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US 2015/0090876 A1Published application
Method to Detect and Sequence Post Translationally Modified Peptides
AssigneeMicromass UK Limited
InventorsChristopher John Hughes, Therese McKenna, David Gordon, Daniel James Kenny
Life of this patent
Estimating the term…
Abstract
A method of detecting and sequencing post translationally modified peptides is disclosed wherein a negative ion precursor scan is performed. A negative ion high resolution MS scan is then performed and then MRM channels in positive ion mode are determined and monitored. A positive ion MS/MS scan is then performed.
Claims8
A method of mass spectrometry comprising:
- providing a mass spectrometer comprising an ion source, a first mass filter or mass analyser, a collision, fragmentation or reaction device arranged downstream of said first mass filter or mass analyser and a second mass filter or mass analyser arranged downstream of said collision, fragmentation or reaction device;
- performing a relatively low resolution neutral loss or gain scan wherein a mass to charge ratio transmission window of said first mass filter or mass analyser is scanned whilst a mass to charge ratio transmission window of said second mass filter or mass analyser is scanned in synchronism with said first mass filter or mass analyser and monitoring for first fragment ions of interest having a first mass to charge ratio difference;
- wherein if first fragment ions of interest are detected then said method further comprises:
- (i) performing a relatively high resolution MS scan wherein a mass to charge ratio transmission window of either said first mass filter or mass analyser or said second mass filter or mass analyser is scanned whilst the other mass filter or mass analyser is operated in a non-resolving mode of operation;
- (ii) determining at least a first Multiple Reaction Monitoring channel corresponding to ions having a first charge state, a second Multiple Reaction Monitoring channel corresponding to ions having a second charge state and a third Multiple Reaction Monitoring channel corresponding to ions having a third charge state;
- (iii) setting and monitoring at least said first, second and third Multiple Reaction Monitoring channels and determining which Multiple Reaction Monitoring channel results in a highest intensity of observed ions;
- (iv) determining a mass to charge ratio or charge state of parent ions which correspond with the Multiple Reaction Monitoring channel which resulted in the highest intensity of observed ions;
- and
- (v) performing a MS/MS scan wherein a mass to charge ratio transmission window of said first mass filter or mass analyser is set so as to correspond with a mass to charge ratio transmission window at which said first mass filter or mass analyser was set for the Multiple Reaction Monitoring channel which resulted in the highest intensity of observed ions, and wherein a mass to charge ratio transmission window of said second mass filter or mass analyser is scanned.
6 more elements
A method of mass spectrometry comprising:
- providing a mass spectrometer comprising an ion source, a first mass filter or mass analyser, a collision, fragmentation or reaction device arranged downstream of said first mass filter or mass analyser and a second mass filter or mass analyser arranged downstream of said collision, fragmentation or reaction device;
- performing a relatively low resolution positive parent ion scan wherein a mass to charge ratio transmission window of said first mass filter or mass analyser is scanned whilst a mass to charge ratio transmission window of said second mass filter or mass analyser is fixed and monitoring for first fragment ions of interest having a first mass to charge ratio;
- wherein if first fragment ions of interest are detected then said method further comprises:
- (i) performing a relatively high resolution positive MS scan wherein a mass to charge ratio transmission window of either said first mass filter or mass analyser or said second mass filter or mass analyser is scanned whilst the other mass filter or mass analyser is operated in a non-resolving mode of operation;
- (ii) determining at least a first negative ion Multiple Reaction Monitoring channel corresponding to negative ions having a first negative charge state, a second negative ion Multiple Reaction Monitoring channel corresponding to negative ions having a second negative charge state and a third negative ion Multiple Reaction Monitoring channel corresponding to negative ions having a third negative charge state;
- (iii) setting and monitoring at least said first, second and third negative ion Multiple Reaction Monitoring channels and determining which Multiple Reaction Monitoring channel results in a highest intensity of observed ions;
- (iv) determining a mass to charge ratio or charge state of parent ions which correspond with the Multiple Reaction Monitoring channel which resulted in the highest intensity of observed ions;
- and
- (v) performing a MS/MS scan wherein a mass to charge ratio transmission window of said first mass filter or mass analyser is set so as to correspond with a mass to charge ratio transmission window at which said first mass filter or mass analyser was set for the Multiple Reaction Monitoring channel which resulted in the highest intensity of observed ions, and wherein a mass to charge ratio transmission window of said second mass filter or mass analyser is scanned.
6 more elements
Dependencies are inferred from the claim text.