JP5742749B2 - Chromatograph data processing apparatus and data processing method - Google Patents

Description

  The present invention relates to a chromatographic data processing apparatus and a data processing method.

  In a chromatograph such as a liquid chromatograph (LC) or a gas chromatograph (GC), a chromatogram in which a peak corresponding to a component contained in a sample appears can be obtained. However, the peak appearing in the chromatogram is not necessarily due to a single component (target component), and may include a component (impurity) that is not the target component. Thus, conventionally, a peak purity determination process has been performed in which whether a peak is derived only from a target component or contains impurities in a chromatogram representing a time change of a component eluted from a column.

Patent Document 1 discloses a technique for determining peak purity in a chromatogram obtained by a liquid chromatograph using a multi-wavelength detector. A liquid chromatograph that uses a multi-wavelength detector irradiates light having a plurality of wavelengths to a component eluted from a column and measures the absorbance of each wavelength that has passed through the component. At each time, the absorbance spectrum of the separated sample is obtained. Such an aggregate of absorbance spectra becomes three-dimensional data of time, wavelength, and absorbance. FIG. 3 schematically shows such three-dimensional data. By appropriately processing the three-dimensional data thus obtained, (1) a relationship between time and absorbance at the target wavelength, that is, a wavelength chromatogram can be obtained, and (2) the wavelength and absorbance at each time. The relationship, that is, the absorbance spectrum can also be obtained.
In Patent Document 1, based on such three-dimensional data, it is determined by the following method whether or not a peak that is a target of purity determination (hereinafter referred to as “target peak”) contains impurities.

  First, the absorbance spectrum at time T0 corresponding to the peak apex of the target peak in the wavelength chromatogram is S0 (λ), and the absorbance spectrum at any time T before and after that is S (λ). To calculate the degree of coincidence between S0 (λ) and S (λ).

As shown in FIG. 2, the target peak is determined according to the degree of coincidence with the peak apex, such as green if the degree of coincidence is 1.0 to 0.8, yellow if it is 0.8 to 0.6, and orange if it is less than 0.6. The color is divided and displayed in the time axis direction according to the color (indicated by shading in the figure). If the target peak is derived only from the target component, as shown in FIG. 2 (a), the degree of coincidence is high near the peak apex and decreases as it goes away from the peak apex, but its shape is the central axis of the peak. It is generally symmetrical with respect to. However, when an impurity peak exists before or after the peak apex of the target peak (that is, when the target peak includes an impurity), the shape of the degree of coincidence of the target peak is asymmetrical with respect to the central axis of the peak. . For example, in the example shown in FIG. 2B, the degree of coincidence on the right side (back side in time) is lower than the left side across the peak apex. Thereby, it can be determined that impurities are included in the time zone around this area.

Japanese Patent No. 2936700

Review of Shimadzu, Vol. 46, No. 1, pp. 21-28

  However, in the conventional determination method described above, when an impurity peak exists in the immediate vicinity of the peak apex of the target peak, the degree of coincidence is high near the peak apex, so the presence of the impurity cannot be correctly determined. there were.

  Further, in the method described in Non-Patent Document 1, in order to obtain a coincidence threshold for determining whether or not an impurity peak exists, a noise vector having a noise magnitude at each wavelength as a component is used as a parameter. Must be set. However, in order to obtain a noise vector, complicated calculation such as sequentially monitoring the magnitude of noise in a predetermined wavelength region detected by the multi-wavelength detector and obtaining the standard deviation of the time variation of noise in the wavelength region. Processing was necessary.

  The present invention has been made to solve the above-mentioned problems, and the object of the present invention is not only to determine whether or not the target peak contains impurities with high accuracy, but also does not require complicated calculation processing. Another object is to provide a chromatographic data processing apparatus and a data processing method.

In order to solve the above problems, the present invention provides a chromatographic method in which a sample is separated in a time direction by a chromatograph, absorbance data at each time is collected, and three-dimensional data including time, wavelength, and absorbance is created. A data processing device for graphs,
a) a three-dimensional data storage unit for storing three-dimensional sample data obtained by measuring a sample containing a target component;
b) a wavelength chromatogram creation unit for creating a wavelength chromatogram for a plurality of absorption wavelengths of the target component for the sample three-dimensional data;
c) In each wavelength chromatogram, a peak retention time acquisition unit that acquires a peak retention time of a peak apex of a target peak that appears in a preset time range including a peak derived from the target component;
d) a peak holding time difference calculating unit that calculates a difference between the maximum peak holding time and the minimum peak holding time among the plurality of acquired peak holding times;
e) a determination unit that determines whether or not the target peak in the sample three-dimensional data contains impurities by comparing the difference with a predetermined determination value;
It is characterized by having.

