JP7071620B2 - Optical measuring device and sensitivity calibration method for optical measuring device - Google Patents

Description

The present invention relates to an optical measuring device that receives and detects fluorescence or scattered light emitted by a sample liquid that has been irradiated with light in order to obtain information about a component to be measured in the sample liquid.

Fluorescence (including intensity and extinguishing time) and scattered light emitted from the measurement target component, the reaction product with the measurement target component, the reagent that reacts with the measurement target component, etc. by irradiating the sample solution with light. An optical measuring device for measuring the presence / absence and concentration of a component to be measured by measuring the response light such as the above is widely used.
When measuring fluorescence, in the laboratory, pre-spectroscopic excitation light is incident on one side of a cell containing a sample solution, and light emitted in a direction of 90 ° with respect to the incident direction is separated to detect fluorescence. The side metering method is common.

Further, in order to increase the detection sensitivity, a device has been proposed in which a sample solution is circulated in a cartridge filled with an adsorbent, the component to be measured is sufficiently adsorbed, and then the cartridge is irradiated with excitation light to measure fluorescence. (Patent Document 1).
In Patent Document 1, a method of irradiating excitation light from an oblique direction with respect to a fluorescence detection path is adopted.

On the other hand, in the field of environmental measurement or the like, when trying to continuously obtain information on the sample liquid, using a member in contact with the sample liquid such as a flow cell or a cartridge has a maintenance problem such as dirt. Therefore, an epi-illumination type fluorescence analyzer that irradiates the liquid surface (overflow surface) of the overflowed sample liquid with excitation light from a vertical direction coaxial with the fluorescence detection path has been proposed (Patent Document 2). ..
Further, in the turbidity meter, the overflow surface is irradiated with light from diagonally above to detect diffusely reflected scattered light (Patent Document 3).

However, the overflow surface rises above the upper surface of the overflow tank due to surface tension. Moreover, the way of swelling depends on the flow rate. Therefore, in an optical measuring device such as Patent Documents 2 and 3, which irradiates the overflow surface with light and receives and detects fluorescence and scattered light, the position of the overflow surface changes when the flow rate of the sample liquid fluctuates. This will lead to measurement errors. Therefore, in such a measuring device, it is required to keep the flow rate of the sample liquid constant.

However, since the calibration liquid for performing sensitivity calibration of such a measuring device is generally expensive, it is not preferable in terms of cost to flow it at the same flow rate as the sample liquid to be measured.
Therefore, Patent Document 2 proposes that sensitivity calibration is performed using fluorescence emitted from a solid-state standard phosphor. Further, in Patent Document 3, by placing a ring having a predetermined thickness on the upper edge of the overflow tank, the position of the liquid level with the overflow surface of the sample liquid to be measured is set even in the state of the pooled water that can be stored in the overflow tank. It has been proposed not to differ.

Japanese Unexamined Patent Publication No. 2013-1919 Japanese Unexamined Patent Publication No. 2004-157018 Japanese Unexamined Patent Publication No. 2005-351831

However, in the case of Patent Documents 2 and 3, the solid standard phosphor and the ring had to be manually placed on the overflow tank at the time of calibration, which was complicated. In addition, it was not possible to avoid an error due to unexpected flow rate fluctuations during the measurement of the sample liquid to be measured.
The present invention has been made in view of the above circumstances, and the fluctuation in the amount of received light due to the fluctuation in the water level of the sample liquid is small, and fluorescence is performed with high accuracy without using a member such as a solid standard phosphor or a ring. It is an object of the present invention to provide an optical measuring device capable of measuring or scattered light.

In order to achieve the above problems, the present invention has adopted the following configurations.
[1] Light source and
An irradiation optical system that guides the light emitted from the light source to the liquid surface of the sample liquid as irradiation light.
A detector that detects the response light emitted from the sample liquid near the liquid surface by the irradiation light, and
It is equipped with a detection optical system that receives the response light and guides it to the detector.
The optical axis of the optical path of the irradiation light by the irradiation optical system and the optical axis of the light receiving range of the response light by the detection optical system do not overlap and are not parallel on the same straight line.
The optical path of the irradiation light by the irradiation optical system and the light receiving range of the response light by the detection optical system intersect.
An optical measuring device characterized in that 90% or more of the volume of the portion where the optical path of the irradiation light and the light receiving range of the response light overlap is located below the water level at which the liquid level of the sample liquid is the lowest.
[2] The optical measuring device according to [1], wherein the response light is fluorescent.
[3] The optical measuring device according to [1], wherein the response light is scattered light.
[4] Further, an overflow cylinder having an opening at the upper end and capable of overflowing the sample liquid from the opening is provided.
The optical measuring device according to any one of [1] to [3], wherein the liquid level of the sample liquid is located in the vicinity of the opening of the overflow cylinder.

