301
|
Abstract
HPLC detector technology has advanced dramatically over the past 20 years, with a range of highly sensitive and specific detectors becoming available. What is still missing from the bioanalyst’s armoury, however, is a highly sensitive detector that gives an equimolar response independent of the compound. This would allow for quantification of compounds without the requirement for a synthetic standard or a radiolabeled analogue. In particular, such a detector applied to metabolism studies would establish the relative significance of the various metabolic routes. The recently issued US FDA guidelines on metabolites in safety testing (MIST) focus on the relative quantitation of human metabolites being obtained as soon as feasible in the drug-development process. In this article, current detector technology is reviewed with respect to its potential for quantitation without authentic standards or a radiolabel and put in the context of the MIST guidelines. The potential for future developments are explored.
Collapse
|
302
|
Pesek JJ, Matyska MT, Loo JA, Fischer SM, Sana TR. Analysis of hydrophilic metabolites in physiological fluids by HPLC-MS using a silica hydride-based stationary phase. J Sep Sci 2009; 32:2200-8. [DOI: 10.1002/jssc.200900270] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
303
|
Nedderman ANR. Metabolites in safety testing: metabolite identification strategies in discovery and development. Biopharm Drug Dispos 2009; 30:153-62. [DOI: 10.1002/bdd.660] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
|
304
|
Luo Q, Rejtar T, Wu SL, Karger BL. Hydrophilic interaction 10 microm I.D. porous layer open tubular columns for ultratrace glycan analysis by liquid chromatography-mass spectrometry. J Chromatogr A 2009; 1216:1223-31. [PMID: 18945436 PMCID: PMC2658773 DOI: 10.1016/j.chroma.2008.09.105] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Revised: 09/17/2008] [Accepted: 09/19/2008] [Indexed: 11/24/2022]
Abstract
The sensitivity of glycan analysis using nano-liquid chromatography interfaced with electrospray ionization mass spectrometry (ESI-MS) increases with the decrease of the mobile phase flow rate, accompanied by reduced ion suppression. In this study, we describe the preparation and performance of high efficiency 10 microm I.D. amine-bonded poly(vinylbenzyl chloride-divinylbenzene) hydrophilic interaction (HILIC) porous layer open tubular (PLOT) columns operated at 20 nL/min for the separation and analysis of glycan mixtures. HILIC-PLOT columns with a uniform porous polymer layer were reproducibly prepared ( approximately 4% RSD in retention time from column-to-column) via in situ polymerization, followed by one step modification with ethylenediamine. When coupled on-line with negative ESI-MS, low detection limits (0.3fmol) for a 3-sialyl-tetrasaccharide were achieved using a 2.5mx10 microm I.D. HILIC-PLOT column. A dextran ladder standard was used to evaluate the performance of the column, and high efficiency separation was achieved with detection of the dextrans up to G22 from approximately 50 fmol amounts injected. As an example of the high sensitivity of the column, MS(6) characterization of glycan structures was possible from the injection of 10 fmol of a neutral and sialylated glycan. As another example of high sensitivity LC-MS analysis of 3 ng of a PNGase F digest of ovalbumin allowed 28 N-linked glycans to be confidently identified from a single analysis. High quality MS/MS spectra for each ovalbumin glycan were acquired and manually interpreted for structure analysis. The HILIC-PLOT column is a very promising approach for LC-MS analysis of glycans at the ultratrace level.
Collapse
Affiliation(s)
- Quanzhou Luo
- Barnett Institute, Northeastern University, Boston, Massachusetts 02115, USA
| | - Tomas Rejtar
- Barnett Institute, Northeastern University, Boston, Massachusetts 02115, USA
| | - Shiaw-Lin Wu
- Barnett Institute, Northeastern University, Boston, Massachusetts 02115, USA
| | - Barry L. Karger
- Barnett Institute, Northeastern University, Boston, Massachusetts 02115, USA
| |
Collapse
|
305
|
van de Meent MHM, de Jong GJ. Potential of long capillary monolithic columns for the analysis of protein digests. J Sep Sci 2009; 32:487-93. [DOI: 10.1002/jssc.200800520] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
306
|
Di Marco VB, Bombi GG, Zambon S, Traldi P. Metal-ligand solution equilibria studied by electrospray ionization mass spectrometry: effect of instrumental parameters. JOURNAL OF MASS SPECTROMETRY : JMS 2009; 44:120-127. [PMID: 18788071 DOI: 10.1002/jms.1481] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Electrospray ionization mass spectrometry (ESI-MS) is being increasingly employed in the study of metal-ligand equilibria in aqueous solution. In the present work, the ESI-MS spectral changes due to different settings of the following instrumental parameters are analyzed: the solution flow rate (F(S)), the nebulizer gas flow rate (F(G)), the sprayer potential (E), and the temperature of the entrance capillary (T). Twenty-eight spectra were obtained for each of six samples containing aluminum(III) and 2,3-dihydroxypyridine at various pH, in the absence or in the presence of a buffer and of sodium ions. Among the considered instrumental parameters, T produced the largest effects on the ionic intensities. F(S) and F(G) affected the ESI-MS spectra to a lower extent than T. In the investigated conditions E had the weakest effects on the spectra.The correlations observed between the ionic intensities and these instrumental parameters were interpreted considering the presence of three kinds of perturbations occurring in the ESI-MS ion source: formation of some dimers in the droplets, different transfer efficiencies from the droplets to the gas phase for different complexes (according to their surface activity), and subsequent partial thermal decomposition of the dimers and of one of the monomeric complexes in the gas phase. Our results show that the evaluation of the effects produced in the ESI-MS spectra by a change of instrumental parameters can allow to identify the perturbations occurring when metal-ligand solutions are studied by ESI-MS.
Collapse
Affiliation(s)
- Valerio B Di Marco
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Padova, Italy.
| | | | | | | |
Collapse
|
307
|
Maxwell EJ, Chen DD. Twenty years of interface development for capillary electrophoresis–electrospray ionization–mass spectrometry. Anal Chim Acta 2008; 627:25-33. [DOI: 10.1016/j.aca.2008.06.034] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Revised: 06/13/2008] [Accepted: 06/19/2008] [Indexed: 11/15/2022]
|
308
|
Chen LC, Nishidate K, Saito Y, Mori K, Asakawa D, Takeda S, Kubota T, Hori H, Hiraoka K. Characteristics of Probe Electrospray Generated from a Solid Needle. J Phys Chem B 2008; 112:11164-70. [DOI: 10.1021/jp803730x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lee Chuin Chen
- Clean Energy Research Center, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511, Japan, Department of Anatomy and Cell Biology and Department of Epigenetic Medicine, Faculty of Medicine, University of Yamanashi, Shimo-Kateau 1110, Chuo, 409-3898, Japan, and Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511, Japan
| | - Kentaro Nishidate
- Clean Energy Research Center, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511, Japan, Department of Anatomy and Cell Biology and Department of Epigenetic Medicine, Faculty of Medicine, University of Yamanashi, Shimo-Kateau 1110, Chuo, 409-3898, Japan, and Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511, Japan
| | - Yuta Saito
- Clean Energy Research Center, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511, Japan, Department of Anatomy and Cell Biology and Department of Epigenetic Medicine, Faculty of Medicine, University of Yamanashi, Shimo-Kateau 1110, Chuo, 409-3898, Japan, and Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511, Japan
| | - Kunihiko Mori
- Clean Energy Research Center, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511, Japan, Department of Anatomy and Cell Biology and Department of Epigenetic Medicine, Faculty of Medicine, University of Yamanashi, Shimo-Kateau 1110, Chuo, 409-3898, Japan, and Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511, Japan
| | - Daiki Asakawa
- Clean Energy Research Center, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511, Japan, Department of Anatomy and Cell Biology and Department of Epigenetic Medicine, Faculty of Medicine, University of Yamanashi, Shimo-Kateau 1110, Chuo, 409-3898, Japan, and Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511, Japan
| | - Sen Takeda
- Clean Energy Research Center, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511, Japan, Department of Anatomy and Cell Biology and Department of Epigenetic Medicine, Faculty of Medicine, University of Yamanashi, Shimo-Kateau 1110, Chuo, 409-3898, Japan, and Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511, Japan
| | - Takeo Kubota
- Clean Energy Research Center, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511, Japan, Department of Anatomy and Cell Biology and Department of Epigenetic Medicine, Faculty of Medicine, University of Yamanashi, Shimo-Kateau 1110, Chuo, 409-3898, Japan, and Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511, Japan
| | - Hirokazu Hori
- Clean Energy Research Center, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511, Japan, Department of Anatomy and Cell Biology and Department of Epigenetic Medicine, Faculty of Medicine, University of Yamanashi, Shimo-Kateau 1110, Chuo, 409-3898, Japan, and Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511, Japan
| | - Kenzo Hiraoka
- Clean Energy Research Center, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511, Japan, Department of Anatomy and Cell Biology and Department of Epigenetic Medicine, Faculty of Medicine, University of Yamanashi, Shimo-Kateau 1110, Chuo, 409-3898, Japan, and Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511, Japan
| |
Collapse
|
309
|
Chen LC, Nishidate K, Saito Y, Mori K, Asakawa D, Takeda S, Kubota T, Terada N, Hashimoto Y, Hori H, Hiraoka K. Application of probe electrospray to direct ambient analysis of biological samples. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2008; 22:2366-2374. [PMID: 18623622 DOI: 10.1002/rcm.3626] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Recently, we have developed probe electrospray ionization (PESI) that uses a solid needle. In this system, the probe needle moves up and down along the vertical axis by a motor-driven system. At the highest position of the probe needle, electrospray is generated by applying a high voltage. In this study, we applied PESI directly to biological samples such as urine, mouse brain, mouse liver, salmon egg, and fruits (orange, banana, etc.). Strong ion signals for almost all the samples were obtained. The amount of liquid sample picked up by the needle is as small as pL or less, making PESI a promising non-invasive technique for detecting biomolecules in living systems such as cells. Therefore, PESI may be useful as a versatile and ready-to-use semi-online analytical tool in the fields of medicine, pharmaceuticals, agriculture, food science, etc.
