26
|
Huo R, Agapiou A, Bocos-Bintintan V, Brown LJ, Burns C, Creaser CS, Devenport NA, Gao-Lau B, Guallar-Hoyas C, Hildebrand L, Malkar A, Martin HJ, Moll VH, Patel P, Ratiu A, Reynolds JC, Sielemann S, Slodzynski R, Statheropoulos M, Turner MA, Vautz W, Wright VE, Thomas CLP. The trapped human experiment. J Breath Res 2011; 5:046006. [DOI: 10.1088/1752-7155/5/4/046006] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
27
|
Stephenson GR, Anson CE, Creaser CS, Daul CA. Spectroscopic, Structural and DFT Study of the Responses of Carbonylmetal Crown Ether Complexes to Alkali Metal Cations. Eur J Inorg Chem 2011. [DOI: 10.1002/ejic.201001274] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
28
|
Kaur-Atwal G, Reynolds JC, Mussell C, Champarnaud E, Knapman TW, Ashcroft AE, O'Connor G, Christie SDR, Creaser CS. Determination of testosterone and epitestosterone glucuronides in urine by ultra performance liquid chromatography-ion mobility-mass spectrometry. Analyst 2011; 136:3911-6. [DOI: 10.1039/c1an15450h] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
29
|
Harry EL, Bristow AWT, Wilson ID, Creaser CS. Real-time reaction monitoring using ion mobility-mass spectrometry. Analyst 2011; 136:1728-32. [DOI: 10.1039/c0an00700e] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
30
|
Brown LJ, Toutoungi DE, Devenport NA, Reynolds JC, Kaur-Atwal G, Boyle P, Creaser CS. Miniaturized ultra high field asymmetric waveform ion mobility spectrometry combined with mass spectrometry for peptide analysis. Anal Chem 2010; 82:9827-34. [PMID: 21049936 DOI: 10.1021/ac102125u] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Miniaturized ultra high field asymmetric waveform ion mobility spectrometry (ultra-FAIMS) combined with mass spectrometry (MS) has been applied to the analysis of standard and tryptic peptides, derived from α-1-acid glycoprotein, using electrospray and nanoelectrospray ion sources. Singly and multiply charged peptide ions were separated in the gas phase using ultra-FAIMS and detected by ion trap and time-of-flight MS. The small compensation voltage (CV) window for the transmission of singly charged ions demonstrates the ability of ultra-FAIMS-MS to generate pseudo-peptide mass fingerprints that may be used to simplify spectra and identify proteins by database searching. Multiply charged ions required a higher CV for transmission, and ions with different amino acid sequences may be separated on the basis of their differential ion mobility. A partial separation of conformers was also observed for the doubly charged ion of bradykinin. Selection on the basis of charge state and differential mobility prior to tandem mass spectrometry facilitates peptide and protein identification by allowing precursor ions to be identified with greater selectivity, thus reducing spectral complexity and enhancing MS detection.
Collapse
|
31
|
Kay RG, Barton C, Velloso CP, Brown PR, Bartlett C, Blazevich AJ, Godfrey RJ, Goldspink G, Rees R, Ball GR, Cowan DA, Harridge SD, Roberts J, Teale P, Creaser CS. High-throughput ultra-high-performance liquid chromatography/tandem mass spectrometry quantitation of insulin-like growth factor-I and leucine-rich alpha-2-glycoprotein in serum as biomarkers of recombinant human growth hormone administration. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2009; 23:3173-3182. [PMID: 19718777 DOI: 10.1002/rcm.4237] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Insulin-like growth factor-I (IGF-I) is a known biomarker of recombinant human growth hormone (rhGH) abuse, and is also used clinically to confirm acromegaly. The protein leucine-rich alpha-2-glycoprotein (LRG) was recently identified as a putative biomarker of rhGH administration. The combination of an ACN depletion method and a 5-min ultra-high-performance liquid chromatography/tandem mass spectrometry (uHPLC/MS/MS)-based selected reaction monitoring (SRM) assay detected both IGF-I and LRG at endogenous concentrations. Four eight-point standard addition curves of IGF-I (16-2000 ng/mL) demonstrated good linearity (r(2) = 0.9991 and coefficients of variance (CVs) <13%). Serum samples from two rhGH administrations were extracted and their uHPLC/MS/MS-derived IGF-I concentrations correlated well against immunochemistry-derived values. Combining IGF-I and LRG data improved the separation of treated and placebo states compared with IGF-I alone, further strengthening the hypothesis that LRG is a biomarker of rhGH administration. Artificial neural networks (ANNs) analysis of the LRG and IGF-I data demonstrated an improved model over that developed using IGF-I alone, with a predictive accuracy of 97%, specificity of 96% and sensitivity of 100%. Receiver operator characteristic (ROC) analysis gave an AUC value of 0.98. This study demonstrates the first large scale and high throughput uHPLC/MS/MS-based quantitation of a medium abundance protein (IGF-I) in human serum. Furthermore, the data we have presented for the quantitative analysis of IGF-I suggest that, in this case, monitoring a single SRM transition to a trypsin peptide surrogate is a valid approach to protein quantitation by LC/MS/MS.
