JPH10153545A - Wavelength calibration device for spectroscopic analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a calibration device which omits the unnecessary calibration time for wavelength while accuracy required for a spectroscopic analysis is being kept, and to enhance the efficiency of a measurement by providing a means, which judges whether the calibration of the wavelength is required every time or not according to an item to be analyzed or to the state of a spectroscope, and executing the calibration of the wavelength automatically as required. SOLUTION: A reference for judging the necessity of the calibration of a wavelength is stored in a memory 10 at a CPU 9. While the judgment reference is being referred to, whether the calibration of the wavelength is executed or not in every measurement of a sample is judged. According to a judged result, whether the calibration of the wavelength is executed automatically every time or whether the measurement of the sample is performed or not without executing the calibration is decided. While an accuracy required for a spectroscopic analysis is being kept, the inessential calibration time of the wavelength is omitted, and the efficiency of the measurement is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spectrometer for analyzing the composition of a sample using an absorption spectrum, and more particularly to a wavelength calibrator for automatically calibrating its wavelength.

[0002]

A conventional spectrometer for automatically performing wavelength calibration automatically performs wavelength calibration each time an individual sample is measured in order to increase the measurement accuracy. Was. For this reason, depending on the analysis item and the state of the spectroscope, there is a problem that the wavelength calibration is performed every time, but the measurement time becomes longer, and the speed is lacking, even though the wavelength calibration is unnecessary.

Accordingly, the present invention provides means for determining whether or not wavelength calibration is necessary each time according to the analysis items and the state of the spectroscope, and performs automatic calibration as necessary.
The purpose of the present invention is to improve the measurement efficiency by eliminating unnecessary wavelength calibration time while maintaining the accuracy required for spectroscopic analysis.

[0004]

In order to achieve the above object, the present invention is configured as follows.

That is, in a spectrometer equipped with a wavelength calibration means for automatically calibrating a wavelength every time a sample is measured, a wavelength calibration necessity for setting in advance a criterion for determining whether or not the wavelength calibration is required every time a sample is measured. Determination criterion setting means, and wavelength calibration execution determining means for determining whether to perform wavelength calibration each time a sample is measured based on the wavelength calibration necessity determination criteria, It is a calibration device.

[0006]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a configuration diagram of a spectroscopic analyzer embodying the present invention. The spectrometer includes a light source 1, a reflecting mirror 2, a diffraction grating 3, a lens 4, a filter wheel 5 for wavelength calibration, a light detector 61 for reflected light, a light detector 62 for transmitted light, a sample cell 7, and a discharge valve 8. And a reflecting mirror 2, a diffraction grating 3, a lens 4, a wavelength calibration filter wheel 5, a sample cell 7, a reflected light photodetector 61, and a transmitted light photodetector 62 are respectively provided on the optical path of the light source 1. Deploy.

As shown in FIG. 2, a wavelength calibration filter wheel 5 transmits a measurement light beam split by the diffraction grating 3 and transmits the measurement light beam as a calibration light beam. Wavelength calibration filter 52, and measurement light passage holes 53, 54 through which the measurement light beam passes as it is.
Are arranged in the circumferential direction, and the wavelength calibration filter wheel 5 is rotated about the rotation shaft 55 to switch to the calibration light beam or the measurement light beam.

FIG. 3 is a block diagram of a wavelength calibration device for a spectrometer embodying the present invention. The wavelength calibration device is CP
Built-in memory (ROM / RAM) 10 in U9, I / O
A personal computer system in which a display device 12, an input device 13 such as a keyboard, and a printing device 14 such as a printer are connected via the board 11. The I / O board 11 includes a light source 1, a driving motor 3a for the diffraction grating 3, a sample cell. 7, transfer motor 7a, reflected light photodetector 61, transmitted light photodetector 6
2. Connect the drive motor 5a of the filter wheel 5 for wavelength calibration.

The wavelength calibration device of the spectrometer according to the present invention has the above-described configuration.
In response to a command from U9, the drive motor 5a of the wavelength calibration filter wheel 5 is rotated to transmit the wavelength calibration filter 51 for transmitted light.
Alternatively, the reflected light wavelength calibration filter 52 is set on the optical path.

Then, the drive motor 3a (stepping motor) of the diffraction grating 3 is rotated to continuously change the angle θ of the diffraction grating 3 with respect to the optical axis. FIG. 4 shows the relationship between the angle θ of the diffraction grating 3 and the wavelength λ of light. As shown in FIG.
When the angle θ of the diffraction grating 3 is changed, the wavelength λ of light split by the diffraction grating 3 also changes.

