JPS6013456B2 - photoacoustic analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photoacoustic analyzer, and more particularly, to a photoacoustic analyzer that irradiates a sample with a photoelectric effect placed in a sample chamber and analyzes the sample from the photoelectrically converted electrical output and the photoacoustic effect output. This invention relates to a photoacoustic analyzer that enables analysis.

Generally, when a material is irradiated with light energy, a portion of the irradiated light energy is absorbed by the material, and a portion of this absorbed light energy is converted into heat energy.

Moreover, since a substance has a unique light absorption spectrum corresponding to a certain condition under certain conditions, the amount of absorption of light energy, that is, the amount of conversion into thermal energy also takes on a unique value depending on the substance. The converted thermal energy increases the temperature of the atmospheric gas surrounding the substance and increases the pressure of the atmospheric gas, so it becomes possible to analyze the substance by detecting this change in pressure. Furthermore, if the substance has a photoelectric effect, a part of the light energy absorbed by the substance is converted into electric energy, and the amount of electricity converted to photoelectricity has a unique value depending on the substance. It is also possible to analyze substances from the amount of electricity generated.

By the way, when a substance is irradiated with light, the absorbed light energy is converted into thermal energy, electrical energy, etc., and the law of conservation of energy is established between them. Furthermore, there are various light-related properties of substances, such as thermal properties, electrical properties, and chemical properties.These properties are organically related to each other, and different properties can be obtained under the same conditions. For example, it is often necessary to measure thermal properties and electrical properties simultaneously, but in the past, these properties had to be measured almost individually, which was inconvenient.

Therefore, an object of the present invention is to provide a photoacoustic analyzer that can simultaneously detect the photoacoustic effect output obtained by irradiating light onto a sample with a photoelectric effect housed in a sample chamber and the photoelectrically converted electrical output. It is about providing.

The present invention, which achieves the above object, connects a sample chamber filled with gas with a reference chamber through a gas passage, and incorporates a thermal flowmeter-type detection element into this gas passage, and inside the sample chamber. A placed sample with a photoelectric effect is intermittently irradiated with light at a constant frequency, and the flow of gas in the gas passage caused by the thermal expansion of the gas in the sample chamber caused by the sample is determined by thermal flow rate. In a device that analyzes a sample by detecting it with a meter-shaped detection element, the amount of electricity emitted from the sample is detected by connecting a conducting wire to the sample with a photoelectric effect placed in the sample chamber. , is characterized in that the sample can be analyzed based on the magnitude of this electrical output and the photoacoustic effect output.

An embodiment of the photoacoustic analyzer according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the photoacoustic analyzer according to the present invention, and reference numeral A in the figure shows an embodiment of the photoacoustic analyzer according to the present invention.
shows a detector that analyzes samples using the photoacoustic effect,
Immediately before this detector A, a light intermittent chopper B is provided,
The sample in the detector A can be intermittently irradiated with light at a constant frequency3.

Photoacoustic effect output signal a. from this detector A. is sent to an operational amplifier C, where it is operationally amplified, and then sent to an instruction recorder D, where it is instructed and recorded. Further, a signal from the optical intermittent chopper B is applied to the operational amplifier C as a signal b indicating intermittent light. On the other hand, the symbol E indicates an amplifier for the photoelectrically converted electrical output, and the amplifier E is supplied with the signal b from the optical chopper B and the photoelectrically converted electrical output a2 via the switch S. Output signal e
4 can be supplied to the instruction recorder D mentioned above.

Next, the details of the structure of the detector A, which constitutes the main part of the present invention, will be explained with reference to FIG.

In FIG. 2, the detector, generally designated by the symbol A, has a main body 1 of the detector, in which a sample chamber 3 for accommodating a sample 2 and a reference chamber 4 are provided. The sample chamber 3 and the reference chamber 4 are connected to each other by a gas passage 5.

These sample chamber 3 and reference chamber 4 are filled with, for example, air or a gas such as nitrogen or helium. The sample 2 may be any material that has the property of converting light energy absorbed by the sample into electrical energy, that is, a sample that has a photoelectric effect.

