Patent ID: 8063357

Claim:
A method of mass spectrometry comprising: analyzing ions with a mass analyzer; mass determining the accurate or exact mass or mass to charge ratio of a first substance or ion, wherein said accurate or exact mass or mass to charge ratio comprises a first integer nominal mass or mass to charge ratio component and a first decimal mass or mass to charge ratio component; and searching for one or more second substances or ions having a decimal mass or mass to charge ratio component which is between 0 to x 1 mDa or milli-mass to charge ratio units greater than said first decimal mass or mass to charge ratio component and/or between 0 to x 2 mDa or milli-mass to charge ratio units lesser than said first decimal mass or mass to charge ratio component by applying a decimal mass or mass to charge ratio window to mass spectral data or a mass spectrum, wherein said decimal mass or mass to charge ratio window filters out, removes, attenuates or at least reduces the significance of second substances or ions having a decimal mass or mass to charge ratio component which falls outside of said decimal mass or mass to charge ratio window; wherein the accurate or exact mass or mass to charge ratio of said first substance or ion minus the accurate or exact mass to charge ratio of a second substance or ion has a value of ΔM Daltons or mass to charge units wherein x 1 and/or x 2 varies as a function of ΔM in a symmetrical or asymmetrical manner; and providing an output based at least in part on said searching.