JP4637643B2 - Spectroscopic analyzer - Google Patents

Description

  The present invention relates to a spectroscopic analysis apparatus, and more particularly to an improvement in the processing mechanism of the spectral data.

Optical measurements such as infrared and Raman spectroscopy are widely used for qualitative and quantitative analysis of substances contained in samples. When performing spectroscopic measurement, it is important to select a measurement position on the sample. If the measurement position is inappropriate, it is possible to obtain only spectral data of a quality that is not suitable for analysis, or to acquire spectral information of the target object well. For example, when a sample with a complicated shape (for example, a medicine in a container) is the object to be measured, depending on the measurement position, only the spectrum of the label attached to the container, bubbles in the container, glass constituting the container, etc. are measured However, it is conceivable that the spectrum of the essential drug cannot be obtained, or that the spectrum data contains noise and background excessively and is not suitable for analysis.
JP 2002-357550 A JP 2001-59772 A

Conventionally, in order to find the optimum measurement position on the sample, there is only a method in which a skilled measurer manually finds the optimum position. That is, there has been no method for the measurer himself / herself to judge from the experience whether the spectrum data is of a quality suitable for analysis, the spectrum data of the target object, or the like from the shape of the measured spectrum. For this reason, it is difficult for a non-expert to easily perform measurement or to perform automatic measurement online.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a spectroscopic analyzer that can easily perform spectroscopic analysis even for non-experts.

In order to achieve the above object, the spectroscopic analyzer of the present invention irradiates a sample with light, collects and detects light from a desired measurement point on the sample, acquires spectral data, and performs spectroscopic analysis. The analyzer is characterized by comprising determination means for determining whether the quality of the spectrum data is suitable for analysis with respect to the acquired spectrum data.
In the spectroscopic analysis apparatus, the spectroscopic measurement is Raman spectroscopic measurement, and the determination unit calculates a baseline of the acquired spectrum data, obtains a degree of bending of the baseline, and sets the degree of bending. It is preferable to determine whether or not the spectral data is suitable for analysis by evaluating the amount of the fluorescent component contained in the spectral data by comparing the threshold value .
In the above-described spectroscopic analysis apparatus, it is preferable that the determination unit determines whether or not the spectrum data is suitable for analysis based on the intensity of the acquired spectrum data.
In the above-described spectroscopic analysis apparatus, the measurement data storage means for storing a plurality of spectrum data acquired at a plurality of measurement points on the sample, and the spectrum data determined to be of a quality suitable for analysis by the determination means On the other hand, it comprises data analysis means for performing analysis, and display control means for controlling display on the display means of analysis results performed by the data analysis means, wherein the analysis means is similar to the plurality of spectral data. It is preferable to divide each group and display the grouping result on the display means by the display control means.
In the above-described spectrometer, comprising a database storing spectral information for known materials, the analyzing means-out group Dzu in the database, it is preferable to correspondence between spectral data and material name grouping.

  According to the spectroscopic analysis apparatus of the present invention, the acquired spectroscopic data is provided with the determining means for determining whether the quality of the spectroscopic data is suitable for analysis from the shape thereof, so that the spectroscopic analysis can be easily performed. it can.

A preferred embodiment according to the present invention will be described below with reference to the drawings. In this embodiment, an example in which Raman spectroscopic measurement is performed will be described. However, the present invention is not limited to this, and can be applied to other spectroscopic measurements.
FIG. 1 is a schematic configuration diagram of a spectroscopic analyzer 10 according to the present embodiment. The spectroscopic analyzer 10 includes a measurement system 12 that measures a spectrum, and a data processing system 14 that includes a computer that performs processing and analysis of spectrum data acquired by the measurement system 12.

  The data processing system 14 includes a determination unit 16 that determines the quality of spectrum data acquired by the measurement system 12, an analysis unit 18 that analyzes spectrum data, and a measurement data storage unit 20 that stores the acquired spectrum data. I have. The spectrum measured by the measurement system 12 is stored in the measurement data storage means 20, and whether the quality of the spectrum data is suitable for analysis by the determination means 16 (for example, whether excessive background and noise are not included excessively). ) Is automatically determined. Then, only the spectrum data determined to have a quality higher than the predetermined standard by the determination unit 16 is analyzed by the analysis unit 18.