On the other hand, on the lower surface of the sample chamber 3, a sample stage 8, which is kept airtight via a sealing element 7 such as an O-ring, is removably installed. A sample plate 9 is mounted on the upper surface of the sample table 8, and the sample 2 is set on top of the blood sample 9. The blood sample 9 is preferably made of an insulating material. Two conductive wires 10, 10 are led out from the sample 2 on the sample plate 9, and these conductive wires 10
, 1 are connected to the output terminal 11. The output terminal 11 is airtightly held in a receiving hole 12 formed in the sample stage 8, and a plurality of lead wires 13 are led out through this output terminal 11. These lead wires 13
The tip of is connected to the electrical power amplifier. A thermal flow meter type detection element 14 is attached to the outlet side of the gas passage 6, and as described later, this detection element 14 is activated at the same period as the period of light interruption by the light interruption chopper B. Detects the periodic pressure fluctuations that occur, and connects lead wire 1.
5 to output an alternating current electrical signal to the outside.

The thermal flow meter type detection element 14 functions as a type of hot wire anemometer composed of two Ni lattices with equal resistance-temperature characteristics, and the temperature of the gas in the sample chamber 3 is When the resistance changes, the resistance changes, and this resistance change can be extracted as a voltage output.

Therefore, according to this thermal flow meter type detection element 14,
The gas vibrations caused between the sample chamber 3 and the reference chamber 4 are
Detected as an alternating current electrical signal. This electric signal is sent as an acoustic effect output to the operational amplifier C shown in FIG. 1, and is amplified after being subjected to operational processing together with a signal indicating the wavelength and intensity of the light flux from the optical chopper B. Since the photoacoustic analyzer according to the present invention is configured as described above,
A sample 2 with a photoelectric effect to be analyzed is housed in the sample chamber 3 of the detector A, and the light from the light source of the Xe lamp is converted into monochromatic light through a spectrometer, and is further converted into intermittent light of a constant frequency by the light intermittent chopper B. The sample 2 is irradiated with the light through the light transmission window 6.

Then, part of the irradiated light energy is absorbed by the sample 2, and part of this light energy is converted into thermal energy, increasing the temperature of the atmospheric gas of the sample 2 and causing thermal expansion of the gas. This thermal expansion of the gas increases the Z pressure of the atmospheric gas of the sample 2. This pressure increase is caused at the same period as the light intermittent period, and as described above, is detected by the thermal flow meter type detection element 14 and is detected as an alternating current electrical signal. This electrical signal was sent to the operational amplifier C shown in Fig. 1 as an indicator of the acoustic effect output, and was processed therein together with the signal indicating the wavelength and intensity of the light beam from the optical chopper B. It will be amplified later. The amplified signal is then sent to the instruction recorder D, where the result is indicated and recorded. On the other hand, a part of the irradiated energy is photoelectrically converted within the sample and converted into an amount of electricity corresponding to the absorbed light energy.

The electrical output a2 is then sent to the amplifier E by closing the switch S, and the amplified output signal e is
Added to instruction recorder D. 3 and 4 respectively show embodiments in which the structure of the detector A is different.

Of these, the one shown in FIG. 3 is an example in which a sample chamber 3 and a reference chamber 4 are stacked vertically, and a light transmission window 6 is arranged at the boundary between the two chambers, and the space between the two chambers is They are connected by a gas passage 5. In this type of detector, output terminal 1
Two conducting wires 10, 10 are led out from the sample 2 through the sample 2, so that an amount of electricity corresponding to the light energy photoelectrically converted and absorbed within the sample 2 can be extracted to the outside. According to the configuration shown in FIG. 3, the gas filled in the reference chamber 4 and the sample chamber 3 also absorbs a part of the irradiated light energy, but at this time, as monochromatic light, the wavelength and intensity are equal. ,
Furthermore, if the reference chamber 4 and the sample chamber 3 are selected to have the same transmission length, the same amount of light energy is absorbed by the gas in the reference chamber 4 and the sample chamber 3, so that they are canceled out. Therefore, a pressure difference is generated between the sample chamber 3 and the reference chamber 4 due only to the thermal expansion of the gas based on the thermal energy of the sample, and the gas flows from the sample chamber 3 to the reference chamber 4. On the other hand, what is shown in FIG. 4 is an example in which the reference chamber 4 has the same structure as the sample chamber 3, and both chambers are connected by a gas passage 5. For example, a measurement sample 2A is set in the sample chamber 3. , and sets the reference sample 2B in the reference chamber 4, irradiates the samples 2A and 2B with light energy under the same conditions, and attempts to detect the photoacoustic effect output based on the difference in the amount of light absorption between the two. It is. In this type of detector, each sample 2
Conductive wires 10, 10 are led out from A, 28, and the electrical output induced in the samples 2A, 2B when irradiated with light energy under the same conditions can be detected to the outside. FIG. 5 shows a cross-sectional view of another embodiment of the invention.

A is the analyzer of the present invention. This analyzer A is a closed container AI
and A2 are juxtaposed. The closed containers AI and A2 each consist of a sample chamber and a reference chamber. 3.3 This is the sample room. Sample chambers 3 and 3 have samples 2 and 20 to be analyzed, respectively, and
Light transmission windows 6 and 60 are provided for irradiating these samples 2 and 20 with light energy. Samples 2 and 20 are placed in sample chamber 3 by being placed on sample stands 8 and 80, respectively.
, 30, and can be replaced by removing the sample stages 8, 80. The sample stands 8 and 80 may be integrally formed as shown in FIG.
It may be a separate item (not shown). 7 and 70 are sealing elements, for example O-rings.

4,401 is the reference room.

The reference chambers 4 and 40 are in communication with the sample chambers 3 and 30 via passages 5 and 50, respectively, so that the sample chamber 3 and the reference chamber 4 and the sample chamber 30 and the reference chamber 4 are connected to each other.
0 form one closed container AI and A2, respectively. The airtight containers AI and A2 are each filled with air or a gas such as nitrogen or helium. Further, thermal flow meter type detection elements 14 and 140 are installed at arbitrary locations in the passages 5 and 50 of the sample chamber 3 and the reference chamber 4, as well as the sample chamber 30 and the reference chamber 40, respectively. During analysis, the analyzer A of the present invention constructed in this manner simultaneously and intermittently irradiates the samples 2 and 201 with light energy having the same wavelength and energy through the light transmission windows 6 and 60, respectively. Note that this light energy may be applied alternately for a certain period of time. However,
The output of each thermal flow meter type detection element 14, 140 is quotient, sum,
Arithmetic processing such as difference and seed is performed to produce the final output.
Moreover, in this detector A, each sample 2,
From 20, conductive wires 10, 100, not shown in detail, are derived and when irradiated with light energy under the same conditions sample 2
, 20 can be led to the outside. As is clear from the above explanation, according to the present invention, a sample to be analyzed with a photoelectric effect housed in a sample chamber is intermittently irradiated with light at a certain frequency, and the resulting photoacoustic The effect output is detected by a thermal flow meter type detection element, and the electrical output absorbed by the sample and photoelectrically converted is also detected, so the thermal and electrical properties of the sample due to light absorption can be detected at the same time. This makes it possible to expand the capabilities and scope of use of analytical equipment.

Furthermore, it is also possible to simultaneously examine the relationship between the photoacoustic effect output and the photoelectrically converted electrical output when a specific sample is irradiated with light energy.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the photoacoustic analyzer according to the present invention, Fig. 2 is a perspective view showing the structure of the detector in cross section, and Figs. FIG. A: Detector, B: Optical intermittent chopper, C: Operational amplifier, D: Indication recorder, E: Amplifier, 1.
...Body, 2...Sample, 3...Sample chamber, 4...Reference chamber, 5...Gas passage, 6...Light transmission window, 8...Sample stage, 9...Sample plate , 10... Conductor wire, 11... Output terminal, 14... Thermal flow meter type detection element. 1 map, 2 maps, 9 maps, 9 maps

Claims (1)

[Scope of Claims] 1. A sample chamber filled with gas and a reference chamber are communicated through a gas passage, and a thermal flow meter type detection element is installed on the gas passage, and the sample chamber is disposed within the sample chamber. The sample is analyzed by irradiating the sample with photoelectric effect intermittently with light at a certain frequency and detecting the gas flow in the gas passage caused by this with the thermal flow meter type detection element. The method is characterized in that the amount of electricity emitted from the sample is detected by connecting a conducting wire to the sample, and the sample can be analyzed from the magnitude of this electrical output and the photoacoustic effect output. photoacoustic analyzer. 2. In the analyzer according to claim 1, a sample is also placed in the reference chamber, and the sample is irradiated with light energy equal to the light energy irradiated to the sample in the sample chamber, either simultaneously or alternately and intermittently. The gas flow in the gas passage caused by each sample is detected by a thermal flowmeter type detection element, and the light between the samples is detected based on the resistance change of the thermal flowmeter type detection element. A photoacoustic analyzer, characterized in that it detects differences in acoustic effect output, and furthermore, a conducting wire is also connected to the sample in the reference chamber, and the amount of electricity emitted from the sample is detected.