JP4626572B2 - Optical emission spectrometer - Google Patents

Description

  The present invention relates to various emission spectroscopic analyzers such as an inductively coupled plasma (ICP) emission spectroscopic analyzer and a laser-excited emission spectroscopic analyzer.

  In an ICP emission spectroscopic analyzer, a sample is introduced into a high-temperature plasma in an ICP torch to cause excitation light emission, and the emission light is wavelength-dispersed and detected by a detector to obtain an emission spectrum. Qualitative analysis (identification) of the element contained in the sample is performed from the wavelength of the appearing spectral line (bright line spectrum), and quantitative analysis of the element is performed from the intensity of the spectral line.

  Usually, in quantitative analysis, an accurate quantitative value (concentration) is calculated by referring to a calibration curve created by a user analyzing a standard sample with a known concentration in advance. Since it is necessary to prepare a calibration curve by analyzing a standard sample every time, the work is complicated and troublesome. On the other hand, when you want to know the approximate content that does not require as much accuracy as quantitative analysis, or when you want to estimate the possibility of interference with coexisting elements and an appropriate quantitative concentration range prior to rigorous quantitative analysis For example, it is desirable to obtain a result with a simpler measurement that does not involve measurement of a standard sample. For these purposes, semi-quantitative analysis that uses the qualitative database provided by the device manufacturer to obtain approximate values (sometimes called semi-quantitative values or qualitative values) of the concentration and content of the target element is useful. .

  As described above, in the quantitative analysis, a quantitative value is calculated with reference to a calibration curve created based on measurement of an actual standard sample. In many cases, an ICP emission spectroscopic analyzer can obtain emission line spectra of a plurality of wavelengths for one element, but in quantitative analysis, the user generally specifies the wavelength of the emission line spectrum for quantitative calculation. is there. On the other hand, in the semi-quantitative analysis, a semi-quantitative value is calculated with reference to a database built in the apparatus. In addition, the wavelength for performing the semi-quantitative calculation is not specified by the user, and an appropriate wavelength is generally automatically selected based on a database. As described above, the quantitative analysis and the semi-quantitative analysis are the same in that the content of the target element is obtained, but the processing contents are considerably different. Therefore, in the conventional ICP emission spectroscopic analysis, the quantitative analysis software and the semi-quantitative analysis software are prepared separately, and the user selects either one to execute measurement or data processing (for example, Non-patent document 1 etc.).

"ICP Luminescence Analyzer (Sequential Series) ULTIMA2", [Online], HORIBA JOBIN YVON (Search June 7, 2006), Internet <URL: http://www.jyhoriba.jp /product_j/icp/ultima2/software.htm>

  For example, when you want to perform quantitative analysis of the target element contained in a sample, to investigate whether there is any interference with the emission line spectrum that performs quantitative calculation of the target element, perform quantitative analysis of the element that causes the interference at the same time. However, for this purpose, it is necessary to measure not only the target element but also the standard sample of the interfering element, which is troublesome. Although it is possible to perform quantitative analysis on the target element and use only the interfering element for semi-quantitative analysis, such work is cumbersome for the user and the analysis result is difficult to understand.

  The present invention has been made to solve the above-described problems, and the object of the present invention is to provide high-use-value information by combining quantitative analysis and semi-quantitative analysis and to improve the efficiency of analysis work. It is an object of the present invention to provide an emission spectroscopic analyzer capable of performing the above.

In order to solve the above-mentioned problems, the present invention is an emission spectroscopy in which a sample containing one or more elements is excited to emit light, and the light is spectroscopically measured to obtain emission spectrum data in a predetermined wavelength range. In the analyzer
a) a quantitative analysis means for calculating a quantitative value from the emission spectrum data of the target element with reference to a calibration curve created by measuring a standard sample;
b) a semi-quantitative analysis means for calculating a semi-quantitative value from emission spectrum data of the target element with reference to a preset qualitative database;
c) Input setting means for the user to input and set the first element group for which a quantitative value is to be obtained and the second element group for which a semi-quantitative value is to be obtained;
d) A quantitative value is calculated for each element of the first element group set by the input setting means by the quantitative analysis means, and a semi-quantitative value is calculated for each element of the second element group by the semi-quantitative analysis means. Processing control means for obtaining and outputting the calculation result of the quantitative value and the semi-quantitative value together so that the determination of the quantitative / semi-quantitative value is possible;
It is characterized by having.

