JPS6182169A - Flow injection method - Google Patents

Abstract

PURPOSE:To eliminate the influence by an extraneous material and to make possible the simultaneous quantitative determination of plural components by using a multielement detector to make the simultaneous detection of multiple wavelengths so as to determine the optical specificity of the plural components to be analyzed in a sample and processing arithmetically the change of the detected values with time. CONSTITUTION:The sample S is fed into a sample injector 3 and is mixed with water 1 which is a carrier. The mixture is fed to a reduction reaction coil 5. On the other hand, a reducing agent A is also fed to the coil 5 and the liquid with which the reduction reaction ends is fed to a reaction coil 7. A color former R is fed to the coil 7 so that the reaction end liquid forms a color. The liquid with which the coloration reaction ends is fed to a flow cell 9 and the formed color is detected by a simultaneous multiple wavelength detector D which detects simultaneously absorbancy and detects also the transition thereof with time. The output from the detector D is subjected to the calculation to fit the same to the spectrum of the sample of which the information on the standard spectrum of the preliminarily stored components to be analyzed is observed by a least squares method at each time on the time axis to determine the concn.-time profile of the intended components in a data processing part 10. The easy analysis is thus exactly executed with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to flow injection, which is a method for quantitatively analyzing a target component in an original sample by detecting optical specificity such as absorbance or fluorescence intensity. It concerns analytical methods.

Conventional technology Spectrophotometry has been widely used as a method for quantitatively analyzing target components in samples, but in recent years, flow injection analysis (hereinafter referred to as rFIAJ) has been developed as a method to automate this spectrophotometry. was developed, and drugs,
It is becoming popular in various fields such as food, chemical industry, and environmental analysis.

FIA adds optical specificity to the target component by adding a reagent to the flow of the original sample to cause the target component in the urine sample to continuously react with the reagent, thereby developing a specific color. The target component is quantified by continuously passing the flow through a 70-cell to detect absorbance and the like.

In this way, in FIA, visible and ultraviolet absorbance is often detected using a visible and ultraviolet spectrometer, but conventional general FIA systems are configured to detect only one specific wavelength. There is usually one.

Problems to be Solved by the Invention As mentioned above, conventional FIA systems are configured to detect only one specific wavelength, so only one component can be quantified at a time, and therefore multiple components cannot be quantified. If you want to quantify each component in the original sample,
I had no choice but to analyze it in two or more parts. If it is possible to simultaneously place each component in an original sample containing multiple components, the fields in which analysis can be applied will dramatically increase, and analysis efficiency will also improve. The benefits are thought to be significant, such as the ability to simultaneously quantify multiple components even in valuable samples that are difficult to analyze.

Furthermore, as described above, the FIA system that detects only one specific wavelength has a problem in that analysis errors tend to increase due to interference from foreign substances.

In other words, in FIA, the target component is detected by adding a reagent that reacts with the target component to be fixed, giving the target component optical specificity, but in reality, components other than the target component (contaminant components) are detected. The presence of contaminants often reacts and affects the absorbance, and therefore the presence of contaminants results in analytical errors.

Among the above problems, in order to solve the problem that it is not possible to simultaneously quantify each component in a sample containing multiple components, it is possible to simultaneously analyze multiple components using the methods described in A-D below. It is being considered that

A: I) Method using H gradient.

8: Method that utilizes reaction rate differences.

C: A method in which the merging zone method is used and the reaction reagents are changed and quantified separately.

D: A method in which the flow path is divided into two or more and analysis is performed using separate reaction systems.

However, in methods A and B, the analysis accuracy is significantly lower, and in methods C and D, the flow path system is extremely complicated, resulting in high costs, and the flow path cleaning, maintenance, and inspection are extremely complicated. Therefore, the reality is that neither method is practical.

In addition, attempts have been made to solve the problem of a decrease in the constant m11 degree due to interference with contaminants by changing the analysis conditions such as reaction reagents, but in this case, it is difficult to consider and set the analysis conditions. Another problem arose, which was that the effects of contaminants could be completely eliminated simply by changing the analytical conditions.

This invention was made against the background of the above-mentioned circumstances, and its basic purpose is to provide a flow injection analysis method that can simultaneously and independently quantify two or more components in an original sample containing multiple components. The purpose is to Another object of the present invention is to improve the accuracy of quantitative analysis of target components by removing the influence of impurities.

