JPH05215604A - Spectroscopic analyzer - Google Patents

Abstract

PURPOSE:To obtain highly accurate analysis results at all times by automatically correcting the amount of shift of peak wavelength when the width of outlet slit of a spectrometer is varied. CONSTITUTION:The spectroscopic analyzer comprises means 10 for setting the width of outlet slit So of a spectrometer 4, and means 12 for drive controlling the outlet slit So to have the width being set by the slit width setting means 10. The spectroscopic analyzer further comprises a memory 16 previously storing the amount of shift of wavelength peak corresponding to the slit width being set by the slit width setting means 10, and means 18 for reading out a corresponding amount of shift from the memory 16 and correcting the peak wavelength of a spectral light detected through a detector 6 based on the amount of shift.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spectroscopic analysis device such as an emission spectroscopic analysis device and an optical absorption spectroscopic analysis device.
The present invention relates to a technique for automatically correcting a wavelength peak shift depending on the size of a slit width of an exit slit of a spectroscope.

[0002]

2. Description of the Related Art Generally, in a spectroscopic analysis device, light from a light source is dispersed by a spectroscope, and spectral light of each of the dispersed wavelengths is detected by a detector to perform various analyses.

In such a spectroscopic analyzer, an exit slit is usually arranged in the spectroscope at a position where spectral light enters, and the exit slit has a pair of slit blades. One of the slit blades is fixed and the other is close to the fixed side slit blade,
It is configured to be slidable so as to be separated from each other.

The width of separation between the slit blades, that is, the slit width can be adjusted according to the analysis conditions. That is, when the slit width is set large, the peak detection sensitivity increases and the stability of analysis increases, while the resolution decreases, and conversely, when the slit width is set small, the resolution improves. On the other hand, since the peak detection sensitivity is reduced and the influence of noise is more likely, the slit width is set to an appropriate value according to the analysis conditions.

Further, the reason why only one of the pair of slit blades can slide is that when both blades slide together, the effect of backlash of the sliding mechanism becomes large, and This is because the width cannot be set accurately and the measurement error increases.

[0006]

By the way, in the case where the slit width is adjusted by moving one of the pair of slit blades forming the exit slit close to or away from the other as described above, Causes the following problems.

FIG. 3 is a front view of the outlet slit So, in which es is a fixed-side slit blade and em is a sliding-side slit blade, the slit width is W ₀ in the same figure (a), and the slit width is _{0 in} the same figure (b). It is assumed that the slit width is set to W ₁ , and the slit width is set to W ₂ in the same figure (c) (however, W ₀ > W ₁ > W ₂ ). At this time, the center position of the slit width W ₀ is C ₀ , the center position of the slit width W ₁ is C ₁ , the center position of the slit width W ₂ is C ₂ , and the slit width is W ₀ → W ₁ → W according to progressively narrowed and _2, the center position is shifted drawing and _{C 0 → C 1 → C 2} , to the left. Therefore, in this way, the exit slit S
When the slit width of o changes, the peak position of the spectrum light of the same wavelength component which passes through the slit and is detected by the detector also changes as shown in FIG. 4 according to the size of the slit width. That is, it is assumed that the peak wavelength is λ ₀ when the slit width is set to W ₀ ((a) in the same figure). When the slit width is changed to W ₁ from this state, the peak wavelength becomes λ ₁ (Fig. (B)), and when the slit width is changed to W ₂ , the peak wavelength becomes λ ₂ (Fig. (c)). That is, even if spectral light having the same wavelength component is incident on the exit slit So, the position of the detected peak wavelength shifts according to the size of the slit width.

In the prior art, this point was not sufficiently taken into consideration, and no correction was made for the shift of the peak wavelength when the slit width was changed. Therefore, even if the spectrum light of the same wavelength component is detected, an erroneous judgment may be made as if the spectrum light of the different wavelength component is detected, and an accurate measurement result may not be obtained. It was

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the shift amount of the peak wavelength when the slit width of the exit slit of the spectroscope is changed automatically. The correction is performed so that accurate analysis results can always be obtained.

