Methods for broad-stability mass analysis using a quadrupole mass filter

Patent metadata

Field	Value
Publication number	US-9536719-B2
Application number	US-201514696237-A
Country	US
Kind code	B2
Filing date	Apr 24, 2015
Priority date	Apr 28, 2014
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

Abstract

A method of mass analysis comprises: generating ions from the sample; delivering the ions to a quadrupole; applying a radio frequency voltage, V, to rods of the quadrupole such that the instantaneous electrical potential of each rod is out of phase with each adjacent rod and a non-oscillatory voltage, U, across each pair of adjacent rods such that a subset of the ions having a range of mass-to-charge (m/z) ratios are selectively transmitted through the quadrupole; varying at least one of voltage U and voltage V such that the range of selectively transmitted m/z ratios is caused to vary and varying at least one additional operational parameter; acquiring a data set comprising a series of temporally-resolved images of spatial distribution patterns of transmitted ions at each combination of U, V and the at least one additional operating parameter; and mathematically deconvolving the data set to generate mass spectra.

First claim

What is claimed is:

1. A method of analyzing a sample by mass spectrometry, comprising the steps of:
generating a stream of ions from the sample;
delivering the ions to an inlet end of a quadrupole, the quadrupole defining a central longitudinal axis and first and second transverse axes;
applying an oscillatory radio frequency (RF) voltage, V, to rods of the quadrupole such that the instantaneous electrical potential of each rod is 180-degrees out of phase with each adjacent rod and a non-oscillatory voltage, U, across each pair of adjacent rods such that a subset of the ions having a range of mass-to-charge (m/z) ratio values are selectively transmitted through the quadrupole to an outlet end of the quadrupole;
varying at least one of the applied voltage U and the applied voltage V such that the range of selectively transmitted m/z ratio values is caused to vary and varying at least one additional operational parameter of the quadrupole, wherein the varying of the at least one additional operational parameter comprises varying a ratio (U/V) between the applied U and the applied V by:
progressively varying both U and V in proportion to one another from a first pair of values (U 1 , V 1 ) to a second pair of values (U 2 , V 2 ) and in accordance with a first constant of proportionality, k 1 , such that U=k 1 V; and
progressively varying both U and V in proportion to one another from a third pair of values (U 3 , V 3 ) to a fourth pair of values (U 4 , V 4 ) and in accordance with a second constant of proportionality, k 2 , such that U=k 2 ;

acquiring a data set comprising a series of temporally-resolved images of spatial distribution patterns of the selectively transmitted ions at each combination of U, V and the at least one additional operating parameter; and
mathematically deconvolving the data set so as to generate a mass spectrum for each combination of U and V.

2. A method as recited in claim 1 , wherein the varying of at least one additional operational parameter further comprises varying an acceleration voltage such that the ions' kinetic energy and a number of RF cycles for which the ions remain within the quadrupole is caused to vary.

Assignees

• Thermo Finnigan Llc

Inventors

• Smith Johnathan Wayne
• Schoen Alan E

Classifications

• H01J49/429

  Scanning an electric parameter, e.g. voltage amplitude or frequency · CPC title

• H01J49/4215

  Quadrupole mass filters (H01J49/4225 takes precedence) · CPC title

• H01J49/025 Primary

  Detectors specially adapted to particle spectrometers (data acquisition H01J49/0036; detectors per se G01T, e.g. G01T1/28, G01T1/29) · CPC title

• H01J49/42

  Stability-of-path spectrometers, e.g. monopole, quadrupole, multipole, farvitrons · CPC title

• G01N27/62 Primary

  by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode · CPC title