambient plasma-based desorption/ionization techniques for analytical MS is presented in Chapter 1. Chapter 2 presents the first investigations into the atmospheric pressure ion transport

  5. Gold Ion-Angiotensin Peptide Interaction by Mass Spectrometry (United States)

    Lee, Jenny; Jayathilaka, Lasanthi P.; Gupta, Shalini; Huang, Jin-Sheng; Lee, Bao-Shiang


    Stimulated by the interest in developing gold compounds for treating cancer, gold ion-angiotensin peptide interactions are investigated by mass spectrometry. Under the experimental conditions used, the majority of gold ion-angiotensin peptide complexes contain gold in the oxidation states I and III. Both ESI-MS and MALDI-TOF MS detect singly/multiply charged ions for mononuclear/multinuclear gold-attached peptides, which are represented as [peptide + a Au(I) + b Au(III) + (e - a -3b) H]e+, where a,b ≥ 0 and e is charge. ESI-MS data shows singly/multiply charged ions of Au(I)-peptide and Au(III)-peptide complexes. This study reveals that MALDI-TOF MS mainly detects singly charged Au(I)-peptide complexes, presumably due to the ionization process. The electrons in the MALDI plume seem to efficiently reduce Au(III) to Au(I). MALDI also tends to enhance the higher polymeric forms of gold-peptide complexes regardless of the laser power used. Collision-induced dissociation experiments of the mononuclear and dinuclear gold-attached peptide ions for angiotensin peptides show that the gold ion (a soft acid) binding sites are in the vicinity of Cys (a soft ligand), His (a major anchor of peptide for metal ion chelation), and the basic residue Arg. Data also suggests that the abundance of gold-attached peptides increases with higher gold concentration until saturation, after which an increase in gold ion concentration leads to the aggregation and/or precipitation of gold-bound peptides.

  6. Sample preparation for quantitation of tritium by accelerator mass spectrometry. (United States)

    Chiarappa-Zucca, Marina L; Dingley, Karen H; Roberts, Mark L; Velsko, Carol A; Love, Adam H


    The capability to prepare samples accurately and reproducibly for analysis of tritium (3H) content by accelerator mass spectrometry (AMS) greatly facilitates isotopic tracer studies in which attomole levels of 3H can be measured in milligram-sized samples. A method has been developed to convert the hydrogen of organic samples to a solid, titanium hydride, which can be analyzed by AMS. Using a two-step process, the sample is first oxidized to carbon dioxide and water. In the second step, the water is transferred within a heated manifold into a quartz tube, reduced to hydrogen gas using zinc, and reacted with titanium powder. The 3H/1H ratio of the titanium hydride is measured by AMS and normalized to standards whose ratios were determined by decay counting to calculate the amount of 3H in the original sample. Water, organic compounds, and biological samples with 3H activities measured by liquid scintillation counting were utilized to develop and validate the method. The 3H/1H ratios were quantified in samples that spanned 5 orders of magnitude, from 10(-10) to 10(-15), with a detection limit of 3.0 x 10(-15), which is equivalent to 0.02 dpm tritium/mg of material. Samples smaller than 2 mg were analyzed following addition of 2 mg of a tritium-free-hydrogen carrier. Preparation of organic standards containing both 14C and 3H in 2-mg organic samples demonstrated that this sample preparation methodology can also be applied to quantify both of these isotopes from a single sample.

  7. Glycoprotein Analysis Using Protein Microarrays and Mass Spectrometry (United States)

    Patwa, Tasneem; Li, Chen; Simeone, Diane M.; Lubman, David M.


    Protein glycosylation plays an important role in a multitude of biological processes such as cell-cell recognition, growth, differentiation, and cell death. It has been shown that specific glycosylation changes are key in disease progression, and can have diagnostic value for a variety of disease types such as cancer and inflammation. The complexity of carbohydrate structures and their derivatives makes their study a real challenge. Improving the isolation, separation, and characterization of carbohydrates and their glycoproteins is a subject of increasing scientific interest. With development of new stationary phases and molecules that have affinity properties for glycoproteins, the isolation and separation of these compounds have advanced significantly. In addition to detection with mass spectrometry, the microarray platform has become an essential tool to characterize glycan structure and to study glycosylation-related biological interactions, by using probes as a means to interrogate the spotted or captured glycosylated molecules on the arrays. Furthermore, the high-throughput and reproducible nature of microarray platforms have been highlighted by its extensive applications in the field of biomarker validation, where a large number of samples must be analyzed multiple times. This review covers a brief survey of the other experimental methodologies that are currently being developed and used to study glycosylation, and emphasizes methodologies that involve the use of microarray platforms. This review describes recent advances in several options of microarray platforms used in glycoprotein analysis, including glycoprotein arrays, glycan arrays, lectin arrays, and antibody/lectin arrays. The translational use of these arrays in applications related to characterization of cells and biomarker discovery is also included. PMID:20077480

  8. Global surveillance of emerging Influenza virus genotypes by mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Rangarajan Sampath


    Full Text Available Effective influenza surveillance requires new methods capable of rapid and inexpensive genomic analysis of evolving viral species for pandemic preparedness, to understand the evolution of circulating viral species, and for vaccine strain selection. We have developed one such approach based on previously described broad-range reverse transcription PCR/electrospray ionization mass spectrometry (RT-PCR/ESI-MS technology.Analysis of base compositions of RT-PCR amplicons from influenza core gene segments (PB1, PB2, PA, M, NS, NP are used to provide sub-species identification and infer influenza virus H and N subtypes. Using this approach, we detected and correctly identified 92 mammalian and avian influenza isolates, representing 30 different H and N types, including 29 avian H5N1 isolates. Further, direct analysis of 656 human clinical respiratory specimens collected over a seven-year period (1999-2006 showed correct identification of the viral species and subtypes with >97% sensitivity and specificity. Base composition derived clusters inferred from this analysis showed 100% concordance to previously established clades. Ongoing surveillance of samples from the recent influenza virus seasons (2005-2006 showed evidence for emergence and establishment of new genotypes of circulating H3N2 strains worldwide. Mixed viral quasispecies were found in approximately 1% of these recent samples providing a view into viral evolution.Thus, rapid RT-PCR/ESI-MS analysis can be used to simultaneously identify all species of influenza viruses with clade-level resolution, identify mixed viral populations and monitor global spread and emergence of novel viral genotypes. This high-throughput method promises to become an integral component of influenza surveillance.

  9. Easy identification of leishmania species by mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Oussama Mouri


    Full Text Available BACKGROUND: Cutaneous leishmaniasis is caused by several Leishmania species that are associated with variable outcomes before and after therapy. Optimal treatment decision is based on an accurate identification of the infecting species but current methods to type Leishmania isolates are relatively complex and/or slow. Therefore, the initial treatment decision is generally presumptive, the infecting species being suspected on epidemiological and clinical grounds. A simple method to type cultured isolates would facilitate disease management. METHODOLOGY: We analyzed MALDI-TOF spectra of promastigote pellets from 46 strains cultured in monophasic medium, including 20 short-term cultured isolates from French travelers (19 with CL, 1 with VL. As per routine procedure, clinical isolates were analyzed in parallel with Multilocus Sequence Typing (MLST at the National Reference Center for Leishmania. PRINCIPAL FINDINGS: Automatic dendrogram analysis generated a classification of isolates consistent with reference determination of species based on MLST or hsp70 sequencing. A minute analysis of spectra based on a very simple, database-independent analysis of spectra based on the algorithm showed that the mutually exclusive presence of two pairs of peaks discriminated isolates considered by reference methods to belong either to the Viannia or Leishmania subgenus, and that within each subgenus presence or absence of a few peaks allowed discrimination to species complexes level. CONCLUSIONS/SIGNIFICANCE: Analysis of cultured Leishmania isolates using mass spectrometry allows a rapid and simple classification to the species complex level consistent with reference methods, a potentially useful method to guide treatment decision in patients with cutaneous leishmaniasis.

