JP2023131244A - Analysis method using spectrum measurement device - Google Patents

Abstract

To acquire spectral data of a component to be analyzed in a solution flowing through a flow cell with high signal intensity.SOLUTION: An analysis method for obtaining spectrum data of a component to be analyzed includes: a step of determining a target wavelength range to be acquired based on the difference in signal intensity between spectrum data of a sample solution acquired by a spectrum measurement device 10 and spectrum data of a solvent acquired in advance; a step of using the spectrum data of the sample solution and the spectrum data of the solvent acquired in a spectrum acquisition step as condition-compatible spectrum data of the sample solution and the solvent, respectively, if the signal intensity level of the spectrum data in the target wavelength range is within a predetermined reference range; and a calculation step of obtaining the spectrum data of the component to be analyzed in the target wavelength range by subtracting the condition-compatible spectrum data of the solvent from the condition-compatible spectrum data of the sample solution in the target wavelength range.SELECTED DRAWING: Figure 1

Description

The present invention relates to an analysis method using a spectrum measuring device.

A liquid chromatograph (hereinafter referred to as LC) is often used to identify the substance of each of a plurality of mixed components. In liquid chromatography, multiple components are separated from each other using a separation column, and changes in the optical properties of the eluate from the separation column are measured using a UV detector, PDA detector, RID detector, etc. It is common to detect each component eluted from the column.

On the other hand, there are some substances for which accurate identification results cannot be obtained with the above-mentioned general LC detector due to problems in chemical properties and sensitivity. In such cases, it is recommended to measure optical properties such as Raman spectra of the components to be analyzed using a device such as a Raman spectrometer (see Patent Document 1), and identify the substance of each component from the measured optical properties. will be held.

JP 2021-117022 Publication

When identifying components separated in an LC separation column using a spectrum measurement device such as a Raman spectrometer, the eluate droplets are dried to evaporate the solvent, and then the spectrometer is used to identify the components to be analyzed. It is common to perform spectral measurements. However, with such a method, it is not possible to carry out the process from component separation to identification online, and the analysis time becomes long. Therefore, it is desirable to directly introduce the eluate from the separation column into a spectrum measuring device to obtain spectrum data of the component to be analyzed.

In order to obtain spectrum data of the target component in real time, it is necessary to introduce the eluate from the separation column into a flow cell and measure the spectrum of the eluate flowing through the flow cell. Since a solvent is included in addition to the target component, the spectra of the target component and the solvent will overlap when measured. Therefore, in order to obtain spectral data derived from the component to be analyzed, arithmetic processing is required to subtract the spectral data of the solvent from the spectral data of the eluate.

However, since the amount of the analyte contained in the eluate from the separation column is overwhelmingly small compared to the amount of solvent, the analyte derived from the analyte obtained by subtracting the spectral data of the solvent from the spectral data of the eluate is The signal strength of the spectral data becomes very small. The signal strength of the spectrum data can be increased by increasing the intensity of the excitation light or by lengthening the spectrum measurement time. However, if the excitation light intensity is made too high, there is a risk that the component to be analyzed will be altered within the flow cell. Furthermore, if the spectrum measurement time is increased, there is a possibility that the spectrum will be measured even after the component to be analyzed has passed through the flow cell, and the accuracy of the spectrum data may decrease. In order to avoid such problems, it may be possible to lower the flow rate of the LC mobile phase to prolong the time that the analyte components flow through the flow cell, but changing the mobile phase flow rate will reduce the flow rate of the components in the separation column. may not be properly separated. In the first place, simply increasing the signal intensity of the spectral data of the sample solution may cause the signal intensity to become saturated somewhere in the measurement wavelength range due to the increase in the signal intensity of the spectral data derived from the solvent.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to enable spectrum data of an analysis target component in a solution flowing through a flow cell to be obtained with high signal strength.