Collapse
|
32
|
Harry EL, Reynolds JC, Bristow AWT, Wilson ID, Creaser CS. Direct analysis of pharmaceutical formulations from non-bonded reversed-phase thin-layer chromatography plates by desorption electrospray ionisation ion mobility mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2009; 23:2597-2604. [PMID: 19630035 DOI: 10.1002/rcm.4152] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The direct analysis of pharmaceutical formulations and active ingredients from non-bonded reversed-phase thin layer chromatography (RP-TLC) plates by desorption electrospray ionisation (DESI) combined with ion mobility mass spectrometry (IM-MS) is reported. The analysis of formulations containing analgesic (paracetamol), decongestant (ephedrine), opiate (codeine) and stimulant (caffeine) active pharmaceutical ingredients is described, with and without chromatographic development to separate the active ingredients from the excipient formulation. Selectivity was enhanced by combining ion mobility and mass spectrometry to characterise the desorbed gas-phase analyte ions on the basis of mass-to-charge ratio (m/z) and gas-phase ion mobility (drift time). The solvent composition of the DESI spray using a step gradient was varied to optimise the desorption of active pharmaceutical ingredients from the RP-TLC plates. The combined RP-TLC/DESI-IM-MS approach has potential as a rapid and selective technique for pharmaceutical analysis by orthogonal gas-phase electrophoretic and mass-to-charge separation.
Collapse
|
33
|
Matharoo-Ball B, Miles AK, Creaser CS, Ball G, Rees R. Serum biomarker profiling in cancer studies: a question of standardisation? Vet Comp Oncol 2009; 6:224-47. [PMID: 19178682 DOI: 10.1111/j.1476-5829.2008.00171.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Companion animals are exposed to similar environmental conditions and carcinogens as humans. In some animal cancers, there also appears to be the same genetic changes associated as in humans. However, little work has been carried out in cancer biomarker identification in animals. The recent dramatic advances in molecular medicine, genomics, proteomics and translational research will allow biomarker identification, which may provide the best strategies for veterinarians and clinicians to combat disease by early diagnosis and administration of effective treatments. Proteomics may have important applications in cancer diagnosis, prognosis and predictive clinical outcome that could directly change clinical practice by affecting critical elemen-ts of care and management. This review summarizes the advances in proteomics that has propelled us to this exciting age of clinical proteomics, and highlights the future work that is required for this to become a reality. In this review, we will discuss the available proteomic technologies and their limitations, and highlight the key areas of research and how they have been used to discover cancer biomarkers. The principles described here are equally applicable to human and animal disease, but implementation of 'omic' technologies requires stringent guidelines for collection of clinical material, the application of analytical techniques and interpretation of the data.
