JPS6082835A - Automatic spectrum measuring device of light and heat - Google Patents

Abstract

PURPOSE:To perform the spectrum analysis of a sample automatically, by intermitently projecting light, whose wavelength is continuously changed, on the sample, and detecting the increase in temperature of the sample. CONSTITUTION:A sample chamber 2 is thermally separated from the surrounding parts. A heat sensitive element 5 is directly attached to a sample 1, which is provided in the sample chamber 2. Meanwhile, light from a light source 8 is intermittently cut by a light shielding machine 14. The light is thereafter imparted to a spectroscope as a wavelength selector, and the wavelength is changed. The light, whose wavelength is changed, is projected on the smaple 1 through a condenser lens 3. The temperature rise of the sample 1 caused by the projection of the light is detected by the heat sensitive element 5, and the value of the temperature rise is recorded and displayed. The value of the temperature rise corresponds to the degree of the absorption of the light by the sample, i.e., absorbance. Therefore, the spectrum of the value of the temperature rise corresponds to the absorbance spectrum. Thus the spectrum analysis of the sample can be automatically performed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a spectroscopic device for performing spectrum analysis of a sample, and in particular to a spectroscopic device for irradiating a sample with light of different wavelengths to increase the temperature of the sample relative to the wavelength of the irradiated light. This invention relates to a photothermal spectrometer that detects .

As is well known in the prior art, when a material is irradiated with light, a portion of the energy of the irradiated light is absorbed by the material. Absorbance, which is the degree of absorption of this light, is determined by the wavelength of the irradiated light and the properties of the material, and can be determined by sequentially irradiating a material with monochromatic light of different wavelengths and measuring the absorbance at each wavelength of the monochromatic light. Absorption spectra of substances can be measured.

This absorption spectrum is unique to the substance, so
A sample substance can be analyzed by measuring the absorption spectrum of the sample, which is generally referred to as absorption spectroscopy.

By the way, conventional absorption spectrometers that use the absorption photometry method do not directly measure the amount of light absorbed by a substance, but instead measure the light that has passed through the substance, and measure the light transmittance, which is the ratio to the irradiated light. The absorbance is determined by calculating the common logarithm of its reciprocal. However, since the measured value of the light transmittance is affected not only by the absorbance of the substance but also by the reflection and scattering of the irradiated light, it is inevitable that a certain amount of error will occur even if precise measurement is performed. Furthermore, in the case of measuring light transmittance, the substance to be measured must be able to transmit light, and it has been impossible to measure solid samples that are opaque and insoluble in solvents.

Therefore, in recent years, methods of measuring absorbance using the photoacoustic effect have been attracting attention. In this photoacoustic spectroscopy, a sample is placed in a cell sealed with an inert gas (photoacoustic cell) and irradiated with intermittent light at a certain frequency. Using this phenomenon, a high-sensitivity microphone detects changes in gas pressure within the cell as sound waves in response to the intermittent frequency of light (modulation frequency), and the signal is processed by a lock-in amplifier in synchronization with the frequency. By doing this, the absorbance of light is detected as the magnitude of the sound wave. The development of photoacoustic spectroscopy has been supported by recent advances in detectors (high-sensitivity microphones), light sources, signal processing technology, etc. In particular, the development of lasers has dramatically expanded the application field of photoacoustic spectroscopy. It is expanding to

The above-mentioned photoacoustic spectroscopy has the feature of being able to obtain absorption spectra even for light-opaque solid samples, which was difficult to measure with conventional measurement methods, and it also uses a high-intensity light source such as a laser beam to measure light absorption. Even small samples can be measured with high sensitivity with a high S/N ratio.Furthermore, since the heat generated by light absorption becomes a signal via the thermal properties of the sample, it is possible to measure the thermal properties of the sample or the sample. It has the advantage of being able to perform various analyzes that are not possible with conventional techniques, such as being able to determine characteristics not only on the surface but also in the depth direction. In order to put this photoacoustic spectrometer into practical use, various inventions and ideas have been made, such as Japanese Patent Application Laid-Open No. 53-47886 and Japanese Patent Publication No. 57-7.
380@, JP-A-54-103386, JP-A-54-
A large number of applications have been filed, such as No. 143691 and JP-A-54-156595.

By the way, an absorbance measurement device that uses the photoacoustic effect uses a microphone to capture and measure weak sound waves emitted from the surroundings of a sample, which is the substance to be measured. In order to efficiently capture weak sound waves from
Furthermore, since measurements are made using relative sound pressure levels, there are various problems that have not yet been resolved, such as the difficulty of calculating the absolute value of the extinction coefficient of the sample.

=11 Higashikoe- This invention was made in view of the above circumstances, and includes a conventional absorbance measurement method that measures the absorbance of a sample by measuring the transmittance of light, and a method that measures the absorbance using the photoacoustic effect. The basic purpose of this invention is to provide a spectroscopic device that uses photothermal spectroscopy, which can be called a new third spectroscopy method, in place of photoacoustic spectroscopy that measures .

In other words, in photoacoustic spectroscopy, the sample is irradiated with light and the temperature rise of the sample due to the absorption of light is detected by a microphone as sound waves in a sealed gas, whereas in this invention, the sample is exposed to light, and the temperature rise in the sample is detected as a sound wave in the sealed gas. The present invention provides a photothermal spectrometer that applies a new photothermal spectroscopy method that directly detects the light energy absorbed by the sample as thermal energy by directly detecting the temperature rise of the sample using a heat-sensitive element.

Developmental research related to this new photothermal spectroscopy has already been published by the present inventor in the following documents.

Analytical Chemistry volume
,49,m13,Nov,1977,P,,2057
~2062:3 ulletin of Ch+mc
al Society of Japan, vol.
153, &10. Oct., 1980; Therefore, the present invention is an apparatus that puts into practical use the above-mentioned new spectroscopic method that has already been announced, and is capable of automatically performing measurements on various samples such as solids, liquids, suspensions, powders, and gel-like substances. A second object of the present invention is to provide an apparatus for performing corrected high-sensitivity measurement and absolute value measurement using two heat-sensitive elements, namely, a sample heat-sensitive element and a reference heat-sensitive element. The purpose of the present invention is to provide a photothermal spectroscopy device that enables the following.

#I of the Invention In order to achieve the above-mentioned object, the automatic photothermal spectrometer of the present invention basically includes the following sample chamber thermally isolated from the surroundings, and a sample chamber installed within the sample chamber. selective irradiation means for irradiating the sample with light of a selected wavelength; irradiation light intermittent control means for intermittent irradiation of the irradiation beam onto the sample; and direct detection of the temperature rise value of the sample due to the irradiation light. The irradiation light Igi has a temperature detection means for recording and displaying a temperature increase value of the sample detected by the temperature detection means.
Each time the sample is irradiated a predetermined number of times (one or more times) by the continuous control means, the wavelength of the irradiation beam irradiated onto the sample is switched by the selective irradiation means, thereby controlling the temperature of the sample in the entire measurement wavelength range. It is configured to record and display the increased value.

Here, as the temperature detection means, for example, two heat-sensitive elements having substantially the same characteristics within the measurement range are used, and one heat-sensitive element is placed in contact with the sample to directly detect the sample temperature. At the same time, the other heat-sensitive element was placed near the sample to measure the temperature around the sample, and the detection signals of both heat-sensitive elements were processed by, for example, a DC bridge or an AC bridge to remove the influence of ambient temperature changes. Configure the automatic photothermal spectrometer to detect temperature increases in the sample only.

Further, the selective irradiation means is constituted by, for example, a high-intensity light source and a wavelength selector consisting of a plurality of bandpass filters or spectrometers, and the filter is replaced or the wavelength of the dispersion element is changed depending on the signal from the irradiation light intermittent control means. The configuration is such that the wavelength incident on the sample can be sequentially changed by driving the selection driver.

Alternatively, a plurality of single wavelength laser light sources or variable wavelength laser light sources are used as the selective irradiation means.

On the other hand, the irradiation light r! As the fIlfcliIIm means, an optical interrupter (so-called shutter) that is inserted and removed from the optical path or an optical interrupter (so-called chopper) that alternately interrupts the light beam is used, and the opening/closing time of the optical interrupter is controlled by a timer, or Alternatively, the output signal of the temperature detection means may be processed and, for example, the opening of the optical circuit breaker may be controlled at the timing when the differential value of the output signal becomes below a certain value, or the optical interrupter (chopper) may be opened at a preset speed. The optical path is opened and closed at a predetermined timing by rotating the optical path at a predetermined timing.

Further, the automatic photothermal spectrometer of the second invention includes a sample T thermally isolated from the surroundings, selective irradiation means for irradiating light of a selected wavelength onto the sample installed in the sample chamber, and a sample T that is thermally isolated from the surroundings. an irradiation light intermittent control means for intermittent irradiation of the irradiation light beam to the sample; a sample temperature detection means for directly detecting a temperature rise of the sample due to the irradiation light; a standard carbon black installed in the sample chamber; means for switchingably guiding a small amount of the irradiation light onto the sample (at least part of it to the standard carbon black; a standard temperature detection means for directly detecting a temperature rise of the standard carbon black; Means for normalizing the temperature rise value of the sample measured by the sample temperature detection means based on the temperature detection signal obtained by the temperature detection means, and a record display for recording and displaying the standardized temperature rise value of the sample. and means, each time the irradiation light intermittent control means finishes irradiating the sample with the luminous flux one or more predetermined times, the selective irradiation means switches the wavelength of the irradiation light to be irradiated to the sample,
As a result, the temperature rise value of the sample was measured over the entire measurement wavelength range, and the carbon black was sequentially irradiated with light over the entire measurement wavelength range simultaneously with or separately from the measurement of the sample, and the temperature increase value obtained from the standard temperature detection means was obtained. The temperature rise value of the sample is normalized over the entire measurement region using the detection signal, and thereby measurement errors due to differences in the energy of each wavelength of the irradiated light are calibrated.

In the apparatus of the second aspect of the invention, for example, the sample temperature detection means is constituted by two heat-sensitive elements having substantially the same characteristics within the measurement range, and the first heat-sensitive element among them is connected to the temperature of the sample. A second heat-sensitive element is placed in the vicinity of the sample to detect the temperature around the sample, and the standard temperature detection means is placed in contact with the carbon black. The third
placed near the heat-sensitive element and carbon black,
The N2 heat-sensitive element may also serve as the heat-sensitive element, or may be configured with a heat-sensitive element other than the second heat-sensitive element, and the output signals of the first heat-sensitive element and the second heat-sensitive element may be processed to detect changes in ambient temperature. In addition to detecting the temperature rise value of only the sample from which the influence has been removed, the influence of ambient temperature changes is eliminated by processing the output signals of the third heat-sensitive element and the second heat-sensitive element or another heat-sensitive element in the vicinity thereof. The temperature increase value of only the removed carbon black is detected.

Further, the automatic photothermal spectrometer of the third invention includes the elements for automatic photothermal spectrometry shown in the first or second invention, and further includes secondary synchrotron radiation (so-called The configuration includes means for detecting fluorescence (fluorescence).

The automatic photothermal spectrometry device of the fourth invention includes, in addition to the elements for automatic photothermal spectrometry shown in the first or second invention, a high-sensitivity pressure-sensitive detector (for example, a high-sensitivity microphone) in the sample chamber. ) is installed to detect the sound caused by the photoacoustic effect from the sample caused by the intermittent irradiation light.

EXAMPLE Below, an automatic photothermal spectrometer according to an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, in which a sample 1 to be measured is placed in a sample chamber 2 that is thermally isolated from the surroundings. As the sample 1, any material such as crystal, amorphous, gel, or powder can be measured.

It is also possible to measure liquids. However, in the case of powder, it is usually measured as a suspension. In the illustrated example, the sample v2 has an inner wall 2A made of a heat insulating material and an outer wall 2 made of a heat insulating material.
The space between the inner wall 2A and the outer wall 2B is filled with liquid 3, resulting in a structure with better heat insulation, but a single wall may be used depending on the sample to be measured. .

A condenser lens 3 is provided on one surface of the outer wall 2B of the sample chamber 2 to condense the irradiation light toward the sample.
Further, a transmission window 4 is provided on the inner wall 2A at a position corresponding to the condenser lens 3. Therefore, the irradiated light from outside the sample chamber is irradiated onto the sample 1 through the condenser lens 3 and the transmission window 4.

A high-sensitivity heat-sensitive element 5, such as a thermistor, for detecting the temperature of the sample 1 is directly attached to the sample 1, and a heat-sensitive element 5 for the sample is installed near the sample 1.
A reference heat-sensitive element 6 made of a high-sensitivity heat-sensitive element such as a thermistor having substantially the same characteristics as the reference heat-sensitive element 6 is arranged. The latter thermal element 6 is provided to eliminate the influence of the ambient temperature of the sample 1 on measurement errors and to detect the temperature rise of the sample 1 itself. Note that it is desirable that each of the heat-sensitive elements 5.6 be arranged at a position where no direct irradiation light is incident.

Further, in the sample chamber 2, a half mirror 7 is disposed as necessary near the irradiation optical path from the condenser lens 3 to the sample 1. This half mirror 7 is used to calibrate the wavelength distribution of the light source 8, which will be described later, and to eliminate measurement errors caused by variations in intensity depending on the wavelength of the light source 8 (that is, to standardize output data). The purpose is to guide a part of the irradiated light to the carbon black 9 installed in the sample chamber 2 as necessary. It is configured so that it can be rotated or moved back and forth between a position M where the irradiation light is reflected onto the carbon black 9) and a position M where it is removed from the irradiation optical path (that is, a position where a part of the irradiation light is not reflected onto the carbon black 9). A standard heat-sensitive element 10, such as a thermistor, having substantially the same characteristics as each of the above-mentioned heat-sensitive elements 5.6 is also attached to the carbon black 9 at a position that does not directly receive irradiation light. Incidentally, during normal measurement without calibrating the wavelength distribution of the light source 8 as described above, the half mirror 6 is kept out of the irradiation optical path.

The light source 8 is a high-intensity light source, such as a xenon light source, and has a filter 11 for cutting unnecessary infrared light from the light source 8 and a condensing lens 12 on the front side thereof.
are arranged in that order. Furthermore, the condenser lens 1
2 and the condensing lens 3 on the sample chamber 2 side, there is a shutter 14 as a light interrupter that constitutes a part of the first irradiation light intermittent control means 13, and a second irradiation light intermittent control means 13. A chopper 16 as a rotary optical interrupter constituting a part of the control means 15 and a spectrometer 17 as a wavelength selector constituting a part of the selective irradiation means are provided in that order.

The shutter 14 is connected to a driving means 18 such as a motor for opening and closing the optical path by inserting and removing the shutter into and out of the optical path, and the shutter driving means 18 includes a driving circuit for driving and controlling the shutter. It is electrically connected to 19.

On the other hand, the chotuba 16 is cut out in a range forming a predetermined angle with respect to the center of rotation to serve as a light transmitting part, and the remaining angular range is used as a light shielding part. The structure is such that the optical path is repeatedly opened and closed. A chopper driving means 20 such as a motor is connected to the chopper 16, and a driving circuit 2 for controlling the chopper driving means 20 is connected to the chopper 16.
1 is electrically connected. Note that a synchronization signal generator 22 is attached to the chopper 16 for outputting a signal synchronized with the opening and closing of the optical path by the chopper 16.

Note that in the above example, the first intermittent irradiation light I! is composed of the shutter 14 and the like. Although the configuration is such that both the I-mityu means and the M2 irradiation light vIT control means 15 consisting of a chopper 16 etc. are installed, in reality it is not necessary to install both of them together, and only one of them can be installed. You can leave it installed.

The spectroscope 17 is for selecting the wavelength of the irradiation light to be irradiated onto the sample 1 from the light source 8, and is for wavelength selection for changing the selected wavelength by rotating the dispersion element 17A such as a plane diffraction grating. A driver 23 is attached. Note that the wavelength selector is composed of a plurality of bandpass filters each having a different wavelength band instead of the spectroscope 17, and by replacing the filter through which the light from the light N8 should pass, the irradiation light on the sample 1 can be changed. It may be configured to select the wavelength. In this case, a plurality of filters may be attached to a rotating disk, for example, and the wavelength of the light irradiated onto the sample 1 may be changed by rotating the rotating disk using a wavelength selection driver such as a motor.

Furthermore, a plurality of single wavelength laser light sources or a variable wavelength laser light source may be used as the light source, and in this case, the aforementioned spectroscope 17 or a wavelength selector consisting of a plurality of bandpass filters can be omitted.

The sample heat-sensitive element 5 and the reference heat-sensitive element 6 are connected to an output difference detection circuit 23 that detects the output difference between them. This output difference detection circuit 23 is for detecting the temperature rise value of only the sample 1 from which the influence of the ambient temperature has been removed. and an oscillator 25 that generates an AC signal of, for example, 10 kHz to drive the AC bridge 24. This AC bridge 24
The output of is sent to the synchronization detection circuit 26. This synchronous detection circuit 26 is for synchronous rectification (synchronous detection) of the output of the AC bridge 24 in synchronization with the AC signal of the oscillator 25, so that the output level of the synchronous detection circuit 26 corrects the ambient temperature. Corresponds to the temperature rise value of sample 1. The output of this synchronization detection circuit 26 is transmitted to a data processing/control section 27.
sent to.

Here, when the chopper 16 is used as the irradiation light intermittent control means, the synchronization detection circuit 26 is connected to the AC bridge 2.
Double synchronous detection is performed in synchronization with two types of signals: the AC signal for driving No. 4 and the synchronizing signal for the chopper 16 (a signal generated by the synchronizing signal generator 22).

In the above example, the output difference detection circuit 23 is connected to the AC bridge 2.
4, but it is of course possible to use a DC bridge depending on the case.

Furthermore, as described above, the standard carbon black 9 installed as necessary is also configured to detect the temperature rise value of the carbon black itself, which has been removed from the influence of the ambient temperature. That is, the standard heat sensitive element 10 attached to the carbon black 9 is also connected to the output difference detection circuit 23, and the output difference detection circuit 23 is used to detect the output difference between the sample heat sensitive element 5 and the reference heat sensitive element 6. It can be configured with a double bridge that combines a bridge for detecting the output difference between the standard heat-sensitive element 10 and the reference heat-sensitive element 6. In some cases, one end of a single bridge may be configured to be switched between the sample heat-sensitive element 5 and the reference heat-sensitive element 10.

In the above example, a heat sensitive element for detecting the ambient temperature of sample 1 is commonly used as a means for detecting the ambient temperature of standard carbon black 9, but in some cases another heat sensitive element may be used for detecting the ambient temperature of carbon black 9. It may be installed nearby.

The data processing/control unit 27 includes the synchronization detection circuit 26
A signal processing section 27A that processes the output of the signal processing section 27A, and a recording display section 27 that records and displays the data obtained by the signal processing section 27A.
B, and a control section 27G that controls the shutter drive circuit 19, the chopper drive circuit 21, and the wavelength selection driver 23 in accordance with the signal from the signal processing section 27A.

Regarding the control of the shutter drive circuit 19, for example, the IIJ Ube 27C is connected to a circuit that processes and determines a signal corresponding to the temperature rise value of the sample itself output from the synchronization detection circuit 26, and a circuit that processes and determines the opening time of the shutter 14. The shutter opening command signal is output based on the result of processing and determining the temperature rise value signal, and the shutter closing command signal is output when the opening time set in the timer has elapsed. That's fine. Specifically, the circuit for processing and determining the sample temperature rise value signal as described above is composed of a circuit that differentiates the temperature rise value and a circuit that compares and determines the differential value with a reference level. If the differential value is a negative value (that is, when the temperature increase value is decreasing), the shutter opening command signal may be output when the absolute value of the differential value falls below a certain level. .

Alternatively, regarding the control of the shutter drive circuit, the control section 27C may be configured to include a timer for setting the shutoff time of the shutter 14 and a timer for setting the open time of the shutter 14, and the shutter will be shut off when the set shutoff time has elapsed. It may be configured to output an opening command signal and output a shutter shutoff command signal when a set opening time has elapsed.

On the other hand, regarding the control of the chopper drive circuit 21, the control section 27C is configured to include chopper rotation speed control means for controlling the rotation speed of the chopper 16 to a preset speed, and by controlling the rotation speed of the chopper 16,
The configuration may be such that the irradiation time and cut-off time of the irradiation light are determined according to 6.

Furthermore, regarding the control of the wavelength selection driver 23, for example, the control section 27G controls the shutter 14 or the chopper 1.
The configuration may include a counting means for counting the interruption of the irradiation light according to No. 6, and output a command signal to change the irradiation wavelength when the number of irradiation times at a certain wavelength reaches a preset number of times. Specifically, an opening command signal or a shutting command signal of the shutter 14, or a signal synchronized with the operation of the chopper 16 from the synchronization signal generator 22 of the chopper 16 is counted, and the counted value reaches a preset value. At the same time, a wavelength change command signal may be output, and the wavelength selection driver may be operated by the command signal, and the counting means may be reset from 1 to 1.

Further, as described above, when the shutter 14 is used as the irradiation light intermittent control means and the temperature rise value is processed and judged by differentiation to open the shutter 14, the wavelength change command signal is output together with the chopper open command signal based on the processing judgment result. It's okay.

In the apparatus shown in FIG. 1, a high-sensitivity pressure-sensitive detector 29, such as a high By installing a sensitive microphone, it is configured to perform photothermal spectroscopic measurements as well as spectroscopic measurements using photoacoustic effects.

FIG. 2 shows a sample heat-sensitive element 5 and a reference heat-sensitive element 6.
A specific example of the AC bridge 24 used in the output difference detection circuit 23 for detecting the output difference will be shown. In FIG. 2, the operational amplifier 28G operates as an operational amplifier of the AC bridge.

9 operates as a bandpass filter of the oscillation frequency of the oscillator 25, for example, 10kl-(Z).

Next, the overall operation of the automatic spectrophotothermal measurement apparatus as described above when analyzing a sample will be explained.

Place the heat-sensitive element 5 on the sample 1 to be measured in advance with its serial number at a predetermined position in the sample chamber 2, and set the wavelength of the light to be irradiated first using a wavelength selector, such as a spectrometer 17 or a bandpass filter. I'll keep it.

This first wavelength is usually automatically set to the upper or lower end wavelength of the entire measurement wavelength range based on the measurement start signal, or 0, the previous measurement end signal.

Then, when the optical path is opened by the shutter 14 or [-16], the sample 1 is irradiated with light of the above wavelength, and the energy absorbed by the sample 1 out of the energy of the irradiated light becomes heat, and the sample 1 The temperature of the sample 1 (which is detected by the heat-sensitive element 5) increases.Meanwhile, the temperature around the sample 1 also rises, and the ambient temperature is detected by the heat-sensitive element 6.The temperature difference between the two is output. A signal detected by the difference detection circuit 23 and corresponding to the temperature obtained by subtracting the ambient temperature from the temperature of sample F11, that is, the temperature rise value of only sample 1 corrected for the ambient temperature, is output from the synchronous detection circuit 26. The signal is sent to the data processing/υ control section 27.

When the irradiation time on the sample 1 reaches the opening time of the shutter 14 preset by the timer, or when the light transmission time determined by the rotation speed of the chopper 16 is reached, the optical path of the irradiation light on the sample 1 is changed to the shutter 14 or the chopper. It is blocked by 16 shielding parts. Due to this optical path interruption, the temperature of the test Fll rapidly decreases, whereas the rate of decrease of the ambient temperature is extremely slow. However, since the ambient temperature is corrected as described above, the data processing/control unit 27 A 1 degree increase value due to the irradiation light of the sample 1 itself with the influence of temperature removed is given.

After the irradiation light to the sample 1 is blocked as shown in upper 'rL, the source is opened again and the irradiation light is irradiated onto the sample 1. Here, the timing at which irradiation is started again after the optical path is interrupted is controlled by the timer setting in the case of the shutter 14 [as described above, or by the differential value of the humidity increase value becoming below a certain value]. and, if a chopper 16 is used, its rotational speed. In any case, the timing at which irradiation is restarted after the optical path is interrupted is set or controlled so that the temperature of the sample 1 has sufficiently decreased to become approximately the same as the ambient temperature. Then, a second measurement at the same wavelength is performed in the same manner as described above. Of course, depending on the situation, it is possible to perform measurement at a certain wavelength (or only once, and when one measurement at a certain wavelength is completed, change the wavelength and move on to measurement at the next wavelength as explained later). .

FIG. 3 shows the waveform of the temperature change of sample 1 measured in this manner over time. In Figure 3, the dashed line B shows the change in the temperature of sample 1 in the case of X without correction for the ambient temperature, and the broken line C shows the change in the ambient temperature. The temperature change of the sample 1, that is, the output waveform of the synchronous detection circuit 26 is shown.The output waveform C of the synchronous detection circuit 26 and the maximum temperature rise value (Δd in FIG. 3) during each irradiation period correspond to the measurement wavelength of the sample 1. It is recorded and displayed on the recording display section 27B as a temperature rise value at .

In actual measurements, either the shutter 14 or the chopper 16 may be used, but normally the shutter 14 is used when the response speed of the thermal element is slow, and the chopper 16 is used when the response speed is sufficiently fast. I can do it.

Once the sample temperature rise value has been measured at the same wavelength one or more times in this way, a control device equipped with a counting means for counting the number of irradiations at that wavelength or a circuit for differentiating the temperature rise value is installed. A wavelength change command signal is output from the section 27C, the wavelength selection driver 23 is operated, and the next wavelength is selected.

Measurement is then performed at the newly selected wavelength in the same manner as described above. Further, measurements are performed at specific wavelengths one after another, and finally the measurements at a certain wavelength range are completed.

It is desirable that the measured values at each wavelength as described above be normalized by the measured values of the heat-sensitive element 10 of the standard carbon black 9. In other words, light it! 8 has wavelength characteristics,
Since the intensity differs depending on the wavelength, it is desirable to eliminate the influence of the wavelength characteristics of the light source 8 in order to obtain the absolute light absorption characteristics of the sample 1. In the above device, half mirror 7
is inserted into the optical path to guide the irradiated light to the carbon black 9, and the temperature increase value is measured for each wavelength in the entire measurement wavelength range using the heat sensitive element 10. The specific measurement method in this case is the same as the measurement for Sample 1.

The temperature rise value of the sample 1 is normalized by dividing the temperature rise value of the sample 1 by the temperature rise value of the carbon black 9 obtained in this manner at each wavelength. The measurement of Naori-Bon Black 9 can be performed at the same time as the measurement of sample 1 if the half mirror 7 is installed as described above, and in such a simultaneous measurement, the measured value of sample 1 can be Although it is possible to standardize on the spot, it is of course necessary to measure carbon black 9 separately from the measurement of sample n1, store the measured value, and read out the measured value of carbon black when measuring sample 1. The measured value of 1 may be normalized. In the latter case, a half mirror
7 can be replaced by an ordinary mirror.

Try as above! By normalizing the temperature rise value of 'jt1 by the temperature rise value of carbon black 9 over the entire CC wavelength range, the temperature rise value spectrum of sample 1 can be obtained. Here, the temperature R value of sample 1 corresponds to the degree of light absorbed by the sample, that is, the absorbance, so
The spectrum of the temperature rise value corresponds to the absorbance spectrum, and therefore it is possible to analyze the sample using this temperature rise value spectrum.

Examples of actual measurements of various samples using the apparatus of the present invention will be shown below.

FIG. 4 shows the output waveform of the synchronization detection circuit 26 at a certain wavelength (corresponding to FIG. 3), where 31 is the output waveform of the carbon black pellet at a wavelength of 460 nm, and 32 is the C
The output waveform of the dS single crystal, 33, shows the output waveform of a methylene blue solution (!! degree 0.33 g/1) at a wavelength of 625 nm, and both show the measurement results at the wavelength where each sample has the largest absorption. Note that in the figure, ON indicates the start of irradiation, and OFF indicates interruption of the irradiation light.

Further, FIG. 5 shows the output waveform of the synchronization detection circuit 26 at a wavelength of 465 nll for a sample of platinum foil coated with red enamel.

Further, FIG. 6 shows the results of measuring the spectrum of a xenon light source using carbon black as a standard sample, and line 34 is the result of measurement using photothermal spectroscopy (PTS) using the apparatus of the present invention. The results are shown, and helix 35 shows the results measured with a conventional radiometer. It can be seen that the results of photothermal spectrometry are in good agreement with the results of measurement using a radiometer.

Figure 7 shows the C(Is and TlO2 spectra (lines 36 and 37) of a single crystal semiconductor obtained by photothermal spectroscopy using the apparatus of the present invention, and the spectrum of the same sample obtained by optical spectroscopy. From this result, the energy gap Eg is 2.4 eV
It can be seen that Tr O2F is 3-OeVF.

Prisoner 8 talked about the film made by vacuum vaporizing CdS.
Spectrum (line 38) and optical absorption spectrum (line 39) obtained by photothermal spectrometry using the device of this invention
shows.

Furthermore, FIG. 9 does not show the spectrum obtained by photothermal spectrometry of CdS powder on brass using the apparatus of the present invention.

Lines 41, 42, and 43 in Fig. 10 represent the azobenzene solution and the Ca C0 with the same amount of azobenzene adsorbed, respectively.
3 powder suspension and Ca without azobenzene adsorbed.
The photothermal spectrum of a CO3 powder suspension is shown.

Furthermore, FIG. 11 shows the temperature rise value of carbon black in response to the light intensity when carbon black is irradiated with light of a constant wavelength at different intensities. It can be seen that the light intensity and the temperature rise value are linearly proportional.

The automatic photothermal spectrometer of the present invention can also be configured to detect secondary emission of a sample (ta<fluorescence) in addition to photothermal spectrometry. Figure 12 shows sample chamber 2 in that case.
and detection system are shown. In FIG. 12, the sample 1 is arranged to be inclined at a predetermined angle with respect to the incident light beam 51, and a fluorescence condensing lens 5 is placed in a direction forming a certain angle with respect to the incident light beam.
2 is arranged, and the fluorescence focused on this condensing lens 52 is guided to a detector 55 via an optical fiber 53 and a filter 54. Here, the fluorescence condensing lens 52 is arranged at a certain solid angle with respect to the sample 1 so that reflected light and scattered light from the surface of the sample 1 are not incident.

In order to simplify the drawing, in FIG. 12, various elements for photothermal spectrometry as shown in the apparatus of FIG. 1, such as the sample heat-sensitive element 5, the reference heat-sensitive element 6, and the carbon black 9, are omitted. However, it goes without saying that these are actually installed within the sample chamber 2.

Effects of the Invention According to the spectrometer of the invention, it can be applied to samples such as solid or semi-solid opaque substances such as crystals, powders, amorphous, and gels, which are difficult to measure using conventional optical absorbance measurement methods. Measurements using photothermal spectroscopy are possible, and can be carried out automatically without being affected by scattering or stray light. In particular, spectral analysis can be carried out automatically, and it is easy to handle, making it a remarkable method that can greatly expand the scope of application of spectroscopic analysis. You can get the following effect.

In addition, the photothermal spectrometer of the present invention is not affected by noise such as external noise compared to photoacoustic spectrometers developed in recent years, and it is also less susceptible to noise such as external noise, which is difficult to measure with photoacoustic spectroscopy. It is also possible to apply solid samples in
Therefore, it has the advantage that measurements such as spectrum analysis can be carried out on the spot on electrodes that are working in a liquid.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the automatic photothermal spectrometer of the present invention, FIG. 2 is a wiring diagram showing an example of an AC bridge as an output difference detection circuit used in the device of FIG. 1, and FIG. Figure 3 shows an example of the temperature change of a sample (output of the synchronization detection circuit 26) when the sample is measured using the device of the present invention.
4 and 5 are waveform diagrams schematically showing the output waveforms of the synchronization detection circuit 26 when samples are actually measured using the apparatus of the present invention for different samples, respectively. Figure 6 shows the photothermal spectrum of carbon black produced by the apparatus of this invention when a Cannon lamp is used as a light source, in comparison with the spectrum of the Cannon light source measured by a radiometer. Figure 8 shows the photothermal spectra of a single crystal of TIO2 in comparison with spectrometer 1 measured by optical spectroscopy.
Figure 9 shows the photothermal spectrum of a dS deposited film, Figure 9 shows the photothermal spectrum of CdS powder on 1R copper using the apparatus of the present invention, and Figure 10 shows the photothermal spectrum of a solution and powder suspension of the present invention. FIG. 11 is a diagram showing the relationship between the irradiation light intensity and temperature rise value for carbon black, and FIG. 12 is a diagram showing the photothermal spectra obtained by the apparatus of the present invention, in which a secondary radiation (fluorescence) detection system is installed. FIG. 2 is a schematic diagram showing a sample chamber when DESCRIPTION OF SYMBOLS 1... Sample, 2... Sample chamber, 5... Heat sensitive element for sample, 6... Heat sensitive element for reference, 8... Light source,
9... Carbon black, 10... Standard heat sensitive element, 13... First irradiation light intermittent control means, 14.
...Shutter (light interrupter), 15...Second irradiation light intermittent control means, 16...Chopper (light intermittent photography)
, 17... Spectrometer as a wavelength selector, 17A.
... Dispersion element, 18 ... Shutter driving means, 20
...Chopper driver stage, 23...Output difference detection circuit, 24...AC bridge, 26...Synchronization detection circuit, 27...Data processing/control unit, 29...
High sensitivity pressure sensitive detector, 55... Detector for secondary radiation detection. 450 500 thousand continuation arrest <t4 (7j type) 1981 special m' [l (A (No. 191206 2, title of invention automatic photothermal spectrometry) 41 City 3 Person who makes correction = Jj li What relationship Special W (Applicant 11 Address: 710-5 Nakamaruko, Nakahara-ku, Yozaki City, Kanagawa Prefecture)
Name Mutsumi 16 Akihaka 2) 4. Agent address 1+13 Minato-ku, Tokyo T I]/l So 18:
No. 5,? lli if211) Ordinance [1i7, amendment part 1): 311114z-submit. (2) As shown in the attached sheet, drawing 11: (Content M change'Q 4:
L,) zi fba: put out.

Claims (1)

[Scope of Claims] (1) A sample chamber thermally isolated from the surroundings, a selective irradiation means for irradiating light of a selected wavelength onto a sample installed in the sample room, and a beam of light irradiating the sample. irradiation light intermittent control means for continuing irradiation of the sample, temperature detection means for directly detecting the temperature rise value of the sample due to the irradiation light, and recording and displaying the temperature rise value of the sample detected by the temperature detection means. recording and displaying means, each time the irradiation light intermittent control means finishes irradiating the sample with the light beam a predetermined number of times, the selective irradiation means switches the wavelength of the irradiation light beam irradiated to the sample; An automatic photothermal spectrometer characterized in that it is configured to record and display the temperature rise value of a sample over the entire measurement wavelength range. (2) Automatic photothermal spectroscopy according to claim 1, wherein the selective irradiation means comprises a high-intensity light source and a wavelength selector for selecting light of a desired wavelength from the light from the light source. measuring device. (3) The wavelength selector is composed of a plurality of bandpass filters each having a predetermined band width, and the filters through which the light from the light source passes are sequentially replaced by a signal from the irradiation light intermittent control means. An automatic photothermal spectrometer according to claim 2, which is configured as follows. (4) The wavelength selector is constituted by a spectroscope in which a dispersion element that separates light from the light source is replaced, and drives a wavelength selection driver of the dispersion element by a signal from the irradiation light intermittent control means. An automatic photothermal spectrometer according to claim 2, which is configured as follows. (5) The automatic photothermal spectrometer according to claim 1, wherein the selective irradiation means is comprised of a plurality of single wavelength laser light sources. (6) The automatic photothermal spectrometer according to claim 1, wherein the selective irradiation means is comprised of a variable wavelength laser light source. (7) The irradiation light intermittent control means includes an optical interrupter, a driving means for inserting the optical interrupter into the optical path and removing it from the optical path, and a control section for controlling the driving means, and controls the optical interrupter. 2. The automatic photothermal spectrometer according to claim 1, wherein the section includes a timer for setting the opening time and closing time of the optical path by the optical interrupter. (8) The irradiation light intermittent control means includes an optical interrupter, a driving means for inserting the optical interrupter into the optical path and removing it from the optical path, and a control section for controlling the driving means, and The control unit is configured to control the timing of opening of the optical path by the optical interrupter based on the result of processing and determining the output signal of the temperature detecting means, and also control the opening time of the optical interrupter based on a time preset in a timer. An automatic photothermal spectrometer according to claim 1. (9) A patent in which the control unit is configured to differentiate the output signal of the temperature detection means and cause an optical interrupter to open the optical path when the differential value becomes smaller than a predetermined value. An automatic photothermal spectrometer according to claim 8. (10) The irradiation light intermittent control means includes a light interrupter in which a light transmitting part and a light blocking part are alternately formed, a drive means for driving the light interrupter, and a control part for controlling the drive means. The automatic photothermal spectrometer according to claim 1, wherein the irradiation light is alternately interrupted by driving the optical interrupter at a preset speed. (11) The automatic photothermal spectrometer according to claim 10, wherein the optical interrupter is a rotary chopper. (12) The automatic photothermal spectrometer according to claim 10, wherein the signal from the temperature detection means is detected in synchronization with the opening and closing of the optical interrupter. (13) The temperature detection means is constituted by two heat-sensitive elements having substantially the same characteristics within the measurement range, one heat-sensitive element is placed in contact with the sample to directly detect the sample temperature, and the other heat-sensitive element is arranged in contact with the sample to directly detect the sample temperature. The heat-sensitive element should detect the temperature around the sample (it should be placed near the sample, and by processing the detection signals of both heat-sensitive elements, it will detect the temperature rise of only the sample, removing the influence of ambient temperature changes). The automatic photothermal spectrometry device according to claim 1. (14) The two heat-sensitive elements are incorporated into a DC bridge or an AC bridge, and the output difference between the two heat-sensitive elements is directly detected or converted into an AC signal. The automatic photothermal spectrometer according to claim 13, which detects with synchronized synchronous rectification and obtains an output signal corresponding to the temperature rise of only the sample. (15) A sample chamber thermally isolated from the surroundings; , selective irradiation means for irradiating a sample installed in the sample chamber with light of a selected wavelength; irradiation light intermittent control means for intermittent irradiation of the irradiation beam onto the sample; and temperature control of the sample due to the irradiation light. A sample temperature detection means for directly detecting an increase; a standard carbon black installed in the sample chamber; and a means for switchably guiding at least a part of the light irradiated onto the sample to the standard carbon black. , a standard temperature detection means for directly detecting a temperature rise of the standard carbon black; and a temperature detection signal obtained by the standard temperature detection means to detect the temperature of the sample measured by the sample temperature detection means. means for normalizing the temperature rise value of the sample; and recording and display means for recording and displaying the standardized temperature rise value of the sample; When the predetermined number of irradiations have been completed, the wavelength of the irradiation light irradiated onto the sample is switched by the selective irradiation means, thereby measuring the sample temperature rise value in the entire measurement wavelength range. ] At the same time or separately from the measurement of the sample, a curl pan black is sequentially irradiated with light over the entire measurement wavelength range, and the temperature of the sample increases over the entire measurement range based on the detection signal obtained from the standard temperature detection means. An automatic photothermal spectrometer is characterized in that it is modernized and thereby calibrates measurement errors based on the relationship between the energies of each wavelength of irradiated light. (16) The sample temperature detection means Consisting of two heat-sensitive elements having substantially the same characteristics, the first heat-sensitive element is placed in contact with the sample to directly detect the sample F1 temperature, and the second heat-sensitive element is placed in contact with the sample to directly detect the sample F1 temperature. The standard temperature detection means includes a third heat-sensitive element disposed near the sample to detect the ambient temperature, and a third heat-sensitive element disposed in contact with the carbon black, and a second heat-sensitive element disposed near the carbon black. A temperature increase of only the sample, which is configured by a heat-sensitive element and a common or different heat-sensitive element, and the influence of ambient temperature changes is removed by processing the output signals of the first heat-sensitive element and the second heat-sensitive element. A temperature increase value of only carbon black, which removes the influence of ambient temperature changes by detecting the value and processing the output signals of the third heat-sensitive element and a second heat-sensitive element in its vicinity or another heat-sensitive element. An automatic photothermal spectrometer according to claim 15, which is adapted to detect. (17) The first and second heat sensitive elements are incorporated into a DC bridge or an AC bridge, and the third heat sensitive element and a second heat sensitive element or another heat sensitive element in the vicinity of the third heat sensitive element are incorporated into a DC bridge or an AC bridge. An automatic photothermal spectrometer according to claim 16, which is incorporated in . (18> A sample chamber thermally isolated from the surroundings, a selective irradiation means for irradiating light of a selected wavelength onto a sample installed in the sample chamber, and intermittent irradiation of the irradiation beam onto the sample. irradiation light intermittent control means for controlling the irradiation light, temperature detection means for directly detecting the temperature rise value of the sample due to the irradiation light, and recording display means for recording and displaying the temperature rise value of the sample detected by the temperature detection means. and each time the irradiation light intermittent control means finishes irradiating the sample with the light beam a predetermined number of times, the selective irradiation means switches the wavelength of the irradiation light beam irradiated onto the sample, thereby controlling the wavelength of all measurement wavelengths. An automatic photothermal spectrometer configured to record and display the temperature rise value of a sample in a region, the sample being installed at a certain angle to the irradiation light, and the secondary synchrotron radiation emitted from the sample. An automatic photothermal spectrometer characterized in that a secondary radiation detection means for detecting radiation is arranged at a certain angle with respect to the incident direction of the irradiation light. (19) A sample thermally isolated from the surroundings. a chamber, a selection precedent means for irradiating a sample installed in the sample chamber with light of a selected wavelength, an irradiation light intermittent control means for intermittent irradiation of the irradiation beam onto the sample, temperature detection means for directly detecting the temperature rise value of the sample, and recording and display means for recording and displaying the temperature rise value of the sample detected by the temperature detection means, and the luminous flux to the sample is controlled by the irradiation light intermittent control means. Each time one or more predetermined number of irradiations are completed, the wavelength of the irradiation beam irradiating the sample is switched by the selective irradiation means, thereby recording and displaying the temperature rise value of the sample in the entire measurement wavelength range. The automatic photothermal spectrometer is configured to have a high-sensitivity pressure-sensitive detector installed in the sample chamber, and is configured to also detect sound due to a photoacoustic effect from a sample caused by intermittent irradiation light. An automatic photothermal spectrometer characterized by: