JPH09297129A - Data processor for chromatography - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve accuracy of identification at the time of continuously analyzing a plurality of unknown samples. SOLUTION: Immediately before and after measurement of an unknown sample, data of a standard sample measured under the same condition as the measurement of the unknown sample is inputted from a chromatographic detector 14. A personal computer 16 estimates the holding time of components in a plurality of unknown samples held in time between two measurements from the peak holding time of specified components of the standard sample respectively detected twice on the basis of a specified reference, and computes the reference of peak identification to each unknown sample. On the basis of this reference, the chromatogram of each unknown sample is analyzed to perform peak identification. The influence of a holding time lag caused by a change with the lapse of time is thereby relaxed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chromatograph data processing device for identifying a peak based on data obtained from a detector of a liquid chromatograph or a gas chromatograph.

[0002]

2. Description of the Related Art Generally, when an unknown substance is identified by a chromatograph, a peak identification table created based on the result of analyzing a known substance is referred to. The type of information that constitutes this peak identification table differs depending on the data processing device, but for example, the retention time (retention time) of the peak of each component, peak shape (peak area or peak height), component concentration, component name, etc. Is.

In the chromatographic analysis, in order to ensure the accuracy of the analysis, the analysis of the standard sample is performed immediately before the analysis of the unknown sample under the same conditions (gas flow rate, column temperature, etc.) as the analysis. Based on the result of this analysis, it is usual to prepare reference data for subsequent peak identification of the unknown sample. That is, in the memory of the data processing device, the peak identification table created based on the standard sample measured at the initial stage (for example, immediately after the delivery of the device) is stored, and when actually measuring the unknown sample, First, a standard sample is measured and peak identification is performed based on the information in the peak identification table stored in the memory. Then, a standard in which the information in the peak identification table is corrected is created based on the identification result at this time, and the peaks of the unknown samples thereafter are identified according to this standard.

When correcting the information in the peak identification table, the retention time of the standard sample measured immediately before may be used as it is as a reference for the subsequent peak identification, or it may be stored in the peak identification table first. It is also possible to calculate the average value of the retention time and the retention time of the standard sample measured immediately before, and use this value as the standard for the subsequent peak identification. In the latter case, even when noise or the like is mixed in and the analysis result is inaccurate when the standard sample is measured immediately before, the influence is reduced by averaging. In any of the methods, the peak identification standard is determined based on the measurement result of the standard sample measured immediately before, so that it is possible to avoid a decrease in analysis accuracy due to a change with time from the initial stage due to deterioration of the column or the like.

[0005]

However, when a plurality of unknown samples are to be continuously analyzed, even if the same analysis conditions are set, the time elapses during the measurement of the plurality of unknown samples. Due to changes and the like, the peak retention times of the same component may shift, which may hinder accurate component identification and quantitative analysis.

The present invention has been made to solve such a problem, and an object of the present invention is to provide chromatographic data which enables accurate identification even when a plurality of unknown samples are analyzed. It is to provide a processing device.

[0007]

Means for Solving the Problems The present invention, which was made to solve the above problems, provides a chromatographic data processing apparatus for performing peak identification based on data obtained from a chromatographic detector. Detection means for detecting a peak based on a predetermined standard from the data of the standard sample measured before and after the measurement of the unknown sample, b) from the peak detection results of the two standard samples, the peak of the unknown sample The present invention is characterized by comprising a calculating means for calculating a criterion for identification for each unknown sample, and c) an identifying means for identifying each unknown sample based on the criterion calculated by the calculating means.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In a data processing apparatus according to the present invention, data of a standard sample measured under the same conditions as the measurement of the unknown sample immediately before and immediately after the measurement of the unknown sample are detected by a chromatograph detector. Input from. The peak detecting means analyzes the data of the standard sample and finds the peak of each predetermined component based on a predetermined standard. Next, the calculating means calculates the retention time difference in the unknown sample measured between the two standard sample measurements in time from the difference between the peak retention times in the two standard sample measurement results. Calculate for each and create a standard for peak identification of the unknown sample. The identification means analyzes the chromatographic measurement data for each unknown sample based on this criterion,
Perform peak identification.

When the calculation means calculates the peak identification standard of the unknown sample, only the peak detection results of the standard sample measured before and after may be used, and further, the peak detection means may identify the peak of the standard sample. The calculation may be performed in consideration of the information of the predetermined reference used for performing.

