University of Manitoba

Other

Her Majesty the Queen in Right of Canada, As Represented by the Minister

Werner N Ens

Kenneth G Standing

Alexandre V Loboda

Victor L Spicer

Andrew N Krutchinsky

Steven J Jones

Heinz Feldmann

Helene Perreault

Joe O'Neil

Mark McComb

Darren Manley

Richard Oleschuk

Art Chow

Harry Duckworth

Lynda Donald

Andrei Krouttchinskikh

Nathalie Bastien

Yan Li

Frank Plummer

Helen Perreault

Oleg Krokhine

Shaun Tyler

A method and apparatus are provided for providing an ion transmission device or interface between an ion source and a spectrometer. The ion transmission device can include a multipole rod set and includes a damping gas, to damp spatial and energy spreads of ions generated by a pulsed ion source. The multipole rod set has the effect of guiding the ions along an ion path, so that they can be directed into the inlet of a mass spectrometer. The invention has particular application to MALDI (matrix-assisted laser desorption/ionization) ion sources, which produce a small supersonic jet of matrix molecules and ions, which is substantially non-directional, and can have ions travelling in all available directions from the source and having a wide range of energy spreads. The ion transmission device can have a number of effects, including: substantially spreading out the generated ions along an ion axis to generate a quasi-continuous beam; reducing the energy spread of ions emitted from the source; and at least partially suppressing unwanted fragmentation of analyte ions. Consequently, a number of pulses of ions can be delivered to the time-of-flight or other spectrometer, for each cycle of the ion generation.

Spectrometer provided with pulsed ion source and transmission device to damp ion motion and method of use

A method and apparatus are provided for selective collision-induced dissociation of a substance, by resonance excitation of ions. An ion stream is supplied into a quadrupole ion guide operated at elevated pressure with a buffer gas. In addition to a radio frequency field for guiding ions through the ion guide, an extra field or other excitation is provided. This field is selected to cause resonance excitation of parent ions of interest. These ions gain kinetic energy and undergo enhanced collision-induced dissociation with a buffer gas. This generates fragment ions, so that the resultant ion stream, containing remaining parent ions and fragment ions can be analyzed in a suitable analyzer. The method essentially enables the two steps of selection of a particular parent ion and generation of fragment ions by collision-induced dissociation to be carried out in a single step, giving a simpler apparatus and enhanced efficiency.

Method of and apparatus for selective collision-induced dissociation of ions in a quadrupole ion guide

The use of non-porous membranes as sample supports for MALDI-TOFMS analysis of peptides and proteins as well as for the analysis of whole blood is herein described. Non-porous membranes have a uniform surface, allowing for greater sensitivity and accuracy. Specifically, the non-porosity favours crystal growth on the surface of the membrane only, thereby providing enhanced spectral quality over membranes with porous structures. Studies were performed using polyurethane (PU) membranes as an example of non-porous MALDI sample supports and showed that PU membranes yielded higher quality spectra compared with porous membrane sample supports such as polyether and poly(vinyl difluoride) and the spectra obtained from PU membranes are of comparable quality as those obtained with metallic targets. However, the sample preparation for use with PU membranes is much less arduous compared with the preparation necessary for metallic targets. On membrane proteolytic digestions of proteins were performed using trypsin. After the completion of the digests, buffer components were washed of leaving peptides bound to the membrane. Addition of matrix followed by MALDI analysis resulted in good quality mass spectra which enabled peptide mapping.

Non-porous membrane for MALDI-TOFMS

An improved apparatus and method for the analysis of ions generated by matrix-assisted laser desorption is disclosed. This apparatus and method enhances the mass spectral resolution compared to previous devices and methods by producing electrical modulation of the kinetic energy imparted to the generated ions in a matrix-assisted laser desorption mass spectrometer. This modulation causes parent ions of interest to be substantially reflected (and detected) or substantially not reflected (and not detected) within the spectrometer, while fragment ions produced from the parent ion of interest are substantially reflected (and detected) independent of said modulation. A difference signal is generated between electrical signals sensed when the parent ions are reflected and electrical signals sensed when the parent ions are not reflected thereby mitigating the effects on the mass spectrum of the undesired fragment ions.

Apparatus and method for matrix-assisted laser desorption mass

Growing community of inventors

Winnipeg, Canada

Werner N Ens