Means for Solving the Problems The flow injection analysis method of the present invention uses a multi-element detector as a photodetector to detect the optical specificity (absorbance or fluorescence intensity, etc.) of a target component in a sample. This method is characterized by performing simultaneous detection at multiple wavelengths and detecting and processing changes in detected values (ie, spectra) over time at the multiple wavelengths.

Furthermore, the flow injection analysis method of the present invention uses a multi-element detector as a photodetector to detect the optical specificity of a target component in a sample, and performs simultaneous detection at multiple wavelengths. When detecting and processing changes over time in detected values (spectrums), calculations are performed to fit each pre-stored standard spectrum wIIi of the component of interest to the spectrum of the 1211I sample using least squares error evaluation. By performing this at each time on the axis, a concentration profile on the time axis of only the target component from which the influence of impurities has been removed is determined.

Roughly speaking, the flow injection analysis method of this invention uses a multi-element detector as a photodetector to detect the optical specificity of a target component in a sample, and performs simultaneous detection at multiple wavelengths. When detecting and processing time changes in detected values (spectrum), if the sample contains multiple components as analysis target components, standard spectral information for each of the multiple components stored in advance is used for observation. The method is characterized in that a concentration profile on the time axis separated for each component is obtained by performing calculations for each time on the time axis to fit the spectrum of the sample using least squares error evaluation.

Function As mentioned above, the flow injection analysis method of the present invention uses a multi-element detector as a photodetector to detect the optical specificity (for example, absorbance) of a sample, and simultaneously performs detection at multiple wavelengths. Therefore, it is possible to simultaneously obtain changes in absorbance, etc. of the target component in the sample depending on the wavelength, that is, spectral information. Of course, like the normal flow injection analysis method, detection is also performed at certain time intervals according to the time course, so it is possible to detect the time course of spectral information such as the absorbance of the target component in the sample.

In the case of conventional spectrophotometers, it was possible to obtain spectra such as absorbance by wavelength scanning (scanning), but since scanning takes time, even if the time interval between the four obtained spectra is shortest, Very long, only a few minutes
It cannot be put to practical use at all in flow injection analysis to determine the concentration profile of each component over time. On the other hand, in the case of the present invention, which simultaneously detects multiple wavelengths using a multi-element detector, the time interval between spectra can be significantly shortened to about 0.1 seconds at the minimum, and the spectral data is almost continuous over time. can be obtained.

As mentioned above, with conventional flow injection systems, only data measured at a single wavelength (concentration profile of the target component over time at a single wavelength) can be obtained, so the degree of freedom is 1. In other words, only information on the concentration of a single component could be obtained, and if there were impurities that affected the absorbance, information that included the interference caused by the impurities could only be obtained. On the other hand, in the case of the method of the present invention, since data is obtained as a time course of a spectrum, the method theoretically has the maximum number of degrees of freedom that allow the spectrum to be divided by wavelength. In this invention, by applying a data processing method that effectively utilizes this feature, it is possible to quantify multiple components at the same time, and to quantify only the target component by removing the influence of interference caused by contaminants. . In other words, the spectrum measured at each time is the sum of the individual spectra of multiple components (two or more types of target components, or target components and impurity components) contained in the sample (
In other words, it can be regarded as a synthetic spectrum), so
The standard spectrum information of the target component that has been stored in advance is 1
By performing a least squares fitting operation on the 131 spectrum, l! The measured spectrum can be separated into spectra of each component, and therefore, by drawing and quantifying the time profile of the concentration of each component from the spectrum separated into each component at each time,
This makes it possible to simultaneously quantify multiple components and eliminate the effects of contaminants.

Specific details of the invention! FIG. 1 shows an example of a flow path system of a 70-injection I injection system for carrying out the flow injection analysis method of the present invention. This flow path system will be described with reference to an example in which the target component in the sample S is reduced by the -H reducing agent A and then reacted with the coloring agent R to develop color.