According to the optical measuring device of the present invention, there is little fluctuation in the amount of received light due to fluctuations in the water level of the sample liquid, and fluorescence and scattered light can be measured accurately without using a member such as a solid standard phosphor or a ring. It is possible to provide an optical measuring device that can be used.

It is a schematic block diagram of the multi-wavelength fluorescence analyzer which concerns on embodiment of this invention. It is sectional drawing of the main part of the multi-wavelength fluorescence analyzer which concerns on embodiment of this invention. It is a figure explaining the influence of the water level fluctuation of the liquid level when this invention is not carried out. It is a figure explaining the influence of the water level fluctuation of the liquid level at the time of carrying out this invention. It is a figure which shows the result of the experimental example 1. FIG.

A multi-wavelength fluorescence analyzer will be described as an embodiment of the optical measuring device of the present invention. As shown in FIG. 1, the multi-wavelength fluorescence analyzer 1 of the present embodiment has a light-shielding partition plate 2 and a light-shielding detection unit case 3 installed above the partition plate 2 and below the partition plate 2. It includes a light-shielding sample case 4 to be installed, and a light-shielding overflow cylinder 6 inserted from below the sample case 4.

A sample liquid outlet 4a is provided at the lower end of the sample case 4. The lower end of the overflow cylinder 6 is a sample liquid inlet 6a, and the upper end is a substantially horizontal upper opening 6b.
The sample liquid S flows into the inside of the overflow cylinder 6 from the sample liquid inlet 6a of the overflow cylinder 6 and overflows from the substantially horizontal upper opening 6b on the upper end side of the overflow cylinder 6 to form the liquid level 7 which is the overflow surface. It is designed to do. Then, the overflowed sample liquid S is guided to the sample liquid outlet 4a and discharged.

In the multi-wavelength fluorescence analyzer 1, in principle, the inflow and outflow of the sample liquid S always continues during continuous measurement, and the liquid level 7 is always formed by the new sample liquid S.
On the other hand, at the time of sensitivity calibration, the calibration liquid is poured into the overflow cylinder 6 with the sample liquid inlet 6a closed until it overflows from the upper opening 6b to form the liquid level 7 in the stored water state.

In the space surrounded by the partition plate 2 and the detection unit case 3, the light source unit 10, the optical path unit 20, the light source side spectroscopic unit 30, the excitation light unit 40, the light receiving unit 60, the detection side spectroscopic unit 70, and the detector unit 80 Is placed.
Further, the multi-wavelength fluorescence analyzer 1 includes a calculation control device 90, and the operation of the entire device is controlled by the calculation control device 90, and necessary calculations and the like are performed based on the signal and the like detected by the detector unit 80. It is supposed to do.

In the present embodiment, the light source unit 10 is the light source in the present invention, and the fluorescence detector 82 in the detector unit 80 is the detector in the present invention. Further, the optical path unit 20, the light source side spectroscopic unit 30, and the excitation light unit 40 constitute the irradiation optical system in the present invention. Further, other than the light receiving unit 60, the detection side spectroscopic unit 70, and the fluorescence detector 82 in the detector unit 80, the detection optical system in the present invention is configured.

As the light source unit 10, a Xe flash lamp (xenon discharge tube), a D ₂ lamp (deuterium discharge tube), or the like can be used.
The optical path unit 20 includes a mounting base 21, a mask 22, a lens 23, a mirror 24, a lens 25, and a mask 26 fixed to the mounting base 21. The optical path unit 20 is configured to adjust the light flux from the light source unit 10 with the masks 22 and 26 and the lenses 23 and 25, change the direction with the mirror 24, and guide the light flux to the light source side spectroscopic unit 30.