FIG. 5 shows an absorption spectrum of the didedium used for the wavelength calibration filter. As shown in FIG. 5, the didemium was 683 nm, 805 nm, 878n.
m has a peak in a specific wavelength range. In the wavelength calibration, the absorbance of the sample whose absorbance peak wavelength is known is measured, and the wavelength corresponding to the angle θ of the diffraction grating 3 is specified. That is, while continuously changing the wavelength by changing the angle θ of the diffraction grating 3, the peak wavelength of the absorbance of the sample whose data is known is searched for. Then, while comparing the peak wavelength detected at this time with the angle θ of the diffraction grating 3, FIG.
The relationship between the angle θ of the diffraction grating 3 and the wavelength λ of light shown in FIG.

In the wavelength calibration apparatus of the present invention, a criterion for determining whether or not wavelength calibration is required every time is set in advance according to an analysis item of a sample to be measured. For example, if moisture, protein, and amylose are measured in the polished rice, the wavelength calibration is not required every time, and the wavelength calibration is required every time a fatty acid is added thereto. FIG. 6 shows a correspondence table in which the necessity of wavelength calibration is set for each sample object and analysis item.

In addition, a criterion for determining whether or not the wavelength calibration is required is set each time according to the variation of the peak wavelength of the absorption spectrum of the wavelength calibration filter measured a plurality of times before the measurement. For example, the average and dispersion of the peak values of the absorption spectrum of the didemium measured a plurality of times are obtained, and the peak values are determined to be 683 nm, 805 nm, and 878 nm.
Correct so that If the variation is within a predetermined value, the wavelength calibration is not required each time.If the variation is outside the predetermined value, it is determined that the wavelength stability is lacking due to the installation conditions of the spectrometer, and the wavelength calibration is performed every time. Set criteria as required. When the magnitude of the variation greatly exceeds a predetermined value, the measurement may be determined to be impossible and the measurement may be stopped.

Further, a predetermined value of the variation is set for each analysis item of the sample to be measured. For example, in the case of rice moisture, the predetermined value of the wavelength variation is set to 0.2 nm, and similarly, protein is 0.1 nm and amylose is 0.0 nm.
5 nm, fatty acid 0.01 nm, taste value 0.01 n
m and whiteness are set to 0.1 nm.

The wavelength calibration apparatus of the present invention stores the above criteria for determining the necessity of wavelength calibration in the memory 10 of the CPU 9 and refers to the criteria to determine whether or not to perform wavelength calibration for each sample measurement. Is determined. Then, as a result of the determination, it is determined whether the wavelength calibration is automatically performed every time or the measurement of the sample is started without performing the wavelength calibration.

Next, in connection with the present invention, a wavelength calibration apparatus for measuring the environmental temperature to determine the wavelength calibration frequency will be described. In this wavelength calibration apparatus, means for measuring an environmental temperature, which is a main factor causing a shift in the wavelength of a spectroscope, is provided inside (or outside) a spectrometer. As shown in FIG. 7, this environmental temperature measuring means inputs a signal of the temperature sensor 15 to the CPU 9 and stores the signal in the memory 10 in the memory 9.
Referring to the correspondence table between the environmental temperature and the wavelength calibration frequency as shown in FIG. 8, the wavelength calibration frequency is determined according to the temperature level detected by the temperature sensor 15, and the content is displayed on the display device 12.

In particular, when the spectrometer is used continuously throughout the day, the measurement environment temperature changes in the range of 5 to 20 ° C. in winter, so that the wavelength of the spectrometer is likely to shift. This wavelength calibration device detects the temperature over time, and determines the frequency of wavelength calibration according to the environmental temperature. Therefore, according to this wavelength calibration apparatus, especially when performing many successive measurements online or in a place where the environmental temperature is likely to change, the wavelength calibration is performed at a necessary frequency according to the environmental temperature, The measurement efficiency can be improved by eliminating unnecessary calibration time while maintaining the accuracy required for spectroscopic analysis.

The wavelength calibration frequency may be simplified, and may be set every time or at two stages, ie, at the start and end of measurement.
Further, the wavelength calibration frequency may be set according to an analysis item or a quality characteristic value of a sample to be measured.

Next, in connection with the present invention, a wavelength calibration apparatus for detecting vibration and determining the frequency of wavelength calibration will be described. In this wavelength calibration device, means for detecting vibration, which is a main factor causing a shift in the wavelength of the spectroscope, is provided inside (or outside) the spectrometer. As shown in FIG. 9, the vibration detecting means inputs a signal of a vibration sensor (acceleration sensor, angular velocity sensor, etc.) 16 to the CPU 9 and stores the signal with the signal of the vibration sensor as shown in FIG. The frequency calibration frequency is determined according to the magnitude of the vibration detected by the vibration sensor 16 with reference to the correspondence table of the magnitude of the wavelength and the wavelength calibration frequency, and the content is displayed on the display device 12.