Therefore, according to the present invention, a spectroscope that disperses the light from the light source and a detector that detects the spectral light of each wavelength dispersed by the spectroscope are provided. Has an exit slit through which one of a pair of slit blades constituting the exit slit is fixed, and the other is slidable so as to approach and separate from the fixed-side slit blade. The spectroscopic analyzer provided has the following configuration.

That is, according to the present invention, the slit width setting means for setting the slit width which is the mutual separation width of the pair of slit blades, and the exit slit to the size of the slit width set by the slit width setting means. The slit width varying means for driving and controlling, the shift amount storing means in which the shift amount of the wavelength peak according to the size of the slit width set by the slit width setting means is stored in advance, and the slit width setting means are set. A shift amount corresponding to the slit width is read from the shift amount storage unit according to the size of the slit width, and a correction unit that corrects the peak wavelength of the spectrum light detected by the detector based on the shift amount is provided. ing.

[0012]

In the above structure, when the slit width of the exit slit is set by the slit width setting means, the slit width varying means drives the exit slit to the set slit width according to the size of the slit width. While controlling, the correction means reads the shift amount corresponding to the set slit width, and corrects the peak wavelength of the spectrum light detected by the detector based on this shift amount.

As a result, when the slit width of the exit slit of the spectroscope is changed, the shift amount of the peak wavelength detected by the detector is automatically corrected by this, and the detection error of the spectral light is eliminated. Therefore, accurate measurement results can always be obtained.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing an embodiment of the spectroscopic analysis device of the present invention.

In the figure, 1 indicates the whole spectroscopic analyzer, 2 is a light source, 4 is a spectroscope that disperses the light from the light source 2, and 6 is spectral light for each wavelength dispersed by the spectroscope 4. A detector such as a photomultiplier tube for detecting. In this example, a Zerniter type is applied as the spectroscope 4. That is, this spectroscope 4
Is an entrance slit Si for limiting divergence of light from the light source 2, two reflecting mirrors M ₁ and M ₂ for collimation, a diffraction grating G that disperses the incident light into spectral light of each wavelength component, and a spectral light. It consists of an exit slit So that limits divergence. The exit slit S ₀ is a pair of slit blades e.
One of the s and em is fixed, and the other em is slidably provided so as to approach and separate from the fixed-side slit blade es.

Numeral 8 is a photometric means for obtaining a photometric signal by integrating the detection current output from the detector 6, and numeral 10 is a slit width which is a distance between the slit blades es and em of the exit slit So. A slit width setting means to be set, which is constituted by, for example, a keyboard.

Reference numeral 12 is a slit width varying means for driving and controlling the slit blade em on one side so that the exit slit So of the spectroscope 4 becomes the size of the slit width set by the slit width setting means 10. It is composed of a piezoelectric element attached to the slit blade em and a variable power source that changes the voltage applied to the piezoelectric element. It is also possible to employ a mechanical drive system that combines a pulse motor and a rack and pinion. A CPU 14 includes a shift amount storage unit 16, a correction unit 18, and a data processing unit 2.
Including 0. The shift amount storage means 16 is composed of, for example, a ROM, and as shown in FIG. 2, the shift amount Δ of the wavelength peak corresponding to the size of the slit width W set by the slit width setting means 10 is stored in advance. ing. Correction means 1
Reference numeral 6 reads the shift amount Δ corresponding to the slit width W set by the slit width setting unit 10 from the shift amount storage unit 16 and causes the detector 6 to detect the shift amount Δ based on the shift amount Δ. The data processing means 20 corrects the peak wavelength λ of the detected spectrum light, and the data processing means 20 performs qualitative and quantitative analysis of the substance based on the corrected peak wavelength of the spectrum light and the photometric intensity. Is.

Reference numeral 22 is a display such as a color CRT for displaying the analysis result obtained by the data processing unit 20.

Next, the operation of the spectroscopic analyzer 1 having the above structure will be described.

