JPH10282060A - Mass spectrometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily visually confirm a peak of a mass spectrum. SOLUTION: When a required mass range is indicated on a mass spectrum through the manipulation of an operation part by a measuring person (S2), a CPU searches for a maximum peak in the mass range (S3), and calculates a ratio of a peak value 10 and a displayable maximum value Imax (S4). A maximum magnification in a range not exceeding the ratio is checked and selected among a plurality of magnifications set beforehand (S4-S8). Each peak in the set mass range is magnified with the selected magnification, and moreover a display color is changed to distinguish the mass range. The peak is displayed on a screen of a display (S9).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a mass spectrometer, and more particularly to display control of a mass spectrum as an analysis result.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram showing an example of a general mass spectrometer. In this mass spectrometer, the ion source 1
At 0, the sample molecules are ionized, and the generated ions are converged by the ion lens 11 and accelerated moderately.
It is introduced into a quadrupole filter (or other mass separator) 12. A voltage obtained by superimposing a DC voltage and a high-frequency voltage is applied to the quadrupole filter 12 by the voltage generator 14, and only ions having a mass number (mass m / charge z) corresponding to the applied voltage selectively pass therethrough. I do. The passed ions are detected by detector 1
3 and is converted into an electric signal corresponding to the number of ions.
The signal processing unit 20 performs predetermined signal processing on the detection signal, and displays the analysis result on the screen of the display 16 or outputs the result to a printer (not shown). Since the mass number of ions passing through the quadrupole filter 12 depends on the applied voltage, an ion intensity signal in a predetermined mass range can be obtained by appropriately scanning the applied voltage. Such an analysis result is represented as a mass spectrum in which the horizontal axis represents the mass number and the vertical axis represents the relative signal intensity.

FIG. 3A is a diagram showing an example of a mass spectrum. Normally, the signal processing unit 20 performs processing such that the peak signal having the maximum intensity is set to 1 and each of the other peak signals is represented by a ratio thereof, that is, displayed by so-called normalization. However, the mass number to be observed in the general analysis is very wide, about several tens to 1000 (or more), and the difference between the maximum value and the minimum value of the peak signal is very large. For this reason, as shown in FIG. 3A, on a mass spectrum, it is very difficult to confirm a peak signal having a small level or to compare such signals. For example, when an electron impact method is used for the ion source 10, the original molecules are easily decomposed during ionization, the number of ions having a mass number close to the original molecular weight is extremely small, and the number of ions generated by the decomposition is large. Become. Therefore, in the mass spectrum, a low peak occurs at a large mass number and a high peak occurs at a small mass number. In such a case, it is possible to estimate the molecular weight of the original molecule based on a plurality of peaks at a small mass number, but it is easier to use the peak corresponding to an ion that has not been decomposed during ionization. The molecular weight of the molecule can be obtained.

[0004] For these reasons, in the actual analysis work, there is often a need to observe in detail the magnitudes and relative magnitudes of a plurality of peaks at a level considerably lower than the maximum intensity signal. Therefore, in the conventional mass spectrometer, for example, the signal intensity of the mass spectrum, that is, the enlarged display in the vertical axis direction can be performed by the following operation. First, the measurer sets a mass range to be enlarged and displayed by operating the operation unit 15 such as a mouse while viewing a normal (non-enlarged) mass spectrum as shown in FIG. Next, an arbitrary peak in the set mass range is designated by a mouse operation or the like, and the designation is released by shifting the peak upward on the mass spectrum on the display screen as it is designated. As a result, an enlargement magnification according to the distance between the initial peak position and the moved peak position is determined, and each peak signal within the set mass range is enlarged and displayed with the enlargement magnification.

[0005]

As described above, in the conventional mass spectrometer, when the operator wants to observe the peak waveform in the desired mass range of the mass spectrum in detail, the user first specifies the mass range and then sets the vertical axis. It was necessary to perform a two-stage operation of performing an operation to determine the magnification of the image. In addition, in the case of the enlargement operation of the vertical axis, the enlargement is not always performed appropriately by one operation, and the tip of the high peak signal within the set mass range is cut off and is not displayed or conversely. Often the overall level is too low. For this reason, in many cases, an appropriate enlarged display is usually performed by performing a plurality of operations.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to easily and easily display peaks in a desired mass range in a mass spectrum by a simple operation. It is to provide a mass spectrometer.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. The present invention provides a mass spectrometer which displays a mass spectrum obtained by analysis on a screen of a display means. Input means operated to set a desired mass range; b) search means for searching for a peak having a maximum signal intensity within the mass range set by the input means; c) search means for searching for a peak having the maximum signal intensity. Selecting means for selecting a magnification for maximizing the peak within a displayable range from among a plurality of predetermined magnifications based on the signal intensity of the peak and a maximum range that can be displayed as a mass spectrum, d) display control means for enlarging each peak within the mass range by the magnification selected by the selection means and displaying the peak together with a mass spectrum outside the mass range. You.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a mass spectrometer according to the present invention,
First, based on the analysis result, when a mass spectrum indicated by a relative signal intensity of the same magnification (usually 1) is displayed on the screen of the display means over the entire mass range, the measurer looks at the display. A desired mass range to be enlarged and confirmed is input and set by the input means. When the mass range is set, the search means searches for a peak having the maximum signal intensity in the mass range, and the selection means calculates a ratio of the maximum displayable range to the peak value. Then, from among a plurality of predetermined enlargement magnifications, the maximum enlargement magnification that is equal to or less than the ratio is selected. The display control means enlarges and displays the peaks within the input and set mass range at the selected magnification, and displays the peaks outside the mass range at the original magnification. Thereby, the peak in the desired mass range is automatically enlarged to the maximum in the displayable range and displayed.

In the mass spectrometer of the present invention, the peaks within the set mass range are colored differently from the other peaks so that the enlarged and displayed range can be easily distinguished from other parts. It is preferable to display with.

[0010]

According to the mass spectrometer of the present invention, as long as the operator specifies the mass range to be enlarged and displayed, each peak included in the mass range is automatically enlarged and displayed so as to be most easily seen. Is done. This eliminates the need for a troublesome operation of appropriately setting the enlargement magnification as in the related art, and facilitates confirmation and determination of the analysis result based on the mass spectrum.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the mass spectrometer according to the present invention will be described below with reference to FIGS. FIG. 2 is a configuration diagram of a main part mainly of the signal processing unit 20 in the mass spectrometer of the present embodiment. A data memory 22, a display control unit 23, an operation unit 15, and the like are connected to the CPU 21, which is the center of signal processing. The CPU 21 operates according to a control program stored in a built-in or external memory, and executes display control processing as described below. The operation unit 15 may use a well-known keyboard, mouse, trackball, or the like.

FIG. 1 is a flowchart showing the operation of display control in the above configuration. The process of controlling the enlarged display of the mass spectrum will be described with reference to this flowchart. First, data constituting a mass spectrum is stored in the data memory 22 by mass analysis, and a mass spectrum as shown in FIG. 3A is displayed on the display 16 based on this data (step S1). At this time, the deviation of the mass number and the like are calibrated by, for example, comparison with the analysis result of a standard sample.

The measurer operates the operation unit 15 to set a mass range to be enlarged and displayed while viewing the mass spectrum on the screen of the display 16 (step S2). Here, for example, it is assumed that only the lower limit M0 of the mass range is indicated. When receiving an instruction from the operation unit 15, the CPU 21 stores data within the set mass range in the data memory 22.
, And sequentially read and compared to find a peak having the maximum signal intensity (step S3).

Next, based on the peak value I0 having the maximum signal intensity and the maximum value Imax that can be displayed in the display area of the mass spectrum as shown in FIG. Select the optimal magnification from among. Specifically, the following processing is executed. Now, as the magnification p [i], p

[0] = 1, p [1] = 5, p
When [2] = 10 and p [3] = 20 are predetermined, i = 0 is set first (step S4), and the ratio Imax / I0 between the maximum displayable value Imax and the peak value I0 is p [i. It is determined whether or not the above is the case (step S5). Imax / I0
Is determined to be equal to or greater than p [i], i is incremented (step S6), and the flow returns to step S5 to execute the determination again.

In step S5, Imax / I0 is p
If it is determined that it is less than [i], j is a value obtained by subtracting 1 from the value of i at that time (step S7),
p [j] is selected as the magnification (step S8).
Then, the CPU 21 multiplies each peak in the set mass range by the magnification p [j] and sends the result to the display control unit 23. Thereby, in the mass spectrum displayed on the screen of the display 16, as shown in FIG.
The data within the set mass range is enlarged and displayed in the vertical axis direction (step S9). At this time, the display control unit 2
No. 3 displays the enlarged peak with a display color different from that outside the mass range. Note that, in FIG. 3B, a portion for changing the display color is indicated by a broken line.

The processing operation according to the flowchart of the above embodiment will be described with specific numerical values. It is assumed that the entire mass range of the mass spectrum is 10 to 1000, and that the lower limit M0 of the mass range is specified to be 700 in step S2. Then, in step S3, a mass number of 700 to
Each peak value within the range of 1000 is compared, and FIG.
A peak having the maximum signal intensity indicated by P is obtained.
Now, it is assumed that the peak value I0 is 0.09, which is a value obtained by normalizing the maximum peak in the entire mass range as 1. In this case, since I0 = 0.09 and Imax = 1, Imax / I0 = 11.1 is obtained. Therefore, when p [3] = 20, step S
The process proceeds from S5 to S7, and j = 2, and p [2] = 10 is selected as the magnification. Thereby, the mass range of 700 to
Each peak of 1000 is magnified 10 times in the vertical axis direction, and is displayed in a color different from each peak of the mass range of 10 to 700.

The above embodiment is merely an example, and it is apparent that changes and modifications can be made within the spirit of the present invention.

[Brief description of the drawings]

FIG. 1 is a view showing a flowchart of a display control processing operation according to an embodiment of the mass spectrometer of the present invention.

FIG. 2 is a configuration diagram of a main part mainly of a signal processing unit of the mass spectrometer of the present embodiment.

FIG. 3 is a diagram showing a mass spectrum displayed in the mass spectrometer of the present embodiment, and before the enlarged display processing (a).
And after the enlarged display processing (b).

FIG. 4 is an overall configuration diagram of a general mass spectrometer.

[Explanation of symbols]

Reference Signs List 15 operation unit 16 display 20 signal processing unit 21 CPU 22 data memory 23 display control unit

Claims (1)

[Claims] 1. A mass spectrometer for displaying a mass spectrum obtained by analysis on a screen of a display means, comprising: a) input means operated to set a desired mass range in the mass spectrum; Searching means for searching for a peak having a maximum signal intensity within the mass range set by the input means, c) based on the signal intensity of the peak searched by the searching means and the maximum range that can be displayed as a mass spectrum, Selecting means for selecting a magnification for maximizing the peak within a displayable range from a plurality of predetermined magnifications, d) each peak in the mass range according to the magnification selected by the selecting means And a display control means for enlarging and displaying together with a mass spectrum outside the mass range.