JPH0740016B2 - Chromatograph / Mass Spectrometer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chromatograph / mass spectrometer in which various chromatographs such as a gas chromatograph and a liquid chromatograph are connected to a mass spectrometer, and more particularly to a selective ion monitor (SIM). The present invention relates to means for creating a SIM measurement table required when the method is applied.

[0002]

2. Description of the Related Art Generally, in a chromatograph / mass spectrometer in which various chromatographs such as a gas chromatograph and a liquid chromatograph are connected to a mass spectrometer, when quantitative analysis of a specific component is performed, selection is made. The ion monitor (SIM) method may be adopted. In this selective ion monitoring method, specific target ions corresponding to the components to be quantified are selected in advance, and the acceleration voltage of the mass spectrometer is set to a value corresponding to the specific mass number (m / z) of the target ions. It is set and the chromatogram showing the time-dependent intensity change of the target ion is measured. In addition,
After that, for the above chromatogram, the peak area
(For example, peak height × half-width) is calculated, and the content of the component or the like is determined based on the calibration curve previously obtained.

As described above, since the selective ion monitor method measures the chromatogram by limiting the ion species in advance, it is not easily affected by coexisting interfering components, and the data collection time for each component is long. S /
It has an excellent N ratio and very high measurement sensitivity and is suitable for quantitative analysis.

When performing the quantitative analysis by the selective ion monitoring method as described above, an identification table necessary for specifying the target ions of the target components to be quantified in advance and the respective chromatograms of these target ions. It is necessary to create the SIM measurement table and the SIM measurement table necessary for determining the measurement conditions of the above.

The above-mentioned identification table and SIM measurement table are conventionally created as follows.

For example, the mass numbers are (m / z) ₁ and (m / z), respectively.
For each of the known target ions a to c of z) ₂ and (m / z) ₃ , when each chromatogram as shown in FIG. 7 is observed, in order to specify these chromatograms, the target ions a to Mass number of c (m / z) ₁ to (m / z) ₃ , standard retention time t _{1 to} t ₃ indicating the peak top position of the chromatogram of each target ion a to c, and fluctuation of the peak top of the chromatogram The allowable retention time width Δt _{1 to} Δt ₃ that determines the width is determined in advance, and these mass numbers (m / z) ₁ to (m / z) ₃ , standard retention times t _{1 to} t ₃ , allowable retention time width Δt ₁ An identification table is created by associating ~ Δt ₃ with each other.

In order to determine the measurement conditions for the chromatogram, the mass numbers (m / z) ₁ to (m / z) of the target ions a to c are determined.
z) ₃ , and the measurement holding time ranges R _{1 to} R ₃ are determined, and further the presence or absence of the measurement holding time ranges R _{1 to} R ₃ is checked,
When the measurement holding time ranges overlap each other (R ₁ and R ₂ overlap in this example), the minimum time range R ₀ that covers these measurement holding time ranges is newly determined as the measurement holding time range. , SI can be obtained by associating these mass numbers (m / z) with the measurement retention time ranges R ₀ and R _3.
Create M measurement table.

[0008]

As described above, in the prior art, since the identification table and the SIM measurement table are created separately, not only is it troublesome to create the table, but also when creating the SIM measurement table. Is
Furthermore, it is necessary to check whether or not the measurement retention time ranges overlap and readjust the ranges, which complicates table creation.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. When an identification table is created, a SIM measurement table is automatically created accordingly. Select ion monitor (SIM)
It enables efficient quantitative analysis based on the method.

Therefore, in the present invention, the mass number of the target ion necessary for specifying the target component to be quantified, and the standard retention time (ti, i = 1, 2, which indicates the peak top position of the chromatogram of each target ion). , ...), and a chromatograph / mass spectrometer with an identification table that gives the allowable retention time width (Δti, i = 1, 2, ...) That determines the fluctuation width of the peak top of the chromatogram. take.