Collapse
Affiliation(s)
- Lee Chuin Chen
- Clean Energy Research Center, University of Yamanashi, Takeda- 4, Kofu 400-8511, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
310
|
Marginean I, Kelly RT, Prior DC, LaMarche BL, Tang K, Smith RD. Analytical characterization of the electrospray ion source in the nanoflow regime. Anal Chem 2008; 80:6573-9. [PMID: 18661954 DOI: 10.1021/ac800683s] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A detailed characterization of a conventional low-flow electrospray ionization (ESI) source for mass spectrometry (MS) using solution compositions typical of reversed-phase liquid chromatography is reported. Contrary to conventional wisdom, the pulsating regime consistently provided better ESI-MS performance than the cone-jet regime for the interface and experimental conditions studied. This observation is supported by additional measurements showing that a conventional heated capillary interface affords more efficient sampling and transmission for the charged aerosol generated by a pulsating electrospray. The pulsating electrospray provided relatively constant MS signal intensities over a wide range of voltages, while the signal decreased slightly with increasing voltage for the cone-jet electrospray. The MS signal also decreased with increasing emitter-interface distance for both pulsating and cone-jet electrosprays due to the expansion of the charged aerosol plume. At flow rates below 100 nL/min, the MS signal increased with increasing flow rate due to increased number of gas-phase ions produced. At flow rates greater than 100 nL/min, the signal reached a plateau due to decreasing ionization efficiency at larger flow rates. These results suggest approaches for improving MS interface performance for low-flow (nano- to micro-) electrosprays.
Collapse
Affiliation(s)
- Ioan Marginean
- Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA
| | | | | | | | | | | |
Collapse
|
311
|
Rosu F, De Pauw E, Gabelica V. Electrospray mass spectrometry to study drug-nucleic acids interactions. Biochimie 2008; 90:1074-87. [DOI: 10.1016/j.biochi.2008.01.005] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Accepted: 01/11/2008] [Indexed: 12/27/2022]
|
312
|
Abstract
Quantitative proteomics approaches using stable isotopes are well-known and used in many labs nowadays. More recently, high resolution quantitative approaches are reported that rely on LC-MS quantitation of peptide concentrations by comparing peak intensities between multiple runs obtained by continuous detection in MS mode. Characteristic of these comparative LC-MS procedures is that they do not rely on the use of stable isotopes; therefore the procedure is often referred to as label-free LC-MS. In order to compare at comprehensive scale peak intensity data in multiple LC-MS datasets, dedicated software is required for detection, matching and alignment of peaks. The high accuracy in quantitative determination of peptide abundance provides an impressive level of detail. This approach also requires an experimental set-up where quantitative aspects of protein extraction and reproducible separation conditions need to be well controlled. In this paper we will provide insight in the critical parameters that affect the quality of the results and list an overview of the most recent software packages that are available for this procedure.
Collapse
Affiliation(s)
- Antoine H P America
- Plant Research International, Wageningen University and Research Centres, Wageningen, The Netherlands.
| | | |
Collapse
|
313
|
Cao M, Koulman A, Johnson LJ, Lane GA, Rasmussen S. Advanced data-mining strategies for the analysis of direct-infusion ion trap mass spectrometry data from the association of perennial ryegrass with its endophytic fungus, Neotyphodium lolii. PLANT PHYSIOLOGY 2008; 146:1501-14. [PMID: 18287492 PMCID: PMC2287329 DOI: 10.1104/pp.107.112458] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2007] [Accepted: 02/18/2008] [Indexed: 05/22/2023]
Abstract
Direct-infusion mass spectrometry (MS) was applied to study the metabolic effects of the symbiosis between the endophytic fungus Neotyphodium lolii and its host perennial ryegrass (Lolium perenne) in three different tissues (immature leaf, blade, and sheath). Unbiased direct-infusion MS using a linear ion trap mass spectrometer allowed metabolic effects to be determined free of any preconceptions and in a high-throughput fashion. Not only the full MS(1) mass spectra (range 150-1,000 mass-to-charge ratio) were obtained but also MS(2) and MS(3) product ion spectra were collected on the most intense MS(1) ions as described previously (Koulman et al., 2007b). We developed a novel computational methodology to take advantage of the MS(2) product ion spectra collected. Several heterogeneous MS(1) bins (different MS(2) spectra from the same nominal MS(1)) were identified with this method. Exploratory data analysis approaches were also developed to investigate how the metabolome differs in perennial ryegrass infected with N. lolii in comparison to uninfected perennial ryegrass. As well as some known fungal metabolites like peramine and mannitol, several novel metabolites involved in the symbiosis, including putative cyclic oligopeptides, were identified. Correlation network analysis revealed a group of structurally related oligosaccharides, which differed significantly in concentration in perennial ryegrass sheaths due to endophyte infection. This study demonstrates the potential of the combination of unbiased metabolite profiling using ion trap MS and advanced data-mining strategies for discovering unexpected perturbations of the metabolome, and generating new scientific questions for more detailed investigations in the future.
Collapse
Affiliation(s)
- Mingshu Cao
- AgResearch Limited, Grasslands Research Centre, Palmerston North 4442, New Zealand
| | | | | | | | | |
Collapse
|
314
|
Choi YS, Wood TD. Silanization of inner surfaces of nanoelectrospray ionization emitters for reduced analyte adsorption. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2008; 22:1265-1274. [PMID: 18357576 DOI: 10.1002/rcm.3502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
During the course of nanoelectrospray ionization (nanoESI) of substance P, an unusual type of signal reduction was observed with flow rates <10 nL/min. This reduction in signal appears to be induced by the adsorption of positively charged analytes onto negatively charged free silanol groups on the inner surface of emitters; analytes with higher pI values (such as substance P) exhibit greater tendency for adsorption. Support for this hypothesis is demonstrated by the decrease in signal reduction in the presence of concentrated salts or for emitters whose internal silanols have been covalently silanized. Emitters treated with hexamethyldisilazane or 3-aminopropyltriethoxysilane showed higher analyte signals for substance P than untreated emitters, suggesting a reduction of analyte adsorption onto the inner walls of silanized emitters. The efficacy of reduced peptide adsorption was demonstrated for emitters silanized with 3-aminopropyltriethoxysilane using a simple peptide mixture as well as a more complex peptide mixture (a tryptic digest of horse hemoglobin).
Collapse
Affiliation(s)
- Yong Seok Choi
- Department of Chemistry, Natural Sciences Complex, State University of New York at Buffalo, Buffalo, New York 14260-3000, USA
| | | |
Collapse
|
315
|
Metz TO, Page JS, Baker ES, Tang K, Ding J, Shen Y, Smith RD. High Resolution Separations and Improved Ion Production and Transmission in Metabolomics. Trends Analyt Chem 2008; 27:205-214. [PMID: 19255623 PMCID: PMC2625305 DOI: 10.1016/j.trac.2007.11.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The goal of metabolomics analyses is the detection and quantitation of as many sample components as reasonably possible in order to identify compounds or "features" that can be used to characterize the samples under study. When utilizing electrospray ionization to produce ions for analysis by mass spectrometry (MS), it is important that metabolome sample constituents be efficiently separated prior to ion production, in order to minimize ionization suppression and thereby extend the dynamic range of the measurement, as well as the coverage of the metabolome. Similarly, optimization of the MS inlet and interface can lead to increased measurement sensitivity. This perspective review will focus on the role of high resolution liquid chromatography (LC) separations in conjunction with improved ion production and transmission for LC-MS-based metabolomics. Additional emphasis will be placed on the compromise between metabolome coverage and sample analysis throughput.