  10. [Rapid identification of microorganisms using MALDI-TOF mass spectrometry]. (United States)

    Sogawa, Kazuyuki; Watanabe, Masaharu; Nomura, Fumio


    In a clinical diagnostic microbiology laboratory, the current method of identifying bacterial isolates is based mainly on phenotypic characteristics, such as the growth pattern on different media, colony morphology, Gram stain, and various biochemical reactions. These techniques collectively allow high-level accuracy in identifying most bacterial isolates, but they are costly and time-consuming. In our clinical microbiology laboratory, we prospectively assessed the ability of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) to identify bacterial strains that were routinely isolated from clinical samples. Bacterial colonies obtained from a total of 468 strains of 92 bacterial species isolated at the Department of Clinical Laboratory at Chiba University were directly placed on target MALDI plates, followed by the addition of CHCA matrix solution. The plates were then subjected to MALDI-TOF MS measurement, and the microorganisms were identified by pattern matching by the libraries in the BioTyper 2.0 software. The identification rates at species and genus levels were 91.7% (429/468) and 97.0% (454/468), respectively. MALDI-TOF MS is a rapid, simple, and high-throughput proteomic technique for the identification of a variety of bacterial species. Since colony to colony differences and the effects of culture duration on the results are minimal, it can be implemented in a conventional laboratory setting. Although for some pathogens, the preanalytic processes should be refined and current database should be improved to obtain more accurate results, the MALDI-TOF MS-based method generally performs as well as the conventional methods and is a promising technology in clinical laboratories.

  11. Letter: A simple ion source set-up for desorption/ionization on silicon with ion mobility spectrometry and ion mobility spectrometry-mass spectrometry. (United States)

    Adamov, Alexey; Sysoev, Alexey A; Grigoras, Kestutis; Laakia, Jaako; Kotiaho, Tapio


    Using a simple ion source set-up, laser desorption/ionization on silicon (DIOS) was demonstrated with the use of a custom-made drift tube ion mobility spectrometer (IMS), mounted on a commercial triple quadrupole mass spectrometer, and with an IMS equipped with a Faraday plate detector. DIOS was tested by mobility measurement of tetrapropylammonium iodide, tetrabutylammonium iodide and tetrapentylammonium iodide, whilst 2,6-di-tert- butylpyridine was used as a standard. The reduced mobilities measured for the test halides are in concordance with previously obtained ion mobility spectrometry-mass spectrometry data.

  12. Mass spectrometry in structural biology and biophysics architecture, dynamics, and interaction of biomolecules

    CERN Document Server

    Kaltashov, Igor A; Desiderio, Dominic M; Nibbering, Nico M


    The definitive guide to mass spectrometry techniques in biology and biophysics The use of mass spectrometry (MS) to study the architecture and dynamics of proteins is increasingly common within the biophysical community, and Mass Spectrometry in Structural Biology and Biophysics: Architecture, Dynamics, and Interaction of Biomolecules, Second Edition provides readers with detailed, systematic coverage of the current state of the art. Offering an unrivalled overview of modern MS-based armamentarium that can be used to solve the most challenging problems in biophysics, structural biol

  13. Innovations in Mass Spectrometry for Precise and Accurate Isotope Ratio Determination from Very Small Analyte Quantities (Invited) (United States)

    Lloyd, N. S.; Bouman, C.; Horstwood, M. S.; Parrish, R. R.; Schwieters, J. B.


    This presentation describes progress in mass spectrometry for analysing very small analyte quantities, illustrated by example applications from nuclear forensics. In this challenging application, precise and accurate (‰) uranium isotope ratios are required from 1 - 2 µm diameter uranium oxide particles, which comprise less than 40 pg of uranium. Traditionally these are analysed using thermal ionisation mass spectrometry (TIMS), and more recently using secondary ionisation mass spectrometry (SIMS). Multicollector inductively-coupled plasma mass spectrometry (MC-ICP-MS) can offer higher productivity compared to these techniques, but is traditionally limited by low efficiency of analyte utilisation (sample through to ion detection). Samples can either be introduced as a solution, or sampled directly from solid using laser ablation. Large multi-isotope ratio datasets can help identify provenance and intended use of anthropogenic uranium and other nuclear materials [1]. The Thermo Scientific NEPTUNE Plus (Bremen, Germany) with ‘Jet Interface’ option offers unparalleled MC-ICP-MS sensitivity. An analyte utilisation of c. 4% has previously been reported for uranium [2]. This high-sensitivity configuration utilises a dry high-capacity (100 m3/h) interface pump, special skimmer and sampler cones and a desolvating nebuliser system. Coupled with new acquisition methodologies, this sensitivity enhancement makes possible the analysis of micro-particles and small sample volumes at higher precision levels than previously achieved. New, high-performance, full-size and compact discrete dynode secondary electron multipliers (SEM) exhibit excellent stability and linearity over a large dynamic range and can be configured to simultaneously measure all of the uranium isotopes. Options for high abundance-sensitivity filters on two ion beams are also available, e.g. for 236U and 234U. Additionally, amplifiers with high ohm (1012 - 1013) feedback resistors have been developed to

  14. Simple and Sensitive Analysis of Blonanserin and Blonanserin C in Human Plasma by Liquid Chromatography Tandem Mass Spectrometry and Its Application


    Zheng, Yunliang; Hu, Xingjiang; Liu, Jian; Wu, Guolan; Zhou, Huili; Zhu, Meixiang; Zhai, You; Wu, Lihua; ShenTu, Jianzhong


    A highly sensitive, simple, and rapid liquid chromatography tandem mass spectrometry method to simultaneously determine blonanserin and blonanserin C in human plasma with AD-5332 as internal standard (IS) was established. A simple direct protein precipitation method was used for the sample pretreatment, and chromatographic separation was performed on a Waters XBridge C8 (4.6 × 150 mm, 3.5  μ m) column. The mobile phase consists of a mixture of 10 mM ammonium formate and 0.1% formic acid in wa...