Collapse
|
34
|
Howdle MD, Eckers C, Laures AMF, Creaser CS. The use of shift reagents in ion mobility-mass spectrometry: studies on the complexation of an active pharmaceutical ingredient with polyethylene glycol excipients. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2009; 20:1-9. [PMID: 18974011 DOI: 10.1016/j.jasms.2008.10.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Revised: 09/30/2008] [Accepted: 10/01/2008] [Indexed: 05/27/2023]
Abstract
Gas-phase ion mobility studies of mixtures containing polyethylene glycols (PEG) and an active pharmaceutical ingredient (API), lamivudine, have been carried out using electrospray ionization-ion mobility spectrometry-quadrupole-time-of-flight mass spectrometry (ESI-IMS-Q-TOF). In addition to protonated and cationized PEG oligomers, a series of high molecular weight ions were observed and identified as noncovalent complexes formed between lamivudine and PEG oligomers. The noncovalent complex ions were dissociated using collision induced dissociation (CID) after separation in the ion mobility drift tube to recover the protonated lamivudine free from interfering matrix ions and with a drift time associated with the precursor complex. The potential of PEG excipients to act as "shift reagents," which enhance selectivity by moving the mass/mobility locus to an area of the spectrum away from interferences, is demonstrated for the analysis of lamivudine in a Combivir formulation containing PEG and lamivudine.
Collapse
|
35
|
Langley MN, Chopra RK, Creaser CS, Taylor RJK, Rose MD, Startin JR, Lee HA, Morgan MRA. Immunoprobes for polychlorinated dibenzodioxins: Synthesis of immunogen and characterization of antibodies. FOOD AGR IMMUNOL 2008. [DOI: 10.1080/09540109209354763] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
|
36
|
Harry EL, Weston DJ, Bristow AW, Wilson ID, Creaser CS. An approach to enhancing coverage of the urinary metabonome using liquid chromatography–ion mobility–mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2008; 871:357-61. [DOI: 10.1016/j.jchromb.2008.04.043] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Revised: 04/24/2008] [Accepted: 04/28/2008] [Indexed: 01/08/2023]
|
37
|
Kaur-Atwal G, Weston DJ, Bonner PL, Crosland S, Green PS, Creaser CS. Immobilised Metal Affinity Chromatography for the Analysis of Proteins and Peptides. CURR ANAL CHEM 2008. [DOI: 10.2174/157341108784587777] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Immobilised metal affinity chromatography (IMAC) has become an established purification procedure for the selective isolation of proteins, peptides and post-translationally modified peptides, using a wide range of metal ions, including Cu(II), Fe(III) and Ga(III). Recently, the potential of interfacing capillary IMAC with mass spectrometry has been explored. This article reviews the development and use of IMAC in protein/peptide analysis, highlighting the benefits of capillary columns and their application to IMAC based enrichment.
Collapse
|
38
|
Kaur-Atwal G, Weston DJ, Green PS, Crosland S, Bonner PLR, Creaser CS. On-line capillary column immobilised metal affinity chromatography/electrospray ionisation mass spectrometry for the selective analysis of histidine-containing peptides. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 857:240-5. [PMID: 17681498 DOI: 10.1016/j.jchromb.2007.07.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Revised: 07/13/2007] [Accepted: 07/16/2007] [Indexed: 10/23/2022]
Abstract
Capillary column immobilised metal affinity chromatography (IMAC) has been combined on-line with electrospray ionisation/quadrupole time-of-flight mass spectrometry for the fractionation of histidine-containing peptides. IMAC beads (Poros 20MC, 20 microm) containing imidodiacetate chelating groups on a cross-linked poly(styrene-divinylbenzene) support were packed into a fused silica column (250 microm i.d.), which was interfaced to the electrospray ion source of the spectrometer. A Cu(II) activated column was used to isolate histidine-containing peptides from tryptic and other peptide mixtures with an average breakthrough of 9.1%, to reduce the complexity of the mass spectral analysis. The analysis cycle time was reduced to less than 15 min, at an optimum flow rate of 7.5 microL/min, without sacrificing peptide selectivity. Direct coupling of capillary IMAC with MS allows on-line separation, using MS compatible loading and elution buffers, and detection in a high-throughput fashion when compared to off-line strategies.