  As a standard for determining the quality of the spectrum data performed by the determination unit 16, for example, in Raman spectroscopic measurement, determination is performed in consideration of the amount of fluorescent component included in the spectrum, peak intensity, and the like. A high-quality spectrum in the Raman spectroscopic measurement means a spectrum having strong Raman intensity and low fluorescence. Therefore, the determination means 16 sets a certain threshold or range for the amount of fluorescent component and the peak intensity, and when the amount of fluorescent component exceeds the threshold or the peak intensity is not within the set range, the quality of the spectral data is determined. Is deemed unsuitable for analysis. Here, the upper limit is set for the peak intensity in order to consider peak saturation.

The analysis means 18 performs analysis (qualitative analysis, quantitative analysis, etc.) on the spectrum data whose quality has been determined by the determination means 16 to be above the standard. In the present embodiment, the data processing system 14 includes a database 22 that stores spectrum information of known substances. Since the database 22 stores spectrum information of known substances in advance, it is possible to check what kind of substance the measured spectrum data corresponds to by searching the spectrum information. As a search method, a conventionally known method may be used, and examples thereof include a correlation method, a Euclidean distance method, and a principal component analysis. The analysis result performed by the analysis unit 18 is stored in the calculation data storage unit 24.
Further, the data processing system 14 is connected to a display means 26 such as a display and an input means 28 such as a keyboard and a mouse, and the above-mentioned spectrum quality judgment result and spectrum analysis result are displayed on the display means 26. Determination and analysis parameters can be set by the input means 28. Further, display control on the display means 38 is performed by the display control means 30.

The measurement system 12 includes a light emitting means 32 composed of a light source and the like, a probe 34 that irradiates light from the light emitting means 32 to a predetermined position on the sample, and collects light from the predetermined position on the sample, Detecting means 36 for detecting light from the sample collected by the probe 34. The probe 34 is connected to the light emitting means 32 and the detecting means 36 by an irradiation side optical fiber 38 and a condensing side optical fiber 40. The light emitted from the light emitting means 32 is guided by the irradiation side optical fiber 38 and guided to the probe 34. The light guided to the probe 34 is irradiated onto the sample from the probe tip, and the Raman scattered light from the sample is collected again at the tip of the probe 34. The Raman scattered light from the sample collected by the probe 34 passes through the collection side optical fiber 40 and is guided to the detection means 36. The detection means 36 includes a spectroscope 42 and a detector 44. The light guided to the detection means 36 is split by the spectroscope 42, and the light intensity is detected by the detector 44. The detection signal detected by the detector 44 is sent to the data processing system 14 constituted by a computer or the like. A detailed configuration of the probe 34 is described in Patent Document 1, for example.
Moreover, although the example which used the probe which integrated the irradiation part which irradiates light to a sample, and the condensing part which condenses the light from a sample was shown as the measurement system 12, an irradiation part and condensing were shown here. You may use what comprised the part as another probe. In addition, the present invention can be applied to a spectroscopic measurement apparatus of any configuration that is normally used without the need for a spectroscopic measurement apparatus using the probe as described above.
The above is the schematic configuration of the present embodiment, and a more detailed description of the apparatus of the present embodiment will be given below.

As an example of spectrum measurement and analysis , let us consider a case where measurement is performed using a chemical contained in a container as a sample (see FIG. 2). The measurer first selects the position of the probe and acquires a spectrum at a certain measurement point. At this time, if the position of the measurement point is not appropriate, only spectral data of a quality that cannot sufficiently withstand the analysis can be obtained. . Therefore, in the apparatus according to the present embodiment, prior to data analysis, whether or not the quality of the spectrum is suitable for analysis is determined by the determination unit 16 shown in FIG. Then, the display control unit 30 displays the determination result by the determination unit 16 on the display unit 26. The measurer looks at the displayed determination result, and when it is determined that the spectrum data is not suitable for the analysis, the position and angle of the probe are changed and the spectrum data is remeasured. If it is determined that it is suitable for analysis, the process proceeds to data analysis.