  15. Development of a liquid chromatography-tandem mass spectrometry method for quantitative analysis of trace d-amino acids. (United States)

    Nakano, Yosuke; Konya, Yutaka; Taniguchi, Moyu; Fukusaki, Eiichiro


    d-Amino acids have recently attracted much attention in various research fields including medical, clinical and food industry due to their important biological functions that differ from l-amino acid. Most chiral amino acid separation techniques require complicated derivatization procedures in order to achieve the desirable chromatographic behavior and detectability. Thus, the aim of this research is to develop a highly sensitive analytical method for the enantioseparation of chiral amino acids without any derivatization process using liquid chromatography-tandem mass spectrometry (LC-MS/MS). By optimizing MS/MS parameters, we established a quantification method that allowed the simultaneous analysis of 18 d-amino acids with high sensitivity and reproducibility. Additionally, we applied the method to food sample (vinegar) for the validation, and successfully quantified trace levels of d-amino acids in samples. These results demonstrated the applicability and feasibility of the LC-MS/MS method as a novel, effective tool for d-amino acid measurement in various biological samples. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  16. Can laser-ionisation time-of-flight mass spectrometry be a promising alternative to laser ablation/inductively-coupled plasma mass spectrometry and glow discharge mass spectrometry for the elemental analysis of solids?

    NARCIS (Netherlands)

    Sysoev, AA; Sysoev, AA


    At the beginning of the age of laser-ionisation mass spectrometry (LIMS) increasing numbers of publications were observed. However, later the method began to run into obstacles associated with poor reproducibility of analysis and large variations in elemental sensitivities so that the wide interest

  17. Ligand induced structural isomerism in phosphine coordinated gold clusters revealed by ion mobility mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ligare, Marshall R.; Baker, Erin S.; Laskin, Julia; Johnson, Grant E.


    Structural isomerism in ligated gold clusters is revealed using electrospray ionization ion mobility spectrometry mass spectrometry. Phosphine ligated Au8 clusters are shown to adopt more “extended” type structures with increasing exchange of methyldiphenylphosphine (MePPh2) for triphenylphosphine (PPh3). These ligand-dependant structure-property relationships are critical to applications of clusters in catalysis.

  18. High-Speed Tandem Mass Spectrometric in Situ Imaging by Nanospray Desorption Electrospray Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lanekoff, Ingela T.; Burnum-Johnson, Kristin E.; Thomas, Mathew; Short, Joshua TL; Carson, James P.; Cha, Jeeyeon; Dey, Sudhansu K.; Yang, Pengxiang; Prieto Conaway, Maria C.; Laskin, Julia


    Nanospray desorption electrospray ionization (nano-DESI) combined with tandem mass spectrometry (MS/MS), high-resolution mass analysis (m/m=17,500 at m/z 200), and rapid spectral acquisition enabled simultaneous imaging and identification of more than 300 molecules from 92 selected m/z windows (± 1 Da) with a spatial resolution of better than 150 um. Uterine sections of implantation sites on day 6 of pregnancy were analyzed in the ambient environment without any sample pre-treatment. MS/MS imaging was performed by scanning the sample under the nano-DESI probe at 10 um/s while acquiring higher-energy collision-induced dissociation (HCD) spectra for a targeted inclusion list of 92 m/z values at a rate of ~6.3 spectra/s. Molecular ions and their corresponding fragments, separated using high-resolution mass analysis, were assigned based on accurate mass measurement. Using this approach, we were able to identify and image both abundant and low-abundance isobaric species within each m/z window. MS/MS analysis enabled efficient separation and identification of isobaric sodium and potassium adducts of phospholipids. Furthermore, we identified several metabolites associated with early pregnancy and obtained the first 2D images of these molecules.

  19. Identification of serum biomarkers for occupational medicamentosa-like dermatitis induced by trichloroethylene using mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Wen-Xu; Liu, Wei [Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055 (China); Zhang, Yanfang [Shenzhen Prevention and Treatment Center for Occupational Disease, Shenzhen 518001 (China); Huang, Peiwu; Yang, Xifei; Ren, Xiaohu; Ye, Jinbo; Huang, Haiyan [Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055 (China); Tang, Haiyan [Shenzhen Prevention and Treatment Center for Occupational Disease, Shenzhen 518001 (China); Zhou, Guifeng [Medical School of Hunan Normal University, Changsha 410006 (China); Huang, Xinfeng; Zhuang, Zhixiong [Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055 (China); Liu, Jianjun, E-mail: [Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055 (China)


    Occupational medicamentosa-like dermatitis induced by trichloroethylene (OMLDT) is an autoimmune disease and it has become a serious occupational health hazard. In the present study, we collected fasting blood samples from patients with OMLDT (n = 18) and healthy volunteers (n = 33) to explore serum peptidome patterns. Peptides in sera were purified using weak cation exchange magnetic beads (MB-WCX), and analyzed by matrix-assisted laser desorption ionization time-of-flight-mass spectrometry (MALDI-TOF-MS) and ClinProTools bioinformatics software. The intensities of thirty protein/peptide peaks were significantly different between the healthy control and OMLDT patients. A pattern of three peaks (m/z 2106.3, 2134.5, and 3263.67) was selected for supervised neural network (SNN) model building to separate the OMLDT patients from the healthy controls with a sensitivity of 95.5% and a specificity of 73.8%. Furthermore, two peptide peaks of m/z 4091.61 and 4281.69 were identified as fragments of ATP-binding cassette transporter family A member 12 (ABCA12), and cationic trypsinogen (PRRS1), respectively. Our findings not only show that specific proteomic fingerprints in the sera of OMLDT patients can be served as a differentiated tool of OMLDT patients with high sensitivity and high specificity, but also reveal the novel correlation between OMLDT with ABC transports and PRRS1, which will be of potential value for clinical and mechanistic studies of OMLDT. - Highlights: • Identify 30 differential protein/peptide peaks between OMLDT and healthy control • The test sensitivity and test specificity were 95.5% and 73.8%, respectively. • ABCA12 and PRSS1 were identified as potential biomarkers in OMLDT patients.

  20. Polydopamine-functionalized poly(ether ether ketone) tube for capillary electrophoresis-mass spectrometry. (United States)

    Zhou, Wei; Zhang, Wenpeng; Liu, Yikun; Yu, Xinhong; Chen, Zilin


    Capillary electrophoresis-mass spectrometry (CE-MS) is a hyphenated technique that combines the advantages like low sample consumption, high separation efficiency, short analytical time in CE and high sensitivity, powerful molecular structure elucidation in MS. Polyimide-coated fused silica capillary has become the most dominant capillary for CE, but it suffers from swelling and aminolysis of polyimide coating when treated with organic solvents and alkaline buffer in the CE-MS interface in which the polyimide coating at the end of the capillary is exposed to the solution, and this phenomenon can result in current instability, irregular electrospray and clogging at outlet after prolonged use. In this work, poly(ether ether ketone) (PEEK) capillary was explored as separation capillary for CE-MS. The problems like swelling and aminolysis of polyimide coating were solved due to the high thermal and chemical stability of PEEK material. After modification with polydopamine, PEEK capillary (PD-PEEK) can generate adjustable electroosmotic flow and provide good separation selectivity. The zwitterion polymer of polydopamine can provide cathodic electroosmotic flow (EOF) at high pH value (pH ≥ 5) and anodic EOF at low pH value (pH ≤ 4), and the EOF mobility can also be adjusted by controlling the modification time of polydopamine. Good separation performance was obtained in the analysis for several classes of compounds including amino acids, phenols and plant hormones at rational EOF direction. Repeatability of the PD-PEEK capillary was studied, with relative standard deviations for intra-day, inter-day runs and between tubes less than 4.94%. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Applying liquid chromatography-tandem mass spectrometry to assess endodontic sealer microleakage