Collapse
|
39
|
Kaur-Atwal G, Weston DJ, Green PS, Crosland S, Bonner PLR, Creaser CS. Analysis of tryptic peptides using desorption electrospray ionisation combined with ion mobility spectrometry/mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2007; 21:1131-8. [PMID: 17318928 DOI: 10.1002/rcm.2941] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
A novel method is reported for rapid protein identification by the analysis of tryptic peptides using desorption electrospray ionisation (DESI) coupled with hyphenated ion mobility spectrometry and quadrupole time-of-flight mass spectrometry (IMS/Q-ToF-MS). Confident protein identification is demonstrated for the analysis of tryptically digested bovine serum albumin (BSA), with no sample pre-treatment or clean-up. Electrophoretic ion mobility separation of ions generated by DESI allowed examination of charge-state and mobility distributions for tryptic peptide mixtures. Selective interrogation of singly charged ions allowed isobaric peptide responses to be distinguished, along with a reduction in spectral noise. The mobility-selected singly charged peptide responses were presented as a pseudo-peptide mass fingerprint (p-PMF) for protein database searching. Comparative data are shown for electrospray ionisation (ESI) of the BSA digest, without sample clean-up, from which confident protein identification could not be made. Implications for the robustness of the DESI method, together with potential insights into mechanisms for DESI of proteolytic digests, are discussed.
Collapse
|
40
|
Budimir N, Weston DJ, Creaser CS. Analysis of pharmaceutical formulations using atmospheric pressure ion mobility spectrometry combined with liquid chromatography and nano-electrospray ionisation. Analyst 2007; 132:34-40. [PMID: 17180177 DOI: 10.1039/b612796g] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The hyphenation of liquid chromatography with atmospheric pressure ion mobility spectrometry is reported using a custom-made dynamic nano-electrospray ionisation (nano-ESI) interface. The analysis of pharmaceutical actives is described, including beta blocker (timolol), antidepressant (paroxetine), analgesic (paracetamol) and opiate (codeine) preparations. On-line ultraviolet diode array (UV) spectroscopic detection was used prior to sample ionisation, to evaluate chromatographic and nano-ESI interface performance. Active drug responses were characterised by chromatographic retention time and electrophoretic ion mobility drift time, and selected ion mobility responses were used to evaluate method performance. Limits of detection for active drugs were in the low-nmol to pmol range. Quantitative responses were investigated using a series of standard solutions of caffeine, showing good linearity (R(2) = 0.9982, n = 6) and reproducibility (RSD = 2.3 %, n = 6). The analysis of an over the counter pharmaceutical formulation demonstrates the potential of ion mobility spectrometry combined with liquid chromatography and nano-electrospray ionisation for the rapid determination of active drugs, as a result of the electrophoretic separation and selectivity afforded by IMS.
Collapse
|
41
|
Creaser CS, Green PS, Kilby PM, Ratcliffe L. Capillary liquid chromatography/atmospheric-pressure matrix-assisted laser desorption/ionisation ion trap mass spectrometry: a comparison with liquid chromatography/matrix-assisted laser desorption/ionisation time-of-flight and liquid chromatography/electrospray ionisation quadrupole time-of-flight for the identification of tryptic peptides. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2006; 20:829-36. [PMID: 16470569 DOI: 10.1002/rcm.2376] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The atmospheric-pressure matrix-assisted laser desorption/ionisation quadrupole ion trap (AP-MALDI-QIT) analysis of tryptic peptides is reported following capillary liquid chromatographic (LC) separation and direct analysis of a protein digest. Peptide fragments were identified by peptide mass fingerprinting from mass spectrometric data and sequence analysis obtained by tandem mass spectrometry of the principal mass spectral peaks using a data-dependent scanning protocol. These data were compared with those from mass spectrometric analysis using capillary LC/MALDI-time-of-flight (TOF) and capillary LC/electrospray ionisation (ESI)-quadrupole TOF. For all three configurations the resulting data were searched against the MSDB database, using MASCOT and the sequence coverage compared for each technique. Complementary data were obtained using the three techniques.