The analysis method according to the present invention includes a flow cell through which a liquid flows, and a photodetector for detecting the amount of light in each wavelength band from the flow cell, and measures the spectrum of the liquid flowing through the flow cell. An analysis method for obtaining spectral data of a component to be analyzed using a configured spectral measurement device, the method comprising:
a spectrum acquisition step of provisionally setting condition parameters for the spectrum measurement of the spectrum measurement device, performing the spectrum measurement on the sample solution containing the component to be analyzed, and acquiring spectrum data of the sample solution;
After the spectrum acquisition step, a target wavelength range in which spectrum data of the analysis target component is to be acquired is determined based on a difference in signal intensity between the spectrum data of the sample solution and the spectrum data of the solvent acquired in advance. a decision step;
When the signal intensity level of the spectral data in the target wavelength range is within a predetermined reference range, the spectral data of the sample solution and the spectral data of the solvent acquired in the spectrum acquisition step are combined with the spectral data of the sample solution and the solvent. If the signal intensity level of the spectral data in the target wavelength range is outside the predetermined reference range, the signal intensity level of the spectral data in the target wavelength range falls within the reference range. The condition parameters are changed so that the spectrum is within the reference range, and the spectrum measurement is re-performed on the sample solution to obtain condition-compatible spectrum data that falls within the reference range for the target wavelength range of the sample solution. a condition-compatible spectrum acquisition step of acquiring condition-compatible spectrum data;
a calculation step of obtaining spectral data of the component to be analyzed in the target wavelength range by subtracting the condition-compatible spectral data of the solvent from the condition-compatible spectral data of the sample solution in the target wavelength range.

Here, determining the target wavelength range based on the difference in signal strength between the spectral data of the sample solution and the solvent means a wavelength range in which the difference in signal strength between the spectral data of the sample solution and the solvent is larger than other wavelength ranges, That is, it means that the wavelength range in which the spectral characteristics of the component to be analyzed are relatively well expressed is set as the target wavelength range. That is, in the analysis method of the present invention, first, the condition parameters for spectrum measurement are provisionally set, a spectrum measurement is performed on a sample solution, and the spectrum data of the sample solution obtained by the spectrum measurement is used as a pre-obtained solvent. The wavelength range in which the spectral characteristics of the component to be analyzed are relatively well expressed is set as the target wavelength range from which the spectral data of the component to be analyzed is obtained. Here, if the signal intensity of the spectrum data of the solvent within the target wavelength range is already within a predetermined reference range, the already acquired spectrum data is treated as "condition-compliant spectrum data." On the other hand, if the signal intensity of the spectrum data of the solvent within the target wavelength range is outside the reference range, the condition parameters are adjusted so that the signal strength level of the spectrum data of the sample solution within the target wavelength range falls within the reference range. The spectral measurement for the sample solution is re-performed by changing the , and finally, "condition-compatible spectral data" for the sample solution and solvent are obtained. Thereafter, the spectral data of the component to be analyzed in the target wavelength range is obtained by performing calculation processing within the target wavelength range to subtract the "condition compatible spectral data" of the solvent from the "condition compatible spectral data" of the sample solution.

As described above, according to the analysis method of the present invention, only the target wavelength range in which the spectral characteristics of the target component appear is focused, and the signal intensity of the spectral data in the target wavelength range deviates from the predetermined reference range. If so, change the condition parameters of the spectrum measurement device so that the signal intensity level of the spectrum data of the sample solution in the target wavelength range falls within the standard range, and re-perform the spectrum measurement.Finally, the analysis Since spectral data with a limited wavelength range is acquired for the target component, spectral data with high signal strength can be obtained for the target wavelength range in which the spectral characteristics of the target component are expressed.

1 is a diagram showing an example of an analysis device including a spectrum measurement device. 3 is a flowchart for explaining one embodiment of an analysis method. This is an example of superimposed spectrum data of a sample solution and spectrum data of a solvent. FIG. 2 is a conceptual diagram for explaining arithmetic processing for subtracting spectrum data of a solvent from spectrum data of a sample solution in a target wavelength range. FIG. 2 is a conceptual diagram for explaining a synthesis process that connects spectrum data of analysis target components in a plurality of target wavelength ranges.