    Directory of Open Access Journals (Sweden)

    André Luiz da Costa MICHELOTTO


    Full Text Available The objective of this study was to describe a new method for the quantitative analysis of a microleakage of endodontic filling materials. Forty extracted single-rooted teeth were randomly divided into three experimental groups. After root canal shaping, the experimental groups were filled using the lateral condensation technique with the Epiphany system (G1, with gutta-percha + Sealapex (G2, and with gutta-percha + AH Plus (G3. Each root was mounted on a modified leakage testing device, and caffeine solution was used as a tracer (2000 ng mL-1, pH 6.0, applied in the coronal direction towards the tooth apex, creating a hydrostatic pressure of 2.55 kPa. Presence of caffeine in the receiving solution was measured after 10, 30, and 60 days, using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS. None of the groups presented microleakage at 10 days. At 30 days, G2 and G3 showed similar infiltration patterns (means: 16.0 and 13.9 ng mL-1, respectively, whereas G1 showed significantly higher values (mean: 105.2 ng mL-1. At 60 days, leakage values were 182.6 ng mL-1for G1, 139.0 ng mL-1 for G2, and 53.5 ng mL-1 for G3. AH Plus showed the best sealing ability and HPLC-MS/MS showed high sensitivity and specificity for tracer quantification.

  2. Accelerator Mass Spectrometry Allows for Cellular Quantification of Doxorubicin at Femtomolar Concentrations

    Energy Technology Data Exchange (ETDEWEB)

    DeGregorio, M W; Dingley, K H; Wurz, G T; Ubick, E; Turteltaub, K W


    Accelerator mass spectrometry (AMS) is a highly sensitive analytical methodology used to quantify the content of radioisotopes, such as {sup 14}C, in a sample. The primary goals of this work were to demonstrate the utility of AMS in determining cellular [{sup 14}C]doxorubicin (DOX) concentrations and to develop a sensitive assay that is superior to high performance liquid chromatography (HPLC) for the quantification of DOX at the tumor level. In order to validate the superior sensitivity of AMS versus HPLC with fluorescence detection, we performed three studies comparing the cellular accumulation of DOX: one in vitro cell line study, and two in vivo xenograft mouse studies. Using AMS, we quantified cellular DOX content up to 4 hours following in vitro exposure at concentrations ranging from 0.2 pg/ml (345 fM) to 2 {micro}g/ml (3.45 {micro}M) [{sup 14}C]DOX. The results of this study show that, compared to standard fluorescence-based HPLC, the AMS method was over five orders of magnitude more sensitive. Two in vivo studies compared the sensitivity of AMS to HPLC using a nude mouse xenograft model in which breast cancer cells were implanted subcutaneously. After sufficiently large tumors formed, DOX was administered intravenously at two dose levels. Additionally, we tested the AMS method in a nude mouse xenograft model of multidrug resistance (MDR) in which each mouse was implanted with both wild type and MDR+ cells on opposite flanks. The results of the second and third studies showed that DOX concentrations were significantly higher in the wild type tumors compared to the MDR+ tumors, consistent with the MDR model. The extreme sensitivity of AMS should facilitate similar studies in humans to establish target site drug delivery and to potentially determine the optimal treatment dose and regimen.

  3. Pep2Path: automated mass spectrometry-guided genome mining of peptidic natural products

    NARCIS (Netherlands)

    Medema, Marnix; Paalvast, Yared; Nguyen, D.D.; Melnik, A.; Dorrestein, P.C.; Takano, Eriko; Breitling, Rainer


    Nonribosomally and ribosomally synthesized bioactive peptides constitute a source of molecules of great biomedical importance, including antibiotics such as penicillin, immunosuppressants such as cyclosporine, and cytostatics such as bleomycin. Recently, an innovative mass-spectrometry-based

  4. Screening of DUB activity and specificity by MALDI-TOF mass spectrometry

    National Research Council Canada - National Science Library

    Ritorto, Maria Stella; Ewan, Richard; Perez-Oliva, Ana B; Knebel, Axel; Buhrlage, Sara J; Wightman, Melanie; Kelly, Sharon M; Wood, Nicola T; Virdee, Satpal; Gray, Nathanael S; Morrice, Nicholas A; Alessi, Dario R; Trost, Matthias


    ... activity using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Unlike other current assays, this method uses unmodified substrates, such as diubiquitin topoisomers...

  5. Doping control analysis of anabolic steroids in equine urine by gas chromatography-tandem mass spectrometry. (United States)

    Wong, April S Y; Leung, Gary N W; Leung, David K K; Wan, Terence S M


    Anabolic steroids are banned substances in equine sports. Gas chromatography-mass spectrometry (GC-MS) has been the traditional technique for doping control analysis of anabolic steroids in biological samples. Although liquid chromatography-mass spectrometry (LC/MS) has become an important technique in doping control, the detection of saturated hydroxysteroids by LC-MS remains a problem due to their low ionization efficiency under electrospray. The recent development in fast-scanning gas-chromatography-triple-quadrupole mass spectrometry (GC-MS/MS) has provided a better alternative with a significant reduction in chemical noise by means of selective reaction monitoring. Herein, we present a sensitive and selective method for the screening of over 50 anabolic steroids in equine urine using gas chromatography-tandem mass spectrometry (GC-MS/MS). Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  6. Technological Development of High-Performance MALDI Mass Spectrometry Imaging for the Study of Metabolic Biology

    Energy Technology Data Exchange (ETDEWEB)

    Feenstra, Adam D. [Iowa State Univ., Ames, IA (United States)


    This thesis represents efforts made in technological developments for the study of metabolic biology in plants, specifically maize, using matrix-assisted laser desorption/ ionization-mass spectrometry imaging.

  7. Screening Samples for Arsenic by Inductively Coupled Plasma-Mass Spectrometry for Treaty Samples (United States)


    quality system in accordance with International Organization for Standardization/International Electrotechnical Commission ( ISO /IEC) 17025 :2005...plasma-mass spectrometry ISO /IEC International Organization for Standardization/International Electrotechnical Commission L lewisite MDL method

  8. Characterization of Microdialysis Acidification for Capillary Isoelectric Focusing Microelectrospray Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)



    A microdialysis junction, based on a microdialysis membrane connecting a separate capillary and a short, sharply tapered microelectrospray emitter capillary, is demonstrated for on-line combination of capillary isoelectric focusing (CIEF) with electrospray ionization mass spectrometry (ESI-MS).

  9. Differentiating organic and conventional sage by chromatographic and mass spectrometry flow-injection fingerprints (United States)

    High performance liquid chromatography (UPLC) and flow injection electrospray ionization with ion trap mass spectrometry (FIMS) fingerprints combined with the principal component analysis (PCA) were examined for their potential in differentiating commercial organic and conventional sage samples. The...

  10. Electrospray and MALDI mass spectrometry: fundamentals, instrumentation, practicalities, and biological applications

    National Research Council Canada - National Science Library

    Cole, Richard B


    .... Electrochemistry of the Electrospray Ion Source Gary J. Van Berkel and Vilmos Kertesz 75 4. ESI Source Design Andries P. Bruins 123 Part III ES and MALDI Coupling to Mass Spectrometry Instrumentation 9. Coup...

