| 摘要 |
A method for determining elemental composition of ions from mass spectral data, comprising obtaining at least one mass measurement from mass spectral data; obtaining a search list of candidate elemental compositions whose exact masses fall within a given mass tolerance range from the accurate mass; reporting a probability measure based on a mass error; calculating an isotope pattern for each candidate elemental composition from the search list; constructing a peak component matrix including at least one of the isotope pattern and mass spectral data; performing a regression against at least one of isotope pattern, mass spectral data, and the peak component matrix; reporting a second probability measure for at least one candidate elemental composition based on the isotope pattern regression; and combining the two the probability measures into an overall probability measure. A method for determining elemental isotope ratios from mass spectral data, comprising obtaining measured mass spectral response; specifying the elemental composition of a given ion; specifying the initial isotope ratios for a given element in the ion; calculating the isotope pattern for the ion; constructing a peak component matrix including at least one of the isotope pattern and measured mass spectral response; performing a regression between measured mass spectral response and the peak component matrix; and reporting a regression residual and repeating the isotope pattern calculation, peak component construction, and regression process with updated isotope ratios to minimize this residual.
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