  A typical embodiment of the emission spectroscopic analysis apparatus according to the present invention is an ICP emission spectroscopic analysis apparatus. The emission spectroscopic analysis apparatus according to the present invention can be applied to so-called sequential ICP, but preferably a multi-type equipped with a multi-element simultaneous detection type detector that simultaneously detects light dispersed in wavelength by a spectroscope. ICP is recommended.

  In the emission spectroscopic analysis apparatus according to the present invention, for example, a target element (first element group) for which a quantitative analysis result is to be obtained in advance and a target element (second element group) for which a semi-quantitative analysis result is to be obtained before measurement of an unknown sample are performed. Is set by the input setting means. For the target element for which a quantitative analysis result is desired, information such as the concentration of a standard sample for creating a calibration curve for each element is set. Then, when the analysis is started, the processing control means collects emission spectrum data of a predetermined wavelength range for the sample, and executes analysis for the quantitative analysis means for each element of the first element group. The semi-quantitative analysis means is instructed to execute analysis for each element of the second element group.

  Upon receiving the instruction, the quantitative analysis means first creates a calibration curve by executing measurement of the standard sample, and calculates a quantitative value from the emission spectrum data of the target element with reference to the calibration curve. On the other hand, the semi-quantitative analysis means that has received the instruction calculates a semi-quantitative value from the emission spectrum data of the target element with reference to the qualitative database. That is, the same emission spectrum data is used as the basis for concentration calculation. The major difference between quantitative analysis and semi-quantitative analysis is that the former has a calibration curve, but the latter does not have a calibration curve. It is to be. Then, when the calculation result of the quantitative value and the semi-quantitative value is obtained, the processing control means displays both on the display screen so that the difference between the quantitative / semi-quantitative value can be easily understood. Etc. to print out.

  Also, quantitative values and semi-quantitative values can be obtained by performing only analysis processing using emission spectrum data already collected by measurement of a sample. In this case, what has already been prepared for the calibration curve is selected as the first element group, and those having no calibration curve may be input and set as the second element group.

  As a typical method of using the emission spectroscopic analyzer according to the present invention, one or more target elements to be quantified with high accuracy are set as a first element group, and an emission line spectrum for quantifying the target elements. One or a plurality of elements that may have an influence on the wavelength of the light may be set as the second element group. Although the semi-quantitative value of each element of the second element group is an approximate value, it can be determined whether or not the selection of the wavelength when obtaining the quantitative value is appropriate based on the value.

  According to the emission spectroscopic analyzer according to the present invention, when displaying the quantitative value of the target element, the semi-quantitative value of any other element can be displayed together. It shows that the wavelength used for quantitative calculation has no influence of interference, and can increase the value of the analysis result, such as making it a source of data reliability. In addition, in order to obtain such analysis results, it is not necessary to measure an additional calibration curve sample, and it is not necessary to perform quantitative analysis and semi-quantitative analysis separately, which complicates the user's work. Can be avoided.

  Furthermore, when the error due to spectral interference is automatically determined based on the semi-quantitative value obtained in parallel with the quantitative value, the wavelength of the emission line spectrum for calculating the quantitative value is automatically changed. Then, recalculation can be executed, or correction calculation that reduces the interference error can be executed. It is also possible to screen high-concentration elements based on the semi-quantitative values and evaluate whether the sample for preparing the calibration curve is appropriate for the analysis of the target sample. Furthermore, from the result, it is possible to present to the user a method for preparing a calibration curve creation sample such as matrix matching.

  Hereinafter, an ICP emission spectroscopic analyzer according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of an ICP emission spectroscopic analyzer of the present embodiment.

  In FIG. 1, the sample solution supplied from the autosampler 12 controlled by the control unit 21 is atomized by a nebulizer (not shown) and then introduced into the light emitting unit 10 and excited by the plasma flame 11. The light generated thereby is collected by the condenser lens 13 and sent to the spectroscope 14 including an echelle diffraction grating. Then, the light wavelength-dispersed by the spectroscope 14 is detected almost simultaneously by a multi-channel detector 15 such as a CCD sensor, and the detection signal is sent to the data processing unit 20.