  11. Quantitation of multisite EGF receptor phosphorylation using mass spectrometry and a novel normalization approach

    DEFF Research Database (Denmark)

    Erba, Elisabetta Boeri; Matthiesen, Rune; Bunkenborg, Jakob


    Using stable isotope labeling and mass spectrometry, we performed a sensitive, quantitative analysis of multiple phosphorylation sites of the epidermal growth factor (EGF) receptor. Phosphopeptide detection efficiency was significantly improved by using the tyrosine phosphatase inhibitor sodium...

  12. Advancements in mass spectrometry for biological samples: Protein chemical cross-linking and metabolite analysis of plant tissues

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Adam [Iowa State Univ., Ames, IA (United States)


    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.

  13. Analysis of electrocautery generated smoke by chromatographic-mass spectrometry. (United States)

    Kalil, Jefferson; Pessine, Francisco B T; Fidelis, Carlos H V; Menezes, Fabio H; Palma, Paulo Cesar Rodrigues


    to analyze the chemical components of the smoke from electrocautery from coagulating muscle and liver tissues of pigs. we collected smoke produced by electrocautery applied to porcine tissue in previously evacuated bottles, with qualitative and quantitative analysis of the compounds present through the hyphenated technique gas chromatography / mass spectrometry. there was a majority of decanal aldehyde in the fumes from the subcutaneous, muscle and liver tissues. Fumes of subcutaneous and muscular tissues also showed the presence of hexanal and phenol. In the fumes of subcutaneous and liver tissues we also found toluene and limonene and, finally, nonanal smoke was present in the muscle and liver tissues. there is increasing evidence showing that smoke from electrocautery used in subcutaneous, muscle and liver tissue is harmful to human health. Thus, there is need to reduce exposure to it or wear masks with filters capable of retaining these particles. analisar quimicamente os componentes da fumaça do eletrocautério, provenientes da coagulação de tecidos, muscular e hepático de suino. coleta de fumaça produzida por eletrocauterização de tecido porcino em frascos previamente evacuados com análise qualitativa e quantitativa dos compostos presentes, através de técnica hifenada, cromatografia a gás/espectrometria de massas. houve presença majoritária do aldeído decanal nas fumaças provenientes dos tecidos subcutâneo, muscular e hepático. Fumaças dos tecidos subcutâneo e muscular mostraram também a presença de hexanal e fenol. Nas fumaças dos tecidos subcutâneo e hepático foram encontrados ainda tolueno e limoneno e, por fim, nonanal estava presente nas fumaças dos tecidos muscular e hepático. há número crescente de evidências mostrando que fumaça proveniente de eletrocauterização de tecidos subcutâneo, muscular e hepático é nociva à saúde de seres humanos. Portanto, há necessidade de reduzir a exposição a ela ou usar máscara com

  14. Identification of Hypoxia-Regulated Proteins Using MALDI-Mass Spectrometry Imaging Combined with Quantitative Proteomics

    DEFF Research Database (Denmark)

    Djidja, Marie-Claude; Chang, Joan; Hadjiprocopis, Andreas


    quantitative proteomics combined with MALDI-mass spectrometry imaging (MALDI-MSI). Here we present a comprehensive hypoxic proteome study and are the first to investigate changes in situ using tumor samples. In vitro quantitative mass spectrometry analysis of the hypoxic proteome was performed on breast cancer...... data were also developed, and computational mapping of MALDI-MSI data to IHC results was applied for data validation. The results and limitations of the methodologies described are discussed....

  15. Mass spectrometry in grape and wine chemistry. Part II: The consumer protection. (United States)

    Flamini, Riccardo; Panighel, Annarita


    Controls in food industry are fundamental to protect the consumer health. For products of high quality, warranty of origin and identity is required and analytical control is very important to prevent frauds. In this article, the "state of art" of mass spectrometry in enological chemistry as a consumer safety contribute is reported. Gas chromatography-mass spectrometry (GC/MS) and liquid-chromatography-mass spectrometry (LC/MS) methods have been developed to determine pesticides, ethyl carbamate, and compounds from the yeast and bacterial metabolism in wine. The presence of pesticides in wine is mainly linked to the use of dicarboxyimide fungicides on vineyard shortly before the harvest to prevent the Botrytis cinerea attack of grape. Pesticide residues are regulated at maximum residue limits in grape of low ppm levels, but significantly lower levels in wine have to be detected, and mass spectrometry offers effective and sensitive methods. Moreover, mass spectrometry represent an advantageous alternative to the radioactive-source-containing electron capture detector commonly used in GC analysis of pesticides. Analysis of ochratoxin A (OTA) in wine by LC/MS and multiple mass spectrometry (MS/MS) permits to confirm the toxin presence without the use of expensive immunoaffinity columns, or time and solvent consuming sample derivatization procedures. Inductively coupled plasma-mass spectrometry (ICP/MS) is used to control heavy metals contamination in wine, and to verify the wine origin and authenticity. Isotopic ratio-mass spectrometry (IRMS) is applied to reveal wine watering and sugar additions, and to determine the product origin and traceability.

  16. Determination of thermodynamic and kinetic properties of biomolecules by mass spectrometry.


    Gülbakan Basri; Barylyuk Konstantin; Zenobi Renato


    Over the past two decades mass spectrometry (MS) has transformed the life sciences. The advances in understanding biomolecule structure and function by MS is progressing at an accelerated pace. MS has also largely been applied to study thermodynamic and kinetic structure of biomolecules. Herein we highlight the recent discussions about native mass spectrometry and studies about determining stable gas phase structures hydrogen/deuterium exchange studies about reaction kinetics and determinatio...

  17. Mass Spectrometry and Affinity Based Methods for Analysis of Proteins and Proteomes


    Sundberg, Mårten


    Proteomics is a fast growing field and there has been a tremendous increase of knowledge the last two decades. Mass spectrometry is the most used method for analysis of complex protein samples. It can be used both in large scale discovery studies as well as in targeted quantitative studies. In parallel with the fast improvements of mass spectrometry-based proteomics there has been a fast growth of affinity-based methods. A common challenge is the large dynamic range of protein concentrations ...

  18. Affinity capture mass spectrometry of biomarker proteins using peptide ligands from biopanning


    Johnson, Erin M.; Walther R. Ellis; Powers, Linda S.; Wysocki, Vicki H.


    Affinity capture mass spectrometry was used to isolate and ionize protein A from Staphylococcus aureus from both a commercial source and cell culture lysate using matrix assisted laser desorption/ionization mass spectrometry. Two surfaces are compared: gold surfaces with immunoglobulin G covalently immobilized and silica surfaces with a covalently bound small peptide discovered via biopanning. A detection limit of 2.22 bacterial cells/mL of culture fluid was determined using the immobilized p...

  19. Towards practical time-of-flight secondary ion mass spectrometry lignocellulolytic enzyme assays


    Goacher, Robyn E; Tsai, Alex Yi-Lin; Master, Emma R.


    Background Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is a surface sensitive mass spectrometry technique with potential strengths as a method for detecting enzymatic activity on solid materials. In particular, ToF-SIMS has been applied to detect the enzymatic degradation of woody lignocellulose. Proof-of-principle experiments previously demonstrated the detection of both lignin-degrading and cellulose-degrading enzymes on solvent-extracted hardwood and softwood. However, these ...