The light source side spectroscopic unit 30 is composed of a mounting base 31, a slit 32 fixed to the mounting base 31, a diffraction grating 33, and a slit 34. That is, the irradiation optical system has a diffraction grating 33 as a spectroscopic means.
The diffraction grating 33 is rotatable by a motor (not shown), and among the light incident from the optical path unit 20 through the slit 32, light having a specific wavelength passes through the slit 34 and the excitation light unit 40. The rotation position can be selected so that it is incident on.

The excitation light unit 40 includes a mounting base 41, a mask 42 fixed to the mounting base 41, a lens 43, a mirror 45, a lens 46, a mask 47, a reference photodetector 51, a mask 52, and a lens 53. There is. The light incident from the light source side spectroscopic unit 30 passes through the mirror 45 while adjusting the luminous flux with the masks 42, 52 and the lenses 43, 46, and the excitation light E is emitted as irradiation light to the liquid surface 7 of the sample liquid S. It is designed to be irradiated.
The excitation light E is incident on the liquid surface 7 from a direction in which the angle θ with respect to the vertical direction is 45 ± 15 °. That is, the optical axis of the excitation light E is 45 ± 15 ° with respect to the vertical direction.

Further, a part of the light incident from the light source side spectroscopic unit 30 is reflected by the mirror 45 and reaches the reference photodetector 51 as the reference light R via the mask 52 and the lens 53, and the reference light R is detected. Will be done. The detection result of the reference light R is sent to the arithmetic control device 90 so that the fluctuation of the light amount of the excitation light E can be compensated.

The light receiving unit 60 includes a mounting base 61, a lens 62 fixed to the mounting base 61, and a lens 63. The light receiving unit 60 is arranged so that fluorescent F (response light) emitted upward in the vertical direction from the vicinity of the liquid surface 7 can be incident. That is, the optical axis of the light receiving range of the fluorescence F is along the vertical direction. The crossing angle between the optical axis Ex and the optical axis Fx is 45 ± 15 °.
Then, the received fluorescence F is adjusted in luminous flux by the lenses 62 and 63 and guided to the detection side spectroscopic unit 70.

The detection-side spectroscopic unit 70 includes a mounting base 71, a slit 72 fixed to the mounting base 71, a diffraction grating 73, and a slit 74. That is, the detection optical system has a diffraction grating 73 as a spectroscopic means.
The diffraction grating 73 is rotatable by a motor (not shown), and among the light incident from the light receiving unit 60 through the slit 72, the light of a specific wavelength passes through the slit 74 and the detector unit 80. The rotation position can be selected so that it is incident on the.

The detector unit 80 includes a mounting base 81, a fluorescence detector 82 fixed to the mounting base 81, a mask 83, a lens 84, and a cut filter 85. As the fluorescence detector 82, a photomultiplier tube, a photodiode, a phototransistor, an avalanche photodiode, or the like can be appropriately used.

In the detector unit 80, the light guided from the detection side spectroscopic unit 70 is adjusted in luminous flux by the mask 83 and the lens 84, and further, the light having an unnecessary wavelength is removed by the cut filter 85, and then the fluorescence detector 82 is used. It has been introduced in. The cut filter 85 removes light having the same wavelength as the excitation light E, whereby scattered light and stray light are removed. The detection result of the fluorescence F by the fluorescence detector 82 is sent to the arithmetic control device 90, and the concentration of the component to be measured and the like can be obtained.

The positional relationship between the optical path Er of the excitation light E, the light receiving range Fr of the fluorescence F, and the overflow cylinder 6 in the present embodiment will be described in detail with reference to FIG.
FIG. 2 is a cross-sectional view of a main part in a plane including the optical axis Ex of the optical path Er and the optical axis Fx of the light receiving range Fr. In the plane of FIG. 2, the optical axis Ex and the optical axis Fx do not overlap on the same straight line and intersect diagonally. Then, a finite overlapping portion W is formed, which is a portion where the optical path Er and the light receiving range Fr overlap.
The optical path Er is a range of excitation light E (irradiation light) emitted from the lens 46 at the end of the irradiation optical system toward the liquid surface 7. The light receiving range Fr is a range in which light can be taken in from the lens 62 at the entrance of the detection optical system, that is, a range in which fluorescent F (response light) can be received.