In advance, by the slit width setting means 10,
When an appropriate slit width W is set according to the analysis condition, the slit width varying means 12 causes the exit slit So to be set accordingly.
One of the slit blades em is driven and controlled, whereby the exit slit So is matched with the desired slit width W.

Here, when the analysis is started, the light from the light source 2 is incident on the spectroscope 4, passes through the entrance slit Si, is reflected by the reflecting mirror M ₁ in the preceding stage, and is spectrum of each wavelength component by the diffraction grating G. Dispersed in light. Then, only spectral light having a specific wavelength component dispersed according to the angle of the diffraction grating G is reflected by the reflecting mirror M ₂ in the subsequent stage and is incident on the exit slit So, and then passes through this exit slit So. It is detected by the detector 6. The detection output is converted into a measurement light signal by the photometry means 8 and input to the correction means 18.

On the other hand, the correction means has a shift amount Δ corresponding to the slit width W previously set by the slit width setting means 10.
Is read, and the value of the peak wavelength of the spectral light determined by the photometric signal output from the photometric means 8 is corrected using this shift amount Δ.

For example, in FIG. 4, the outlet slit S
_When the slit width of ₀ is W ₀ , the peak wavelength of the spectral light determined by the photometric signal output from the photometric means 8 is at the position of λ ₀ (see FIG. 4A), and at this time, FIG. Therefore, the shift amount is zero. On the other hand, if the slit width of the exit slit So is set to W ₁ now, the peak wavelength without any correction is shifted from the position of λ _{0 to} the position of λ ₁ . However, since the shift amount of the peak wavelength in the slit width W ₁ is Δ _{1 according} to the relationship of FIG. 2, the correcting unit 18 corrects the peak wavelength as λ ₁ + Δ ₁ . That is, even if the detected peak wavelength shifts due to the change in slit width, the correction unit 18 cancels this shift amount and corrects it so that the shift amount is at the peak wavelength λ ₀ position. The peak wavelength value λ ₁ + Δ ₁ is sent to the data processing means 20. Therefore, the data processing means 20 can extract accurate qualitative and quantitative analysis results without being affected by the size of the slit width of the exit slit So.

[0024]

According to the present invention, when the slit width of the exit slit of the spectroscope is changed, the shift amount of the peak wavelength detected by the detector is automatically corrected. The detection error of is eliminated, and accurate measurement results can always be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a spectroscopic analyzer according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a relationship between a slit width and a shift amount stored in a shift amount storage means.

FIG. 3 is an explanatory diagram of a state in which the center position shifts when the slit width of the exit slit is changed.

FIG. 4 is an explanatory diagram showing a state in which the peak wavelength detected when the slit width of the exit slit is changed is shifted for the spectrum light having the same wavelength component.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Spectral analyzer, 2 ... Light source, 4 ... Spectrometer, 6 ... Detector, 10 ... Slit width setting means, 12 ... Slit width changing means, 14 ... CPU, 16 ... Shift amount storage means, 18 ...
Correcting means, So ... exit slit, es ... fixed side slit blade, em ... sliding side slit blade.

Claims (1)

[Claims] 1. A spectroscope that disperses light from a light source, and a detector that detects spectroscopic light of each wavelength dispersed by the spectroscope, wherein the spectroscopic light is incident on the spectroscope. It has an exit slit, and this exit slit is
One of a pair of slit blades constituting this is fixed, and the other is slidably provided so as to approach and separate from the fixed-side slit blade, in which the slit blades are mutually Slit width setting means for setting the slit width which is the separation width of the slit width, slit width varying means for driving and controlling the exit slit to the size of the slit width set by the slit width setting means, and the slit width setting means The shift amount storage means stores in advance the shift amount of the wavelength peak according to the size of the slit width to be set, and the shift amount storage means according to the size of the slit width set by the slit width setting means. And a correction means for correcting the peak wavelength of the spectrum light detected by the detector based on the shift amount. A spectroscopic analysis device comprising: