QUANTITATIVE ANALYSIS METHOD USING MASS SPECTROMETER

摘要

In an MS unit, both an intensity of an ion having the highest intensity among the ions originating from a compound as the target of quantitative determination and an intensity of an isotopic ion are measured. A saturation detector determines whether or not digital data produced by an A/D converter from ion-intensity signals have reached a saturation level. A data selection controller selects the ion-intensity data showing the highest intensity when the signal is not saturated or the intensity data of the isotopic ion when the saturation has occurred or is probable to occur. When the latter data is selected, an ion intensity converter converts the intensity data into values corresponding to the intensity data of the highest-intensity ion by multiplying the intensity data by a factor calculated from a known isotopic abundance ratio.

主权项

1. A quantitative analysis method for determining a quantity of a target compound based on an ion intensity obtained by detecting an ion originating from the target compound using a mass spectrometer, the method using an intensity of a product ion obtained by selecting and fragmenting an ion originating from a target compound, and the method including following steps:
in a measurement of a sample containing a target compound, an ion intensity at a mass-to-charge ratio of an ion having a highest intensity among product ions obtained by performing an MSn analysis using different kinds of ions originating from the target compound as precursor ions is detected, and additionally, an ion intensity at a mass-to-charge ratio of another ion having an intensity lower than the highest intensity by a predetermined proportion is detected; a detection result of the ion intensity at the mass-to-charge ratio of the ion having the intensity lower than the highest intensity is converted into the ion intensity at the mass-to-charge ratio of the ion having the highest intensity; and in a case where the ion intensity at the mass-to-charge ratio of the ion having the highest intensity is expected or probable to exceed a saturation level, the ion intensity obtained by the aforementioned conversion is used to create a calibration curve for quantitative determination or to derive a quantitative value with reference to the calibration curve.