Collapse
Affiliation(s)
- Thomas O. Metz
- Biological Sciences Division Pacific Northwest National Laboratory Richland, WA
| | - Jason S. Page
- Biological Sciences Division Pacific Northwest National Laboratory Richland, WA
| | - Erin S. Baker
- Biological Sciences Division Pacific Northwest National Laboratory Richland, WA
| | - Keqi Tang
- Biological Sciences Division Pacific Northwest National Laboratory Richland, WA
| | - Jie Ding
- Biological Sciences Division Pacific Northwest National Laboratory Richland, WA
| | - Yufeng Shen
- Biological Sciences Division Pacific Northwest National Laboratory Richland, WA
| | - Richard D. Smith
- Biological Sciences Division Pacific Northwest National Laboratory Richland, WA
| |
Collapse
|
316
|
Kelly RT, Page JS, Zhao R, Qian WJ, Mottaz HM, Tang K, Smith RD. Capillary-based multi nanoelectrospray emitters: improvements in ion transmission efficiency and implementation with capillary reversed-phase LC-ESI-MS. Anal Chem 2008; 80:143-9. [PMID: 18044958 PMCID: PMC2587435 DOI: 10.1021/ac701647s] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We describe the coupling of liquid chromatography (LC) separations with mass spectrometry (MS) using nanoelectrospray ionization (nano-ESI) multiemitters. The array of 19 emitters reduced the flow rate delivered to each emitter, allowing the enhanced sensitivity that is characteristic of nano-ESI to be extended to higher flow rate separations. The signal for tryptic fragments from proteins spiked into a human plasma sample increased 11-fold on average when the multiemitters were employed, due to increased ionization efficiency and improved ion transfer efficiency through a newly designed heated multicapillary MS inlet. Additionally, the LC peak signal-to-noise ratio increased approximately 7-fold when the multiemitter configuration was used. The low dead volume of the emitter arrays preserved peak shape and resolution for robust capillary LC separations using total flow rates of 2 microL/min.
Collapse
Affiliation(s)
- Ryan T Kelly
- Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA
| | | | | | | | | | | | | |
Collapse
|
317
|
Horvatovich P, Govorukhina NI, Reijmers TH, van der Zee AGJ, Suits F, Bischoff R. Chip-LC-MS for label-free profiling of human serum. Electrophoresis 2007; 28:4493-505. [DOI: 10.1002/elps.200600719] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
318
|
Mawhinney DB, Stanelle RD, Hamelin EI, Kobelski RJ. Enhancing the response of alkyl methylphosphonic acids in negative electrospray ionization liquid chromatography tandem mass spectrometry by post-column addition of organic solvents. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2007; 18:1821-6. [PMID: 17719237 DOI: 10.1016/j.jasms.2007.07.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2007] [Revised: 07/18/2007] [Accepted: 07/18/2007] [Indexed: 05/16/2023]
Abstract
A method to enhance the signal intensity and signal-to-noise of several alkyl methylphosphonic acids in negative electrospray ionization liquid chromatography tandem mass spectrometry (ESI LC-MS/MS) is presented. This class of compound represents the initial metabolites and environmental degradants of the nerve agents: VX, rVX (Russian VX), GB (Sarin), GF (Cyclosarin), and GD (Soman). Compared with the post-column addition of the mobile phase, the post-column addition of aprotic solvents and longer chain alcohols enhance the signal intensity and signal-to-noise ratio (S/N) of the chromatographic peaks by factors of up to 60 and 19, respectively. The post-column addition of water, methanol, and ethanol resulted in little or no relative signal enhancement. It is proposed that the post-column addition of these solvents do not result in the same enhancements due to stabilization of analyte solvation through hydrogen bonding.
Collapse
Affiliation(s)
- Douglas B Mawhinney
- US Centers for Disease Control and Prevention, National Center for Environmental Health, Division of Laboratory Sciences, Emergency Response and Air Toxicants, Atlanta, Georgia 30341, USA.
| | | | | | | |
Collapse
|
319
|
Ramanathan R, Zhong R, Blumenkrantz N, Chowdhury SK, Alton KB. Response normalized liquid chromatography nanospray ionization mass spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2007; 18:1891-9. [PMID: 17766144 DOI: 10.1016/j.jasms.2007.07.022] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2007] [Revised: 07/22/2007] [Accepted: 07/23/2007] [Indexed: 05/17/2023]
Abstract
The widely different LC-MS response observed for many structurally different compounds limits the use of LC-MS in full scan detection mode for quantitative determination of drugs and metabolites without using reference standard. The recently introduced nanospray ionization (NSI) technique shows comparable MS response for some compounds under non-LC-MS conditions. However, in the presence of numerous endogenous compounds commonly associated with biological samples such as urine, plasma, and bile, LC-MS is required to separate, detect, identify, and measure individual analytes. An LC-NSI-MS system was devised and the MS response obtained in this system for a variety of pharmaceutical drugs and their metabolites. The set-up involves two high-performance liquid chromatography (HPLC) systems, a chip-based NSI source and a quadrupole-time-of-flight (Q-TOF) mass spectrometer. Herein this is referred to as the response normalized-liquid chromatography NSI-MS (RNLC-NSI-MS) system. One HPLC unit performs the analytical separation, while the other unit adds solvent post-column with an exact reverse of the mobile phase composition such that the final composition entering the NSI source is isocratic throughout the entire HPLC run. The data obtained from four different structural classes of compounds [vicriviroc (VCV), desloratadine (DL), tolbutamide, and cocaine] and their metabolites indicate that by maintaining the solvent composition unchanged across the HPLC run, the influence of the solvent environment on the ionization efficiency is minimized. In comparison to responses obtained from radiochromatograms, responses from conventional LC-ESI-MS overestimated the VCV and DL responses, respectively, by 6- and 20-fold. Although VCV and DL responses obtained using LC-NSI-MS are within 2- to 6-fold from the respective radiochromatographic responses, the response normalization modification results in nearly uniform LC-NSI-MS response for all compounds evaluated.
Collapse
Affiliation(s)
- Ragu Ramanathan
- Department of Drug Metabolism and Pharmacokinetics, Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA.
| | | | | | | | | |
Collapse
|
320
|
Hoffmann P, Häusig U, Schulze P, Belder D. Microfluidic glass chips with an integrated nanospray emitter for coupling to a mass spectrometer. Angew Chem Int Ed Engl 2007; 46:4913-6. [PMID: 17516595 DOI: 10.1002/anie.200605152] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Peter Hoffmann
- Institut für Analytische Chemie, Chemo- und Biosensorik, Universität Regensburg, 93040 Regensburg, Germany
| | | | | | | |
Collapse
|
321
|
Pereira-Medrano AG, Sterling A, Snijders APL, Reardon KF, Wright PC. A systematic evaluation of chip-based nanoelectrospray parameters for rapid identification of proteins from a complex mixture. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2007; 18:1714-25. [PMID: 17689093 DOI: 10.1016/j.jasms.2007.06.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2006] [Revised: 06/15/2007] [Accepted: 06/22/2007] [Indexed: 05/16/2023]
Abstract
HPLC-MS/MS is widely used for protein identification from gel spots and shotgun fractions. Although HPLC has well recognized benefits, this type of sample infusion also has some undesirable attributes: relatively low sample throughput, potential sample-to-sample carryover, time-varying sample composition, and no option for longer sample infusion for longer MS analyses. An automated chip-based ESI device (CB-ESI) has the potential to overcome these limitations. This report describes a systematic evaluation of the information-dependant acquisition (IDA) and sample preparation protocols for rapid protein identification from a complex mixture using a CB-ESI source compared with HPLC-ESI (gradient and isocratic elutions). Cytochrome c and a six-protein mixture (11-117 kDa) were used to develop an IDA protocol for rapid protein identification and to evaluate the effects of sample preparation protocols. MS (1-10 s) and MS/MS (1-60 s) scan times, sample concentration (50-500 fmol/microL), and ZipTipC(18) cleanup were evaluated. Based on MOWSE scores, protein coverage, experimental run time, number of identified proteins, and reproducibility, a 12.5 min experiment (22 cycles, each with one 3 s MS and eight 10 s MS/MS scans) was determined to be the optimal IDA protocol for CB-ESI. This work flow yielded up to 220% greater peptide coverage compared with gradient HPLC-ESI and provided protein identifications with up to a 2-fold higher throughput rate than either HPLC-ESI approach, whilst employing half the amount of sample over the same time frame. The results from this study support the use of CB-ESI as a rapid alternative to the identification of protein mixtures.