An embodiment of the analysis method according to the present invention will be described below with reference to the drawings.

An example of an analysis system used to carry out the analysis method of the present invention is shown in FIG.

The analysis system in FIG. 1 is an LC system, and includes an analysis channel 2, a liquid pump 4, an injector 6, a separation column 8, a spectrum measurement device 10, an arithmetic processing device 12, a display 14, and an input device 16.

The liquid feed pump 4 feeds the mobile phase into the analysis channel 2 . The injector 6 injects the sample into the mobile phase flowing through the analysis channel 2 . The separation column 8 is for separating components contained in the sample injected into the mobile phase by the injector 6 from each other. The spectrum measurement device 10 includes a flow cell 18 through which the eluate from the separation column 8 flows, an excitation light source 20 that irradiates the eluate flowing through the flow cell 18 with excitation light, and a flow cell 18 that emits excitation light from the eluate excited by the excitation light. This is a Raman spectrometer equipped with a light detection section 22 that detects Raman scattered light for each wavelength band and measures the Raman spectrum of the eluate. The arithmetic processing device 12 is a computer device configured to perform arithmetic processing using Raman spectrum data output from the photodetector 22 of the spectrum measurement device 10. The display 14 is for displaying various information output from the arithmetic processing unit 12. The input device 16 is a device, such as a keyboard, that allows the user to input information to the arithmetic processing device 12.

Next, an example of an analysis method using the above-mentioned analysis system will be described using the flowchart of FIG. 2 together with FIG.

[Step 101: Spectrum measurement]
LC analysis is performed by setting conditions (mobile phase flow rate, column temperature, etc.) that allow the target component to be well separated from other components as LC analysis conditions. At this time, the condition parameters (excitation light intensity, exposure time, number of integrations, slit width, etc.) of the spectrum measuring device 10 are temporarily set, and the portion of the eluate from the separation column 8 containing the component to be analyzed (sample solution ) and the Raman spectra of the part (solvent) that does not contain the target component. The spectral data of the sample solution and the solvent acquired by the spectrum measuring device 10 are read into the arithmetic processing device 12 and displayed on the display 14. At this time, in order to make it easier to compare the spectrum data of the sample solution and the solvent with each other, it is preferable to display them on the display 14 in a state where they are superimposed on each other.

[Step 102: Determination of target wavelength range]
The spectral data of the sample solution and the solvent displayed on the display 14 are compared, and one or more wavelength ranges (wavenumber ranges) in which the difference in signal intensity between the two is larger than other wavelength ranges (wavenumber ranges) are selected. ) are determined as target wavelength ranges. Alternatively, the target wavelength range may be a wavelength range in which there is no peak in the spectrum data of the solvent and a peak in the spectrum data of the sample solution. Since the target wavelength range determined here is considered to be a characteristic part of the Raman spectrum of the component to be analyzed within the entire measurement wavelength range, the following steps are executed focusing only on the target wavelength range.

[Step 103: Evaluation of signal strength]
For each of the one or more target wavelength ranges determined in step 102 above, it is evaluated whether the signal intensity level of the spectral data within each target wavelength range is within a predetermined reference range. The predetermined reference range is a reference range for determining whether there is room to improve the signal intensity of the spectral data of the sample solution within each target wavelength range without saturating it, or whether it is better to improve it. , can be set based on the detection limit intensity of the spectrum measuring device 10. The reference range can be set, for example, with an upper limit of 100% of the detection limit intensity and a lower limit of 80% of the detection limit intensity. Whether or not the signal intensity level is within the reference range can be determined by, for example, whether the maximum value of the signal intensity of the spectrum data of the sample solution within the target wavelength range has reached the upper limit of the reference range, or whether the signal intensity level is within the target wavelength range. The determination can be made based on whether the minimum value of the signal intensity of the spectrum data of the sample solution is equal to or higher than the lower limit of the reference range.

