Patent ID: 9698001
Date: 2017-07-04
CPC Classifications: G01N,H01J,Y10T

Claim:
1. A method of purifying one or more ions from interfering contaminant ions during tandem mass spectrometry, the method comprising: (a) providing a mixture comprising an isobarically labeled target polypeptide and one or more molecules able to generate contaminant ions during mass spectrometry; (b) generating a first distribution of precursor ions from the mixture during MS (c) identifying a target range of mass-to-charge ratios of the first distribution of precursor ions, wherein said target range includes mass-to-charge ratios of precursor ions generated from the isobarically labeled target polypeptide as well as contaminant ions, and isolating precursor ions from the first distribution of precursor ions, where the isolated precursor ions have mass-to-charge ratios within the identified target range; (d) selectively changing the mass-to-charge ratios of the isolated precursor ions by a known amount, thereby generating a distribution of mass-to-charge-manipulated precursor ions; (e) identifying a desired range of mass-to-charge ratios of the distribution of mass-to-charge-manipulated precursor ions, wherein the desired range includes mass-to-charge ratios of precursor ions generated from the isobarically labeled target polypeptide and manipulated by a known amount as described in step (d), and wherein the desired range does not include mass-to-charge ratios of contaminant ions manipulated as described in step (d), and (f) fragmenting ions corresponding to the isolated mass-to-charge-manipulated precursor ions during MS (g) measuring the mass-to-charge ratios of the first product ions, thereby generating first product ion mass spectrometry data; thereby generating mass spectrometry data using ions purified during tandem mass spectrometry.