  The chromatograph may be a liquid chromatograph or a gas chromatograph.

The target peak is a peak including a peak derived from the target component, which appears in a preset time range and is a target of purity determination processing.
This “preset time range” may be set by obtaining a peak holding time of a peak derived from a sample of the target component from a database or the like and providing a predetermined time range before and after that. The operator may input directly.
The target peak may consist of only the peak derived from the target component, or the peak derived from the target component and the peak derived from the impurity may be integrated. The target peak containing a large amount of impurities may have a peak vertex derived from the impurity peak in addition to the peak vertex derived from the peak of the target component in the above time range. An acquisition part acquires the peak holding time of each peak vertex.

  The method for obtaining the “plural absorption wavelengths of the target component” is not particularly limited, but the operator may directly input the wavelength value, or the operator may specify the target component and set the corresponding absorption wavelength band. The wavelength value may be automatically picked up from the absorption wavelength band by obtaining from a database or the like.

In the chromatographic data processing apparatus according to the present invention, first, a sample containing a target component is measured, and three-dimensional sample data including time, wavelength, and absorbance is obtained. The acquired sample three-dimensional data is stored in the sample three-dimensional data storage unit. The wavelength chromatogram creation unit creates a wavelength chromatogram for a plurality of absorption wavelengths of the target component based on the three-dimensional sample data. When all the wavelength chromatograms are created, the peak holding time acquisition unit acquires the peak holding time in each wavelength chromatogram for the peak apex of the target peak appearing in a preset time range.
When all the peak holding times are acquired, the peak holding time difference calculating unit calculates a difference between the maximum peak holding time and the minimum peak holding time among the plurality of peak holding times. Then, the determination unit determines whether or not the target peak contains impurities by comparing the difference with a predetermined determination value.

  When the target peak does not contain impurities, the peak retention time at the peak apex of the target peak in the wavelength chromatogram is theoretically the same regardless of the absorption wavelength. On the other hand, when the target peak includes an impurity, the peak retention time in the wavelength chromatogram relating to the wavelength included in the absorption wavelength band of the impurity deviates from the peak retention time in the wavelength chromatogram relating to other absorption wavelengths. The chromatographic data processing apparatus according to the present invention performs peak purity determination processing using such a deviation.

In addition, the present invention, which has been made to solve the above problems, separates a sample in a time direction by a chromatograph, collects absorbance spectrum data at each time, and creates three-dimensional data including time, wavelength, and absorbance. A chromatographic data processing method for
a) a three-dimensional data storage step for storing sample three-dimensional data obtained by measuring a sample containing a target component;
b) a wavelength chromatogram creating step for creating a wavelength chromatogram for a plurality of absorption wavelengths of the target component for the sample three-dimensional data;
c) In each wavelength chromatogram, a peak retention time acquisition step of acquiring a peak retention time of a peak apex of a target peak that appears in a preset time range including a peak derived from the target component;
d) a peak holding time difference calculating step for calculating a difference between the maximum peak holding time and the minimum peak holding time among the plurality of acquired peak holding times;
e) a determination step of determining whether or not the target peak in the sample three-dimensional data contains impurities by comparing the difference with a predetermined determination value;
It is characterized by having.

The chromatographic data processing apparatus and data processing method according to the present invention acquires the peak retention time of the peak apex of the target peak in each of a plurality of wavelength chromatograms created based on the sample three-dimensional data, and provides the maximum peak retention. The difference between the time and the minimum peak holding time is calculated, and the peak purity determination process is performed by comparing this difference with a predetermined determination value. Therefore, it can be determined with high accuracy whether or not the target peak contains impurities.
Also, in the present invention, unlike the above-described prior art, it is not necessary to set a noise vector as a parameter, so that the peak purity determination process can be performed by a relatively simple calculation process.