Collapse
|
42
|
Weston DJ, Bateman R, Wilson ID, Wood TR, Creaser CS. Direct Analysis of Pharmaceutical Drug Formulations Using Ion Mobility Spectrometry/Quadrupole-Time-of-Flight Mass Spectrometry Combined with Desorption Electrospray Ionization. Anal Chem 2005; 77:7572-80. [PMID: 16316164 DOI: 10.1021/ac051277q] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A novel approach to the rapid analysis of pharmaceutical drug formulations using hyphenated ion mobility spectrometry (IMS) and time-of-flight mass spectrometry (ToF-MS) that requires no sample pretreatment or chromatographic separation is described. A modified quadrupole time-of-flight mass spectrometer containing an ion mobility drift cell was used for gas-phase electrophoretic separation of ions prior to ToF-MS detection. The generation of sample ions directly from tablets and cream formulations was effected by desorption electrospray ionization (DESI) using a modified electrospray ion source. The analysis of a range of over-the-counter and prescription tablet formulations is described, including histamine H2 receptor antagonist (ranitidine), analgesic (paracetamol), opiate (codeine), and aromatase inhibitor anticancer (anastrozole) drugs. The successful determination of active drugs from soft formulations, such as an antiseptic cream (chlorhexidine) and a nicotine-containing skin patch, is also presented. Limits of detection for the active drugs using the DESI/IMS/ToF-MS method fell within the high-picomole to nanomole range. In all cases, the use of ion mobility drift tube separation showed increased selectivity for active drug responses (present as low as 0.14% w/w) over excipient responses such as poly(ethylene glycol). Tandem mass spectrometric analysis of precursor ions separated by IMS allowed positive confirmation of active drugs with little loss of ion mobility efficiency. The ability to analyze hard or soft pharmaceutical formulations directly by DESI combined with ion mobility spectrometry/mass spectrometry in approximately 2 min demonstrates the potential applicability of this novel method to pharmaceutical screening of low-molecular-weight drug formulations with high selectivity over the formulation vehicle.
Collapse
|
43
|
Creaser CS, Griffiths JR, Bramwell CJ, Noreen S, Hill CA, Thomas CLP. Ion mobility spectrometry: a review. Part 1. Structural analysis by mobility measurement. Analyst 2004. [DOI: 10.1039/b404531a] [Citation(s) in RCA: 186] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
44
|
Anson CE, Creaser CS, Malkov AV, Mojovic L, Stephenson G. Flavonoid derivatives as organometallic bioprobes. J Organomet Chem 2003. [DOI: 10.1016/s0022-328x(02)02146-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
45
|
Creaser CS, Reynolds JC, Hoteling AJ, Nichols WF, Owens KG. Atmospheric pressure matrix-assisted laser desorption/ionisation ion trap mass spectrometry of synthetic polymers: a comparison with vacuum matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2003; 9:33-44. [PMID: 12748400 DOI: 10.1255/ejms.528] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Atmospheric pressure matrix-assisted laser desorption/ionisation quadrupole ion trap (AP-MALDI/QIT) mass spectrometry has been investigated for the analysis of polyethylene glycol (PEG 1500) and a hyperbranched polymer (polyglycidol) in the presence of alkali-metal salts. Mass spectra of PEG 1500 obtained at atmospheric pressure showed dimetallated matrix/analyte adducts, in addition to the expected alkali-metal/PEG ions, for all matrix/alkali-metal salt combinations. The relative intensities of the desorbed ions were dependent on the matrix, the alkali-metal salt added to aid cationisation and the ion trap interface conditions [capillary temperature, in-source collisionally-induced dissociation (CID)]. These data indicate that the adducts are rapidly stabilised by collisional cooling enabling them to be transferred into the ion trap. Experiments using identical sample preparation conditions were carried out on a vacuum MALDI time-of-flight (ToF) mass spectrometer. In all cases, vacuum MALDI-ToF spectra showed only alkali-metal/PEG ions and no matrix/analyte adducts. The tandem mass spectrometry (MS/MS) capability of the ion trap has been demonstrated for a lithiated polyglycol yielding a rich fragment-ion spectrum. Analysis of the hyperbranched polymer polyglycidol by AP-MALDI/QIT reveals the characteristic ion series for these polymers as also observed under vacuum MALDI-ToF conditions.