In FIG. 1, water 1 as a carrier is sent by a liquid feed pump P1 via a damper 2 to a sample injector 3 as a sample injection port, and a sample S is injected and mixed in this sample injector 3.
The sample solution injected and mixed is sent to the reduction reaction coil 5. On the other hand, the reducing agent A is also sent to the reduction reaction coil 5 via the damper 6 by the liquid sending pump P2. In this reduction reaction coil 5, the sample liquid containing the sample S and the reducing agent A are mixed, and the reduction reaction of the sample S proceeds. The sample liquid after the reduction reaction is sent to the reaction coil 7. -5 Coloring agent R is sent to the reaction coil 7 via a damper 8 by a liquid sending pump P3. In this reaction coil 7, the sample solution containing the reduced sample and the color former R
The coloring reaction of the sample progresses. The sample liquid in which this coloring reaction has substantially completed is sent from the reaction coil 7 to the flow cell 9. In this flow cell 9, the absorbance of the sample liquid at multiple wavelengths is simultaneously detected by a multi-wavelength simultaneous detection device consisting of a multi-element detector (multi-wavelength visible and ultraviolet detector), as will be explained later in detail. is detected. The output of this photodetector is sent to a data processing section 10 such as a computer, and the data processing result is displayed on a display section 11 such as an x-Y70 monitor.

FIG. 2 shows an example of a double beam type multi-wavelength simultaneous detection device 0 used in the device shown in FIG.

Light from a multi-wavelength light source 12 such as a white light source is split into two beams by a beam splitter 13, and each beam passes through a reference chamber 14 and a sample chamber 15, respectively. Sample chamber 15
The aforementioned flow cell (not shown) is provided inside.
A liquid containing the reacted sample passes through this flow cell. On the other hand, the reference chamber 14 is provided with an empty cell or a cell containing a standard substance. See above! 14 and the sample chamber 15, respectively, are alternately chopped by a chopper 16, and then split into multiple channels (for example, 32 channels) of light of different wavelengths by a spectroscopic means 17 such as an enclosing grating. Further, the sample light and reference light of each wavelength pass through a beam mixer 18 and enter a multi-element detector 19 consisting of, for example, a 32-channel photodiode array. For example, 32 unit detection elements 2 constitute this multi-element detector 19.
0, light of each wavelength (each channel) that has been split into multiple wavelengths is input alternately with the reference light and sample light, and a signal corresponding to the sample light intensity normalized by the output of the reference light is output. be done. That is, from the multi-element detector 19, ! l
The wave N region is divided into 32 channels, and 32 channels of signals corresponding to the sample light intensity in each channel (each wavelength) are simultaneously output.

FIGS. 3(A), (B), and (C) show the multi-element detector 1.
The detection output from 9 is stored as three-dimensional information, that is, information in three dimensions of the wavelength axis (channel axis), time axis, and detection axis (absorbance axis or light intensity axis, etc.), and the information contained in the sample. Standard spectral information obtained in advance through experiments about the expected components (components to be analyzed) is stored in advance, and the information corresponds to the three-dimensional information about the 1181m sample and the known components contained in that sample. A data processing unit 10 comprising a computer or the like is shown for calculating and processing pre-stored standard spectral information to separate Ii Fuchi data into concentration time profiles for each target component.

In particular, FIG. 3(A) shows a circuit portion 10A for not reading out signals of 32 channels detected by a 32-channel photodiode array as a multi-element detector 19, and FIG. FIG. 3(A) shows a processing control section 10B for digitizing the read values and processing them as three-dimensional information corresponding to the time axis and wavelength channel axis and performing various controls.
C) reads the stored information from the information storage section (floppy disk section) in which standard spectral waveform information of various components prepared in advance is stored, performs a-measurement, and obtains three-dimensional information about the stored sample. A data station section 10G that calculates .

In the data processing unit 10 shown in FIGS. 3(A) to 3(C), 1131! The wavelength range to be detected is divided into 32 channels, and the detected value (in this case, the sample light intensity) in each channel is output from the multi-element detector 19, and is sent to the main amplifier 23 via the preamplifier 22 corresponding to each channel. Sent to, its main bottle width! The signal is logarithmically amplified by the logarithmic amplifier 23A in the 123 and synchronously detected by the synchronous switch 23B. In addition, the synchronization switch 23
B is controlled by a synchronization signal from a synchronization signal generation circuit 23C. The output of the main amplifier 23 of each channel synchronously detected in this way is sequentially read out by an analog switch 24 consisting of a multiplexer, passed through a range switching circuit 25, and is digitized by an A/D converter 26 in FIG. 3(B). and is read into the main computer 28 via the interface 27. Note that the analog switch 24 is switched and controlled by a υJIB signal from the main computer 28. Then, the main computer 28 detects the detected signal (logarithmic amplification value) on the time axis and wavelength axis (channel).
A signal corresponding to the data, that is, three-dimensional information, is sent to the external computer section, that is, the data station 1ioc, shown in FIG. It will be done.