  The data processing unit 20 converts the detection signal into digital data (emission spectrum data), stores it in the spectrum data storage unit 22, and performs arithmetic processing according to a predetermined algorithm, thereby qualitative analysis, semi-quantitative analysis, and quantitative analysis of the sample. Execute. For this purpose, the data processing unit 20 includes a qualitative analysis processing unit 203, a semi-quantitative analysis processing unit 202, a quantitative analysis processing unit 201, a qualitative database 205 used for qualitative analysis and semi-quantitative analysis, and a calibration curve used for quantitative analysis. A calibration curve storage unit 204 for storing the function as a function. Further, as will be described later, a processing control unit 206 is provided to execute the semi-quantitative analysis and the quantitative analysis in combination. The operations of the data processing unit 20 and other units are comprehensively controlled by the control unit 21, and many of the functions of the control unit 21 and the data processing unit 20 execute predetermined programs on a general-purpose personal computer 23. Is achieved. The personal computer 23 is connected to an input unit 24 including a keyboard for a user to input analysis conditions and the like, and a display unit 25 including a display for displaying measurement results and the like.

  Next, a characteristic analysis operation in the ICP emission spectroscopic analyzer of the present embodiment will be described with an example. Now, when the user wants to execute the quantitative / semi-quantitative simultaneous analysis, when the user performs a predetermined operation from the input unit 24, the measurement element registration table 30 as shown in FIG. Necessary inputs are made in each column of the table 30. In this example, an accurate concentration (quantitative value) of two elements Cd and As is obtained, and an approximate concentration (semi-quantitative value) is obtained for an Fe element that may have an influence on the Cd quantification. Shall. In this case, as shown in FIG. 2, Cd, As, and Fe are entered in the element name entry fields of the measurement element registration table 30, and the wavelengths for quantitative calculation are entered for the two elements for quantitative analysis. Then, quantitative or semi-quantitative is designated as the analysis type.

  As for the two elements to be quantitatively analyzed, a standard sample for creating a calibration curve containing these elements with known concentrations is registered in the standard sample registration table 31 displayed on the display unit 25 as shown in FIG. . Such a standard sample is prepared in advance and attached to the autosampler 12 together with an unknown sample for analysis.

  When the start of analysis is instructed after the above preparation is completed, the autosampler 12 first selects a standard sample and introduces it into the light emitting unit 10 under the control of the control unit 21, and the data processing unit 20 Emission spectrum data for the emitted light is collected. Then, the quantitative analysis processing unit 201 extracts the spectrum intensity at the wavelength set in the standard sample registration table 31, creates a calibration curve as shown in FIG. 4 representing the relationship between the concentration and the intensity, and calculates the calibration curve. Stored in the line storage unit 204. That is, only a calibration curve for Cd and As is created.

  Next, the autosampler 12 selects an unknown sample and introduces it into the light emitting unit 10, and the data processing unit 20 collects emission spectrum data corresponding to the emitted light and stores it in the spectrum data storage unit 22. The spectrum data obtained at this time has a predetermined wavelength resolution over a predetermined wavelength range. When the emission spectrum data is obtained, the quantitative analysis processing unit 201 reads out the wavelength data (intensity) for the elements Cd and As set in the measurement element registration table 30, and for each element stored in the calibration curve storage unit 204. The concentration, that is, the quantitative value is calculated with reference to the calibration curve.

  On the other hand, the semi-quantitative analysis processing unit 202 first determines a wavelength for calculating a semi-quantitative value with reference to the qualitative database 205 for the element Fe set in the measurement element registration table 30, and obtains spectral data (intensity) of the wavelength. read out. Then, an approximate concentration, that is, a semi-quantitative value is calculated with reference to a semi-quantitative database included in the qualitative database 205 as an alternative to the calibration curve. However, if interference due to coexisting elements is a problem, use spectral data of wavelengths other than the wavelength determined at the beginning, or perform appropriate processing such as correcting errors due to interference. The accuracy of semi-quantitative values can be improved.

  Then, the processing control unit 206 receives the calculation results of the quantitative values of the elements Cd and As and the semi-quantitative value of the element Fe, and can clearly identify whether the quantitative value or the semi-quantitative value is shown in FIG. These values are output to the display unit 25 so as to be displayed at the same time. Conventionally, when quantitative analysis was performed, a semi-quantitative value could not be output at the same time for those that did not create a calibration curve, such as the element Fe, but according to the apparatus of this example, the element at the same time A semi-quantitative value of Fe can be displayed. Here, it can be seen that the quantitative values of elements such as Cd and As are calculated at a wavelength without (or small) the interference of Fe, and it can be seen that the reliability of the quantitative values is high.

