Operating a mass spectrometer for sample quantification
View Patent ↗Targeted quantification for mass spectrometry is described. In one aspect, a mass spectrometer can generate survey mass spectra and identify the compounds of a sample using the survey mass spectra. Compounds that elute within a same time range and do not form interfering product ions upon fragmentation can be identified, and grouped together for an MS2 scan. A series of MS2 scans can then be generated to acquire MS2 mass spectra.
1. A method of operating a mass spectrometer to analyze a sample, comprising:
receiving a sample;
performing MS2 scans of the sample to generate survey mass spectra, the MS2 scans performed by advancing a first isolation window across a mass range of interest;
identifying, using the survey mass spectra, a first compound in a first mass range within the mass range of interest and a second compound in a second mass range within the mass range of interest that elutes to the mass spectrometer within a first time range and form product ions when fragmented that do not interfere with each other within a threshold range;
fragmenting, based on the identification, the first compound and the second compound isolated using a second isolation window having a mass range that at least partially includes the first mass range and the second mass range to form the product ions;
acquiring a first product ion mass spectrum based on the product ions fragmented from the first compound and the second compound; and
quantifying the first compound and the second compound based on the first product ion mass spectrum.
2. The method of claim 1 , further comprising:
identifying, using the survey mass spectrum, a third compound in a third mass range within the mass range of interest that elutes to the mass spectrometer within the first time range and forms product ions when fragmented that do interfere with the product ions of the first compound or the second compound within the threshold intensity range;
fragmenting the third compound using a third mass isolation window having a range that includes the third mass range, the third mass isolation window not including the first mass range and not including the second mass range; and
acquiring a second product ion mass spectrum based on the product ions fragmented from the third compound.
3. The method of claim 2 , wherein the second isolation window is wider than the third isolation window.
4. The method of claim 2 , wherein the third mass range is adjacent to the first mass range, and the first mass range is adjacent to the second mass range.
5. The method of claim 1 , wherein the first compound and the second compound are peptides.
6. The method of claim 1 , wherein the second isolation window is wider than the first isolation window.
7. The method of claim 1 , wherein the first mass range and the second mass range each correspond to different positions of the first isolation window advanced through the mass range of interest.
8. The method of claim 1 , wherein the survey mass spectra are MS2, and the first product ion mass spectrum is MS2.
9. A mass spectrometer configured to receive a sample, and having a controller circuit configured to:
perform product ion scans of the sample to generate survey mass spectra, the product ion scans performed by advancing a first isolation window across a mass range of interest;
identify, using the survey mass spectra, a first compound in a first mass range within the mass range of interest and a second compound in a second mass range within the mass range of interest that elute to the mass spectrometer within a first time range and form product ions when fragmented that do not interfere with each other within a threshold range;
fragment the first compound and the second compound isolated using a second isolation window having a mass range that includes at least portions of the first mass range and the second mass range to form the product ions; and
acquire a first product ion mass spectrum based on the product ions fragmented from the first compound and the second compound.
10. The mass spectrometer of claim 9 , wherein the controller circuit is further configured to:
quantify the first compound and the second compound based on the first product ion mass spectrum.
11. The mass spectrometer of claim 9 , wherein the controller circuit is further configured to:
identify, using the survey mass spectra, a third compound in a third mass range within the mass range of interest that elutes to the mass spectrometer within the first time range and forms product ions when fragmented that do interfere with the product ions of the first compound or the second compound within the threshold intensity range;
fragment the third compound using a third mass isolation window having a range that includes the third mass range, the third mass isolation window not including the first mass range and not including the second mass range; and
acquire a second product ion mass spectrum based on the product ions fragmented from the third compound.
12. The mass spectrometer of claim 11 , wherein the second isolation window is wider than the third isolation window.
13. The mass spectrometer of claim 11 , wherein the third mass range is adjacent to the first mass range, and the first mass range is adjacent to the second mass range.
14. The mass spectrometer of claim 9 , wherein the first compound and the second compound are peptides.
15. The mass spectrometer of claim 9 , wherein the second isolation window is wider than the first isolation window.
16. The mass spectrometer of claim 9 , wherein the first mass range and the second mass range each correspond to different positions of the first isolation window advanced through the mass range of interest.
17. The mass spectrometer of claim 9 , wherein the survey mass spectra are is MS2, and the first product ion mass spectrum is MS2.