JP4470811B2 - Chromatographic analyzer - Google Patents

Description

  The present invention includes a gas chromatograph (GC), a liquid chromatograph (LC), or a chromatograph mass spectrometer (GC / MS or LC / MS) combining such a chromatograph and a mass spectrometer (MS). The present invention relates to a chromatographic analyzer.

  In chromatographic analysis using a separation column, analysis conditions that match the characteristics of the column are set prior to analysis of the target sample, and the analysis is automatically performed according to this. In general, a standard sample containing a compound to be analyzed is actually analyzed, and optimal analysis conditions are set based on the result. Hereinafter, a gas chromatograph mass spectrometer (GC / MS) combining a gas chromatograph (GC) and a mass spectrometer (MS) will be described as an example.

In GC / MS, so-called scan measurement and SIM (selected ion monitoring) measurement are known as data collection methods in the MS unit, and usually one of them is selected (see, for example, Patent Document 1). In the scan measurement, since repeatedly scans the mass at a predetermined mass (strictly mass-to-charge ratio m / z) within the limits, all ions contained in the quality Ryohan circumference is detected. Therefore, it is useful when a qualitative analysis of an unknown sample, mass of analyte is unknown. On the other hand, in the SIM measurement, it detects only ions having 1 or more specific mass designated in advance by selectively time division. Therefore, it is useful when the substance to be analyzed is known and quantitative analysis of the substance is performed with high sensitivity.

The data collection conditions for performing a scan measurement (scanning measurement parameters), simultaneously with the measurement for quality Ryohan circumference, it is necessary to set the measurement start time and measurement end time. For example, the quality Ryohan Range: 100 to 500, measurement start time: 5 minutes, the measurement end time: 18 minutes and when it is set, the time when the sample is injected into the sample vaporizing chamber provided in the column inlet zero, 13 minutes up to the point of 18 minutes from the time the five minutes have passed has passed, it collects detected data while repeating the mass scan Te than the 100-500 quality Ryohan circumference at a predetermined quality Ryosu step width .

On the other hand, the data acquisition condition in the case of performing SIM measurement (SIM measurement parameters), it is necessary to simultaneously set the measurement start time and measurement end time 1 to a plurality of mass to be measured, usually, from the column to measure different mass in accordance with the elution time of the various components, which is a measurement time range defined by the measurement start time and measurement end time to allow multiple settings. For example,
Measurement time range: 5 to 8 minutes, measurement Weight: 151,120,130
Measurement time range: 8 to 10 minutes, measurement Weight: 250,273,157,311,256,450
Measurement time range: 10 to 12 minutes, measurement Weight: 167,345,327
As described above, it sets one or a plurality of measurement Mass separated measurement time range for each measurement time range of. The time of analysis performed in the MS unit collects detection data while sequentially switching the quality of the measured object with the lapse of time from sample injection time according to the setting. In this specification, one measurement time range of this SIM measurement is called an ion set. That is, in the above example, three ion sets are set.

  By the way, in the gas chromatograph, the time when the peak of the same component appears on the chromatogram varies due to various factors. For example, when the capillary column is cut for a predetermined length for maintenance of the column, when the temperature rising program of the column oven, which is one of the analysis conditions, is changed, or when the column is sized such as inner diameter and length, etc. Is replaced with a different one.

  In GC / MS, if there is a factor that causes such fluctuations in the time axis direction of the chromatogram, the data collection conditions as described above (specifically, the time within the measurement time range, etc. therein) Parameter) must be changed. In the case of scan measurement, it is only necessary to change the two time parameters, measurement start time and measurement end time, but in the case of SIM measurement, all measurement start time and measurement end time of each ion set must be changed. I must. In the existing GC / MS, the maximum number of ion sets that can be set is, for example, 32, 64 or more, and when a large number of ion sets are set, the time parameter change as described above is not possible. This is a laborious operation for the operator.

In GC / MS, there are cases where scan measurement and SIM measurement are combined or MS / MS (MS ⁿ ) analysis is performed. In such measurement, various parameters are set for each elution time of the compound from the column. Therefore, if there are fluctuations in the time axis direction of the chromatogram as described above, these parameters must be changed.If there are many compounds to be measured, the change work is very troublesome and laborious. It takes.