Collapse
Affiliation(s)
- Ana Gabriela Pereira-Medrano
- Biological and Environmental Systems Group, Department of Chemical and Process Engineering, University of Sheffield, Sheffield, United Kingdom
| | | | | | | | | |
Collapse
|
322
|
Schmelzer CEH, Schöps R, Reynell L, Ulbrich-Hofmann R, Neubert RHH, Raith K. Peptic digestion of β-casein. J Chromatogr A 2007; 1166:108-15. [PMID: 17720176 DOI: 10.1016/j.chroma.2007.08.015] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Revised: 08/01/2007] [Accepted: 08/02/2007] [Indexed: 11/21/2022]
Abstract
Numerous peptides obtained by enzymatic digestion of food proteins have been reported to exhibit biological activities. In this study, the focus was placed on peptides of beta-casein from bovine milk after a gastro-analogous in vitro digestion with pepsin, a protease with broad specificity. In order to study the time course of the digestion, the process was stopped after specific times and the samples were subjected to HPLC separation followed by matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) and nanoelectrospray (nanoESI) quadrupole time-of-flight (qTOF) mass spectrometry. A combined sequencing approach using de novo interpretation and databases was employed. Overall, 100% of the beta-casein sequence was covered by identifying 125 peptides of 4-84 residues in length, including 3 phosphorylated species. The results show that the peptic hydrolysis starts at the C-terminus of the protein. The release of known bioactive peptides from beta-casein following the peptic digestion under simulated gastric conditions is unlikely with a few exceptions. Furthermore, an amino acid variation was found, providing evidence for the existence of an additional genetic variant of beta-casein.
Collapse
Affiliation(s)
- Christian E H Schmelzer
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Strasse 4, 06120 Halle (Saale), Germany
| | | | | | | | | | | |
Collapse
|
323
|
Page JS, Kelly RT, Tang K, Smith RD. Ionization and transmission efficiency in an electrospray ionization-mass spectrometry interface. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2007; 18:1582-90. [PMID: 17627841 DOI: 10.1016/j.jasms.2007.05.018] [Citation(s) in RCA: 169] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Revised: 05/24/2007] [Accepted: 05/25/2007] [Indexed: 05/03/2023]
Abstract
The ionization and transmission efficiencies of an electrospray ionization (ESI) interface were investigated to advance the understanding of how these factors affect mass spectrometry (MS) sensitivity. In addition, the effects of the ES emitter distance to the inlet, solution flow rate, and inlet temperature were characterized. Quantitative measurements of ES current loss throughout the ESI interface were accomplished by electrically isolating the front surface of the interface from the inner wall of the heated inlet capillary, enabling losses on the two surfaces to be distinguished. In addition, the ES current lost to the front surface of the ESI interface was spatially profiled with a linear array of 340-microm-diameter electrodes placed adjacent to the inlet capillary entrance. Current transmitted as gas-phase ions was differentiated from charged droplets and solvent clusters by measuring sensitivity with a single quadrupole mass spectrometer. The study revealed a large sampling efficiency into the inlet capillary (>90% at an emitter distance of 1 mm), a global rather than a local gas dynamic effect on the shape of the ES plume resulting from the gas flow conductance limit of the inlet capillary, a large (>80%) loss of analyte ions after transmission through the inlet arising from incomplete desolvation at a solution flow rate of 1.0 microL/min, and a decrease in analyte ions peak intensity at lower temperatures, despite a large increase in ES current transmission efficiency.
Collapse
Affiliation(s)
- Jason S Page
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | | | | | | |
Collapse
|
324
|
Kuprowski MC, Boys BL, Konermann L. Analysis of protein mixtures by electrospray mass spectrometry: effects of conformation and desolvation behavior on the signal intensities of hemoglobin subunits. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2007; 18:1279-85. [PMID: 17500007 DOI: 10.1016/j.jasms.2007.04.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Revised: 03/31/2007] [Accepted: 04/05/2007] [Indexed: 05/15/2023]
Abstract
The determination of solution-phase protein concentration ratios based on ESI-MS intensity ratios is not always straightforward. For example, equimolar mixtures of hemoglobin alpha- and beta-subunits consistently result in much higher peak intensities for the alpha-chain. The current work explores the origin of this effect. Under mildly acidic conditions (pH 3.4) alpha-globin is extensively unfolded, whereas beta-globin retains residual structure. Because of its greater nonpolar character, the more unfolded alpha-subunit can more effectively compete for charge. This leads to suppression of beta-globin signals under conditions where the protein ion yield is limited by the charge concentration on the initially formed ESI droplets. More balanced intensities are observed when operating under charge excess conditions and/or in a solvent environment where both proteins are unfolded to a similar degree (pH 2.2). However, even in these cases the overall alpha-globin peak intensity is still twice as high as that of the beta-subunit. The persistent imbalance under these conditions originates from the different declustering behaviors of the two proteins. A considerable fraction of beta-globin undergoes incomplete desolvation during ESI, thereby reducing the intensity of bare [beta + zH](z+) ions. When including the contributions of incompletely desolvated species, the overall alpha:beta ion intensity ratio is close to unity. The alpha:beta intensity imbalance can also be eliminated by a strongly elevated declustering potential in the ion sampling interface. In conclusion, important factors that have to be considered for the ESI-MS analysis of protein mixtures are (1) conformational effects, resulting in differential surface activities, and (2) dissimilarities in the protein desolvation behavior.
Collapse
Affiliation(s)
- Mark C Kuprowski
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada
| | | | | |
Collapse
|
325
|
Hoffmann P, Häusig U, Schulze P, Belder D. Mikrofluidische Glas-Chips mit integriertem Nanospray-Emitter zur Kopplung mit der Massenspektrometrie. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200605152] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
326
|
Metz TO, Zhang Q, Page JS, Shen Y, Callister SJ, Jacobs JM, Smith RD. The future of liquid chromatography-mass spectrometry (LC-MS) in metabolic profiling and metabolomic studies for biomarker discovery. Biomark Med 2007; 1:159-185. [PMID: 19177179 DOI: 10.2217/17520363.1.1.159] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The future utility of liquid chromatography-mass spectrometry (LC-MS) in metabolic profiling and metabolomic studies for biomarker discover will be discussed, beginning with a brief description of the evolution of metabolomics and the utilization of the three most popular analytical platforms in such studies: NMR, GC-MS, and LC-MS. Emphasis is placed on recent developments in high-efficiency LC separations, sensitive electrospray ionization approaches, and the benefits to incorporating both in LC-MS-based approaches. The advantages and disadvantages of various quantitative approaches are reviewed, followed by the current LC-MS-based tools available for candidate biomarker characterization and identification. Finally, a brief prediction on the future path of LC-MS-based methods in metabolic profiling and metabolomic studies is given.
Collapse
Affiliation(s)
- Thomas O Metz
- Biological Science Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, USA
| | | | | | | | | | | | | |
Collapse
|
327
|
Cañas B, Piñeiro C, Calvo E, López-Ferrer D, Gallardo JM. Trends in sample preparation for classical and second generation proteomics. J Chromatogr A 2007; 1153:235-58. [PMID: 17276441 DOI: 10.1016/j.chroma.2007.01.045] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2006] [Revised: 12/18/2006] [Accepted: 01/12/2007] [Indexed: 11/16/2022]
Abstract
Sample preparation is a fundamental step in the proteomics workflow. However, it is not easy to find compiled information updating this subject. In this paper, the strategies and protocols for protein extraction and identification, following either classical or second generation proteomics methodologies, are reviewed. Procedures for: tissue disruption, cell lysis, sample pre-fractionation, protein separation by 2-DE, protein digestion, mass spectrometry analysis, multidimensional peptide separations and quantification of protein expression level are described.