  20. Bibliometric mapping: eight decades of analytical chemistry, with special focus on the use of mass spectrometry. (United States)

    Waaijer, Cathelijn J F; Palmblad, Magnus


    In this Feature we use automatic bibliometric mapping tools to visualize the history of analytical chemistry from the 1920s until the present. In particular, we have focused on the application of mass spectrometry in different fields. The analysis shows major shifts in research focus and use of mass spectrometry. We conclude by discussing the application of bibliometric mapping and visualization tools in analytical chemists' research.

  1. Automated mass correction and data interpretation for protein open-access liquid chromatography-mass spectrometry. (United States)

    Wagner, Craig D; Hall, John T; White, Wendy L; Miller, Luke A D; Williams, Jon D


    Characterization of recombinant protein purification fractions and final products by liquid chromatography-mass spectrometry (LC/MS) are requested more frequently each year. A protein open-access (OA) LC/MS system was developed in our laboratory to meet this demand. This paper compares the system that we originally implemented in our facilities in 2003 to the one now in use, and discusses, in more detail, recent enhancements that have improved its robustness, reliability, and data reporting capabilities. The system utilizes instruments equipped with reversed-phase chromatography and an orthogonal accelerated time-of-flight mass spectrometer fitted with an electrospray source. Sample analysis requests are accomplished using a simple form on a web-enabled laboratory information management system (LIMS). This distributed form is accessible from any intranet-connected company desktop computer. Automated data acquisition and processing are performed using a combination of in-house (OA-Self Service, OA-Monitor, and OA-Analysis Engine) and vendor-supplied programs (AutoLynx, and OpenLynx) located on acquisition computers and off-line processing workstations. Analysis results are then reported via the same web-based LIMS. Also presented are solutions to problems not addressed on commercially available, small-molecule OA-LC/MS systems. These include automated transforming of mass-to-charge (m/z) spectra to mass spectra and automated data interpretation that considers minor variants to the protein sequence-such as common post-translational modifications (PTMs). Currently, our protein OA-LC/MS platform runs on five LC/MS instruments located in three separate GlaxoSmithKline R&D sites in the US and UK. To date, more than 8000 protein OA-LC/MS samples have been analyzed. With these user friendly and highly automated OA systems in place, mass spectrometry plays a key role in assessing the quality of recombinant proteins, either produced at our facilities or bought from external

  2. Laser mass spectrometry of polyglycols: comparison with other mass spectral techniques

    Energy Technology Data Exchange (ETDEWEB)

    Mattern, D.E.; Hercules, D.M.


    Laser mass spectrometry (LMS) has been investigated as a tool for polyglycol analysis. Accurate anti M/sub n/ (number average molecular weight) values were determined for polyglycol samples with average molecular weights less than or equal to1000. anti M/sub n/ values derived from LMS data were reproducible to +/-2% relative standard deviation and consistent with those obtained using field desorption (FD) and electrohydrodynamic ionization (EH). In addition, the relative selectivity of oligomers toward alkali metal ions was determined for PEG (polyethylene glycol) and PPG (polypropylene glycol). Selectivity orders and ratios measured by LMS were similar to those obtained from EHMS and solvent extraction data. Therefore, the applicability of LMS for anti M/sub n/ determinations and for probing oligomer-ion interactions for polyglycols has been established. 30 references, 4 figures, 3 tables.

  3. C60 Secondary Ion Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Donald F.; Robinson, Errol W.; Tolmachev, Aleksey V.; Heeren, Ronald M.; Pasa-Tolic, Ljiljana


    Secondary ion mass spectrometry (SIMS) has seen increased application for high spatial chemical imaging of complex biological surfaces. The advent and commercial availability of cluster and polyatomic primary ion sources (e.g. Au and Bi cluster and buckminsterfullerene (C60)) provide improved secondary ion yield and decreased fragmentation of surface species, thus accessibility to intact molecular ions. Despite developments in primary ion sources, development of mass spectrometers to fully exploit their advantages has been limited. Tandem mass spectrometry for identification of secondary ions is highly desirable, but implementation has proven to be difficult. Similarly, high mass resolution and high mass measurement accuracy would greatly improve the chemical specificity of SIMS. Here we combine, for the first time, the advantages of a C60 primary ion source with the ultra-high mass resolving power and high mass measurement accuracy of Fourier transform ion cyclotron resonance mass spectrometry. Mass resolving power in excess of 100,000 (m/Δm50%) is demonstrated, with mass measurement accuracies below 3 parts-per-million. Imaging of mouse brain tissue at 40 μm pixel size is shown. Tandem mass spectrometry of ions from biological tissue is demonstrated and molecular formulae can be assigned to fragment ions.

  4. Coupling Front-End Separations, Ion Mobility Spectrometry, and Mass Spectrometry For Enhanced Multidimensional Biological and Environmental Analyses (United States)

    Zheng, Xueyun; Wojcik, Roza; Zhang, Xing; Ibrahim, Yehia M.; Burnum-Johnson, Kristin E.; Orton, Daniel J.; Monroe, Matthew E.; Moore, Ronald J.; Smith, Richard D.; Baker, Erin S.


    Ion mobility spectrometry (IMS) is a widely used analytical technique for rapid molecular separations in the gas phase. Though IMS alone is useful, its coupling with mass spectrometry (MS) and front-end separations is extremely beneficial for increasing measurement sensitivity, peak capacity of complex mixtures, and the scope of molecular information available from biological and environmental sample analyses. In fact, multiple disease screening and environmental evaluations have illustrated that the IMS-based multidimensional separations extract information that cannot be acquired with each technique individually. This review highlights three-dimensional separations using IMS-MS in conjunction with a range of front-end techniques, such as gas chromatography, supercritical fluid chromatography, liquid chromatography, solid-phase extractions, capillary electrophoresis, field asymmetric ion mobility spectrometry, and microfluidic devices. The origination, current state, various applications, and future capabilities of these multidimensional approaches are described in detail to provide insight into their uses and benefits. PMID:28301728

  5. Coupling Front-End Separations, Ion Mobility Spectrometry, and Mass Spectrometry For Enhanced Multidimensional Biological and Environmental Analyses

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Xueyun; Wojcik, Roza; Zhang, Xing; Ibrahim, Yehia M.; Burnum-Johnson, Kristin E.; Orton, Daniel J.; Monroe, Matthew E.; Moore, Ronald J.; Smith, Richard D.; Baker, Erin M.


    Ion mobility spectrometry (IMS) is a widely used analytical technique for rapid molecular separations in the gas phase. IMS alone is useful, but its coupling with mass spectrometry (MS) and front-end separations has been extremely beneficial for increasing measurement sensitivity, peak capacity of complex mixtures, and the scope of molecular information in biological and environmental sample analyses. Multiple studies in disease screening and environmental evaluations have even shown these IMS-based multidimensional separations extract information not possible with each technique individually. This review highlights 3-dimensional separations using IMS-MS in conjunction with a range of front-end techniques, such as gas chromatography (GC), supercritical fluid chromatography (SFC), liquid chromatography (LC), solid phase extractions (SPE), capillary electrophoresis (CE), field asymmetric ion mobility spectrometry (FAIMS), and microfluidic devices. The origination, current state, various applications, and future capabilities for these multidimensional approaches are described to provide insight into the utility and potential of each technique.