Collapse
|
46
|
Creaser CS, Lamarca DG, dos Santos LMF, New AP, James PA. A universal temperature controlled membrane interface for the analysis of volatile and semi-volatile organic compounds. Analyst 2003; 128:1150-6. [PMID: 14529022 DOI: 10.1039/b305085h] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A universal temperature controlled membrane interface (TCMI) has been constructed for hollow-fibre membranes. The membrane temperature is controllable in the range -70 to 250 degrees C using an electric heater and a flow of cooled nitrogen or helium gas. Volatile and semi-volatile organic compounds may be detected either by continuous diffusion across the membrane or by in-membrane pre-concentration followed by thermal desorption into the detector. The TCMI interface is demonstrated in combination with mass spectrometry and GC-MS, for the determination of VOCs and SVOCs in aqueous and air samples and for the on-line monitoring of a bioreactor.
Collapse
|
47
|
Bramwell CJ, Colgrave ML, Creaser CS, Dennis R. Development and evaluation of a nano-electrospray ionisation source for atmospheric pressure ion mobility spectrometry. Analyst 2002; 127:1467-70. [PMID: 12475036 DOI: 10.1039/b206847h] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A nano-electrospray ionisation source has been designed and constructed for a high temperature ion mobility spectrometer. The drift cell was modified by replacement of the 63Ni atmospheric pressure chemical ionisation source with a tube lens/desolvation region and operated using commercial nano-electrospray capillaries. Ions were introduced into the drift region via a Bradbury-Nielson gate (pulse width 50 micros, repetition period 20 ms). A unidirectional flow of nitrogen was used as the drift gas at temperatures in the range 100-150 degrees C to aid desolvation. The performance of the nano-electrospray ion source has been demonstrated for analytes including crown ethers, amino acids and peptides. Reduced mobilities determined by nano-ESI were consistent with those reported using a 63Ni ion source.
Collapse
|
48
|
Creaser CS, Crosland S. Continuous flow fast atom bombardment mass spectrometry using a modified electron impact source. Anal Chem 2002. [DOI: 10.1021/ac00186a029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
49
|
Bonner PLR, Lill JR, Hill S, Creaser CS, Rees RC. Electrospray mass spectrometry for the identification of MHC class I-associated peptides expressed on cancer cells. J Immunol Methods 2002; 262:5-19. [PMID: 11983215 DOI: 10.1016/s0022-1759(02)00009-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Electrospray ionisation (ESI) mass spectrometry (MS) has been used extensively for the detection of peptides presented by major histocompatibility complex (MHC) molecules. This review focuses on the optimisation of electrospray mass spectrometry and the use of tandem mass spectrometry to sequence MHC class I peptides. We review the isolation of MHC class I peptides from the surface of cells with particular reference to tumour cells. In addition, we also discuss the advantages and disadvantages of the methods available to concentrate and fractionate the peptides prior to analysis by electrospray mass spectrometry.
Collapse
|
50
|
Creaser CS, Reynolds JC, Harvey DJ. Structural analysis of oligosaccharides by atmospheric pressure matrix-assisted laser desorption/ionisation quadrupole ion trap mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2002; 16:176-184. [PMID: 11803538 DOI: 10.1002/rcm.563] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
An ion source incorporating a fibre optic interface has been constructed for atmospheric pressure matrix-assisted laser desorption/ionisation quadrupole ion trap mass spectrometry. The configuration has been applied to the study of linear and complex oligosaccharides. Multi-stage tandem mass spectrometry (MSn, n = 2-4) experiments carried out in the ion trap enable extended fragmentation pathways to be investigated that yield structural information. Collisional activation of sodiated oligosaccharides, as demonstrated on the model compound maltoheptaose, produces primarily B and Y fragments resulting from cleavage of glycosidic bonds; fragments from cross-ring cleavages are also observed following further stages of tandem mass spectrometry, providing additional linkage information. The analyses of mixtures of complex oligosaccharides are demonstrated for N-linked glycans from chicken egg glycoproteins and a ribonuclease glycan mixture. Mass spectrometric and tandem mass spectrometric data for sugars with molecular weights up to 4000 Da is shown for mixtures of linear dextrans and N-linked glycans. The use of MSn (n = 3, 4) on these complex molecules enabled structural information to be elucidated that confirms data observed in the MS/MS spectra.
Collapse
|