Since the standard sample contains only the target component or the concentration of the target component is extremely high, the peak of the target component appears clearly and independently in the chromatogram. Therefore, at the time of peak detection of the standard sample, the detection window width (time margin for peak detection set before and after the retention time) is widened so that the peak can be detected reliably even if the retention time deviation is large. It is good to On the other hand, in an unknown sample, the peaks of a plurality of components generally appear close to each other.Therefore, a narrow detection window width is set as a reference with respect to the retention time calculated by the calculation means so that the peak of the unknown sample can be accurately identified. It is desirable to do.

[0011]

According to the data processor for a chromatograph according to the present invention, when a plurality of unknown samples are continuously analyzed, the peaks of the unknown samples are calculated based on different criteria in consideration of the change over time in the analysis conditions. Since identification is performed, accurate component identification and quantitative analysis can be performed in chromatographic analysis.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a chromatographic data processing apparatus according to the present invention will be described with reference to FIGS. FIG.
FIG. 1 is an overall configuration diagram of a liquid chromatograph analysis device using the data processing device of this embodiment. The liquid chromatograph analyzer 10 includes a sample changer 11 for automatically exchanging a plurality of samples, a separation column 12, an auto-injector 13 for automatically injecting a sample into the separation column 12, and a detector provided at the outlet of the separation column 12. 14, a control unit 15 that controls the operation of each of the above-described units, a personal computer 16 (hereinafter referred to as “personal computer”) connected to the detector 14, and the like. An external memory 21, a display 22, a printer 23, a keyboard 24, etc. are connected to the personal computer 16.

When performing chromatographic analysis, first,
By giving a signal for selecting a predetermined sample from the control unit 15 to the sample changer 11, the predetermined sample is injected from the auto-injector 13 into the mobile phase flowing through the separation column 12. Separation column 12 for each component in the sample
Since the time to pass through (holding time) depends on the component,
In the mobile phase that has passed through the separation column 12, each component of the sample is temporally separated. The detector 14 is the separation column 12
The liquids eluted from the PC are sequentially detected, and the detection signal is sent to the PC 1.
Enter in 6. The printer 23 connected to the personal computer 16 creates a chromatogram based on the detection signal. Further, the personal computer 16 analyzes the detection signal as described later to perform the qualitative analysis and the quantitative analysis of the components contained in the sample, and outputs the result to the display 22 and the printer 23.

Data processing executed mainly by the personal computer 16 will be described below with reference to the processing flowchart of FIG. First, the control unit 15 controls each unit to execute the chromatographic measurement of a plurality of samples according to the analysis schedule instructed by the personal computer 16 (step S1).
Now, when it is desired to analyze three unknown samples, measurement of the standard sample is performed once before and after that, and a total of five chromatographic measurements are performed. The analysis schedule showing the measurement order in this case is as shown in FIG. The sample changer 11 is in the order dictated by this analysis schedule,
Replace the sample set by the measurer. Sample number 1
The five chromatographic measurements 5 to 5 are all performed under the same conditions (mobile phase moving speed, temperature cycle of the separation column 12, etc.).

The personal computer 16 receives the detection signal from the detector 14 and stores this data in the external memory 21 (step S2). After the measurement of the five samples is completed and all the data are stored in the external memory 21, the personal computer 16 reads the data of the standard samples of predetermined sample numbers 1 and 5 and executes peak detection (step S3). As a reference for peak detection, for example, when the slope of the chromatogram curve, which is the change over time of the detection signal, becomes equal to or greater than a predetermined start slope value, it is determined that the peak has started, and then the time when the slope becomes zero has passed. Then, the slope value becomes negative, and when the absolute value becomes equal to or smaller than the predetermined end slope value, it is possible to determine the peak end. In this case, the time when the inclination becomes zero within the peak is defined as the peak top.

Then, the detected peak is identified by referring to a predetermined peak identification table (step S4). As shown in FIG. 4, the peak identification table stores information such as the component name, the retention time of the component, and the detection window width for peak identification. This holding time may be a value based on the result of initially measuring the standard sample, or may be obtained by calculation or the like. In the example of FIG. 4, for example, when the peak top exists in the range of 1.75 to 2.25 minutes with respect to the standard sample, it is identified as the component of the component number 1. Now, assuming that the chromatograms of the two standard samples of sample numbers 1 and 5 are respectively FIGS. 5 (a) and 5 (b), each peak conforms to the criteria of the above identification table. , And is determined to be the peak of the component of component number 1.