  6. Alkaloid profiling of the Chinese herbal medicine Fuzi by combination of matrix-assisted laser desorption ionization mass spectrometry with liquid chromatography-mass spectrometry

    NARCIS (Netherlands)

    Wang, J.; Heijden, R. van der; Spijksma, G.; Reijmers, T.; Wang, M.; Xu, G.; Hankemeier, T.; Greef, J. van der


    A matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) method was developed for the high throughput and robust qualitative profiling of alkaloids in Fuzi-the processed lateral roots of the Chinese herbal medicine Aconitum carmichaeli Debx (A. carmichaeli). After optimization,

  7. Mass spectrometry. Environment, biology, oenology, medicine, geology, chemistry, archaeology, mechanisms; Spectrometrie de masse. Environnement, biologie, oenologie, medecine, geologie, chimie, archeologie, mecanismes

    Energy Technology Data Exchange (ETDEWEB)



    This document provides the papers (communications and posters) presented at the 16. French days of mass spectrometry, held September 6-9, 1999 in Nancy, France. 5 papers are interesting for the INIS database and are analyzed separately. (O.M.)

  8. Mass spectrometry. Environment, biology, oenology, medicine, geology, chemistry, archaeology, mechanisms; Spectrometrie de masse. Environnement, biologie, oenologie, medecine, geologie, chimie, archeologie, mecanismes

    Energy Technology Data Exchange (ETDEWEB)



    This document provides the papers (communications and posters) presented at the 16. French days of mass spectrometry, held September 6-9, 1999 in Nancy, France. 7 papers are interesting for the ETDE database and are analyzed separately. (O.M.)

  9. Quantitative Thin-Layer Chromatography/Mass Spectrometry Analysis of Caffeine Using a Surface Sampling Probe Electrospray Ionization Tandem Mass Spectrometry System

    Energy Technology Data Exchange (ETDEWEB)

    Ford, Michael J [ORNL; Deibel, Michael A. [Earlham College; Tomkins, Bruce A [ORNL; Van Berkel, Gary J [ORNL


    Quantitative determination of caffeine on reversed-phase C8 thin-layer chromatography plates using a surface sampling electrospray ionization system with tandem mass spectrometry detection is reported. The thin-layer chromatography/electrospray tandem mass spectrometry method employed a deuterium-labeled caffeine internal standard and selected reaction monitoring detection. Up to nine parallel caffeine bands on a single plate were sampled in a single surface scanning experiment requiring 35 min at a surface scan rate of 44 {mu}m/s. A reversed-phase HPLC/UV caffeine assay was developed in parallel to assess the mass spectrometry method performance. Limits of detection for the HPLC/UV and thin-layer chromatography/electrospray tandem mass spectrometry methods determined from the calibration curve statistics were 0.20 ng injected (0.50 {mu}L) and 1.0 ng spotted on the plate, respectively. Spike recoveries with standards and real samples ranged between 97 and 106% for both methods. The caffeine content of three diet soft drinks (Diet Coke, Diet Cherry Coke, Diet Pepsi) and three diet sport drinks (Diet Turbo Tea, Speed Stack Grape, Speed Stack Fruit Punch) was measured. The HPLC/UV and mass spectrometry determinations were in general agreement, and these values were consistent with the quoted values for two of the three diet colas. In the case of Diet Cherry Coke and the diet sports drinks, the determined caffeine amounts using both methods were consistently higher (by 8% or more) than the literature values.

  10. Xlink-identifier: an automated data analysis platform for confident identifications of chemically cross-linked peptides using tandem mass spectrometry. (United States)

    Du, Xiuxia; Chowdhury, Saiful M; Manes, Nathan P; Wu, Si; Mayer, M Uljana; Adkins, Joshua N; Anderson, Gordon A; Smith, Richard D


    Chemical cross-linking combined with mass spectrometry provides a powerful method for identifying protein-protein interactions and probing the structure of protein complexes. A number of strategies have been reported that take advantage of the high sensitivity and high resolution of modern mass spectrometers. Approaches typically include synthesis of novel cross-linking compounds, and/or isotopic labeling of the cross-linking reagent and/or protein, and label-free methods. We report Xlink-Identifier, a comprehensive data analysis platform that has been developed to support label-free analyses. It can identify interpeptide, intrapeptide, and deadend cross-links as well as underivatized peptides. The software streamlines data preprocessing, peptide scoring, and visualization and provides an overall data analysis strategy for studying protein-protein interactions and protein structure using mass spectrometry. The software has been evaluated using a custom synthesized cross-linking reagent that features an enrichment tag. Xlink-Identifier offers the potential to perform large-scale identifications of protein-protein interactions using tandem mass spectrometry.

  11. Role of opposite charges in protein electrospray ionization mass spectrometry. (United States)

    Samalikova, Maria; Grandori, Rita


    The conformation dependence of protein spectra recorded by electrospray ionization mass spectrometry (ESI-MS) is an interesting and useful phenomenon, whose origin is still the object of debate. Different mechanisms have been invoked in the attempt to explain the lower charge state of folded versus unfolded protein ions in ESI-MS, such as electrostatic repulsions, solvent accessibility, charge availability, and native-like interactions. In this work we try to subject to direct experimental test the hypothesis that conformation-dependent neutralization of charges with polarity opposite to the net charge of the protein ion could play a critical role in such an effect. We present results of time-of-flight nano-ESI-MS on the peptide angiotensin II, indicating that negative charges of carboxylate groups can contribute to spectra recorded in positive-ion mode when stabilized by favorable electrostatic interactions, which is the central assumption of our hypothesis. Comparison of horse and spermwhale myoglobin (Mb) shows that changing the total number of basic residues within a given three-dimensional structure shifts the charge-state distribution (CSD) of the folded protein in positive-ion mode. This result appears to be in contrast to models in which electrostatic repulsions or availability of charges in the ESI droplets represent the limiting factor for the ionization of folded protein ions in ESI-MS. At the same time, it suggests a role of acidic residues in conformational effects in positive-ion mode. Furthermore, an attempt is made to rationalize those cases in which, in contrast, the main charge state observed in ESI-MS under non-denaturing conditions deviates considerably from the net charge expected on the basis of the amino-acid composition. These cases usually correspond to proteins with quite balanced content in basic and acidic residues, suggesting that this might be a factor influencing their charging behavior in ESI-MS. Experiments on mutants of

  12. A comparison of the techniques of secondary ion mass spectrometry and resonance ionization mass spectrometry for the analysis of potentially toxic element accumulation in neural tissue. (United States)

    Jones, O R; Perks, R M; Abraham, C J; Telle, H H; Oakley, A E


    A comparison is made of the techniques of secondary ion mass spectrometry (SIMS) and resonance ionization mass spectrometry (RIMS) for the detection of the neuro-toxic element aluminium in cortical tissue. Experiments were performed using a reflectron-type time-of-flight mass spectrometer (TOFMS) in conjunction with an Ar+ source for target sputtering and a pulsed tuneable dye laser system for resonance ionization. It is shown how isobaric interference of species such as CNH and C2H3 in the case of aluminium greatly affect the quantitative accuracy and the detection limit of aluminium in biological samples when analysed using SIMS. In contrast the use of RIMS virtually eliminates this problem, so allowing easier quantification and much lower detection limits to be achieved. Detection limits of approximately 3 ppm for aluminium in brain tissue homogenates were achieved using RIMS, with a spatial resolution of less than 100 microns.