In the multi-wavelength fluorescence analyzer 1 of the present embodiment, the water level of the liquid level 7 of the sample liquid S is located in the vicinity of the substantially horizontal upper opening 6b on the upper end side of the overflow cylinder 6. The water level of the liquid level 7 of the sample liquid S becomes the lowest when the water flow to the overflow cylinder 6 is stopped and the water is stored, and the minimum liquid level 7a which is the liquid level 7 at that time is the upper opening. It is equal to or slightly raised at position 6b.
On the other hand, the water level of the liquid level 7 of the sample liquid S when water is passed through the overflow cylinder 6 and overflows rises to the upper side of the upper opening 6b than in the case of the stored water state.
Therefore, the liquid level 7 of the sample liquid S does not fall below the upper opening 6b under normal use conditions.
Since the entire overlapping portion W is located at a position lower than the substantially horizontal upper opening 6b on the upper end side of the overflow cylinder 6, the entire overlapping portion W is located below the minimum liquid level 7a of the sample liquid S. It has become.

According to the multi-wavelength fluorescence analyzer 1 of the present embodiment, the reason why the fluctuation of the light receiving amount due to the fluctuation of the water level of the sample liquid is reduced will be described with reference to FIGS. 3 and 4. In FIGS. 3 and 4, the optical path Er of the excitation light E is a parallel optical path so that the range of the overlapping portion can be easily understood. In addition, the refraction of light that occurs at the interface between air and sample liquid is not reflected in the figure.

As shown in FIG. 3A, when the optical axis Ex and the optical axis Fx are crossed at the minimum liquid level 7a, the range in which fluorescence can be generated by the excitation light E is the minimum liquid level 7a or less. Optical path Er. Further, the range in which the fluorescent F generated from the light can be received is the light receiving range Fr having a minimum liquid level of 7a or less.
Therefore, the amount of light that can be detected by the fluorescence detector 82 is substantially proportional to the volume of the overlapping portion _W1 below the liquid surface in the overlapping portion W of the optical path Er and the light receiving range Fr. Strictly speaking, it should be considered that the excitation light E and the fluorescence F are attenuated by scattering / absorption by the sample liquid S, but ignoring this, it is considered that the amount of detectable light is substantially proportional to the volume. Can be done.
The overlapping portion W ₂ above the liquid surface does not generate the fluorescent F to be detected, and therefore does not contribute to the amount of light that can be detected.

In the apparatus set as shown in FIG. 3A, when the liquid level of the sample liquid S becomes the highest liquid level 7b higher than the lowest liquid level 7a as shown in FIG. 3B, the overlapping portion W _The portion below the liquid level is the overlapping portion W1 and the overlapping portion _W3 . Therefore _, the amount of light that can be detected by the fluorescence detector 82 is substantially proportional to the _total volume of the overlapping portion W1 and the overlapping portion W3. The overlapping portion W ₄ above the liquid surface does not generate the fluorescent F to be detected, and therefore does not contribute to the amount of light that can be detected.
Therefore, the amount of light that can be detected in FIG. 3 (b) is (1 + [volume of W ₃ ] / [volume of W ₁ ]) times that of the amount of light that can be detected in FIG. 3 (a), and the same sample liquid is used. Even if it is S, the amount of detected light increases.

On the other hand, as shown in FIG. 4A, the optical axis Ex and the optical axis Fx intersect sufficiently below the minimum liquid level 7a, and the entire overlapping portion W is equal to or less than the minimum liquid level 7a of the sample liquid S. The amount of light that can be detected by the fluorescence detector 82 is substantially proportional to the volume of the entire overlapping portion W of the optical path Er and the light receiving range Fr.
Further, in the apparatus set as shown in FIG. 4 (a), even when the liquid level of the sample liquid S becomes the highest liquid level 7b higher than the minimum liquid level 7a as shown in FIG. 4 (b), the fluorescence is also fluorescent. The amount of light that can be detected by the detector 82 is substantially proportional to the volume of the entire overlapping portion W of the optical path Er and the light receiving range Fr.

Therefore, the amount of light that can be detected in FIG. 4B is substantially the same as the amount of light that can be detected in FIG. 4A.
Since the position of the overlapping portion W with respect to the liquid surface becomes slightly deeper, the light is attenuated by the sample liquid S. Therefore, the amount of light that can be detected in FIG. 4B is the amount of light that can be detected in FIG. 4A. Slightly below. However, the effect is smaller than the effect of changing the volume of the portion below the liquid surface in the overlapping portion W.

