Quadrupole robustness

Patent metadata

Field	Value
Publication number	US-9941106-B2
Application number	US-201515316569-A
Country	US
Kind code	B2
Filing date	Jun 10, 2015
Priority date	Jun 11, 2014
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

An apparatus for filtering ions is disclosed comprising a separation device for separating ions temporally according to a first physico-chemical property and a first quadrupole rod set for filtering ions according to their mass to charge ratio, wherein the first quadrupole rod set comprises a plurality of rods and wherein the first quadrupole rod set is arranged downstream of the separation device. The apparatus further comprises a control system arranged and adapted during a single cycle of separation of the separation device: (i) to operate the first quadrupole rod set in a first resolving mode of operation wherein ions of interest are selected by the first quadrupole rod set; and (ii) to operate the first quadrupole rod set in a second non-resolving or transmission mode of operation at separation times when substantially no ions of interest are present so that substantially no ions impact upon the rods of the first quadrupole rod set.

First claim

The invention claimed is:

1. An apparatus for filtering ions comprising:
a separation device for separating ions temporally according to a first physico-chemical property;
a filtering device for filtering ions according to their mass to charge ratio, wherein said filtering device is arranged downstream of said separation device and wherein said filtering device comprises an analytical quadrupole rod set and a pre-filter quadrupole rod set arranged upstream of said analytical quadrupole rod set; and
a control system arranged and adapted during a single cycle of separation of said separation device:
(i) to operate said filtering device in a first mode of operation wherein said pre-filter quadrupole rod set is operated in a transmissive mode of operation and wherein ions of interest are selected by said analytical quadrupole rod set; and
(ii) to operate said filtering device in a second mode of operation at separation times when substantially no ions of interest are present wherein said pre-filter quadrupole rod set is operated in a non-transmissive mode of operation so that substantially no ions impact upon the rods of said analytical quadrupole rod set.

2. An apparatus as claimed in claim 1 , wherein said control system is arranged and adapted in said first mode of operation to operate said analytical quadrupole rod set with a first mass to charge ratio transmission window, and to operate said pre-filter quadrupole rod set with a second mass to charge ratio transmission window, wherein said second mass to charge ratio transmission window is greater than or equal to and encompasses said first mass to charge ratio transmission window.

3. An apparatus as claimed in claim 1 wherein said filtering device comprises a post-filter quadrupole rod set arranged downstream of said analytical quadrupole rod set.

4. An apparatus for filtering ions comprising:
a separation device for separating ions temporally according to a first physico-chemical property;
a first quadrupole rod set for filtering said ions according to their mass to charge ratio, wherein said first quadrupole rod set comprises a plurality of rods and wherein said first quadrupole rod set is arranged downstream of said separation device; and
a control system arranged and adapted during a single cycle of separation of said separation device:
(i) to operate said first quadrupole rod set in a first substantially resolving mode of operation at separation times when ions of interest are expected to emerge from said separation device so that said ions of interest are selected by or filtered according to their mass to charge ratio by said first quadrupole rod set; and
(ii) to operate said first quadrupole rod set in a second substantially non-resolving or transmission mode of operation at separation times when substantially no ions of interest are expected to emerge from said separation device so that substantially no ions impact upon said rods of said first quadrupole rod set.

5. An apparatus as claimed in claim 4 , wherein said control system is further arranged and adapted to determine the location of said ions of interest in or from a survey scan.

6. Apparatus as claimed in claim 5 , wherein said survey scan comprises a multi-dimensional survey scan.

7. An apparatus as claimed in claim 4 , wherein said first physico-chemical property is either: (i) uncorrelated with mass to charge ratio; or (ii) at least partially correlated with mass to charge ratio.

8. An apparatus as claimed in claim 4 , wherein said first physico-chemical property comprises mass, mass to charge ratio or time of flight.

9. An apparatus as claimed in claim 8 , wherein said separation device comprises a time of flight separation device and/or an ion trap.

10. An apparatus as claimed in claim 4 , wherein said first physico-chemical property comprises ion mobility or differential ion mobility.

11. An apparatus as claimed in claim 10 , wherein said separation device comprises an ion mobility separator or a differential ion mobility separator.

12. An apparatus as claimed in claim 4 , wherein said control system is arranged and adapted to select multiple different ions of interest during said single cycle of separation.

13. An apparatus as claimed in claim 4 , wherein said control system is arranged and adapted in said first mode of operation to operate said first or analytical quadrupole rod set with a first mass to charge ratio transmission window such that at least some ions having mass to charge ratio values outside of said first mass to charge ratio transmission window are caused to impact upon said rods of said first or analytical quadrupole rod set.

14. An apparatus as claimed in claim 4 , further comprising an ion trap arranged upstream of said separation device.

15. An apparatus as claimed in claim 14 , wherein said ion trap is arranged and adapted to pulse one or more packets or ions into said separation device.

16. A method of filtering ions comprising:
separating ions temporally according to a first physico-chemical property using a separation device;
filtering said ions according to their mass to charge ratio using a first quadrupole rod set, wherein said first quadrupole rod set comprises a plurality of rods and wherein said first quadrupole rod set is arranged downstream of said separation device; and
during a single cycle of separation of said separation device:
operating said first quadrupole rod set in a first substantially resolving mode of operation at separation times when ions of interest are expected to emerge from said separation device so that said ions of interest are selected by or filtered according to their mass to charge ratio by said first quadrupole rod set; and
operating said first quadrupole rod set in a second substantially non-resolving or transmission mode of operation at separation times when substantially no ions of interest are expected to emerge from said separation device so that substantially no ions impact upon said rods of said first quadrupole rod set.

17. A method of mass spectrometry comprising a method of filtering ions as claimed in claim 16 .

18. A mass spectrometer comprising an apparatus for filtering ions as claimed in claim 4 .

Assignees

• Micromass Ltd

Inventors

• Wildgoose Jason Lee

Classifications

• H01J49/061 Primary

  Ion deflecting means, e.g. ion gates · CPC title

• H01J49/4215

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

• H01J49/426

  Methods for controlling ions · CPC title

• H01J49/0031

  Step by step routines describing the use of the apparatus (H01J49/0081 takes precedence) · CPC title