US 5,352,891 A · Method and apparatus for estimating molecular mass from electrospray spectra

Abstract

The production of mass spectra of chemical compounds of high molecular weights having a multiplicity of peaks is improved by generating an enhanced mass spectrum from the observed mass-to-charge spectrum. The intensity at each point within the enhanced spectrum is based upon a plurality of successive discrete peaks within the mass-to-charge spectrum. The intensities of the sequence of mass-to-charge peaks are combined to form a normalized product which is the new enhanced intensity at an assumed molecular weight. The intensities of the mass-to-charge spectrum at each integral fraction of the assumed molecular weight are included in the product. Only those intensities above a certain predetermined threshold, however, are included to avoid transfer of noise into the enhanced spectrum. Signal-to-noise ratio can in some applications be improved by including in the product all portions within the discrete peaks in the mass-to-charge spectrum which are contained within a window around each of the discrete peaks.

Claims20

Dependent claims

A method for identifying the molecular weight of distinct polyatomic parent molecular species in a mass spectrometer comprising the steps of:

generating populations of multiply charged ions on said distinct polyatomic parent molecular species, the number of charges on said ions defining each of said ion's charge state number, said population of ions comprising a plurality of subpopulations, each of said subpopulations corresponding to an intensity peak in a mass-to-charge spectrum of said molecular species, said population including one of said subpopulations for at least one possible integral value of a charged state number;
analyzing subpopulations in said mass spectrometer to produce said mass-to-charge spectrum;
determining a mass-to-charge range to be used with said mass-to-charge spectrum;
determining a range of assumed masses to be used within an enhanced mass spectrum;
and
generating for each assumed mass in said enhanced mass spectrum an intensity equal in magnitude to the product of all of said intensity peaks of said subpopulations of said assumed mass,
whereby determination of said molecular weight of said polyatomic parent molecule species is more readily discernible.

4 more elements

An improved combination of a mass spectrometer and computer comprising:

means for generating a mass spectrum comprised of a sequence of discrete peaks due to multiply charged ions of a distinct polyatomic parent molecular species;
means for storing said mass spectrum within said computer;
means for generating an enhanced mass spectrum by combining said sequence of discrete peaks due to multiply charged ions of said distinct polyatomic parent molecular species to form an intensity for each assumed mass within said enhanced spectrum, said discrete peaks being combined in a product,
whereby analysis of said peaks of said enhanced spectrum to determine the molecular weight of said distinct polyatomic parent molecular species is facilitated.

1 more element

Dependencies are inferred from the claim text.

Method and apparatus for estimating molecular mass from electrospray spectra

Life of this patent

Method and apparatus for estimating molecular mass from electrospray spectra

Life of this patent

Abstract

Claims20