  In addition to GC / MS, for example, preparative liquid chromatographs, such as preparative liquid chromatographs, are used to perform processing that depends on processing conditions including temporal parameters such as fractionation and fractionation of sample components that have been temporally separated by a column. Similar problems arise when doing so. Even in such a case, for example, when there are a large number of sample components to be sorted and fractionated, changing the processing conditions is troublesome.

JP-A-10-283984

  The present invention has been made in order to solve the above-mentioned problems, and the object of the present invention is already set when there is a factor causing a change in the time axis direction of the chromatogram, for example, the inlet end excision of a capillary column. It is an object of the present invention to provide a chromatographic analyzer that can reduce the burden on the operator and work errors by simply changing the data collection conditions and processing conditions.

  Until now, for example, in order to accurately identify the peak of the unknown component appearing in the chromatogram obtained by chromatographic analysis of a certain sample, the peak of the unknown component is based on the measured retention time of the peak of the known component. The retention time is corrected and the corrected retention time is checked against the qualitative database for peak identification, or the retention time recorded in the qualitative database is corrected and the corrected value is used to identify the peak. Data processing is performed. That is, after collecting chromatogram data, the fluctuation in the time axis direction of the chromatogram is corrected for the data, or the analysis parameter for identifying the data is corrected in the time axis direction of the chromatogram. This is to correct for fluctuations.

  Such conventional correction is performed after the analysis for the target sample is performed. However, the present invention applies the correction to the data collection conditions and processing conditions for the analysis before performing the analysis for the target sample. It is intended to achieve the purpose.

That is, the first invention made to solve the above-mentioned problems is to detect a sample component temporally separated by a column according to a preset separation condition by a mass spectrometer according to a preset data collection condition. detected data a collection to torque chromatograph analyzer Te, the data acquisition condition is, as the time parameter relates to the elapsed time from sample introduction point to the column, the scan measurement or selected ion monitoring measurement in the mass spectrometer In the measurement time range when performing ,
first memory to keep the condition storage and retention time of a given component under data collection conditions in the first separation conditions under the separation conditions set by the operator for analysis of a) the target sample Means,
b) after being changed from the first separation conditions, chromatography under the second separation conditions analysis of the target sample is actually performed, an analysis result performed on a standard sample containing the predetermined components An actual measurement value obtaining means for obtaining an actual measurement value of the retention time of the predetermined component based on the gram;
c) the condition storage means under the first separation conditions stored the predetermined component information and Motoma' was the predetermined component of the retention time by the measured value acquisition means relating to the retention time of the measured value and the predetermined By applying to the calculation formula, the retention time in which the deviation of the retention time of the peak of the target component in the target sample due to the change of the separation condition is corrected is estimated, and data stored in the condition storage unit based on this and correction means for correcting the measurement time range that is included in the collection conditions,
Is characterized by performing the analysis of the target sample in the provided state where all of the measurement time range included in the data acquisition conditions is corrected by said correction means.
Further, the chromatographic analyzer according to the second invention uses a retention index instead of the retention time of the predetermined component under the first separation condition in the first invention.

  The “separation conditions” here are a part of the analysis conditions. Conditions that affect the separation of the sample components in the column, specifically the column type, column size (length and inner diameter), column temperature (Temperature increase program), the moving speed of the mobile phase, and the like.

In the chromatographic analyzer according to the present invention, prior to performing analysis on the target sample, a chromatogram is obtained by analyzing a standard sample containing a known predetermined component under the same second separation conditions as the analysis. . Chromatogram of this may be either a mass chromatogram focusing on mass of total ion chromatogram, or a predetermined component and for all ions. Since the peak of the predetermined component appears in the obtained chromatogram, the actual measurement value obtaining unit obtains the retention time of the predetermined component from the position of the peak. Correcting means utilizing the measured values of the retention time, but to modify the measurement time range included in the data acquisition conditions that are stored in the condition storage means may take either of two ways at that time.