Collapse
Affiliation(s)
- Benito Cañas
- Dept. Química Analítica, Facultad de CC, Químicas, UCM, Av.Complutense s/n, Madrid 28040, Spain.
| | | | | | | | | |
Collapse
|
328
|
Prakash C, Shaffer CL, Nedderman A. Analytical strategies for identifying drug metabolites. MASS SPECTROMETRY REVIEWS 2007; 26:340-69. [PMID: 17405144 DOI: 10.1002/mas.20128] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
With the dramatic increase in the number of new chemical entities (NCEs) arising from combinatorial chemistry and modern high-throughput bioassays, novel bioanalytical techniques are required for the rapid determination of the metabolic stability and metabolites of these NCEs. Knowledge of the metabolic site(s) of the NCEs in early drug discovery is essential for selecting compounds with favorable pharmacokinetic credentials and aiding medicinal chemists in modifying metabolic "soft spots". In development, elucidation of biotransformation pathways of a drug candidate by identifying its circulatory and excretory metabolites is vitally important to understand its physiological effects. Mass spectrometry (MS) and nuclear magnetic resonance (NMR) have played an invaluable role in the structural characterization and quantification of drug metabolites. Indeed, liquid chromatography (LC) coupled with atmospheric pressure ionization (API) MS has now become the most powerful tool for the rapid detection, structure elucidation, and quantification of drug-derived material within various biological fluids. Often, however, MS alone is insufficient to identify the exact position of oxidation, to differentiate isomers, or to provide the precise structure of unusual and/or unstable metabolites. In addition, an excess of endogenous material in biological samples often suppress the ionization of drug-related material complicating metabolite identification by MS. In these cases, multiple analytical and wet chemistry techniques, such as LC-NMR, enzymatic hydrolysis, chemical derivatization, and hydrogen/deuterium-exchange (H/D-exchange) combined with MS are used to characterize the novel and isomeric metabolites of drug candidates. This review describes sample preparation and introduction strategies to minimize ion suppression by biological matrices for metabolite identification studies, the application of various LC-tandem MS (LC-MS/MS) techniques for the rapid quantification and identification of drug metabolites, and future trends in this field.
Collapse
Affiliation(s)
- Chandra Prakash
- Pfizer Global Research and Development, Eastern Point Road, Groton, Connecticut 06340, USA.
| | | | | |
Collapse
|
329
|
Tang X, Bruce JE, Hill HH. Characterizing electrospray ionization using atmospheric pressure ion mobility spectrometry. Anal Chem 2007; 78:7751-60. [PMID: 17105168 PMCID: PMC3633478 DOI: 10.1021/ac0613380] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Reduced flow rate electrospray ionization has been proven to provide improved sensitivity, less background noise, and improved limits of detections for ESI-MS analysis. Miniaturizing the ESI source from conventional electrospray to microelectrospray and further down to nanoelectrospray has resulted in higher and higher sensitivity; however, when effects of flow rate were investigated for atmospheric pressure ESI-IMS using a nanospray emitter, a striking opposite result was observed. The general tendency we observed in ESI-IMS was that higher flow rate offered higher ion signal intensity throughout a variety of conditions investigated. Thus, further efforts were undertaken to rationalize these contradictory results. It is well accepted that decreased flow rate increases both ionization efficiency and transmission efficiency, thus improving ion signal in ESI-MS. However, our study revealed that decreased flow rate results in decreased ion signal because ion transfer is constant, no matter how flow rate changes in ESI-IMS. Since ion transfer is constant in atmospheric pressure ESI-IMS, ionization efficiency can be studied independently, which otherwise is not possible in ESI-MS in which both ionization efficiency and transmission efficiency vary as conditions alter. In this article, we present a systematic study of signal intensity and ionization efficiency at various experimental conditions using ESI-IMS and demonstrate the ionization efficiency as a function of flow rate, analyte concentration, and solvent composition.
Collapse
|
330
|
Hatsis P, Brockman AH, Wu JT. Evaluation of high-field asymmetric waveform ion mobility spectrometry coupled to nanoelectrospray ionization for bioanalysis in drug discovery. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2007; 21:2295-300. [PMID: 17577878 DOI: 10.1002/rcm.3093] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The potential of high-field asymmetric waveform ion mobility spectrometry (FAIMS) coupled to nanoelectrospray ionization (nanoESI) as a method to improve sample throughput for bioanalysis in a discovery pharmaceutical setting was explored in this work. The ability of FAIMS to separate gas-phase ions in the millisecond timescale was exploited to eliminate the need for liquid chromatography. Samples were introduced into the FAIMS electrodes/mass spectrometer using offline nanoESI at 20 nL/min and 1.5 kV. Signals were averaged for 30 s after which the next sample could be analyzed. The separation of simple mixtures, e.g., the removal of metabolite and endogenous interferences from parent drug, was demonstrated. Moreover, the application of nanoESI attenuated the ion suppression effects that normally plague conventional electrospray. On average, approximately two-thirds of the neat sample signal intensity was preserved in extracted plasma samples. Standard curves were prepared for several compounds and linearity was obtained over approximately two to three orders of magnitude. This methodology was further tested with the analysis of plasma samples from a mouse pharmacokinetic study. Concentration values determined using nanoESI-FAIMS were comparable to those determined using conventional LC/MS as demonstrated by percent differences of less than 30%. This work demonstrated the proof of concept that the combination of FAIMS and nanospray ionization can be a potentially useful tool to improve the throughput of discovery bioanalysis.
Collapse
Affiliation(s)
- Panos Hatsis
- Department of Drug Metabolism and Pharmacokinetics, Millennium Pharmaceuticals, Inc., 35 Landsdowne St, Cambridge, MA 02139, USA.
| | | | | |
Collapse
|
331
|
Trunzer M, Graf D, Kiffe M. Comparison of a two-dimensional liquid chromatography/mass spectrometry approach with a chip-based nanoelectrospray device for structural elucidation of metabolites in a human ADME study using a quadrupole time-of-flight mass spectrometer. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2007; 21:937-44. [PMID: 17295360 DOI: 10.1002/rcm.2918] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The study of the metabolic fate of drugs is essential for the safety assessment of new compounds in the drug development process. However, the characterization and structural elucidation of metabolites from in vivo experiments is still a very challenging task. In this paper, we compare a two-dimensional liquid chromatography/mass spectrometry (LC/MS) approach using either a capillary LC/MS system or the recently introduced chip-based nanoelectrospray/MS system (Nanomate) as the second dimension for structural elucidation of metabolites by MS. More than 30 radioactive fractions of a chromatographic separation from a human urine sample were analyzed and 54 metabolites could be identified. The long persisting and stable nanoelectrospray enabled the search for unknown metabolites by precursor-ion scanning experiments followed by product-ion scanning experiments of potential metabolites using a quadrupole time-of-flight (qTOF) mass spectrometer. The number of fragments produced by nanoelectrospray with product-ion scanning was significantly higher compared to LC/MS experiments with in-source fragmentation. Therefore, the assignment of possible modifications in metabolites to certain moieties of the drug could be investigated with higher accuracy. The capillary LC/MS system for the second dimension was more sensitive in the case of low abundant metabolites. These metabolites could not be detected by direct nanoelectrospray infusion, which limits the application of the Nanomate for trace metabolites.
Collapse
MESH Headings
- Chromatography, High Pressure Liquid/instrumentation
- Chromatography, High Pressure Liquid/methods
- Electrophoresis, Gel, Two-Dimensional/instrumentation
- Electrophoresis, Gel, Two-Dimensional/methods
- Equipment Design
- Equipment Failure Analysis
- Lab-On-A-Chip Devices
- Microchip Analytical Procedures/methods
- Nanotechnology/instrumentation
- Nanotechnology/methods
- Reproducibility of Results
- Sensitivity and Specificity
- Spectrometry, Mass, Electrospray Ionization/instrumentation
- Spectrometry, Mass, Electrospray Ionization/methods
- Urinalysis/instrumentation
- Urinalysis/methods
Collapse
Affiliation(s)
- Markus Trunzer
- Novartis Pharma AG, Drug Metabolism and Pharmacokinetics, CH-4002 Basel, Switzerland.
| | | | | |
Collapse
|
332
|
Choi YS, Wood TD. Polyaniline-coated nanoelectrospray emitters treated with hydrophobic polymers at the tip. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2007; 21:2101-8. [PMID: 17546654 DOI: 10.1002/rcm.3068] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
In nanoelectrospray ionization (nanoESI) techniques, the hydrophilic character of the emitters generally produces large bases for the Taylor cones, thereby generating relatively large droplet sizes and consequently reduced sensitivity. In order to minimize this 'wetting' effect in nanoESI, a model hydrophobic polymer (an acrylic paint) was coated at the tip of commercial polyaniline (PANI)-coated emitters, and their performance was compared with that of unmodified PANI emitters using oxytocin and neuropeptide Y (NPY) solutions. In experiments with oxytocin, the hydrophobic emitter produced higher signal intensities (up to 3.6 times) as well as higher signal-to-noise ratios (33% increase) than those from the unmodified PANI emitter. In addition, the hydrophobic emitter showed reusability and a slightly wider linear dynamic range (10 nM to 50 microM, r2=0.9938) than that from the unmodified PANI emitter (10 nM to 10 microM, r2=0.9904). In the case of NPY, the hydrophobic emitter also enabled an approximately 350-fold overall increase in sensitivity than the unmodified PANI emitter (70 zmol vs. 25 amol). The enhanced performance of the hydrophobic emitter clearly indicates potential for further increases in nanoESI sensitivity using emitters with tailored hydrophobic overcoatings.