[Step 104: Obtaining optimized spectral data]
For the target wavelength range evaluated in step 103 as being within the predetermined reference range, the spectral data of the sample solution and the spectral data of the solvent obtained in step 101 are used. can be used as "condition-compatible spectral data" for each of the sample solution and solvent for the target wavelength range.

On the other hand, for the target wavelength range for which the signal strength level of the spectral data within the target wavelength range was evaluated to be outside the predetermined reference range in step 103, the signal strength of the spectral data within the target wavelength range is Condition parameters that fall within the reference range are set in the spectrum measurement device 10, and the spectrum measurement is performed again for each of the sample solution and solvent without changing the LC analysis conditions. If there are multiple target wavelength ranges in which the signal strength level of spectral data deviates from a predetermined reference range, the condition parameters of the spectrum measurement device 10 are set so that the signal strength of the spectral data falls within the reference range for each target wavelength range. Spectrum measurements are performed on the sample solution and solvent under each condition parameter. The spectral data of the sample solution and the spectral data of the solvent obtained in the re-implemented spectral measurement are respectively defined as "condition-compliant spectral data" of the sample solution and the solvent for the target wavelength range.

[Step 105: Arithmetic processing]
By performing calculation processing in each target wavelength range to subtract the "condition compatible spectral data" of the solvent from the "condition compatible spectral data" of the sample solution acquired in step 104 above, the spectral data of the analysis target component in each target wavelength range is get. Note that in the explanation so far, spectra are measured for each of the sample solution and the solvent to obtain condition-compatible spectra for each of the sample solution and the solvent, but the present invention is not limited to this. The spectral data of the solvent may be prepared in advance. In that case, the spectral data prepared in advance before analysis can be corrected in consideration of the condition parameters changed in order to obtain the condition-compatible spectrum of the sample solution, and can be used as the condition-compatible spectrum data of the solvent.

[Step 106: Composition processing]
A synthesis process is performed in which the spectral data of the component to be analyzed in each target wavelength range acquired in step 105 is connected to each other to create virtual spectral data for the component to be analyzed. The spectral data that are joined together in this synthesis process may not be based on data acquired under the same measurement conditions (condition parameters), but they can be used to identify the substance being analyzed. There is no problem with the data. Note that when there is only one target wavelength range, this combining process can result in spectrum data in which signal intensities other than the target wavelength range become the reference strength (for example, zero).

[Step 107: Identification of the component to be analyzed]
The virtual spectral data for the analysis target component created in step 106 above can be stored in a database within the arithmetic processing unit 12 or in a database storing spectral information of substances on a network to which the arithmetic processing unit 12 is connected. Identify what kind of substance the target substance is by referring to .

A specific example of the above analysis method will be explained using the data of FIGS. 3 to 5 as well as FIG. 2.

Assume that spectrum data as shown in FIG. 3 is obtained for the sample solution and solvent by the spectrum measurement in step 101 above. The horizontal axis in FIG. 3 is the Raman shift [cm ^-1 ], which indicates the amount of shift in the wavelength of Raman scattered light with respect to the wavelength of excitation light. The waveform drawn with a thin line is the spectrum data of the solvent (eluate that does not contain the target component). In the example in Figure 3, the two ranges of 1100cm ^-1 to 1600cm ^-1 and 1750cm ^-1 to 2050cm ^-1 have larger differences in signal intensity between the sample solution and solvent spectrum data than other ranges. Since it appears that there are many parts (characteristics of the component to be analyzed are clearly expressed), these two ranges were designated as target wavelength range 1 and target wavelength range 2, respectively (FIG. 2: step 102).

Next, the signal strength in each of the target wavelength range 1 and the target wavelength range 2 is evaluated (FIG. 2: step 103).

Regarding target wavelength range 1, the maximum value of the signal intensity of the sample solution has reached near the detection limit intensity (within the predetermined reference range), so it can be determined that there is no need to improve the signal intensity of the sample solution. . Therefore, the spectral data of the sample solution and the spectral data of the solvent obtained in the spectral measurement in step 101 are defined as "condition-compliant spectral data for target wavelength range 1" (FIG. 2: step 104).