As mentioned above, the detected value is usually detected as the light intensity of the sample and logarithmically amplified, but in normal analysis it is often used as its reciprocal, that is, the logarithmic absorbance, and in that case, it is converted to the reciprocal as appropriate. In the following explanation, the detected value will be expressed as absorbance.

Furthermore, in FIG. 3(B), 30 is a multi-channel D.
This is an AC output interface for reading raw data that is not subjected to calculations to the recorder of the X-Y plotter 11 when an external computer section (data station section) is not connected, and 31 is for each Front panel with command display, instruction switches, etc., 3
Reference numeral 2 denotes a memory for temporarily storing at least a part of the output signal from the multi-element detection n19 and reading it out as necessary.

On the other hand, the data station section (external computer section) 10C in FIG. 3(C) includes an interface 29', a computer 34, a floppy disk section 35, a CRT 36,
It is composed of a printer 37 and an output interface 38, and the output interface 38 is connected to the XY plotter 11. Floppy disk section 3
Reference numeral 5 constitutes an information storage unit for storing standard spectral waveform information of various target components expected to be included in the sample, and this floppy disk unit 35 is used to store the aforementioned observed components. It also stores three-dimensional information and waveforms of each separated component.

The computer 34 then has a floppy disk section 35.
The standard spectral waveform information read out from the IBM sample and the three-dimensional information about the IBMed sample are processed using the least squares error evaluation method to derive the time profile of the concentration separated for each target component, and the separated A one-hour concentration profile is displayed on the X-Y plotter 11.

Next, a method of the present invention for quantitative analysis using the above-mentioned apparatus will be explained.

FIG. 4 shows a section of three-dimensional information detected by one multi-element rendering device for a sample containing a plurality of components as analysis target components. Here, the X axis in the horizontal plane represents time °C, and YL! :fJ represents the wavelength λ, and Z'l in the height direction represents the absorbance. In this example, the peaks of the time profile (i.e., the waveform in the plane formed by the time axis and the absorbance l1li axis) for concentration (actually absorbance or logarithmic absorbance) are not separated for each component. 1
It is a one-hour synthetic concentration profile of one component. Of course, the spectral waveform (waveform in the plane formed by wavelength circulation and absorbance glaze) is also a composite spectral waveform of multiple components.

FIG. 5 is a diagram schematically showing the relationship between the spectral waveform, one-hour concentration profile, and the three-dimensional information in an easy-to-understand manner. In this diagram, an example is shown in which the sample contains two components as the target components for analysis. The following explanation will be given with reference to this figure. Here, it is assumed that there is no interference between the respective components of the multi-component spectrum, and that linearity holds in rl between the amount of each component (composition ratio) and the spectrum intensity information (including the absorbance of the logarithmically converted value).

First, although the types of components contained in the observed sample are known, the one-hour concentration profile of the observed sample consisting of these known components (therefore, the one-hour profile of the composite of multiple known components) ) The calculation method according to the present invention for determining the one-hour concentration profile of each separated component in the case where the peaks of the two components overlap will be explained.

In this case, read out the standard spectrum waveform (stored in advance) of each component contained in the observed sample, multiply the standard spectrum of each component by the concentration of each component (unknown amount), and calculate the composite value. I! Synthetic spectrum of carved sample (
By fitting the three-dimensional information (wavelength axis - absorbance axis information) using the least squares method, a certain I! By determining the component ratio of each component at each measurement time and performing the same calculation at each time on the observation time axis, a separated one-hour concentration profile of each sample component is determined.

In other words, if the observed sample contains ■ even known components, and the observed wavelength fijll is divided into n channels (32 channels in the above example) at equal intervals, the horizontal axis of the spectrum at a certain time [ Vertical axis based on the third standard of one standard spectrum (standard spectrum corresponding to each even component stored with ft1) at the i-th equinox among n equally spaced equidistant points of (wavelength axis) Let II (absorbance) be Rlj. Let the component IXj of the j-th component be 911, and multiply the [Xj by the corresponding fir axis value RiJ of the standard spectrum, I! An operation may be performed to match the tIl axis W1(@light rJ[)Si of the first equinox point of the channel on the wavelength axis of the composite spectrum of the wet sample.