Collapse
Affiliation(s)
- Yong Seok Choi
- Department of Chemistry, Natural Sciences Complex, State University of New York at Buffalo, Buffalo, NY 14260-3000, USA
| | | |
Collapse
|
333
|
Paine MD, Alexander MS, Stark JPW. Nozzle and liquid effects on the spray modes in nanoelectrospray. J Colloid Interface Sci 2007; 305:111-23. [PMID: 17028003 DOI: 10.1016/j.jcis.2006.09.031] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2006] [Revised: 08/15/2006] [Accepted: 09/15/2006] [Indexed: 10/24/2022]
Abstract
Unforced nanoelectrospray can exhibit a number of stable spray modes. These include low frequency pulsations, high frequency pulsations, and a steady cone-jet. Experiments are reported here on such pulsations that have been observed in various salt loaded solutions of ethylene glycol, triethylene glycol and water. The spray current was monitored with 1 mus time resolution to show that spray regime characteristics depend on nozzle diameter and liquid conductivity. The frequency of pulsations was found to increase with both increased liquid conductivity and decreasing nozzle diameter. The charge ejected during a pulse is lower for smaller nozzles spraying higher conductivity liquids. Water solutions were observed undergoing high frequency pulsations, with these pulsations often occurring in lower frequency bursts. The frequencies of water pulsations were as high as 635 kHz but the charge ejected by each pulsation was an order of magnitude lower than that observed in triethylene glycol. An unforced electrospray of water was also identified as being in the steady cone-jet mode with a higher degree of confidence than previously. The values for stable pulsation frequency and charge ejected observed in ethylene glycol lay between those of TEG and water.
Collapse
Affiliation(s)
- Mark D Paine
- Department of Engineering, Queen Mary, University of London, Mile End Road, London E1 4NS, UK.
| | | | | |
Collapse
|
334
|
Kelly RT, Page JS, Luo Q, Moore RJ, Orton DJ, Tang K, Smith RD. Chemically etched open tubular and monolithic emitters for nanoelectrospray ionization mass spectrometry. Anal Chem 2006; 78:7796-801. [PMID: 17105173 PMCID: PMC1769309 DOI: 10.1021/ac061133r] [Citation(s) in RCA: 212] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have developed a new procedure for fabricating fused-silica emitters for electrospray ionization-mass spectrometry (ESI-MS) in which the end of a bare fused-silica capillary is immersed into aqueous hydrofluoric acid, and water is pumped through the capillary to prevent etching of the interior. Surface tension causes the etchant to climb the capillary exterior, and the etch rate in the resulting meniscus decreases as a function of distance from the bulk solution. Etching continues until the silica touching the hydrofluoric acid reservoir is completely removed, essentially stopping the etch process. The resulting emitters have no internal taper, making them much less prone to clogging compared to, e.g., pulled emitters. The high aspect ratios and extremely thin walls at the orifice facilitate very low flow rate operation; stable ESI-MS signals were obtained for model analytes from 5-microm-diameter emitters at a flow rate of 5 nL/min with a high degree of interemitter reproducibility. In extensive evaluation, the etched emitters were found to enable approximately four times as many LC-MS analyses of proteomic samples before failing compared with conventional pulled emitters. The fabrication procedure was also employed to taper the ends of polymer monolith-containing silica capillaries for use as ESI emitters. In contrast to previous work, the monolithic material protrudes beyond the fused-silica capillaries, improving the monolith-assisted electrospray process.
Collapse
Affiliation(s)
- Ryan T. Kelly
- Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
| | - Jason S. Page
- Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
| | - Quanzhou Luo
- Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
| | - Ronald J. Moore
- Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
| | - Daniel J. Orton
- Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
| | - Keqi Tang
- Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
| | - Richard D. Smith
- Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
| |
Collapse
|
335
|
Smith RD. Future directions for electrospray ionization for biological analysis using mass spectrometry. Biotechniques 2006; 41:147-8. [PMID: 16925015 DOI: 10.2144/000112217] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- Richard D Smith
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
| |
Collapse
|
336
|
Lanckmans K, Van Eeckhaut A, Sarre S, Smolders I, Michotte Y. Capillary and nano-liquid chromatography-tandem mass spectrometry for the quantification of small molecules in microdialysis samples: comparison with microbore dimensions. J Chromatogr A 2006; 1131:166-75. [PMID: 16938304 DOI: 10.1016/j.chroma.2006.07.090] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2006] [Revised: 07/14/2006] [Accepted: 07/21/2006] [Indexed: 11/29/2022]
Abstract
Enhanced sensitivity is a well known benefit of miniaturised LC-electrospray (ESI)-MS/MS methods. The suitability of miniaturised LC-MS/MS for quantification of small molecules in dialysates was investigated using the anti-epileptic drug oxcarbazepine, its active metabolite, 10,11-dihydro-10-hydroxycarbamazepine, and the internal standard for microdialysis probe calibration, 2-methyl-5H-dibenz(b,f)azepine-5-carboxamide, as test compounds. ESI-MS detection is sensitive to matrix effects. Therefore, dialysate matrix effects were investigated by comparing the responses of standards made in water, Ringer's solution (salt solution used as perfusion fluid) and blank dialysate matrix. Due to the occurrence of ion suppression or enhancement, direct injection of dialysis samples onto the analytical column could not be applied for quantification of small molecules in dialysis samples. Column switching was necessary for desalting and preconcentration of the dialysates. However, this approach was not able to completely eliminate salt effects when the injection volume exceeded 1 microL. No differences in response between Ringer's solution and dialysate matrix were detected at capillary and nano-dimensions. Calibration standards should be prepared with Ringer's solution instead of water for quantitative analysis of microdialysates. A microbore, capillary and nano-LC-ESI-MS/MS method were compared in terms of method feasibility, linearity, sensitivity, accuracy and precision. Downscaling to capillary and nano-dimensions resulted in a gain in detection sensitivity of 5 and 50, respectively. Miniaturised LC-MS/MS was found to be fit for quantification of small molecules in dialysates with acceptable accuracy and method precision.
Collapse
Affiliation(s)
- Katrien Lanckmans
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium
| | | | | | | | | |
Collapse
|
337
|
Zhou L, Zhai L, Yue B, Lee ED, Lee ML. New interface plate for microspray ionization mass spectrometry. Anal Bioanal Chem 2006; 385:1087-91. [PMID: 16736166 DOI: 10.1007/s00216-006-0523-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Revised: 04/20/2006] [Accepted: 05/02/2006] [Indexed: 11/26/2022]
Abstract
A new interface plate was employed in microspray ionization mass spectrometry (microESI-MS) to improve ion transmission from the sprayer into the sampling nozzle of the mass spectrometer at atmospheric pressure. Using a time-of-flight mass spectrometer (TOFMS), a fivefold increase in ion intensity and a sevenfold reduction in method detection limit were observed. The interface plate attenuated the dependence of the ion intensity on the sprayer position. Even when the distance between the sprayer tip and sampling nozzle was 15.0 mm, ion signals were still stronger than when the sprayer tip was positioned 3.0 mm in front of the sampling nozzle with the original interface plate. This enhancement in the performance of microESI-MS was due to the improved shapes of the equipotential lines near the sprayer tip and the long desolvation distance between the sprayer and the sampling nozzle of the MS.
Collapse
Affiliation(s)
- Li Zhou
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602-5700, USA
| | | | | | | | | |
Collapse
|
338
|
Zimmer JSD, Monroe ME, Qian WJ, Smith RD. Advances in proteomics data analysis and display using an accurate mass and time tag approach. MASS SPECTROMETRY REVIEWS 2006; 25:450-82. [PMID: 16429408 PMCID: PMC1829209 DOI: 10.1002/mas.20071] [Citation(s) in RCA: 254] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Proteomics has recently demonstrated utility for increasing the understanding of cellular processes on the molecular level as a component of systems biology approaches and for identifying potential biomarkers of various disease states. The large amount of data generated by utilizing high efficiency (e.g., chromatographic) separations coupled with high mass accuracy mass spectrometry for high-throughput proteomics analyses presents challenges related to data processing, analysis, and display. This review focuses on recent advances in nanoLC-FTICR-MS-based proteomics approaches and the accompanying data processing tools that have been developed to display and interpret the large volumes of data being produced.
Collapse
Affiliation(s)
- Jennifer S D Zimmer
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | | | | | | |
Collapse
|
339
|
Smith RD, Tang K, Shen Y. Ultra-sensitive and quantitative characterization of proteomes. MOLECULAR BIOSYSTEMS 2006; 2:221-30. [PMID: 16880940 DOI: 10.1039/b601468b] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electrospray ionization mass spectrometry combined with high efficiency capillary liquid chromatography provides high sensitivity and broad dynamic range measurements for the characterization of biological macromolecules in complex matrices, and is an increasingly powerful analytical tool for systems biology research.