Then, a standard for identifying the unknown samples of sample numbers 2 to 4 is calculated from the peak identification result of the standard sample previously obtained (step S5). That is, the retention time for identifying the component of each unknown sample is calculated for each unknown sample. The retention time of each unknown sample measured during the measurement of two standard samples temporally is calculated, for example, by the following calculation formula. T (i) = T (S1) + [(T (S2) -T (S1)) / (N + 1)] × i (1) where i is the order of measurement (sample number), T (i) Is the retention time of the predetermined component in the i-th sample, T (S1) is the retention time of the predetermined component in the standard sample of sample number 1 (data file name STD1), T (S2) is the sample number 5 (data file name S
The retention time of the predetermined component in the standard sample of TD2), N is the number of unknown samples (3 in the above example).

In the case of the measurement result of the standard sample as shown in FIG.
Since T (S1) = 1.8, T (S2) = 2.2, and N = 3,
The retention time T (i) in the unknown sample of i = 2 to 4 is calculated by the formula (1)
From these, we obtain 1.9, 2.0, and 2.1, respectively (Fig. 5).
(See (c), (d) and (e)). This value is the retention time for the component of component number 1 when identifying each unknown sample. By performing such a calculation for a plurality of components, a reference for peak identification that differs for each unknown sample is created, and this is used as the external memory 21 or the personal computer 1.
It is held in the internal memory in 6.

Next, the predetermined data of the unknown sample are sequentially read out to perform peak detection, and the detected peaks are identified in accordance with the above-calculated standard (step S).
6). At this time, the detection window width for peak identification is narrower than the detection window width for peak identification of the standard sample, as shown in FIG. This enables accurate identification even if there are peaks of other components in the vicinity of the desired peak. For example, in the unknown sample of sample number 2, the component of component number 1 is identified on the basis of the retention time of 1.9 minutes and the detection window width of 0.1 minute.

In the above embodiment, when the holding time is calculated in step S5, the holding times T (S1) and T (S2) which are the measurement results of the standard sample are used as they are. However, you may make it calculate the average value with the value stored in the peak identification table, and calculate the retention time for each unknown sample based on this average value. For example, in the above example, the retention time of component number 1 in the peak identification table is 2.0 minutes, so this retention time and T (S1) and T (S2)
, And 1.9 and 2.1 minutes may be respectively taken as T (S1) and T (S2) in the equation (1). In this case,
The retention times T (i) of the i = 2 to 4th unknown samples are calculated from the equation (1) as 1.95, 2.0, and 2.05, respectively.

Further, it is considered that the deviation of the retention time on the chromatogram for one sample is uniform, and the deviation of the retention time for each unknown sample calculated from the peak deviation of one component in the standard sample. Therefore, the retention times of all components for peak identification in one unknown sample may be corrected. That is, the standard sample may contain only one component for the purpose of detecting the retention time deviation, and the unknown sample may contain no such component.

Furthermore, the above-described embodiment is merely an example, and it is obvious that appropriate changes and modifications can be made in accordance with the spirit of the present invention.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a liquid chromatograph analysis device using an embodiment of a data processing device according to the present invention.

FIG. 2 is a processing flowchart of this data processing device.

FIG. 3 is a diagram showing an analysis schedule in this example.

FIG. 4 is a diagram showing a part of a peak identification table in this embodiment.

FIG. 5 is a waveform chart showing an example of a chromatogram in this example.

[Explanation of symbols]

 10 ... Liquid chromatograph analyzer 11 ... Sample changer 12 ... Separation column 13 ... Auto injector 14 ... Detector 15 ... Control unit 16 ... PC 21 ... External memory

Claims (1)

[Claims] 1. A data processor for a chromatograph, which performs peak identification based on data obtained from a chromatographic detector, comprising: a) data of a standard sample measured before and after a series of unknown sample measurements. Detecting means for detecting a peak based on a predetermined reference, b) from the peak detection results of the two standard samples, calculating means for calculating a reference for identifying the peak of the unknown sample for each unknown sample, c) A chromatograph data processing device, comprising: an identification unit that identifies each of the unknown samples based on the reference calculated by the calculation unit.