On the other hand, for target wavelength range 2, there is a difference of several tens of percent between the detection limit intensity and the maximum signal intensity of the sample solution (less than the lower limit of the predetermined reference range), and the signal intensity of the sample solution It can be judged that there is room for improvement. Therefore, the condition parameters of the spectrum measuring device 10 are set so that the signal intensity of the sample solution in this target wavelength range 2 falls within the reference range (for example, 80% or more and 100% or less of the detection limit intensity), and Spectral measurements are performed for each of the solvents. As a result, "condition-compliant spectrum data for target wavelength range 2" having high signal strength in target wavelength range 2 is obtained (FIG. 2: step 104). Note that "condition-compliant spectral data for target wavelength range 2" may indicate that the signal intensity of the sample solution is saturated in a wavelength range other than target wavelength range 2 (for example, target wavelength range 1); There is no problem because the spectrum data is used only for the target wavelength range 2. Rather, it focuses on wavelength ranges where the signal strength level is low, such as target wavelength range 2, and performs spectrum measurements that increase the signal strength without considering whether the signal strength will be saturated in other wavelength ranges. This is important in the analysis method according to the present invention.

Next, for each of target wavelength ranges 1 and 2, arithmetic processing is performed to subtract the condition-compatible spectral data of the solvent from the condition-compatible spectral data of the sample solution, and as shown in FIG. Obtain spectrum data of the component to be analyzed (FIG. 2: step 105). Although only the calculation process for target wavelength range 1 is illustrated in Figure 4, calculation processing is also performed for target wavelength range 2 using "condition-compatible spectrum data for target wavelength range 2" of the sample solution and solvent. do.

Next, a synthesis process is performed to connect the spectral data of the component to be analyzed in target wavelength ranges 1 and 2, respectively, to create a virtual spectrum of the component to be analyzed in the entire measurement wavelength range, as shown in the lower part of Figure 5. Create data (FIG. 2: step 106). Thereafter, the component to be analyzed is identified using the created virtual spectrum data (FIG. 2: step 107).

In the above embodiment, a Raman spectrometer is used as the spectrum measurement device, but the present invention can be similarly applied even when FIIR is used as the spectrum measurement device.

The example described above is only one example of the embodiment of the analysis method according to the present invention. Embodiments of the analysis method according to the present invention are as follows.

An embodiment of the analysis method according to the present invention includes a flow cell through which a liquid flows, and a photodetector for detecting the amount of light in each wavelength band from the flow cell, and measures the spectrum of the liquid flowing through the flow cell. An analysis method for obtaining spectral data of a component to be analyzed using a spectral measurement device configured to perform
a spectrum acquisition step of provisionally setting condition parameters for the spectrum measurement of the spectrum measurement device, performing the spectrum measurement on the sample solution containing the component to be analyzed, and acquiring spectrum data of the sample solution;
After the spectrum acquisition step, a target wavelength range in which spectrum data of the analysis target component is to be acquired is determined based on a difference in signal intensity between the spectrum data of the sample solution and the spectrum data of the solvent acquired in advance. a decision step;
When the signal intensity level of the spectral data in the target wavelength range is within a predetermined reference range, the spectral data of the sample solution and the spectral data of the solvent acquired in the spectrum acquisition step are used as respective condition-compatible spectral data. , if the signal intensity level of the spectral data in the target wavelength range is outside the predetermined reference range, the condition parameter is adjusted so that the signal intensity level of the spectral data in the target wavelength range falls within the reference range. and re-performing the spectral measurement on the sample solution to obtain condition-compatible spectral data that falls within the reference range for the target wavelength range of the sample solution, and obtain condition-compatible spectral data for the solvent. a condition-compatible spectrum acquisition step;
a calculation step of obtaining spectral data of the component to be analyzed in the target wavelength range by subtracting the condition-compatible spectral data of the solvent from the condition-compatible spectral data of the sample solution in the target wavelength range.