Collapse
Affiliation(s)
- Richard D Smith
- Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MS K8-98, Richland, WA 99352, USA.
| | | | | |
Collapse
|
340
|
Manisali I, Chen DD, Schneider BB. Electrospray ionization source geometry for mass spectrometry: past, present, and future. Trends Analyt Chem 2006. [DOI: 10.1016/j.trac.2005.07.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
341
|
Mungur R, Glass ADM, Goodenow DB, Lightfoot DA. Metabolite fingerprinting in transgenic Nicotiana tabacum altered by the Escherichia coli glutamate dehydrogenase gene. J Biomed Biotechnol 2006; 2005:198-214. [PMID: 16046826 PMCID: PMC1184043 DOI: 10.1155/jbb.2005.198] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
With about 200 000 phytochemicals in existence, identifying
those of biomedical significance is a mammoth task. In the
postgenomic era, relating metabolite fingerprints, abundances,
and profiles to genotype is also a large task. Ion analysis
using Fourier transformed ion cyclotron resonance mass
spectrometry (FT-ICR-MS) may provide a high-throughput
approach to measure genotype dependency of the inferred
metabolome if reproducible techniques can be established. Ion
profile inferred metabolite fingerprints are coproducts. We
used FT-ICR-MS-derived ion analysis to examine gdhA
(glutamate dehydrogenase (GDH; EC 1.4.1.1)) transgenic
Nicotiana tabacum (tobacco) carrying out altered
glutamate, amino acid, and carbon metabolisms, that
fundamentally alter plant productivity. Cause and effect
between gdhA expression, glutamate metabolism, and
plant phenotypes was analyzed by 13NH4+ labeling of amino acid fractions, and by FT-ICR-MS analysis of
metabolites. The gdhA transgenic plants increased
13N labeling of glutamate and glutamine
significantly. FT-ICR-MS detected 2 012 ions reproducible in
2 to 4 ionization protocols. There were 283 ions in
roots and 98 ions in leaves that appeared to significantly
change abundance due to the measured GDH activity. About 58%
percent of ions could not be used to infer a corresponding
metabolite. From the 42% of ions that inferred known
metabolites we found that certain amino acids, organic acids,
and sugars increased and some fatty acids decreased. The
transgene caused increased ammonium assimilation and
detectable ion variation. Thirty-two compounds with biomedical
significance were altered in abundance by GDH including 9
known carcinogens and 14 potential drugs. Therefore, the GDH
transgene may lead to new uses for crops like tobacco.
Collapse
Affiliation(s)
- R. Mungur
- Department of Molecular and Medical Biochemistry, Southern Illinois University, Carbondale, IL 62901, USA
| | - A. D. M. Glass
- Department of Botany, University of British Columbia, Vancouver, Canada V6T 1Z4
| | - D. B. Goodenow
- Phenomenome Discoveries Inc. 941 University Drive, Saskatoon, Canada S7N 0K2
| | - D. A. Lightfoot
- Department of Molecular and Medical Biochemistry, Southern Illinois University, Carbondale, IL 62901, USA
- *D. A. Lightfoot:
| |
Collapse
|
342
|
Smith DR, Moy MA, Dolan AR, Wood TD. Analytical performance characteristics of nanoelectrospray emitters as a function of conductive coating. Analyst 2006; 131:547-55. [PMID: 16568172 DOI: 10.1039/b516188f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
As miniaturization of electrospray continues to become more prevalent in the mass spectrometry arsenal, numerous types of conductive coatings have been developed with miniaturized electrospray emitters. Different conductive coatings have different properties that may lead to differences in analytical performance. This paper investigates and compares the analytical properties of a series of applied conductive coatings for low-flow electrospray ionization developed in this laboratory vs. commercially-available types. Evaporated graphite is thoroughly compared with commercially available polyaniline (PANI) coated emitters and metal coated emitters. Each set of emitters was investigated to determine various performance characteristics, including susceptibility to electrical discharge in both positive and negative ionization modes, as well as emitter reproducibility and generation of a standard curve to determine each emitter coating's limit of detection and limit of quantitation. Furthermore, evaporated graphite and polyaniline coated fused silica capillaries were investigated to determine which coating is more stable over long-term analyses and during electrical discharge.
Collapse
Affiliation(s)
- Douglas R Smith
- Nanogenesys, Inc., Baird Research Park, Suite 224, 1576 Sweet Home Rd., Amherst, NY 14228, USA
| | | | | | | |
Collapse
|
343
|
Valaskovic GA, Utley L, Lee MS, Wu JT. Ultra-low flow nanospray for the normalization of conventional liquid chromatography/mass spectrometry through equimolar response: standard-free quantitative estimation of metabolite levels in drug discovery. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2006; 20:1087-96. [PMID: 16506151 DOI: 10.1002/rcm.2414] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Nanospray experiments were performed on an ensemble of drug molecules and their commonly known metabolites to compare performance with conventional electrospray ionization (ESI) and to evaluate equimolar response capabilities. Codeine, dextromethorphan, tolbutamide, phenobarbital, cocaine, and morphine were analyzed along with their well-known metabolites that were formed via hydroxylation, dealkylation, hydrolysis, and glucuronidation. Nanospray exhibited a distinct trend toward equimolar response when flow rate was reduced from 25 nL/min to less than 10 nL/min. A more uniform response between the parent drug and the corresponding metabolites was obtained at flow rates of 10 nL/min or lower. The largest discrepancy was within +/-50% for plasma samples. Nanospray was used as a calibrator for conventional ESI liquid chromatography/tandem mass spectrometry (LC/MS/MS) and normalization factors were applied to the quantitation of an acyl-glucuronide metabolite of a proprietary compound in rat plasma. A nanospray calibration method was developed with the standard curve of the parent drug to generate quantitative results for drug metabolites within +/-20% of that obtained with reference standards and conventional ESI. The nanospray method provides a practical solution for the quantitative estimation of drug metabolites in drug discovery when reference standards are not available.
Collapse
MESH Headings
- Calibration/standards
- Chromatography, Liquid/instrumentation
- Chromatography, Liquid/methods
- Chromatography, Liquid/standards
- Drug Design
- Drug Evaluation, Preclinical/instrumentation
- Drug Evaluation, Preclinical/methods
- Equipment Design
- Equipment Failure Analysis
- Flow Injection Analysis/methods
- Flow Injection Analysis/standards
- Microfluidics/instrumentation
- Microfluidics/methods
- Microfluidics/standards
- Nanotechnology/instrumentation
- Nanotechnology/methods
- Nanotechnology/standards
- Pharmaceutical Preparations/analysis
- Pharmaceutical Preparations/metabolism
- Reference Values
- Spectrometry, Mass, Electrospray Ionization/instrumentation
- Spectrometry, Mass, Electrospray Ionization/methods
- Spectrometry, Mass, Electrospray Ionization/standards
Collapse
|
344
|
Andrews CL, Li F, Yang E, Yu CP, Vouros P. Incorporation of a nanosplitter interface into an LC-MS-RD system to facilitate drug metabolism studies. JOURNAL OF MASS SPECTROMETRY : JMS 2006; 41:43-9. [PMID: 16317713 DOI: 10.1002/jms.944] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In the work reported here, a novel interface, the nanosplitter, is incorporated into the drug metabolism laboratory in order to enhance the analytical capabilities of detecting and identifying drug-related metabolites to support drug metabolism studies during the drug development process. When an existing LC-MS-radiometric detector (RD) system is coupled with this nanosplitter, the system becomes capable of performing dynamic microspray under a typical analytical LC method. With the superior MS sensitivity offered by this system, most of the analytical LC methods developed for metabolite profiling can then be easily adopted for metabolite identification work. The improvement of these analytical capabilities can streamline the entire process of the drug metabolism study. In the experiments presented here, the nanosplitter interface coupled with analytical HPLC systems (e.g. 4.6 x 250 mm column @ 1 ml/min) demonstrated significant increases in MS signal (2x to 40x peak area) when compared to the standard LC-MS interface for both in vitro and in vivo metabolism studies. Furthermore, this signal gain facilitated the MS detection of additional metabolites (observed in the radiometric trace) that were below the MS level of detection when using the standard interface.
