QUANTITATIVE ANALYSIS METHOD USING MASS SPECTROMETER
First Claim
1. A method of an analysis using a liquid chromatograph/mass spectrometer, comprising the steps of:
- mixing a standard molecule in a solution for the analysis;
acquiring a first mass chromatogram of ions originated from the standard molecule in a condition that mixing of a sample for the analysis in the solution for the analysis is negligible;
acquiring a second mass chromatogram of ions originated from the standard molecule in a condition that the sample for the analysis is mixed in the solution for the analysis;
performing a level adjustment of the first and the second mass chromatograms;
calculating an inconsistency between the first and the second mass chromatograms, and comparing the inconsistency with a threshold of an inconsistency stored in advance;
detecting a time region for the analysis in a condition that the inconsistency is smaller than the threshold of an inconsistency; and
collecting data for the analysis of the sample for the analysis acquired in the time region for the analysis,wherein a height of hydrophobicity of the standard molecule mixed in the solution for the analysis is changed according to a ratio of an organic solvent in a mobile phase of the liquid chromatograph.
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Abstract
In quantitation without using the isotope labeling technique, there is no means to detect the presence/absence and the time region of the occurrence of quantitative analysis-inhibitory factors in data for the analysis, and the reliability of the data for the analysis cannot be evaluated. Also, the error of the data due to the occurrence of the quantitative analysis-inhibitory factors cannot be evaluated. In order to solve the problems, first, an internal standard to be detected simultaneously with a component for the analysis is mixed in a mobile phase or an eluate of a liquid chromatograph; under the condition where no quantitative analysis-inhibitory factors occur, a blank sample is analyzed to acquire a mass chromatogram of ions originated from the internal standard; and the result is stored in a data storage unit. Then, a sample for the analysis is mixed to acquire data for the analysis of the sample; and the intensity of ions originated from the internal standard is compared with that of the blank sample in the analysis real time in a data analysis unit. At this time, if an inconsistency exceeding a predetermined threshold is detected, the occurrence of the quantitative analysis-inhibitory factors can be detected. Further, based on the inconsistency, the error range of the data can be given to a data set and the like.
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Citations
20 Claims
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1. A method of an analysis using a liquid chromatograph/mass spectrometer, comprising the steps of:
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mixing a standard molecule in a solution for the analysis; acquiring a first mass chromatogram of ions originated from the standard molecule in a condition that mixing of a sample for the analysis in the solution for the analysis is negligible; acquiring a second mass chromatogram of ions originated from the standard molecule in a condition that the sample for the analysis is mixed in the solution for the analysis; performing a level adjustment of the first and the second mass chromatograms; calculating an inconsistency between the first and the second mass chromatograms, and comparing the inconsistency with a threshold of an inconsistency stored in advance; detecting a time region for the analysis in a condition that the inconsistency is smaller than the threshold of an inconsistency; and collecting data for the analysis of the sample for the analysis acquired in the time region for the analysis, wherein a height of hydrophobicity of the standard molecule mixed in the solution for the analysis is changed according to a ratio of an organic solvent in a mobile phase of the liquid chromatograph. - View Dependent Claims (2, 3, 4, 5, 8, 9, 10)
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6. A method of an analysis using a liquid chromatograph/mass spectrometer, comprising the steps of:
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mixing a standard molecule having an isoelectric point or a dissociation constant of approximately 2 or more and 8 or less and a standard molecule having that of 8 or more in a solution for the analysis; acquiring a first mass chromatogram of ions originated from the standard molecules in a condition that mixing of a sample for the analysis in the solution for the analysis is negligible; acquiring a second mass chromatogram of ions originated from the standard molecules in a condition that the sample for the analysis is mixed in the solution for the analysis; performing a level adjustment of the first and the second mass chromatograms; calculating an inconsistency between the first and the second mass chromatograms, and comparing the inconsistency with a threshold of an inconsistency stored in advance; detecting a time region for the analysis in a condition that the inconsistency is smaller than the threshold of an inconsistency; and collecting data for the analysis of the sample for the analysis acquired in the time region for the analysis, wherein a positive ion detection mode and a negative ion detection mode is switched in one time of liquid chromatograph/mass spectrometry.
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7. A method of an analysis using a liquid chromatograph/mass spectrometer, comprising the steps of:
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mixing a hydrophilic standard molecule and a hydrophobic standard molecule in a solution for the analysis; acquiring a first mass chromatogram of ions originated from the hydrophilic and the hydrophobic standard molecules in a condition that mixing of a sample for the analysis in the solution for the analysis is negligible; acquiring a second mass chromatogram of ions originated from the hydrophilic and the hydrophobic standard molecules in a condition that the sample for the analysis is mixed in the solution for the analysis; performing a level adjustment of the first mass chromatogram and the second mass chromatogram of ions originated from the hydrophilic standard molecule and the hydrophobic standard molecule; calculating an inconsistency between the first and the second mass chromatograms, and comparing the inconsistency with a threshold of an inconsistency stored in advance; detecting a time region for the analysis in a condition that the inconsistency is smaller than the threshold of an inconsistency; and collecting data for the analysis of the sample for the analysis acquired in the time region for the analysis.
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- 11. An internal standard, wherein the internal standard is an internal standard used to detect a quantitative analysis-inhibitory factor in an analysis of positive ions using a liquid chromatograph/mass spectrometer, and is acidic.
- 14. An internal standard, wherein the internal standard is an internal standard used to detect a quantitative analysis-inhibitory factor in an analysis of negative ions using a liquid chromatograph/mass spectrometer, and is basic.
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17. A method of an analysis of a solution for the analysis containing an object substance for the analysis by using a sample preparation unit, an ionization unit, a mass-analysis unit, a control unit and a storage unit, comprising:
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a step of mixing an internal standard in the solution for the analysis; a step of introducing the solution for the analysis mixed with the internal standard to the ionization unit to produce ions; a first step of measuring an intensity of ions originated from the internal standard by the mass-analysis unit in a condition that the internal standard is mixed in the solution for the analysis containing a constant or less concentration of the object substance for the analysis, and storing a result thereof in the storage unit; a second step of measuring intensities of ions originated from the object substance for the analysis and the internal standard by the mass-analysis unit in a condition that the internal standard is mixed in the solution for the analysis containing an unknown concentration of the object substance for the analysis, and storing results thereof in the storage unit; a step of calculating an inconsistency between the intensities of ions originated from the internal standard measured in the first and the second steps, and comparing the difference with a threshold of an inconsistency stored in advance in the storage unit, in the control unit; a step of judging weather or not the difference exceeds the threshold of an inconsistency in the control unit; and a step of changing the analysis condition of the solution for the analysis in the sample preparation unit, remeasuring the solution for the analysis containing the object substance for the analysis, and calculating a quantitative value of the object substance for the analysis, in the control unit, depending on the judgment. - View Dependent Claims (18, 19, 20)
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Specification