One is based on the retention time of a given component when the first analysis condition is the source for setting the data acquisition conditions that are stored in the condition storage means Te than analyzed standard sample Is the method. The retention time of the predetermined component fluctuates according to the difference in analysis conditions from this reference time, and it can be estimated that the retention time of various components other than the predetermined component also varies with the same tendency. it is possible to correct the measurement time range that is included in the collection conditions.

The other is a method that uses a retention index (retention index) of the target component. As is well known, the retention index is a relative value using, for example, the n-alkane homologue series as a reference substance, and unlike the retention time, the analysis conditions such as mobile phase (for example, carrier gas) flow rate and column temperature are used. Does not depend on Therefore, if the retention index of the target component is known, the retention time is obtained by analyzing the reference substance as the predetermined component, and the retention of the target component is obtained from the measured value of the retention time and the retention index of the target component. estimating the variation of the time, thereby to correct the measurement time range included in the data acquisition conditions.

In any case, the measurement time range included in the data acquisition conditions corrected by said correcting means, that point, that because they reflect the separation characteristics of the column at the time to be analyzed the target sample, which the detection data by performing the analysis of the target sample by gathering be Rukoto, it is possible to obtain good results where the operator intends based on.

According to chromatographic analysis apparatus according to the present invention as described above, even if it contains a large number of temporal parameters to the data collection conditions, the operator is not required to work to change this every time individually, the operator of the burden Can be reduced, and errors such as input mistakes associated with the change work can be prevented. In particular, for example, when the number of ion sets for SIM measurement in GC / MS is large, when complicated parameter setting is required in a measurement mode in which SIM measurement and scan measurement are performed simultaneously, or in MS / MS measurement, If it is used when necessary parameter settings are required, a significant improvement in work efficiency can be expected.

First, a method for correcting temporal parameters included in data collection conditions and processing conditions in the chromatographic analyzer according to the present invention will be described. The correction of the temporal parameter is based on a process of estimating the peak retention time of the target component after the separation condition change based on the peak retention time of the target component before the separation condition change. There are the following two methods as this processing method.
[Method I] Method for Estimating Retention Time of Target Component Peak Based on Measured Value of Retention Time of Reference Component for Calibration
[Method II] Method of estimating peak retention time of target component based on information of retention index of target component

  First, method I will be described. Now, it is assumed that a chromatogram (total ion chromatogram in GC / MS) obtained by analysis under a certain separation condition (separation condition F1) is as shown in FIG. Peaks A and B appearing in this chromatogram are both reference component peaks for calibration, and peak X sandwiched in time between these two peaks A and B is the target component of the original analysis target. It is a peak. When the separation condition is changed from the time when this analysis is performed, for example, when the inlet end of the column is excised, the length of the column is shortened by the amount of the excision, so that each component introduced into the column passes faster than before the excision. Now, it is assumed that a standard sample for calibration is analyzed under the separation condition after column excision (referred to as separation condition F2), and a chromatogram as shown in FIG. 2B is obtained.

The calculation formula for estimating the retention time of the peak of the target component when changing from the analysis under the separation condition F1 to the analysis under the separation condition F2 is the following expression (1).
tx = (Tx−T1) / (T2−T1) × (t2−t1) + t1 (1)
here,
tx: Estimated value of retention time of target component peak X t1: Actual value of retention time of first reference component under separation condition F2 t2: Actual value of retention time of second reference component under separation condition F2 Tx: retention time of the target component peak under separation condition F1 T1: retention time of the first reference component under separation condition F1 T2: retention time of the second reference component under separation condition F1, Both are shown in FIGS. 2 (a) and 2 (b). As a result, since the retention time of the peak of the target component after the separation condition is changed is almost known, the time for detecting the data on the target component peak and processing the target component is premised on this. Parameters can be modified.