  13. MASSyPup--an 'out of the box' solution for the analysis of mass spectrometry data. (United States)

    Winkler, Robert


    Mass spectrometry has evolved to a key technology in the areas of metabolomics and proteomics. Centralized facilities generate vast amount of data, which frequently need to be processed off-site. Therefore, the distribution of data and software, as well as the training of personnel in the analysis of mass spectrometry data, becomes increasingly important. Thus, we created a comprehensive collection of mass spectrometry software which can be run directly from different media such as DVD or USB without local installation. MASSyPup is based on a Linux Live distribution and was complemented with programs for conversion, visualization and analysis of mass spectrometry (MS) data. A special emphasis was put on protein analysis and proteomics, encompassing the measurement of complete proteins, the identification of proteins based on Peptide Mass Fingerprints (PMF) or LC-MS/MS data, and de novo sequencing. Another focus was directed to the study of metabolites and metabolomics, covering the detection, identification and quantification of compounds, as well as subsequent statistical analyses. Additionally, we added software for Mass Spectrometry Imaging (MSI), including hardware support for self-made MSI devices. MASSyPup represents a 'ready to work' system for teaching or MS data analysis, but also represents an ideal platform for the distribution of MS data and the development of related software. The current Live DVD version can be downloaded free of charge from Copyright © 2014 John Wiley & Sons, Ltd.

  14. Extending and refining the mass surface around $^{208}$Pb by high-precision Penning-trap mass spectrometry with ISOLTRAP

    CERN Multimedia

    Herfurth, F; Stora, T; Blaum, K; Beck, D; Kowalska, M; Schwarz, S; Stanja, J; Herlert, A J; Yamaguchi, T

    We propose high-precision mass spectrometry of nuclides around the doubly magic $^{208}$Pb. On the neutron-rich side, we aim to extend the knowledge of Fr, At, Hg, and Au masses to study the robustness of the N = 126 shell closure and to provide mass data necessary for modeling the rapid-neutron-capture process. On the proton-rich side, we aim at high-resolution mass spectrometry of selected Au, At, and Fr isotopes to verify the predicted existence of very low-lying isomeric states. The proposal will make use of newly-available laser-ionization schemes for Au and At. Finally, the recently implemented multi-reflection time-of-flight mass separator for auxiliary isobaric purification now allows measurements which were not feasible before.

  15. Structural Characterization of Polymers by MALDI Spiral-TOF Mass Spectrometry Combined with Kendrick Mass Defect Analysis (United States)

    Sato, Hiroaki; Nakamura, Sayaka; Teramoto, Kanae; Sato, Takafumi


    High-resolution mass spectrometry (HRMS) continues to play an important role in the compositional characterization of larger organic molecules. In the field of polymer characterization, however, the application of HRMS has made only slow progress because of lower compatibility between matrix-assisted laser desorption/ionization (MALDI) and ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICRMS). In this study, a newly developed type of MALDI high-resolution time-of-flight mass spectrometry (TOFMS) with a spiral ion trajectory (MALDI spiral-TOFMS) was applied to the structural and compositional characterization of polymers. To create a graphical distribution of polymer components on a two-dimensional plot converted from complex mass spectra, we adopted a slightly modified Kendrick mass defect (KMD) analysis based on accurate masses determined using spiral-TOFMS. By setting the Kendrick mass scale based on the mass of the repeating units of a given polymer, components with common repeat units lined up in the horizontal direction on the KMD plot, whereas those components with different structures were shifted vertically. This combination of MALDI spiral-TOFMS measurement and KMD analysis enabled the successful discrimination of the polymer components in a blend of poly(alkylene oxide)s, the compositional analysis of poly(ethylene oxide)/poly(propylene oxide) block copolymers, and profiling of the end-group distribution of poly(ɛ-caprolactone)s synthesized under different conditions.

  16. Profiling Changes in Histone Post-translational Modifications by Top-Down Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Mowei; Wu, Si; Stenoien, David L.; Zhang, Zhaorui; Connolly, Lanelle; Freitag, Michael; Pasa-Tolic, Ljiljana


    Top-down mass spectrometry is a valuable tool for charactering post-translational modifications on histones for understanding of gene control and expression. In this protocol, we describe a top-down workflow using liquid chromatography coupled to mass spectrometry for fast global profiling of changes in histone proteoforms between a wild-type and a mutant of a fungal species. The proteoforms exhibiting different abundances can be subjected to further targeted studies by other mass spectrometric or biochemical assays. This method can be generally adapted for preliminary screening for changes in histone modifications between samples such as wild-type vs. mutant, and control vs. disease.

  17. Improving the performance of a quadrupole time-of-flight instrument for macromolecular mass spectrometry

    NARCIS (Netherlands)

    Heuvel, van den R.H.H.; Duijn, van E.; Mazon, H.; Synowsky, S.A.; Lorenzen, K.; Versluis, C.; Brouns, S.J.J.; Langridge, D.; Oost, van der J.; Hoyes, J.; Heck, C.K.


    We modified and optimized a first generation quadrupole time-of-flight (Q-TOF) 1 to perform tandem mass spectrometry on macromolecular protein complexes. The modified instrument allows isolation and subsequent dissociation of high-mass protein complexes through collisions with argon molecules. The

  18. Assembly of a Vacuum Chamber: A Hands-On Approach to Introduce Mass Spectrometry (United States)

    Bussie`re, Guillaume; Stoodley, Robin; Yajima, Kano; Bagai, Abhimanyu; Popowich, Aleksandra K.; Matthews, Nicholas E.


    Although vacuum technology is essential to many aspects of modern physical and analytical chemistry, vacuum experiments are rarely the focus of undergraduate laboratories. We describe an experiment that introduces students to vacuum science and mass spectrometry. The students first assemble a vacuum system, including a mass spectrometer. While…

  19. Seed Storage Proteins as a System for Teaching Protein Identification by Mass Spectrometry in Biochemistry Laboratory (United States)

    Wilson, Karl A.; Tan-Wilson, Anna


    Mass spectrometry (MS) has become an important tool in studying biological systems. One application is the identification of proteins and peptides by the matching of peptide and peptide fragment masses to the sequences of proteins in protein sequence databases. Often prior protein separation of complex protein mixtures by 2D-PAGE is needed,…

  20. Analysis of the lipidated recombinant outer surface protein A from Borrelia burgdorferi by mass spectrometry

    NARCIS (Netherlands)

    Bouchon, B.; Klein, Michele; Bischoff, Rainer; Van Dorsselaer, A.; Roitsch, C.


    The outer surface protein A, OspA, from the spirochete Borrelia burgdorferi is a lipoprotein of 25 kDa. The recombinant OspA (rOspA) expressed in Escherichia coli has been purified and analyzed by electrospray mass spectrometry (ESMS). A heterogenous spectrum gave a measured mass of 28,462 +/- 9 Da