Shimadzu Corporation

Takashi Sumiyoshi

Yuki Sakamoto

Jun Watanabe

Yoshiro Hiramatsu

A GC/MS measurement under an ionization by an electron ionization method is performed for a target sample (S). Peaks are detected on a chromatogram based on obtained data, and a mass spectrum corresponding to each peak is compared with a compound database to identify a compound (S-S). A compound identified with a low degree of similarity is extracted as the measurement compound. For this compound, a measurement window including the retention time of a peak corresponding to the compound is set, and a control program for performing an ionization by a chemical ionization method only within the measurement window is created (S-S). According to this control program, a GC/MS measurement for the target sample is performed, with the device controlled so that a reagent gas is supplied into an ionization chamber and a filament for generating thermions is energized within the measurement window, whereas the supply of the reagent gas is discontinued and the filament is deenergized within time ranges other than the measurement window (S). Since no reagent-gas ion is generated within the time ranges other than the measurement window, the adhesion of the ions to the inside of the ionization chamber and other locations will be reduced. Accordingly, a stable measurement can be performed for a long period of time.

Gas chromatograph mass spectrometer

A chromatograph mass spectrometer has a function that: based on a compound table in which an elution time range and a measurement ion is described for respective compounds, divides an overall measurement time into multiple segments and assigns one or more compounds to each segment; determines an event time for each compound by dividing a previously given measurement loop time in accordance with a number of compounds belonging to the respective segments; and determines a dwell time, which is a data collection time for each ion, based on the event time and the number of ions to be measured for each compound; the chromatograph mass spectrometer allowing an analysis operator to designate whether or not to perform a high-sensitivity analysis for each compound.

Chromatograph mass spectrometer and program

A mass spectrometry method includes: creating a plurality of measurement conditions corresponding to all combinations of precursor-ion candidates generated from the target compound and collision-energy-value candidates; performing a product-ion scan measurement using each of the plurality of measurement conditions and performing a plurality of reference measurements for detecting a predetermined kind of ion generated from the target compound under the same condition, within an introduction time during which the target compound is introduced; creating a peak function, which is a function representing a change in the amount of introduction of the target compound into the mass spectrometer within the introduction time, based on the result of the reference measurement; creating a normalization function for normalizing the amount of introduction of the target compound within the introduction time, based on the peak function; and normalizing the intensity of product-ion spectra obtained by the product-ion scan measurements performed for all combinations.

Mass spectrometry method, chromatograph mass spectrometer, and program for mass spectrometry

In the case where a peak on a mass spectrum is saturated due to, for example, signal saturation in a detector or an amplifier provided downstream thereof, a data processor performs fitting with a Gaussian function using data included in the rising part and the falling part (range A) of the peak which are not affected by the saturation, to thereby obtain a desired approximate peak shape B. Then, a mass spectrum in which the saturated peak is replaced with the approximate peak thus obtained is created, the mass-to-charge ratio of the peak top is calculated for this mass spectrum, and this mass spectrum is then displayed on a display screen. Moreover, an extracted ion chromatogram is created on the basis of information on mass-to-charge ratio to intensity of this modified mass spectrum and displayed.

Mass analysis data processing apparatus

Segments into which time is divided are set at a point where predicted elution time ranges of compounds in a compound table do not overlap. One or more compounds are allotted to each segment. Subsequently, the dwell time per ion is calculated in each segment, based on the number of assigned compounds, loop time and the like. If the dwell time is shorter than the lower limit value (No in S), the one segment is forcedly subdivided such that each subdivision include a predetermined number of compounds (S). A compound having an elution time range trespassing the new segment boundary is allotted as a measurement target to both segments across the boundary (S). If the dwell time is of at least the lower limit in every segment regenerated by the subdivision (Yes in S), the process for this segment is finished. Such subdivision and compound reassignment in every segment can automatically create a parameter table for a measurement method capable of achieving high quantitativeness.

Chromatograph mass spectrometer

After an analysis condition table for measuring each compound is automatically generated in accordance with a compound table, the loop time is calculated for each measurement section for which the overlapping of measurement events differs. If the loop time exceeds a specified value in a given measurement section of a given compound, the event with the earliest end time and the event with the latest start time are extracted from among the overlapping measurement events, and the intermediate time between the end time and the start time is found to adjust the length of each measurement event. By repeating this process, a parameter in the analysis condition table is corrected so that the loop time becomes equal to or less than the specified value.

In a chromatograph mass spectrometer capable of defining an appropriate measurement time range and selectively performing a scan measurement, selected ion monitoring (SIM) measurement or simultaneous scan/SIM measurement in that time range, a total ion chromatogramobtained by a scan measurement of a standard sample and a previously-created compound tableare displayed on the screen of a display unit in the process of setting parameters in a measurement condition table. An operator selects a compound that should undergo the simultaneous scan/SIM measurement, then places a checkmark in an appropriate check box in the compound table, and finally clicks the 'Auto-Create' button. Then, a measurement time range for the selected compound is defined by adding a time span before and after the retention time of that compound, respectively, and a measurement condition tableis automatically created and displayed on the screen. This table includes instructions for performing a simultaneous scan/SIM measurement at specific mass-to-charge ratios characteristic of the selected compound during the aforementioned measurement time range.

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Kyoto, Japan

Takashi Sumiyoshi