Next, Method II will be described. Here, the retention index when the most common n-alkane homologue series is used as a reference substance is considered. Now, with reference to the appearance position of the peak of methane (CH ₄ ) having a carbon number n of 1 in the chromatogram shown in FIG. 3, the peak of substance X is located between the adjacent Cn and Cn + 1 peaks of n-alkane. Shall exist. In the case of the temperature rising analysis, the retention index Ix of the target component X is defined by the following equation (2).
Ix = [(tx−tc1) / (tc2−tc1)] × 100 + 100 × n (2)
here,
Tx: retention time of target component peak tc1: retention time of n-alkane peak having n carbon atoms tc2: retention time of n-alkane peak having n + 1 carbon atoms The retention index is a value that does not depend on the column size or mobile phase velocity. Therefore, if the retention index Ix of the target component is known, the peak retention time of the target component under the condition of the separation condition F2 can be estimated by using the formula (3) obtained by modifying the formula (2).
tx = (Ix / 100-n) * (t2-t1) + t1 (3)
tx: Estimated value of retention time of target component peak X t1: Measured value of retention time of Cn peak under separation condition F2 t2: Measured value of retention time of peak of Cn + 1 under separation condition F2 As a result, as in Method I, the retention time of the peak of the target component after the separation conditions have been changed is almost known, and on that assumption, data relating to the target component peak is detected and the target component is processed. It is possible to modify the time parameter for

  Next, GC / MS, which is an embodiment of the chromatographic analyzer according to the present invention, will be described with reference to the drawings. FIG. 1 is a block diagram of the main part of the GC / MS according to this embodiment.

  In the GC unit 10, a sample vaporizing chamber 11 is provided at the inlet of a column 15 that is heated to an appropriate temperature by a column oven 14, and a carrier gas (typical) is supplied to the sample vaporizing chamber 11 through a carrier gas channel 13. Is supplied with He gas) and flows into the column 15. When a small amount of liquid sample is injected into the sample vaporization chamber 11 by the microsyringe 12 in this state, the liquid sample is immediately vaporized and is carried on the carrier gas flow and sent into the column 15. While passing through the column 15, each component in the sample gas is temporally separated, reaches the outlet thereof, and is introduced into the ionization chamber 21 of the MS unit 20.

In the MS unit 20, an ionization chamber 21, an ion optical system 22, a quadrupole mass filter 23, and a detector 24 are arranged in a vacuum container 25 that is vacuum-sucked by a vacuum pump (not shown). As described above, the sample molecules or atoms sequentially introduced into the ionization chamber 21 as the GC analysis proceeds are ionized, for example, by contact with thermoelectrons. The generated ions are extracted to the outside of the ionization chamber 21, converged by the ion optical system 22, and introduced into the space in the long axis direction of the quadrupole mass filter 23 composed of four rod electrodes. The quadrupole mass filter 23 voltage obtained by superimposing a DC voltage and a high frequency voltage is applied, only the ions having a mass corresponding to the applied voltage passes through the space of the axial direction, reaching the detector 24 Is detected.

  A detection signal from the detector 24 is converted into digital data by the A / D converter 30 and sent to the data processing unit 31. The data processing unit 31 performs a predetermined calculation process to appropriately create a mass spectrum, a mass chromatogram, a total ion chromatogram, or the like, and further performs a quantitative analysis or a qualitative analysis based on a predetermined algorithm. The operation of each block constituting the GC unit 10 and the MS unit 20 is controlled in an integrated manner by the control unit 33. Each function of the control unit 33 and the data processing unit 31 is achieved by executing a predetermined control / processing program on the personal computer 35 provided with the operation unit 36 and the display unit 37.

  In the GC / MS of the present embodiment, as a characteristic configuration, an analysis condition information storage unit 34 is provided in the control unit 33, and an analysis having a function of correcting the information content of the analysis condition information storage unit 34 in the data processing unit 31. A condition change processing unit 32 is provided. In other words, the analysis condition information storage unit 34 stores all the various conditions necessary for performing the GC / MS analysis, such as the separation conditions that affect the separation characteristics in the column as described above and the SIM measurement parameters that are the data collection conditions. It is a storage means for storing. The analysis condition change processing unit 32 corrects the data collection conditions stored in the analysis condition information storage unit 34 based on the method described above.