To do this with least squares error estimation, the following (1
) in the equation can be minimized.

Q-, Σ[Si-ΣX'j -Rijl ” ・
...(1)+@+j However, it is assumed here that the standard spectrum has been determined sufficiently accurately compared to the raw data 5t.

The normal equation obtained by finding 2Q/lXn and substituting it with O is the following equation (2).

Here, if the symbols A and Y1B are as follows, formula (2) can be expressed as AY-8...(3). If the solution to equation (2) is expressed in a matrix using A, Y, and B, it can be obtained in the form Y-(ATA ri IATB (4)).

In order to obtain this solution, there are a method of solving so-called simultaneous equations without using matrix operations, a method of directly executing the matrix operation of equation (4), etc. Since (AA) is a symmetric matrix of IXI, as can be seen, the calculation of equation (4) is performed using the Choleski method.
) method is used. In any case, since the normal equations are linear simultaneous equations, their solutions can be obtained by conventionally known programs.

In this way, each component amount X of m components at a certain time
j (j-1 to m) is obtained. Then perform such an operation l! By performing this one after another over the entire area of the inter-survey axis, the component values of each component at each time can be obtained over the entire area of the observation time axis. Therefore, the time change in the amount of each sample component at a certain wavelength, that is, the time profile of m degrees, is separated and determined.

The above explanation is for the simultaneous quantification of two or more components in a sample containing two or more components. In the case of doing so, the same calculation process can be performed. That is, by processing the number ring of the constituent components as 1, it is possible to obtain an accurate TR layer-m degree profile of only the target component, which removes the influence of interference caused by impurities.

Examples An example in which the flow injection analysis method of the present invention was applied to a sample containing iron ions (Ili) and copper ions (If@[i>) in which these ions were simultaneously quantified is described below. explain.

As a flow path system, a device as shown in Fig. 1 is used, and as an optical system, a 3! system as shown in Fig. 2 is used. The position was used. The multi-element detector 19 has 32 elements for visible and ultraviolet detection.
An otodiode array was used.

Here, each element of the multi-element detector 19 is 1T: 10
Data on the wavelength width of rv was output, so that the multi-element detector as a whole covered 380 nm to 700 nl. The flow cell used had an inner diameter of 1 square inch and an optical path length of 5 square meters.

Water was used as the carrier liquid, and ascorbic acid was used as the reducing agent. This is to reduce the coexisting iron IIJi ions and steel III ions, respectively, into iron ion and copper 11li ion.

On the other hand, as a coloring agent (chelating reagent), 2゜4.6-tris(2-pyridyl) has specificity with the target metal and the absorption spectrum of the complex formed is different.
-S-furiazine (abbreviation TPZ: iron ion chelating reagent) and 3 arhocuoro+ned+su+r
on+c acid sodium salt (abbreviated as Bath)
; standard for copper ion chelates) was used.

Under the above conditions, a heated sample of iron ions <m> and circular ions (n) whose S degree is 6 x 10'' S mol for both iron ions and copper ions, 8 x 10° S mol, l
Figure 6 shows the three-dimensional FIA chart obtained by injecting 0x10''5 mol, 15x101 mol, and 20x10 i mol into the sample injector every 2 minutes and analyzing it.In other words, the chart in Figure 6 is can be said to be information indicating the time course of the absorbance spectra of samples containing various concentrations of iron complexes and copper complexes. Calculation processing is performed to fit the standard spectrum of the complex by the method of least squares, and l1 of the iron complex at that time is calculated.
FIG. 7 shows the results of operations for determining the concentrations of fJi and the copper complex over all times. In other words, Figure 7 shows the result of the iron complex from the combined data of Figure 5! The time profile of Maro and the concentration profile of the copper complex were obtained by independently separating them.

The results of plotting each peak value of the concentration profile of the iron complex and each peak value of the concentration profile of the copper mirror shown in FIG. 7, obtained by the method of the present invention as described above, against the 'a degree at that time. is indicated by the 0 mark in FIG. 8(A) and FIG. 8(B).

On the other hand, 1! Figures 8(A) and 8 show the results of plotting each peak value of each concentration profile against the concentration at that time when FIA analysis was performed for each of the complexes of iron ions and copper ions individually according to the conventional method. Not indicated by the Δ mark in figure (B).