As described above, according to the spectroscopic analysis apparatus of the present embodiment, it is not necessary for the measurer himself / herself to determine whether or not the spectrum data has a quality suitable for analysis. Spectroscopic analysis can be performed.
Further, when analyzing the acquired spectrum data, the spectrum data acquired by referring to the database 22 storing the spectrum information of the known substance by the analyzing means 18 and the substance name can be displayed in correspondence with each other on the display means 26. Is preferred. As a result, the measurer can easily confirm whether or not the acquired spectrum data is of a substance that is not the object of analysis (for example, paper constituting the label, glass constituting the container, etc. in the example of FIG. 2). .

In the above description, the form of determining the quality of spectrum data every time a measurement is performed has been described. However, the acquisition of spectrum data at a plurality of measurement points is performed first, and the quality of a plurality of spectrum data acquired in a lump afterwards. It is also preferable to adopt a configuration that performs determination and analysis.
In this case, the measurer first collects spectrum data at a plurality of measurement points while changing the measurement points. These spectrum data are stored in the measurement data storage means 20. The determination means 16 determines the quality of the spectrum data for a plurality of spectrum data, and the analysis means 18 analyzes the spectrum data when the data quality is suitable for analysis. The analyzing means 18 groups a plurality of spectrum data for each similar spectrum data. Then, qualitative analysis is performed on the spectrum data divided into groups based on the spectrum information of known substances stored in the database 22. The order of spectrum identification by grouping or database search may be either. The plurality of classified measurement data is displayed by the display control means 30 as shown in FIG. 3, for each group, the number of spectrum data belonging to that group, and the substance name (not in the database) when it corresponds to a known substance in the database. In this case, a blank or a message to that effect is displayed). By referring to this list display, the measurer can determine which group of spectral data is necessary or not, and move on to a more detailed analysis. Also, when displaying the list of classification results, do not display in advance the names of substances that are known to be unnecessary in advance (for example, paper constituting the label, glass constituting the container, etc. in the example of FIG. 2). It is also possible to set it.

  Thus, when it is set as the structure which acquires the data in a several measurement position, it is suitable to provide the measurement position change means 46 which changes a measurement point automatically as shown in FIG. The measurement position changing means 46 may be configured as a sample stage that changes the direction and position of the sample itself to change the light irradiation position and the light collection position, or may be configured to move the probe 34 side relative to the sample. Good. In this way, it is possible to automatically change the light irradiation position on the sample and the light collection position on the sample. Analysis can be performed using high-quality spectral data.

Spectral Quality Judgment Criteria The acquired spectral data is judged based on the following judgment criteria as to whether the data has quality suitable for analysis. In the present embodiment, the determination is made based on the curve of the baseline due to fluorescence, the peak intensity from the baseline, and the maximum value of the spectrum intensity. As shown in FIG. 4, the determination unit 16 includes a maximum value acquisition unit 50, a baseline extraction unit 52, a peak detection unit 54, and a comparison determination unit 56. The maximum value acquisition unit 50 obtains the maximum value of the acquired spectrum data. The baseline extraction unit 52 obtains the baseline of the acquired spectrum data and calculates the degree of bending of the baseline. The peak detection unit 54 performs peak detection on the acquired spectrum data and calculates the peak intensity measured from the baseline. The comparison / determination unit 56 determines whether the acquired spectrum data is suitable for analysis by comparing with the threshold values set for the maximum value of the spectrum data calculated in this way, the degree of curve of the baseline, and the peak intensity. Get the result. This determination result is transmitted to the analysis means and the display control means (see FIG. 1). The individual determination criteria will be described below.