In the first aspect of the above-described embodiment, the target range determining step is executed two or more times to determine a plurality of target wavelength ranges that do not overlap with each other, and the condition-compatible spectrum is obtained for each of the determined target wavelength ranges. and the calculation step, thereby obtaining spectral data of the component to be analyzed in each of the plurality of target wavelength ranges.

In the first aspect, in the condition-compatible spectrum acquisition step, the condition parameters, which are different from each other for each of the plurality of target wavelength ranges, may be set in the spectrum measuring device to obtain a plurality of condition-compatible spectra. This enables spectrum measurements to be performed by setting different condition parameters for each target wavelength range, increasing the degree of freedom in selecting target wavelength ranges and making it possible to use many wavelength ranges to identify target components. become.

In the first aspect, the method further includes a synthesizing step of connecting the spectrum data of the component to be analyzed in each of the plurality of target wavelength ranges to create one virtual spectrum data of the component to be analyzed. ing. This makes it possible to obtain virtual spectrum data of the component to be analyzed over a wide wavelength range, making it possible to accurately identify the component to be analyzed.

In the second aspect of the above-described embodiment, in the target range determining step, the target wavelength range is a wavelength range in which a peak exists in the sample spectrum and a peak does not exist in the solvent spectrum. In such a wavelength range, when the difference between the spectrum of the sample solution and the spectrum of the solvent is taken, a characteristic spectrum of the component to be analyzed is likely to appear, which can contribute to improving the identification accuracy of the component to be analyzed.

In a third aspect of the above embodiment, the lower limit of the reference range is 80% of the detection limit intensity of the spectrum measuring device. As a result, spectral data with high signal strength in the target wavelength range of the sample solution can be obtained by re-performing the spectrum measurement, and the signal strength of the spectral data in the target wavelength range of the analytical component that is finally obtained also becomes high.

In a fourth aspect of the above embodiment, the upper limit of the reference range is 100% of the detection limit intensity of the spectrum measuring device. This can prevent the signal strength within the target wavelength range from becoming saturated.

In a fifth aspect of the above-described embodiment, the spectrum measurement device is a Raman spectrometer, and the spectrum measurement involves constant exposure operation in which the detection unit detects the amount of Raman scattered light per unit time from the flow cell. It is executed periodically at time intervals,
The condition parameters include an exposure time, which is the length of the unit time in one exposure operation, and the cumulative number of times, which is the number of exposure operations included in the spectrum measurement.

In a sixth aspect of the above-described embodiment, the condition parameter includes the intensity of light with which the flow cell is irradiated.

In a seventh aspect of the above-described embodiment, the condition parameter includes the intensity of light with which the flow cell is irradiated, and in the condition-compatible spectrum acquisition step, the signal intensity of the spectrum data exceeds the upper limit of the reference range. If the intensity exceeds the limit, the intensity of the light is reduced.

In an eighth aspect of the above-described embodiment, the condition parameter includes the intensity of light irradiated onto the flow cell, and in the condition-compatible spectrum acquisition step, the signal intensity of the spectrum data is less than the lower limit of the reference range. In this case, the intensity of the light is increased.

In a ninth aspect of the above-described embodiment, an eluate from a separation column of a liquid chromatograph is allowed to flow in the flow cell. With this aspect, the analysis method according to the present invention can be applied to an LC system.

In the tenth aspect of the above-described embodiment, the substance of the component to be analyzed is identified based on the spectrum data of the component to be analyzed acquired in the calculation step.

