A method for identifying ions that generated mass spectral data, comprises acquiring raw mass spectral data in profile mode containing at least one ion of interest; performing at least one of mass spectral calibration involving peak shape and a determination of actual peak shape function associated with the acquired raw mass spectral data; considering at least one possible elemental composition of the ion; calculating theoretical mass spectral data for said elemental composition using the actual peak shape function; performing a normalization between corresponding parts of the theoretical mass spectral data and that of the raw or calibrated mass spectral data; and displaying mass spectral congruence between at least two mass spectra where one spectrum is the normalized version of the other corresponding to said possible elemental composition. The unique display and method assist in readily identifying ions. A data storage medium having computer code thereon for causing a computer to performing the method; also in combination with a mass spectrometer.