  In Raman measurement, fluorescence becomes an extra background. Therefore, by evaluating the amount of the fluorescent component included in the spectrum data, it is determined whether or not the spectrum data is suitable for analysis. In the case of data with little fluorescence, the baseline (shown by the dotted line in the figure) becomes almost flat as shown in FIG. 5 (a), whereas when the amount of fluorescence increases, it is shown in FIG. 5 (b). As a result, the baseline is greatly bent. Therefore, the determination unit 16 calculates a baseline for the acquired spectrum data by the baseline extraction unit 52, and the comparison determination unit 56 determines the quality of the data from the shape information of the baseline. That is, the comparison / determination unit 56 compares the degree of bending of the baseline with a set threshold value, and determines that the data to be determined is not suitable for analysis if the determination data is equal to or greater than the threshold value. Here, regarding the calculation of the baseline, for example, as described in detail in Patent Document 2, the wavelength range of the measurement range is divided into a plurality of sections, and (local) average value and (local) dispersion within each section. What is necessary is just to calculate a value.

  The peak detector 54 detects the peaks of the spectrum data and obtains the intensity of these peaks from the baseline. Then, the comparison / determination unit 56 checks whether the peak intensity is greater than or equal to a predetermined reference. As shown in FIG. 6, the spectrum data includes a noise component, and the obtained peak may be simply noise. Therefore, in order to distinguish between noise and a real peak, a certain threshold is set for the peak intensity measured from the baseline, and among detected peaks, those whose intensity is less than the threshold are estimated as noise. Therefore, the comparison / determination unit 56 determines that the detected peak has a quality suitable for analysis when there is a peak whose intensity is equal to or greater than the threshold value. On the other hand, when all the peak intensities are smaller than the threshold, it is determined that they are not suitable for analysis.

Further, the comparison / determination unit 56 also checks whether or not the maximum value of the spectrum data obtained by the maximum value acquisition unit 50 is not less than a predetermined value. That is, as shown in FIG. 7, when the maximum value of the intensity of the spectrum data has a detection limit value determined by the performance of the detector, A / D converter, etc., the spectrum data is regarded as saturated and is not suitable for analysis. Judge.
In the present embodiment, an example in which Raman spectroscopic measurement is performed as spectroscopic measurement is shown, but the present invention is not limited to this, and other spectroscopic measurement such as infrared, visible, and ultraviolet may be used. For example, in the infrared spectroscopic measurement, in addition to the judgment criteria such as peak intensity, whether or not a large amount of characteristic peaks due to CO ₂ and H ₂ O is included may be considered.

1 is a schematic configuration diagram of a spectroscopic analyzer according to an embodiment of the present invention. Explanatory drawing of the measurement using the spectroscopic analyzer concerning embodiment of this invention Example of display screen The block diagram which shows typically the structure of the determination means of the apparatus concerning embodiment of this invention Illustration of spectrum quality criteria Illustration of spectrum quality criteria Illustration of spectrum quality criteria

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Spectroscopic analyzer 12 Measurement system 14 Data processing system 16 Determination means 18 Analysis means

Claims (3)

In a Raman spectroscopic analyzer for performing Raman spectroscopic analysis for irradiating a sample with light, collecting and detecting Raman scattered light from a desired measurement point on the sample, obtaining spectral data, and analyzing the spectrum ,
By calculating the baseline of the acquired spectral data, determining the degree of bending of the baseline, comparing the degree of bending with a set threshold value, and evaluating the amount of fluorescent component contained in the spectral data Raman spectroscopic analysis apparatus characterized by quality of the spectral data with a determination means for determining whether suitable for analysis. The spectroscopic analyzer according to claim 1 ,
Measurement data storage means for storing a plurality of spectrum data acquired at a plurality of measurement points on the sample;
Data analysis means for analyzing the spectrum data determined to be of a quality suitable for analysis by the determination means;
Display control means for controlling display on the display means of the analysis results performed by the data analysis means;
And the analysis means groups the plurality of spectral data into similar groups, and the display control means displays the grouping result on the display means. The spectroscopic analyzer according to claim 2 ,
Comprising a database storing spectral information for known materials, the analysis means, spectrometer, characterized by association with the database-out group Dzu, spectral data and material name grouping.

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