Patent ID: 8536521

Claim:
A method for detecting signals arising from an essentially sinusoidal motion along a component axis of populations of ions with distinct mass-to-charge ratios, and thus distinct oscillation frequencies, in a Fourier transform mass spectrometer (FTMS) comprising: a) acquiring in an FTMS instrument a time-dependent voltage signal arising from the motion of ions produced by analyzing a mixture of unknown analytes; b) determining a model phase function φ(f) that relates the phase of any ion resonances as a function of its frequency f comprising: i) detecting oscillating signals produced by populations of ions with distinct mass-to-charge ratios; and ii) estimating the frequency and phase of each such signal; and c) applying the model phase function φ(f) to perform phase-enhanced detection of signals comprising: i) selecting a family of signal models describing the oscillating signals produced by populations of ions with distinct mass-to-charge ratios, wherein the family represents a set of distinct frequencies, and in which each member of the family, identified by its frequency f, has a phase parameter given by φ(f); ii) calculating the complex-valued overlap sum between the observed spectrum and each member of the family of signal models; and iii) recording distinct frequency values where the real component of the complex-valued overlap sum exceeds a threshold value; so as to detect signals produced by distinct populations of ions in the FTMS.