Figure 8 (A), ? From Figure 118 (B), the results of simultaneous determination of each component according to the method of this invention are in extremely good agreement with the results of determining each component individually using the conventional method.
Therefore, it is clear that the method of the present invention actually makes it possible to simultaneously quantify each component in a mixed sample containing multiple components.

In addition, in the above example, if iron ions are considered as the target component for analysis and copper ions are considered as impurity components, accurate quantification of iron ions, which are the target components, can be achieved by removing the influence of copper ions as impurity components. can be considered to be possible. That is, from the above results, it can be seen that the influence of impurity components has been removed and accurate quantification of only the target component has become possible.

As is clear from the effects of the invention, the flow injection analysis method of the present invention can simultaneously quantify two or more components of a sample containing the components above 2LJ. Moreover, with the method of the present invention, there is no risk of problems such as a significant decrease in analysis accuracy or a significant complexity in the flow path system. As a result of being able to simultaneously quantify multiple components with high precision, the efficiency of scheduled analysis has been significantly improved compared to the past, and it has also become possible to analyze multiple components even in minute amounts of samples, making it possible to perform flow injection analysis. can be applied to a much wider range of fields than before.

Furthermore, according to the flow injection analysis method of the present invention, even when quantifying only a single target component, it is possible to
It is possible to accurately draw the concentration profile of only the target component over an hour by removing the influence of substances, and therefore it is possible to significantly improve the constant I11 degree than before. High-precision analysis can be easily performed without the need to set specific conditions.

A schematic block diagram showing an example of a flow path system of an ion analysis system, FIG. Figures 3 (A), (B), and (C) are schematic diagrams showing an example of the optical system of the detection device; FIGS. A block diagram, FIG. 4 is a waveform diagram showing an example of three-dimensional information (3-dimensional FIA chart 1-.) obtained from a multi-element detector in the method of the present invention, and FIG. 5 is a waveform diagram showing the three-dimensional information and spectrum. Figure 6 is a waveform diagram showing a three-dimensional FIA chart based on the actual performance of this invention. Figure 7 is a schematic diagram showing the relationship between the waveform and 'a concentration time profile in principle. FIG. 8 is a waveform diagram showing the WA degree one-hour profile of each target component obtained by minute L#1 from the three-dimensional chart in the figure. Therefore, this is a graph showing a comparison of each peak value when the target component is quantified as I) PI, and FIG. 8(A) is a graph showing the seriform body, and FIG. 8(B) is a graph showing the heli complex. .

3... Sample injector, 5... Reduction reaction coil, 7... Reaction coil, 9... Flow cell, D... Multi-wavelength simultaneous detection device, 10... Data processing unit, 11...・Display section (X-Y plotter), 12
...Light source, 15...Sample, 17...Spectroscopy means, 19...Multi-element detector, 20...Unit detection element.

Figure 8 (A) $ Natsume Ryo (XIO-5M) 8th rj! J (B) Kai Yuyu (xlO-5M) Procedure Amendment (Method) October 1985
23rd of the month

Claims (3)

[Claims] (1) A multi-element detector is used as a photodetector to detect the optical specificity of the target component in the sample, and simultaneous detection is performed at multiple wavelengths, and time changes in detected values at multiple wavelengths are calculated. A flow injection analysis method characterized by processing. (2) Use a multi-element detector as a photodetector to detect the optical specificity of the target component in the sample, perform simultaneous detection at multiple wavelengths, and calculate time changes in detected values at multiple wavelengths. In processing, the time axis of the target component is adjusted by performing calculations at each time on the time axis to fit the standard spectral information of the target component to be analyzed to the spectrum of the observed sample using the least squares error method. A flow injection analysis method characterized by determining the concentration profile on the top. (3) Use a multi-element detector as a photodetector to detect the optical specificity of the target component in the sample, perform simultaneous detection at multiple wavelengths, and calculate time changes in detected values at multiple wavelengths. In processing, when the sample contains multiple components as analysis target components, a calculation is performed to fit pre-stored standard spectral information of each of the multiple components to the observed spectrum of the sample using the least squares error method. The flow injection analysis method is characterized by determining the concentration profile on the time axis separated for each component by performing the analysis at each time on the time axis.