That is, in the apparatus of the present invention, as shown in the functional block diagram of FIG. 1, the measurement holding time width (f) obtained by multiplying the allowable holding time width (Δti) by a constant value (f) is based on the identification table.・ Δti) is calculated and this measurement holding time width
(f · Δti) and the standard retention time (ti), the measurement retention time range for each target ion (Ri = ti−f · Δti
Measurement holding time range setting means 1 for setting up to ti + f · Δti)
And a time chart creating means 2 for creating a time chart by plotting each measurement holding time range (Ri) set by the measurement holding time range setting means 1 on the time axis for each target ion, and this time chart The target ions whose measurement retention time ranges (Ri) of the time chart created by the creating means 2 overlap each other are defined as one group, and the minimum measurement target time range (Ri) of all target ions included in each group is covered. A SIM in which the time range is determined as the optimum measurement retention time range (Ti) and the mass number of the target ion and the optimum measurement retention time range (Ti) are associated with each other for each group.
SIM measurement table creating means 3 for creating a measurement table
It has and.

[0012]

In the above structure, the measurement holding time range setting means 1 sets the measurement holding time range (Ri) for each target ion based on the identification table, and then the time chart creating means 2 sets the measurement holding time range. Retention time range
(Ri) is plotted for each target ion on the time axis to create a time chart. Subsequently, the optimum measurement retention time range creation means 3 sets the target ions whose measurement retention time ranges (Ri) on the time chart overlap each other as one group, and sets the measurement retention time range (Ri) of the target ions included in each group. ) Is determined as the optimum measurement holding time range (Ti) and a SIM measurement table is created.

That is, once the identification table is created, the SIM measurement table is automatically created accordingly.

[0014]

FIG. 2 is a block diagram showing the entire gas chromatograph / mass spectrometer according to an embodiment of the present invention.

In the figure, reference numeral 10 indicates the entire gas chromatograph / mass spectrometer, 12 is a gas chromatograph, 14 is a mass spectrometer, 16 is a gas chromatograph 12 and the operation of the mass spectrometer 14 is controlled, A CPU, 18 for processing data obtained by the analyzer 14 is a necessary control program, an identification table described later, and a SIM.
Measurement table and memory where measurement data is stored,
Reference numeral 20 is a keyboard for inputting parameters of the identification table, and 22 is a CRT for displaying the contents of the memory 18.

The measurement holding time range setting means 1, the time chart creating means 2 and the SIM measurement table creating means 3 shown in the functional block diagram of FIG. 1 are realized by the CPU 16 and the memory 18 in this example.

Next, the operation of creating the SIM measurement table by the gas chromatograph / mass spectrometer 10 having the above-mentioned configuration will be described.

Now, for example, it is assumed that an identification table as shown in FIG. 3 is created in order to quantify seven kinds of components. This identification table is created, for example, by repeatedly scanning a predetermined mass range and measuring mass spectra of all mass numbers within the range, and based on the result, a mass chromatogram showing the time change of each component is obtained. Ask. Then, from this mass chromatogram, the mass number of the target ion corresponding to each component a to g (m / z) ₁ to (m / z) ₇ , the standard retention time indicating the peak top position of the chromatogram of each target ion (ti, i = 1 to 7), and the allowable retention time width (Δt
i, i = 1 to 7) are respectively determined, and these respective parameters are input from the keyboard 20.
The identification table created in this way is stored in the memory 18.

Next, the CPU 16 determines the allowable holding time width (Δt based on the identification table stored in the memory 18).
The measurement retention time width (f · Δti) is calculated by multiplying i) by a fixed value (f). Here, (f) is a value that gives the measurement holding time range in which the peak start point and the peak end point are within the measurement holding time range and the peak can be detected.

Next, from the measured retention time width (f.Δti) and the standard retention time (ti), the measured retention time range (Ri = ti-f.Δti to ti + f.Δti, i) for each target ion is obtained.
= 1 to 7) is set.

Next, the measurement retention time range (Ri) is set for each target ion (in this example, the mass number (m / z) ₁ to (m / z) ₇
Plot each time) on the time axis to create a time chart as shown in FIG.

Subsequently, target ions having overlapping measurement retention time ranges (Ri) on the time chart are grouped together. In this example, R ₁ , R ₂ , and R ₄ are overlapped so that one group is formed. R ₃ has no overlap, so that one group is independently formed, and R ₅ , R ₆ , and R ₇ are overlapped so that one group is formed. I have a group.