The conventional wavelength calibration apparatus requires time because the wavelength calibration is performed prior to the measurement for each measurement of each measurement sample, but the wavelength calibration is performed even under the condition that the wavelength calibration is not required. This wavelength calibrating device is provided with a means for measuring vibration, and determines the frequency calibration frequency according to the magnitude of vibration, which is a main factor causing a shift in the wavelength of the spectroscope. Therefore, according to this wavelength calibration device, stable measurement can be performed in an appropriate measurement time while maintaining the accuracy required for spectroscopic analysis without performing wavelength calibration more than necessary. In particular, since vibrations are likely to occur in an online environment, by measuring the vibrations over time, it is possible to confirm the suddenly occurring vibrations and invalidate the analysis data at the time of occurrence according to the level. . As described above, when a vibration larger than a predetermined value is detected, the reliability of the analysis data can be improved by invalidating or disabling the analysis data.

Next, in connection with the present invention, a description will be given of an abnormality detecting device which detects an impact and reports an abnormality. In this abnormality detection device, means for detecting an impact, which is a main factor causing a shift in the wavelength of the spectroscope, is provided inside (or outside) the spectrometer. This abnormality detection device is shown in FIG.
As shown in (5), the signal of the shock (vibration) sensor 17 is input to the CPU 9 and the abnormality determination value stored in the memory 10 is compared with the signal. If the magnitude of the shock exceeds a specified level, the display device 12 On the other hand, an error is displayed, an alarm is sounded, or an error is notified to a related computer through a network.

This abnormality detecting device is configured to operate even when the power of the spectrometer is turned off, and when the impact detected during the turning off of the power exceeds a specified level, the power is turned on next time or immediately. The power is turned on automatically and the abnormality is notified.

When the shock detected during the measurement exceeds a specified level, the abnormality detection device notifies the abnormality and stops the measurement. When the measurement is stopped, the wavelength information is re-measured or the wavelength calibration is automatically performed, and the learning content of the automatic wavelength calibration is canceled.

With the conventional spectrometer, when the wavelength shift occurs, it is not possible to identify the cause or to determine whether an excessive impact was applied during movement or transportation. This abnormality detection device detects an excessive impact regardless of whether the power of the spectroscopic analyzer is on or off, and reports the abnormality by detecting it. Therefore, according to this abnormality detection device, it is clear that the wavelength shift is due to shock or vibration, and when the wavelength shift occurs after movement or transportation,
The cause can be investigated. Further, it is possible to more specifically explain and guide the user's handling of the shock and the vibration.

[0026]

According to the conventional spectrometer for automatically performing wavelength calibration, the wavelength calibration is automatically performed every time each sample is measured. The wavelength calibration device of the spectrometer according to the present invention is provided with means for determining whether or not wavelength calibration is necessary each time according to the analysis item and the state of the spectroscope, and performs automatic calibration as necessary. Therefore, according to the present invention, the wavelength calibration is not performed every time it is determined that the wavelength calibration is unnecessary, so that the measurement time can be reduced as compared with the conventional one while maintaining the same analysis accuracy as the conventional one.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a spectroscopic analyzer of the present invention.

FIG. 2 is a schematic diagram of a wavelength calibration filter wheel.

FIG. 3 is a block diagram of a wavelength calibration device of the spectrometer according to the present invention.

FIG. 4 is a graph showing the relationship between the angle θ of the diffraction grating and the wavelength of light.

FIG. 5 is an absorption spectrum of a didemium.

FIG. 6 is a correspondence table in which the necessity of wavelength calibration is set for each object and analysis item.

FIG. 7 is a block diagram of environmental temperature measuring means.

FIG. 8 is a correspondence table of the environmental temperature and the wavelength calibration frequency.

FIG. 9 is a block diagram of a vibration detection unit.

FIG. 10 is a correspondence table between a vibration sensor output and a wavelength calibration frequency.

FIG. 11 is a block diagram of an abnormality detection device.

[Explanation of symbols]

 Reference Signs List 1 light source 2 reflecting mirror 3 diffraction grating 4 lens 5 wavelength calibration filter wheel 6 photodetector 7 sample cell 8 discharge valve 9 CPU 10 memory 11 I / O board 12 display device 13 input device 14 printing device 15 temperature sensor 16 vibration Sensor 17 Impact sensor

Claims (1)

[Claims] 1. A spectroscopic analyzer comprising a wavelength calibration means for automatically calibrating a wavelength every time a sample is measured, wherein a wavelength calibration necessity is set in advance to determine whether or not wavelength calibration is required every time a sample is measured. Determination reference setting means, and a wavelength calibration execution determining means for determining whether to perform wavelength calibration every time a sample is measured based on the wavelength calibration necessity determination criteria, and a wavelength characterized by comprising: Calibration device.