The schematic block diagram which shows the principal part of the data processor which concerns on one Example of this invention, and a liquid chromatograph. It is a figure which shows the example which displayed the information regarding a coincidence degree with the peak by the method of the conventional peak purity determination process, (a) is an example of the peak which does not contain an impurity, (b) is an example of the peak which contains an impurity. . The conceptual diagram showing the wavelength chromatogram created from three-dimensional data and this three-dimensional data. The flowchart which shows operation | movement of the data processor which concerns on a present Example. It is a conceptual diagram explaining the data processing method which concerns on a present Example, (a) is a wavelength chromatogram which shows the target peak which does not contain an impurity, (b) An example of the contour map of the target peak which does not contain an impurity, (c) Is a wavelength chromatogram showing a target peak containing impurities, and (d) is an example of a contour map of a target peak containing impurities.

An embodiment of a chromatographic data processing apparatus according to the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a chromatographic data processing apparatus (hereinafter simply referred to as “data processing apparatus”) and a chromatograph connected thereto in the present embodiment. In this embodiment, a liquid chromatograph (LC) 1 is used as a chromatograph.

In LC1, the liquid feed pump 12 sucks the mobile phase from the mobile phase container 11 and feeds it to the sample injection unit 13 at a constant flow rate. The sample injection unit 13 injects a sample into the mobile phase at a predetermined timing. The sample components are sent to the column 14 together with the mobile phase, and are separated in the time direction for each component while passing through the column 14, and are eluted from the column 14.
A PDA detector 15, which is a kind of multi-wavelength detector, is provided at the outlet of the column 14 as a detector for detecting a sample component in the eluate from the column 14. The PDA detector 15 irradiates the eluent with light from a light source (not shown), wavelength-separates the light transmitted through the eluate, and simultaneously detects the separated light of each wavelength by a PDA (Photo Diode Array). The detection signal obtained by the PDA detector 15 is converted into a digital signal by the A / D converter 16 and then output to the data processing device 2 as three-dimensional data.

  The data processing device 2 includes a three-dimensional data storage unit 21 for storing the three-dimensional data output from the A / D converter 16, and a wavelength chromatogram relating to a plurality of absorption wavelengths of the target component based on the three-dimensional data. And a peak retention time acquisition unit 23 for acquiring the peak retention time of the peak apex of the target peak (that is, the peak appearing in a preset time range including the peak derived from the target component). And a peak holding time difference calculating unit 24 for calculating a difference between the maximum peak holding time and the minimum peak holding time among the acquired peak holding times, and comparing the difference with a predetermined determination value to obtain a target peak. A determination unit 25 that determines whether or not impurities are included is included as a functional block.

The display unit 3 is for displaying various information such as wavelength chromatograms and determination results. The operation unit 4 is operated by the operator to input and set information necessary for data processing such as the absorption wavelength of the target component.
Note that some or all of the functions of the data processing device 2 are achieved by executing dedicated control / processing software installed in a personal computer. The display unit 3 is a general liquid crystal monitor or the like, and the operation unit 4 is a keyboard or a mouse that is a standard equipment of a personal computer.

Next, the operation of the data processing apparatus 2 according to the present embodiment will be described with reference to the flowchart of FIG. 4 and the conceptual diagram of FIG.
First, chromatographic analysis of a sample is performed in LC1, and three-dimensional data representing the time change of the absorbance spectrum in a predetermined wavelength range is output from the PDA detector 15 to the three-dimensional data storage unit 21 via the A / D converter 16. And stored in the three-dimensional data storage unit 21 (step S1 in FIG. 4).
Next, the wavelength chromatogram creation unit 22 reads out the sample three-dimensional data, and creates a wavelength chromatogram relating to a plurality of absorption wavelengths of the target component preset by the operator (step S2). In this embodiment, the operator sets in advance five wavelength values of 200 nm, 210 nm, 220 nm, 230 nm, and 240 nm using the operation unit 4. The operator designates a target component and acquires the corresponding absorption wavelength band from a database or the like. Thus, a plurality of wavelength values may be automatically picked up from the absorption wavelength band.

Further, the peak retention time acquisition unit 23 sets a peak appearing within a preset time range from the start point T _S to the end point T _E in each of these five wavelength chromatograms, and the peak of the target peak. The peak retention time of the vertex is acquired (step S3 in FIG. 4). The time of the start point T _S and the end point T _E is set by acquiring the peak retention time of the peak derived from the sample in advance by measuring the sample of the target component, and providing a predetermined time range around it. The Alternatively, the start time and end time of the peak derived from the standard may be applied as they are as the time of the start point T _S and the end point T _E , or the operator may input the time of the start point T _S and the end point T _E. .
In addition, when the target peak includes a large amount of impurities, and there are a plurality of peak vertices within the time range, the peak retention time acquisition unit 23 calculates the peak retention time corresponding to each of the plurality of peak vertices. get.

  When the peak retention times are acquired for the five wavelength chromatograms, the peak retention time difference calculation unit 24 calculates the difference between the maximum peak retention time and the minimum peak retention time among these peak retention times (step of FIG. 4). S4).

When the target peak does not contain impurities, the contour line shape of the target peak in the sample three-dimensional data is axisymmetric with respect to a line that includes the peak apex and is orthogonal to the time axis t, as shown in FIG. In this case, the peak retention times of the peak vertices of the target peaks in the five wavelength chromatograms are substantially the same as shown in FIG. 5 (a) (however, all peak retention times are complete due to the influence of unavoidable noise and the like). Are rarely the same).
On the other hand, when the target peak contains impurities, the contour line shape of the target peak in the sample three-dimensional data is distorted as shown in FIG. Accordingly, the peak retention time in the wavelength chromatogram relating to the wavelength included in the absorption wavelength band of the impurity among the five wavelength chromatograms is as shown in FIG. 5 (c) in the wavelength chromatogram relating to the other absorption wavelengths. It deviates from the peak retention time (FIG. 5 (c)).
In the case of FIG. 5C, the peak retention times at the peak apexes in the wavelength chromatograms for the wavelength values of 200 nm and 210 nm are shifted from the peak retention times in the wavelength chromatograms for the other wavelength values. From this, it can be seen that this target peak includes impurities having an absorption wavelength band in the vicinity of 200 nm to 210 nm.

Further, when the difference between the maximum peak retention time and the minimum peak retention time is calculated by the peak retention time difference calculation unit 24, the determination unit 25 compares a predetermined determination value J set in advance with the magnitude of the difference. (Step S5 in FIG. 4).
The determination value J described above is set as follows.
With respect to three-dimensional data (corresponding to “standard three-dimensional data” of the present invention) obtained by measuring a sample containing a sample of the target component in advance, the wavelength chromatogram creation unit 22 performs wavelength chromatography on a plurality of absorption wavelengths of the target component While creating a gram, the peak retention time acquisition unit 23 acquires peak retention times of peaks derived from the target component in the plurality of wavelength chromatograms. The peak retention time difference calculation unit 24 calculates a difference between the maximum peak retention time and the minimum peak retention time among the plurality of peak retention times (this is referred to as “standard difference”). A value obtained by multiplying the standard difference by 3 is applied as the determination value J.

  In step S5, if the difference calculated by the peak holding time difference calculation unit 24 is smaller than the determination value J described above (Yes in step S5 in FIG. 4), the target peak in the sample three-dimensional data includes impurities. In other words, it is determined that the target peak is a single peak (step S6). On the other hand, if the difference is larger than the determination value J (No in step S5 in FIG. 4), it is determined that the target peak contains impurities (step S7). The obtained determination result is notified to the operator by the display unit 3.

As described above, the data processing apparatus 2 according to the present embodiment acquires the peak retention time of the peak apex of the target peak for each of a plurality of wavelength chromatograms created based on the sample three-dimensional data, and obtains the maximum peak. The difference between the retention time and the minimum peak retention time is calculated, and the difference is compared with the determination value J to perform the peak purity determination process. By comprising in this way, it can be determined with high precision whether the target peak contains impurities.
Further, in the present embodiment, unlike the above-described conventional technique, it is not necessary to set a noise vector as a parameter, so that the peak purity determination process can be performed by a relatively simple calculation process.

The data processing apparatus 2 according to the present embodiment is theoretically operable if at least two absorption wavelengths are set. However, from the viewpoint of sufficiently obtaining the accuracy of the determination result and suppressing the time required for the calculation process. It is desirable to set the number of absorption wavelengths to about 4 to 16.
In this embodiment, a value obtained by multiplying the standard difference by 3 is applied as the determination value J. However, a number other than 3 may be multiplied. When it is known in advance that the standard difference does not change greatly regardless of the type of the target component, the determination value J obtained from the standard difference of a certain target component may be used as a determination value common to all components.