2 Analysis channel 4 Liquid pump 6 Injector 8 Separation column 10 Spectrum measurement device 12 Arithmetic processing device 14 Display 16 Input device

Claims (13)

Using a spectrum measuring device configured to measure the spectrum of the liquid flowing through the flow cell, including a flow cell through which a liquid flows, and a photodetector for detecting the amount of light in each wavelength band from the flow cell. An analysis method for obtaining spectral data of a component to be analyzed,
a spectrum acquisition step of provisionally setting condition parameters for the spectrum measurement of the spectrum measurement device, performing the spectrum measurement on the sample solution containing the component to be analyzed, and acquiring spectrum data of the sample solution;
After the spectrum acquisition step, a target wavelength range in which spectrum data of the analysis target component is to be acquired is determined based on a difference in signal intensity between the spectrum data of the sample solution and the spectrum data of the solvent acquired in advance. a decision step;
When the signal intensity level of the spectral data in the target wavelength range is within a predetermined reference range, the spectral data of the sample solution and the spectral data of the solvent acquired in the spectrum acquisition step are combined with the spectral data of the sample solution and the solvent. If the signal intensity level of the spectral data in the target wavelength range is outside the predetermined reference range, the signal intensity level of the spectral data in the target wavelength range falls within the reference range. The condition parameters are changed so that the spectrum is within the reference range, and the spectrum measurement is re-performed on the sample solution to obtain condition-compatible spectrum data that falls within the reference range for the target wavelength range of the sample solution. a condition-compatible spectrum acquisition step of acquiring condition-compatible spectrum data;
an calculation step of obtaining spectral data of the component to be analyzed in the target wavelength range by subtracting the condition-compatible spectral data of the solvent from the condition-compatible spectral data of the sample solution in the target wavelength range; Method. Executing the target range determination step two or more times to determine a plurality of target wavelength ranges that do not overlap with each other, and performing the condition-compatible spectrum acquisition step and the calculation step for each of the determined target wavelength ranges, and The analysis method according to claim 1, wherein spectral data of the component to be analyzed in each of the plurality of target wavelength ranges is obtained. 3. The analysis method according to claim 2, wherein in the condition-compatible spectrum acquisition step, the condition parameters, which are different from each other for each of the plurality of target wavelength ranges, are set in the spectrum measuring device to obtain a plurality of the condition-compatible spectra. Claim 2 or 3, further comprising a synthesizing step of connecting spectral data of the component to be analyzed in each of the plurality of target wavelength ranges to create one virtual spectral data of the component to be analyzed. Analytical method described in. The analysis according to any one of claims 1 to 4, wherein in the target range determining step, the target wavelength range is a wavelength range in which a plurality of peaks are present in the sample spectrum and no peak is present in the solvent spectrum. Method. The analysis method according to any one of claims 1 to 5, wherein the lower limit of the predetermined reference range is 80% of the detection limit intensity of the spectrum measuring device. The analysis method according to any one of claims 1 to 6, wherein the upper limit of the predetermined reference range is 100% of the detection limit intensity of the spectrum measuring device. The spectrum measurement device is a Raman spectrometer, and the spectrum measurement is performed by periodically performing an exposure operation at regular time intervals in which the detection unit detects the amount of Raman scattered light per unit time from the flow cell. can be,
Any one of claims 1 to 7, wherein the condition parameters include an exposure time that is the length of the unit time in one exposure operation, and the cumulative number of times that the exposure operation is performed in the spectrum measurement. The analytical method described in item (1) above. The analysis method according to any one of claims 1 to 7, wherein the condition parameter includes the intensity of light with which the flow cell is irradiated. The condition parameter includes the intensity of light irradiated to the flow cell,
9. The method according to claim 1, wherein in the condition-compatible spectrum acquisition step, the intensity of the light is reduced if the signal intensity of the spectral data exceeds the upper limit of the predetermined reference range. Analysis method. The condition parameter includes the intensity of light irradiated to the flow cell,
According to any one of claims 1 to 8, and 10, in the condition-compatible spectrum acquisition step, the intensity of the light is increased when the signal intensity of the spectrum data is less than the lower limit of the predetermined reference range. Analytical methods described. The analysis method according to any one of claims 1 to 11, wherein an eluate from a separation column of a liquid chromatograph is passed through the flow cell. The analysis method according to any one of claims 1 to 12, wherein the substance of the analysis target component is identified based on the spectrum data of the analysis target component acquired in the calculation step.

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