Assume that the operator sets SIM measurement parameters as shown in FIG. 4 as data collection conditions under a certain separation condition F1. That is, three ion sets different measurement Mass is designated respectively are set. When analysis is performed under the separation condition F1, detection data may be collected by performing SIM measurement in the MS unit 20 in accordance with the SIM measurement parameters. When the separation conditions are changed, the chromatogram moves in the time axis direction as described above, and therefore it is necessary to change all measurement start times and measurement end times of each ion set of the SIM measurement parameters.

  At this time, the operator instructs parameter correction processing through the operation unit 36. Upon receiving this instruction, the control unit 33 first executes GC / MS analysis of a predetermined calibration standard sample under the changed separation condition F2. At this time, since it is necessary to acquire a total ion chromatogram, scan measurement in a predetermined mass number range is automatically set. Since the standard sample includes a plurality of reference components, as a result of the analysis, the data processing unit 31 creates a chromatogram in which peaks of these reference components appear. Thereafter, peak detection is performed on the chromatogram, and each peak is identified, whereby an actually measured value of the retention time of the reference component is obtained.

Next, a correction process is performed on the SIM measurement parameter stored in the analysis condition information storage unit 34. Specifically, the measurement start time of the ion set in the Nth row of the table shown in FIG. 4 is Ts [N] and the measurement end time is Te [N], and each time is assumed to be Tx in the equation (1). Thus, the obtained tx value is set as a corrected measurement start time Ts ′ [N] and a corrected measurement end time Te ′ [N]. That is, when the measurement start time and measurement end time of the ion set in the Nth row are sandwiched between the holding time of the first reference component and the holding time of the second reference component, the following equations (4) and (5) ) To calculate each value.
Ts ′ [N] = (Ts [N] −T1) / (T2−T1) × (t2−t1) + t1 (4)
Te ′ [N] = (Te [N] −T1) / (T2−T1) × (t2−t1) + t1 (5)
Ts ′ [N]: Value after correction of the measurement start time of the ion set in the Nth row Te ′ [N]: Value after correction of the measurement start time of the ion set in the Nth row t1: Retention of the first reference component Measured value of time t2: Measured value of retention time of second reference component Ts [N]: Set value of measurement start time of ion set on Nth row (value in FIG. 4)
Te [N]: Setting value of the measurement start time of the ion set in the Nth row (value in FIG. 4)
T1: retention time of the first reference component under the separation condition F1 T2: retention time of the second reference component under the separation condition F1

For all the ion sets, the measurement start time and the measurement end time are calculated by executing the same calculation based on the retention time information of the reference component for calibration for each ion set, as shown in FIG. Correct each value. Accordance SIM measurement parameters this fix in GC / MS analysis of the target sample is performed subsequently, the mass chromatogram creation of measurement Mass is switched in for example the measurement Mass each for each measurement time range Is done. In this example, there are three ion sets. However, in an actual apparatus, the number of ion sets is often much larger than this, and all the SIM measurement parameters are automatically analyzed by the above processing to analyze the target sample. By appropriately modifying according to the separation conditions to be performed, the work burden on the operator is greatly reduced.

  In the above description, the correction process is performed according to the method I. However, as described above, the correction process may be performed according to the method II. In that case, from the relationship between the measurement start time Ts [N] and measurement end time Te [N] of the ion set in the Nth row shown in FIG. 4 and the n-alkane retention time under the separation condition F1. The holding index values Is [N] and Ie [N] corresponding to the measurement start time Ts [N] and the measurement end time Te [N] are obtained in advance. Then, even after changing to the separation condition F2, the standard sample of n-alkane is analyzed to create a total ion chromatogram, and peaks corresponding to the number of carbon atoms are detected to obtain actual measured values of the respective retention times.

When the measurement start time and measurement end time of the ion set in the Nth row are sandwiched between the holding time of the first reference component and the holding time of the second reference component, the following ( The corrected values of the measurement start time and the measurement end time are calculated by the formulas (6) and (7).
Ts ′ [N] = (Is [N] / 100−n) × (t2−t1) + t1 (6)
Te ′ [N] = (Ie [N] / 100−n) × (t2−t1) + t1 (7)
t1: Measured value of retention time of Cn peak under separation condition F2 t2: Measured value of retention time of peak of Cn + 1 under separation condition F2 Can modify all the SIM measurement parameters and perform SIM measurements based on the modified values.