Collapse
Affiliation(s)
- Christine L Andrews
- Department of Chemistry and Chemical Biology, Barnett Institute, Northeastern University, Boston, MA 02115, USA
| | | | | | | | | |
Collapse
|
345
|
El-Faramawy A, Siu KWM, Thomson BA. Efficiency of nano-electrospray ionization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2005; 16:1702-7. [PMID: 16095913 DOI: 10.1016/j.jasms.2005.06.011] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2004] [Revised: 06/20/2005] [Accepted: 06/20/2005] [Indexed: 05/03/2023]
Abstract
The efficiency of nano-electrospray ionization, defined as the flux of ions reaching the detector of a triple-quadrupole mass spectrometer divided by the flux of analyte ions leaving the needle, has been measured in a series of controlled experiments with dodecyltrimethyl ammonium (DDTMA) bromide, myoglobin, Glu- [1]-fibrinopeptide, and gramicidin S. By varying the flow rate from each needle, the optimum efficiency was determined. In general, the efficiency increased as the flow rate decreased. For DDTMA, efficiencies of up to 12% were measured, although efficiencies of approximately 1% were more common. Ion current measurements indicated efficient transfer of ions from the needle through to the detector. Significant needle-to-needle variations in efficiency were encountered and attributed to variations in ion-generation efficiency.
Collapse
Affiliation(s)
- Ayman El-Faramawy
- Department of Chemistry and Center for Research in Mass Spectrometry, York University, Toronto, Ontario, Canada
| | | | | |
Collapse
|
346
|
Shen Y, Kim J, Strittmatter EF, Jacobs JM, Camp DG, Fang R, Tolié N, Moore RJ, Smith RD. Characterization of the human blood plasma proteome. Proteomics 2005; 5:4034-45. [PMID: 16152657 DOI: 10.1002/pmic.200401246] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We describe methods for broad characterization of the human plasma proteome. The combination of stepwise immunoglobulin G (IgG) and albumin protein depletion by affinity chromatography and ultrahigh-efficiency capillary liquid chromatography separations coupled to ion trap-tandem mass spectrometry enabled identification of 2392 proteins from a single plasma sample with an estimated confidence level of > 94%, and an additional 2198 proteins with an estimated confidence level of 80%. The relative abundances of the identified proteins span a range of over eight orders of magnitude in concentration (< 30 pg/mL to approximately 30 mg/mL), facilitated by the attomole-level sensitivity of the analysis methods. More than 80% of the observed proteins demonstrate interactions with IgG and/or albumin, and the human plasma protein loss in the affinity chromatography/strong cation exchange/reversed-phase liquid chromatography-tandem mass spectrometry methodology was investigated in detail. The results of this study provide a basis for a wide range of plasma proteomics studies, including broad quantitation of relative abundances in comparative studies of the identification of novel protein disease markers, as well as further studies of protein-protein interactions.
Collapse
Affiliation(s)
- Yufeng Shen
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
347
|
Verkerk UH, Kebarle P. Ion-ion and ion-molecule reactions at the surface of proteins produced by nanospray. Information on the number of acidic residues and control of the number of ionized acidic and basic residues. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2005; 16:1325-41. [PMID: 15979326 DOI: 10.1016/j.jasms.2005.03.018] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2004] [Revised: 02/14/2005] [Accepted: 03/16/2005] [Indexed: 05/03/2023]
Abstract
Mass Spectra of charge states of folded proteins were obtained with nanospray and aqueous solution containing 20 microM the protein (ubiquitin, cytochrome c, lysozyme) and one of the NaA salts NaCl, NaI, NaAc (acetate) (1-10 mM). At very low collision activated decomposition (CAD), the mass spectra of a protein with charge z exhibited a replacement of zH+ with zNa+ and also multiple adducts of NaA. Higher CAD converts the NaA adduct peaks to Na minus H peaks. These must be due to loss of HA where the H was provided by the protein. The degree of HA loss with increasing CAD followed the order I < Cl < Ac. Significantly, the intensity of the ions with n (Na minus H) adducts showed a downward break past an n(MAX) which is equal to the number of acidic residues of the protein plus the charge of the protein. All the observations could be rationalized within the framework of the electrospray mechanism and the charge residue model, which predict that due to extensive evaporation of solvent, the solutes will reach very high concentrations in the final charged droplets. At such high concentrations, positive ions such as Na+, NH4+ form ion pairs with ionized acidic residues and the negative A- form ion pairs with ionized basic residues of the protein. Adducts of Na+, and NaA to backbone amide groups occur also. This reaction mechanism fits all the experimental observations and provides predictions that the number of acidic and basic groups at the surface of the gaseous protein that remain ionized can be controlled by the absence or presence of additives to the solution.
Collapse
Affiliation(s)
- Udo H Verkerk
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | | |
Collapse
|
348
|
Liu Y, Urgaonkar S, Verkade JG, Armstrong DW. Separation and characterization of underivatized oligosaccharides using liquid chromatography and liquid chromatography–electrospray ionization mass spectrometry. J Chromatogr A 2005; 1079:146-52. [PMID: 16038300 DOI: 10.1016/j.chroma.2005.03.011] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Native cyclodextrin-based columns are particularly useful for the analysis of oligosaccharides because the retention of these carbohydrates is based mainly on the hydrogen bonding interactions of oligosaccharide hydroxyl groups with the stationary phase. Thus, the retention time predictably increases with the number of analyte hydroxyl groups, which corresponds to the elongation of the oligosaccharide chain. High-performance liquid chromatography (HPLC) coupled to electrospray ionization (ESI) mass spectrometry (MS) was used for the separation and characterization of underivatized oligosaccharide mixtures. With the limits of detection as low as 50 pg, all individual components of oligosaccharide mixtures (up to 11 glucose units long) were baseline resolved on a Cyclobond I 2000 column and detected using ESI-MS. Low flow rates and narrow I.D. columns increase the ESI-MS sensitivity significantly. The method showed potential usefulness for the sensitive and quick analysis of hydrolysis products of polysaccharides, and for trace levels of individual oligosaccharide or oligosaccharide isomers from biological systems.
Collapse
Affiliation(s)
- Ying Liu
- Department of Chemistry, Iowa State University, Ames, IA 50011-3111, USA
| | | | | | | |
Collapse
|
349
|
Tang K, Shvartsburg AA, Lee HN, Prior DC, Buschbach MA, Li F, Tolmachev AV, Anderson GA, Smith RD. High-sensitivity ion mobility spectrometry/mass spectrometry using electrodynamic ion funnel interfaces. Anal Chem 2005; 77:3330-9. [PMID: 15889926 PMCID: PMC1829302 DOI: 10.1021/ac048315a] [Citation(s) in RCA: 223] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The utility of ion mobility spectrometry (IMS) for separation of mixtures and structural characterization of ions has been demonstrated extensively, including in biological and nanoscience contexts. A major attraction of IMS is its speed, several orders of magnitude greater than that of condensed-phase separations. Nonetheless, IMS combined with mass spectrometry (MS) has remained a niche technique, substantially because of limited sensitivity resulting from ion losses at the IMS-MS junction. We have developed a new electrospray ionization (ESI)-IMS-QTOF MS instrument that incorporates electrodynamic ion funnels at both front ESI-IMS and rear IMS-QTOF interfaces. The front funnel is of the novel "hourglass" design that efficiently accumulates ions and pulses them into the IMS drift tube. Even for drift tubes of 2-m length, ion transmission through IMS and on to QTOF is essentially lossless across the range of ion masses relevant to most applications. The rf ion focusing at the IMS terminus does not degrade IMS resolving power, which exceeds 100 (for singly charged ions) and is close to the theoretical limit. The overall sensitivity of the present ESI-IMS-MS system is comparable to that of commercial ESI-MS, which should make IMS-MS suitable for analyses of complex mixtures with ultrahigh sensitivity and exceptional throughput.
Collapse
Affiliation(s)
- Keqi Tang
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
350
|
Thompson JW, Eschelbach JW, Wilburn RT, Jorgenson JW. Investigation of electrospray ionization and electrostatic focusing devices using a three-dimensional electrospray current density profiler. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2005; 16:312-323. [PMID: 15734324 DOI: 10.1016/j.jasms.2004.11.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2004] [Revised: 11/17/2004] [Accepted: 11/17/2004] [Indexed: 05/24/2023]
Abstract
A novel instrument for profiling the current density of nanoelectrospray ionization plumes in three dimensions has been developed. A hemispherically-shaped electrostatic lens at atmospheric pressure is found to be able to compress the space-charge in nano-ESI and increase the average current density in the plume to three times the nominal value. Ion transmission into a single-quadrupole mass spectrometer is found to roughly double using the electrostatic lens. Data also suggest that ion transmission into the first vacuum region for a skimmer-type mass spectrometer interface using nano-ESI may be typically 40% or better with no special focusing device used.
Collapse
Affiliation(s)
- J Will Thompson
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA.
| | | | | | | |
Collapse
|