US 6,982,414 B2
Method of mass spectrometry and a mass spectrometer
Robert Harold Bateman, Knutsford (United Kingdom); James Ian Langridge, Sale (United Kingdom); Therese McKenna, Preston (United Kingdom); and Keith Richardson, High Peak (United Kingdom)
Assigned to Micromass UK Limited, Manchester (United Kingdom)
Filed on Jun. 19, 2003, as Appl. No. 10/464,513.
Claims priority of provisional application 60/412800, filed on Sep. 24, 2002.
Claims priority of application No. 0217146 (GB), filed on Jul. 24, 2002; application No. 0218719 (GB), filed on Aug. 12, 2002; application No. 0221914 (GB), filed on Sep. 20, 2002; and application No. 0305796 (GB), filed on Mar. 13, 2003.
Prior Publication US 2004/0041091 A1, Mar. 04, 2004
Int. Cl. B01D 59/44 (2006.01)
U.S. Cl. 250—282 73 Claims
OG exemplary drawing
 
1. A method of mass spectrometry comprising:
passing parent ions from a first sample to a fragmentation device;
repeatedly switching said fragmentation device between a high fragmentation mode wherein at least some of said parent ions from said first sample are fragmented into one or more fragment ions and a low fragmentation mode wherein substantially fewer parent ions are fragmented;
passing parent ions from a second sample to a fragmentation device;
repeatedly switching said fragmentation device between a high fragmentation mode wherein at least some of said parent ions are fragmented into one or more fragment ions and a low fragmentation mode wherein substantially fewer parent ions are fragmented;
automatically determining the intensity of first parent ions from said first sample which have a first mass to charge ratio;
automatically determining the intensity of second parent ions from said second sample which have said same first mass to charge ratio; and
comparing the intensity of said first parent ions with the intensity of said second parent ions;
wherein if the intensity of said first parent ions differs from the intensity of said second parent ions by more than a predetermined amount then either said first parent ions and/or said second parent ions are considered to be parent ions of interest.