1 ... LC
DESCRIPTION OF SYMBOLS 2 ... Data processor 3 ... Display part 4 ... Operation part 11 ... Mobile phase container 12 ... Liquid feed pump 13 ... Sample injection part 14 ... Column 15 ... PDA detector 16 ... A / D converter 21 ... Three-dimensional data storage part 22 ... Wavelength chromatogram creation unit 23 ... Peak retention time acquisition unit 24 ... Peak retention time difference calculation unit 25 ... Determination unit

Claims (6)

A chromatographic data processing apparatus that separates a sample in a time direction by a chromatograph, collects data of an absorbance spectrum at each time, and creates three-dimensional data including the time, wavelength, and absorbance,
a) a three-dimensional data storage unit for storing three-dimensional sample data obtained by measuring a sample containing a target component;
b) a wavelength chromatogram creation unit for creating a wavelength chromatogram for a plurality of absorption wavelengths of the target component for the sample three-dimensional data;
c) In each wavelength chromatogram, a peak retention time acquisition unit that acquires a peak retention time of a peak apex of a target peak that appears in a preset time range including a peak derived from the target component;
d) a peak holding time difference calculating unit that calculates a difference between the maximum peak holding time and the minimum peak holding time among the plurality of acquired peak holding times;
e) a determination unit that determines whether or not the target peak in the sample three-dimensional data contains impurities by comparing the difference with a predetermined determination value;
A chromatographic data processing apparatus comprising: a) The three-dimensional data storage unit stores standard three-dimensional data obtained by measuring a sample of the target component,
b) The wavelength chromatogram creation unit creates a wavelength chromatogram for the standard three-dimensional data for a plurality of absorption wavelengths of the target component,
c) the peak retention time acquiring unit acquires the peak peak retention time from the target component in a plurality of wavelength chromatogram created for the standard three-dimensional data,
d) The peak holding time difference calculating unit calculates a difference between the maximum peak holding time and the minimum peak holding time among the plurality of peak holding times acquired for the standard three-dimensional data,
e) The determination unit compares the difference calculated for the sample three-dimensional data with the difference calculated for the standard three-dimensional data, thereby including impurities in the target peak in the sample three-dimensional data. The chromatographic data processing apparatus according to claim 1, wherein it is determined whether or not the data has been detected.   If the difference calculated for the sample three-dimensional data is greater than a value obtained by multiplying the difference calculated for the standard three-dimensional data by a predetermined coefficient, the target peak in the sample three-dimensional data is determined. The chromatographic data processing apparatus according to claim 2, wherein it is determined that an impurity is contained in the chromatogram. A chromatographic data processing method for separating a sample in a time direction by a chromatograph, collecting absorbance spectrum data at each time, and creating three-dimensional data including time, wavelength, and absorbance,
a) a three-dimensional data storage step for storing sample three-dimensional data obtained by measuring a sample containing a target component;
b) a wavelength chromatogram creating step for creating a wavelength chromatogram for a plurality of absorption wavelengths of the target component for the sample three-dimensional data;
c) In each wavelength chromatogram, a peak retention time acquisition step of acquiring a peak retention time of a peak apex of a target peak that appears in a preset time range including a peak derived from the target component;
d) a peak holding time difference calculating step for calculating a difference between the maximum peak holding time and the minimum peak holding time among the plurality of acquired peak holding times;
e) a determination step of determining whether or not the target peak in the sample three-dimensional data contains impurities by comparing the difference with a predetermined determination value;
A chromatographic data processing method characterized by comprising: a) In the three-dimensional data storage step, standard three-dimensional data obtained by measuring a sample of the target component is stored;
b) In the wavelength chromatogram creation step, for the standard three-dimensional data, a wavelength chromatogram is created for a plurality of absorption wavelengths of the target component,
c) In the peak holding time acquisition step acquires the peak peak retention time from the target component in a plurality of wavelength chromatogram was developed for the standard three-dimensional data,
d) In the peak holding time difference calculating step, a difference between the maximum peak holding time and the minimum peak holding time among the plurality of peak holding times acquired for the standard three-dimensional data is calculated,
e) In the determination step, an impurity is included in the target peak in the sample 3D data by comparing the difference calculated for the sample 3D data with the difference calculated for the standard 3D data. 5. The chromatographic data processing method according to claim 4, wherein it is determined whether or not the data is processed.   In the determination step, if the difference calculated for the sample three-dimensional data is greater than a value obtained by multiplying the difference calculated for the standard three-dimensional data by a predetermined coefficient, the target peak in the sample three-dimensional data 6. The chromatographic data processing method according to claim 5, wherein it is determined that an impurity is contained in the gas chromatograph.

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