| 摘要 |
PROBLEM TO BE SOLVED: To accurately identify a monoisotopic ion peak derived from a compound whose element composition is unknown to calculate mass of the compound with high accuracy.SOLUTION: A mass spectrometric data processing method includes the steps of: using as estimation model an approximate expression based on the result obtained by analysing a relationship between mass and the number of constituent elements of a large number of known compounds belonging to the same category as a target compound, and estimating a chemical formula on the basis of the estimation model when actually measured mass corresponding to a peak is given (S231-S232); calculating the mass from the chemical formula, and determining that the estimated chemical formula is correct if a difference between the mass and the actually measured mass falls within a prescribed threshold (S233-S236); if a mass difference exceeds the prescribed threshold, adding or subtracting the elements to modify the chemical formula depending on the difference, and calculating the mass again (S237-S238) and then returning to the S234; and calculating a theoretical isotope distribution if the repetition of the steps provides the chemical formula (S24). The isotope distribution on a mass spectrum is discriminated by fitting using this theoretical isotope distribution, thereby identifying a monoisotopic ion peak. |