  Although the above embodiment has been described with respect to the case of correcting the time parameter among the SIM measurement parameters, that is, the measurement start time and the measurement end time of each ion set, the same applies to the scan measurement parameter instead of the SIM measurement parameter. It can be corrected by a technique, and can also be used for correcting various temporal parameters set in the measurement mode in which the scan measurement and the SIM measurement are performed simultaneously or in the MS / MS analysis mode.

The block block diagram of the principal part of GC / MS which is one Example of this invention. The figure which shows an example of the chromatogram for demonstrating the correction method of the time parameter in this invention. The figure which shows an example of the chromatogram for demonstrating the correction method of the time parameter in this invention. The figure for demonstrating the correction process of the SIM measurement parameter in GC / MS of a present Example. The figure for demonstrating the correction process of the SIM measurement parameter in GC / MS of a present Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... GC part 11 ... Sample vaporization chamber 12 ... Micro syringe 13 ... Carrier gas flow path 14 ... Column oven 15 ... Column 20 ... MS part 21 ... Ionization chamber 22 ... Ion optical system 23 ... Quadrupole mass filter 24 ... Detector 25 ... Vacuum container 30 ... A / D converter 31 ... Data processing unit 32 ... Analysis condition change processing unit 33 ... Control unit 34 ... Analysis condition information storage unit 35 ... Personal computer 36 ... Operation unit 37 ... Display unit

Claims (2)

The sample components that are temporally separated by column according to a preset separation conditions, a torque chromatograph analyzer to collect detection data detected by the mass spectrometer according to preset data collection condition, the data collection condition is, as the time parameter relates to the elapsed time from sample introduction point to the column, in which includes the measurement time range for performing the scan measurement or selected ion monitoring measurement in the mass spectrometer,
first memory to keep the condition storage and retention time of a given component under data collection conditions in the first separation conditions under the separation conditions set by the operator for analysis of a) the target sample Means,
b) after being changed from the first separation conditions, chromatography under the second separation conditions analysis of the target sample is actually performed, an analysis result performed on a standard sample containing the predetermined components An actual measurement value obtaining means for obtaining an actual measurement value of the retention time of the predetermined component based on the gram;
c) the condition storage means under the first separation conditions stored the predetermined component information and Motoma' was the predetermined component of the retention time by the measured value acquisition means relating to the retention time of the measured value and the predetermined By applying to the calculation formula, the retention time in which the deviation of the retention time of the peak of the target component in the target sample due to the change of the separation condition is corrected is estimated, and based on this, the data stored in the condition storage means and correction means for correcting the measurement time range that is included in the collection conditions,
The provided, chromatographic analysis apparatus characterized by performing the analysis of the target sample in a state where all of the measurement time range included in the data acquisition conditions is corrected by said correction means. A chromatographic analyzer that collects detection data by detecting a sample component temporally separated by a column according to a preset separation condition by a mass spectrometer according to a preset data collection condition, the data collection The conditions include a measurement time range when performing a scan measurement or a selected ion monitoring measurement in a mass spectrometer as a temporal parameter related to the elapsed time from the sample introduction time to the column.
a) Condition storage means for storing the data collection condition under the first separation condition set by the operator for analyzing the target sample and the retention index of the predetermined component under the first separation condition When,
b) Chromatography, which is the result of analysis performed on the standard sample containing the predetermined component under the second separation condition in which the analysis on the target sample is actually performed after the change from the first separation condition. An actual measurement value obtaining means for obtaining an actual measurement value of the retention time of the predetermined component based on the gram;
c) The information regarding the retention index of the predetermined component under the first separation condition stored in the condition storage unit and the measured value of the retention time of the predetermined component obtained by the measured value acquisition unit By applying to the calculation formula, the retention time in which the deviation of the retention time of the peak of the target component in the target sample due to the change of the separation condition is corrected is estimated, and based on this, the data stored in the condition storage means Correction means for correcting the measurement time range included in the collection conditions;
A chromatographic analyzer, wherein the analysis is performed on the target sample in a state where all the measurement time ranges included in the data collection conditions are corrected by the correcting means.

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