Then, for each group, the measurement retention time range (Ri) of the target ions contained in that group
The minimum time range that covers all of the above is determined as the optimum measurement retention time range (Ti). So in this example,
T ₁ , T ₂ , and T ₃ are the optimum measurement holding time range. Here, T ₁ = t ₁ −f · Δti to t ₄ + f · Δt ₄ , T ₂ = t _{3
-F · Δt 3 ~t 3 + f} · Δt 3, T 3 = t 5 -f · Δt 5 ~t 7 + f ·
Δt ₇ .

Thus, the optimum measurement holding time range (Ti, i
= 1 to 3) is determined, the mass number of the target ion and the optimum measurement retention time range (Ti) are associated with each other for each group to create a SIM measurement table as shown in FIG. The SIM measurement table thus created by the CPU 16 is stored in the memory 18.

When quantitatively analyzing each component based on the selected ion monitor method, the CPU 16 refers to both the identification table shown in FIG. 3 and the SIM measurement table shown in FIG. As shown, when the retention time of the components obtained by gas chromatograph separation is within one optimum measurement retention time range T ₁ , the acceleration voltage of the mass spectrometer is set to each mass number (m / z) _{1 of the} target ions. , (M / z) ₂ , (m
/ z) Time division into three values corresponding to ₄ (for example, 0.
The data of the chromatogram of each target ion is collected by switching every 5 seconds. The same applies to the other optimum holding time ranges T ₂ and T ₃ .

In this embodiment, the apparatus in which the gas chromatograph and the mass spectrometer are combined has been described.
It goes without saying that the present invention can be applied to a liquid chromatograph and other devices in which a chromatograph and a mass spectrometer are combined.

[0027]

According to the present invention, once the identification table is created, the SIM measurement table is automatically created accordingly.
Compared with the case where the M measurement table and the M measurement table are created separately, the time and effort required to create the table can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a functional block diagram of a chromatograph / mass spectrometer of the present invention.

FIG. 2 is a block diagram showing an entire gas chromatograph / mass spectrometer according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing the contents of an identification table.

FIG. 4 is a time chart created by a time chart creating means.

FIG. 5: SI created by SIM measurement table creation means
It is an explanatory view of an M measurement table.

FIG. 6 is an explanatory diagram of a case where quantitative analysis is performed by a selective ion monitoring method based on an identification table and a SIM measurement table.

FIG. 7 is a chromatogram obtained based on the target ion of each component.

[Explanation of symbols]

1 ... Measurement holding time range setting means, 2 ... Time chart creating means, 3 ... SIM measurement table creating means, 10 ... Chromatograph / mass spectrometer, 16 ... CPU, 18 ... Memory.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01J 49/26 4230-5E

Claims (1)

[Claims] 1. A mass number of a target ion required to specify a target component to be quantified, and a standard retention time (ti, i = 1, 2, ...) Indicating a peak top position of a chromatogram of each target ion. , And the allowable retention time width (Δt that determines the fluctuation width of the peak top of the chromatogram
i, i = 1, 2, ...) In a chromatograph / mass spectrometer provided with an identification table, the allowable retention time width (Δti) is multiplied by a constant value (f) based on the identification table. The measurement retention time width (f · Δti) is calculated, and the measurement retention time range (Ri = ti−f ·) for each target ion is calculated from the measurement retention time width (f · Δti) and the standard retention time (ti). The measurement retention time range setting means (1) for setting Δti to ti + f · Δti) and the measurement retention time range (Ri) set by the measurement retention time range setting means (1) are set as a time axis for each target ion. Time chart creation means (2) that plots above and creates a time chart,
The target ions whose measurement retention time ranges (Ri) of the time chart created by this time chart creation means (2) overlap each other are made into one group, and the measurement retention time range (Ri) of the target ions contained in each group is set. Optimum minimum time range that covers all measurement retention time range
(Ti), and the mass number of the target ion and the optimum measurement retention time range for each group
SIM measurement table creating means (3) for creating a SIM measurement table in which (Ti) is associated with each other, and a chromatograph / mass spectrometer.