  In the above embodiment, the measurement of the unknown sample is actually executed after registering the measurement element. However, all the emission spectrum data in the predetermined wavelength range obtained by the measurement of the unknown sample, that is, the spectrum data storage unit regardless of the wavelength. 22 is stored in the measurement element registration table 30. By adding an arbitrary element for semi-quantitative analysis later to the re-analysis, a quantitative value and semi-quantitative value can be obtained without re-measurement of an actual unknown sample. The value can be determined.

  In the above description, only the quantitative value or semi-quantitative value of the element preset by the user is calculated and displayed. However, the quantitative value was calculated by determining the size and wavelength of the semi-quantitative value. The degree of interference at a particular wavelength can be determined, and when the degree of interference is large, the processing can be expanded to perform processing such as automatically changing the wavelength for performing quantitative analysis and performing reanalysis.

  Moreover, the said Example is an example of this invention, and it is natural that it is included by this invention even if it changes, corrects, and adds suitably in the range of the meaning of this invention. For example, although the multi-type ICP is shown in the above embodiment, the present invention can also be applied to a sequential ICP. However, as a matter of course, in sequential ICP, it takes time to collect emission spectrum data in a predetermined wavelength range without omission, so there are restrictions such as not only taking measurement time but also continuing to supply unknown samples during that time. is there. Needless to say, the multi-type ICP is preferable in this respect.

  Further, the present invention is not applied only to the ICP emission spectroscopic analyzer as described above, and other various laser excitation plasma emission spectroscopic analyzers, solid state emission spectroscopic analyzers, glow discharge emission spectroscopic analyzers, etc. It can also be applied to an emission spectroscopic analyzer.

1 is a schematic configuration diagram of an ICP emission spectroscopic analyzer that is one embodiment of the present invention. FIG. The figure which shows an example of the measurement element registration table displayed on a display part in the ICP emission-spectral-analysis apparatus of a present Example. The figure which shows an example of the standard sample registration table displayed on a display part in the ICP emission-spectral-analysis apparatus of a present Example. The figure which shows an example of the calibration curve produced in the ICP emission-spectral-analysis apparatus of a present Example. The figure which shows an example of the analysis result displayed on a display part in the ICP emission-spectral-analysis apparatus of a present Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Light emission part 11 ... Plasma flame 12 ... Autosampler 13 ... Condensing lens 14 ... Spectroscope 15 ... Multichannel type detector 20 ... Data processing part 201 ... Quantitative analysis processing part 202 ... Semi-quantitative analysis processing part 203 ... Qualitative analysis Processing unit 204 ... Calibration curve storage unit 205 ... Qualitative database 206 ... Processing control unit 21 ... Control unit 22 ... Spectral data storage unit 23 ... Personal computer 24 ... Input unit 25 ... Display unit 30 ... Measurement element registration table 31 ... Standard sample registration table

Claims (2)

In an emission spectroscopic analyzer that excites a sample containing one or more elements to emit light, and spectroscopically measures the light to obtain emission spectrum data in a predetermined wavelength range.
a) a quantitative analysis means for calculating a quantitative value from the emission spectrum data of the target element with reference to a calibration curve created by measuring a standard sample;
b) a semi-quantitative analysis means for calculating a semi-quantitative value from emission spectrum data of the target element with reference to a preset qualitative database;
c) Input setting means for the user to input and set the first element group for which a quantitative value is to be obtained and the second element group for which a semi-quantitative value is to be obtained;
d) A quantitative value is calculated for each element of the first element group set by the input setting means by the quantitative analysis means, and a semi-quantitative value is calculated for each element of the second element group by the semi-quantitative analysis means. Processing control means for obtaining and outputting the calculation result of the quantitative value and the semi-quantitative value together so that the determination of the quantitative / semi-quantitative value is possible;
An emission spectroscopic analysis device comprising: The emission spectroscopic analysis apparatus according to claim 1, further comprising a multi-element simultaneous detection type detector that simultaneously detects light wavelength-dispersed by the spectrometer.

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