John Brian Hoyes

HGSG · Research

A novel mass spectrometry system is described here comprising a quadrupole-multireflecting time-of-flight design. The new multireflecting time-of-flight analyzer has an effective path length of 48 m and employs planar, gridless ion mirrors providing fourth-order energy focusing resulting in resolving power over 200 000 fwhm and sub-ppm mass accurac...

The poster is about limitations of mass accuracy of multi-reflecting TOF mass spectrometers at sub-ppm level, and linearity of mass scale.

Method of 3D spectrometry of mixture of proteins is described, where dimension of fragmentation energy is added to LC and MS dimensions

FT mass spectrometers have ultimate resolutions exceeding those of conventional TOF mass spectrometers. However in order to achieve this, long acquisition times are required (of up to several seconds in some cases). In contrast, high performance TOF mass spectrometers have typical flight times of tens of microseconds. This makes it possible, for ex...

The clamp-loader complex plays a crucial role in DNA replication by loading the β-clamp onto primed DNA to be used by the replicative polymerase. Relatively little is known about the stoichiometry, structure and assembly pathway of this complex, and how it interacts with the replicative helicase, in Gram-positive organisms. Analysis of full and par...

The computational simulation of complete proteomic data sets and their utility to validate detection and interpretation algorithms, to aid in the design of experiments and to assess protein and peptide false discovery rates is presented. The simulation software has been developed for emulating data originating from data-dependent and data-independe...

Collision cross sections in both helium and nitrogen gases were measured directly using a drift cell with RF ion confinement inserted within a quadrupole/ion mobility/time-of-flight hybrid mass spectrometer (Waters Synapt HDMS, Manchester, U.K.). Collision cross sections for a large set of denatured peptide, denatured protein, native-like protein,...

A new type of mass analyzer is described, which allows low-resolution axial ion ejection to be obtained from a traveling wave based, stacked ring collision cell. Linking this ejection temporally with the scanning of the second quadrupole of a tandem quadrupole mass spectrometer provides an improvement in sampling duty cycle, which results in signif...

We modified and optimized a first generation quadrupole time-of-flight (Q-TOF) 1 to perform tandem mass spectrometry on macromolecular protein complexes. The modified instrument allows isolation and subsequent dissociation of high-mass protein complexes through collisions with argon molecules. The modifications of the Q-TOF 1 include the introducti...

Ion mobility has emerged as an important technique for determining biopolymer conformations in solvent free environments. These experiments have been nearly exclusively performed on home built systems. In this paper we describe modifications to a commercial high performance mass spectrometer, the Waters UK “Ultima” Q-Tof, that allows high sensitivi...

A tandem quadrupole time-of-flight (Q-TOF) mass spectrometer has been programmed such that phosphorylated peptides can automatically be discovered and identified in a way similar to that of the use of precursor ion or neutral loss scanning, but without the need to scan the quadrupole mass filter. Instead, the method capitalizes on the innate capabi...

Ions experience small deflections in the vicinity of grids in accelerators and ion mirrors in time-of-flight (TOF) mass spectrometers. Recent experiments with an orthogonal acceleration (oa) TOF instrument have verified that the effect can significantly degrade resolution when ions approach grids at an angle deviating from 90 degrees. The phenomeno...

Data for samples from thein vivo metabolism of diclofenac was acquired using a novel acquisition mode on a quadrupole-time of flight hybrid mass spectrometer. This mode allowed the discovery and identification of precursor ions of drug-related molecules, based upon the detection of accurately measured, pre-defined fragment ions and neutral losses....

A non-contact scanning system is described which is capable of producing two-dimensional ultrasonic images of defects in opaque materials. Lasers are used both for generation and detection of ultrasound. Short-duration high-power ( approximately 2 MW) laser pulses are used to generate ultrasound on the surface of a sample. Such ultrasound in the fo...

We have identified two peptides corresponding to the male-specific HY minor histocompatibility Ags presented by HLA-B27 in transgenic rodents, isolated from whole cell extracts and from immunoprecipitated B27 molecules of male B27 rat spleen cells. HPLC peptide fractions that sensitized female B27 targets for lysis by B27-restricted anti-HY CTL wer...

Consideration of the special problems encountered in ultra-high sensitivity biopolymer sequencing studies has led to the development of a novel quadrupole/erthogonal-acceleration time-of-flight tandem mass spectrometer described for the first time here. The performance characteristics of this new geometry are demonstrated, including fully resolved...

Angular intensity distribution of molecular ions ejected in matrix-assisted laser desorption/ionization (MALDI) have been measured for two symmetrical positions of the laser beam with respect to the sample surface normal (+60° and −60°). It is shown that the molecular ions are ejected in the direction opposite to the incident laser beam with an ave...

Matrix-assisted laser desorption/ionization (MALDI) spectra of underivatized oligosaccharides of the type attached to asparagine in glycoproteins (N-linked oligosaccharides) were examined with linear time-of-flight (TOF) and magnetic sector instruments using 2,5-dihydroxybenzoic acid (2,5-DHB), -cyano-4-hydroxycinnamic acid, sinapinic acid, 1,4-dih...

An “off-line” combination of capillary electrophoresis (CE) with matrix-assisted laser-desorption mass spectrometry (MALDI-MS) has been developed for the structural characterization of CE-separated peptides and proteins. Using a sheath flow interface, similar to that developed for “on-line” CE—fast atom bombardment MS and CE—electrospray MS, an eff...

We have developed a method to rapidly identify the antigenic determinant for an antibody using in situ proteolysis of an immobilized antigen-antibody complex followed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI/TOF). A mouse anti-bombesin monoclonal antibody was immobilized to agarose beads and then the an...

Identification of ligands separated with affinity chromatography has been facilitated by direct analysis of the bound ligand using matrix-assisted laser desorption time-of-flight mass spectrometry. Tbe mass spectral detection of analytes separated by immunoaffinity chromatography and immobilized metal ion affinity chromatography is shown. For examp...