Therefore, according to the multi-wavelength fluorescence analyzer 1 of the present embodiment, even when the sample liquid S overflows and the water level of the liquid level 7 becomes higher than the minimum liquid level 7a, the water level of the liquid level 7 is the lowest liquid level. It is possible to obtain the same amount of light received as in the case of 7a.
As can be understood from the explanation using FIG. 4, the optical path Er of the excitation light E may be a parallel optical path or a focused optical path, but since it is easy to obtain high excitation efficiency, the present embodiment It is preferably a focused optical path as in the multi-wavelength fluorescence analyzer 1.

Further, the light receiving range Fr may be a range having a focal point or a range having no focal point, but since it is easy to obtain high detection sensitivity, the multi-wavelength fluorescence analyzer 1 of the present embodiment is used. , It is preferable that the range has a focal point. Further, the focal position is preferably near the liquid level at the time of measuring the sample liquid to be measured. When the sample liquid to be measured overflows and the overflow surface is set to the liquid level 7, it is preferable to focus on the vicinity of the overflow surface.

In the multi-wavelength fluorescence analyzer 1 of the above embodiment, the entire overlapping portion W is located below the minimum liquid level 7a of the sample liquid S, but in the present invention, 90% or more of the overlapping portion W is present. It suffices if the volume of is present at the minimum liquid level 7a or less. That is, the ratio of the overlapping portion existing below the minimum liquid level 7a of the sample liquid S to the entire overlapping portion W may be 90% or more in terms of volume ratio.

When 90% of the overlapping portion W is present below the minimum liquid level 7a and the remaining 10% is above the minimum liquid level 7a, the liquid level rises and the entire overlapping portion W becomes the minimum liquid level 7a or less. When it becomes, the volume of the overlapping portion under the liquid surface becomes (100/90) times. On the other hand, the effect of making the water depth of the overlapping portion deeper than before the liquid level rise works in the direction of attenuating the detectable amount of light, and as a result, when 90% of the volume of the overlapping portion W is present at the minimum liquid level 7a or less. The error due to the fluctuation of the liquid level is considered to be within about 10%.

From the viewpoint of minimizing the error due to the liquid level fluctuation, the ratio of the volume in which the overlapping portion W exists below the minimum liquid level 7a is preferably 95% or more, more preferably 98% or more, and 99%. The above is more preferable, and 100% is particularly preferable.
However, if the light attenuation effect of the sample liquid S when the liquid level rises is large due to the large turbidity of the sample liquid S, the wide range of liquid level fluctuation, etc., it may be preferably less than 100%. be.

From the viewpoint of avoiding light attenuation due to the sample liquid S, it is preferable that the water depth of the overlapping portion W is as shallow as possible. That is, when the entire overlapping portion W is present at the minimum liquid level 7a or less, the distance between the highest position of the overlapping portion W and the minimum liquid level 7a is preferably small. The permissible distance between the highest position of the overlapping portion W and the lowest liquid level 7a varies depending on the degree of turbidity of the sample liquid S, the width of the liquid level fluctuation, the intensity of the excitation light E, the permissible measurement error, and the like.
When the entire overlapping portion W is present at the minimum liquid level 7a or less, the distance between the highest position of the overlapping portion W and the minimum liquid level 7a is preferably 20 mm or less, more preferably 10 mm or less, still more preferably 5 mm or less. It is particularly preferably 0 mm.

Further, in the multi-wavelength fluorescence analyzer 1 of the above embodiment, the optical axis Fx of the light receiving range Fr of the fluorescence F is in the vertical direction, but the optical axis Fx may be inclined diagonally with respect to the vertical direction. ..
Further, the plane including the optical axis Ex of the optical path Er and the optical axis Fx of the light receiving range Fr may be along the vertical direction or may be inclined diagonally with respect to the vertical direction.
Further, in the above embodiment, the crossing angle between the optical axis Ex and the optical axis Fx is 45 ± 15 °, but the crossing angle is not particularly limited.

However, the optical axis Ex and the optical axis Fx must not be coaxial. That is, they must not overlap on the same straight line. Further, the optical axis Ex and the optical axis Fx must not be parallel to each other. If the optical axis Ex and the optical axis Fx overlap or are parallel to each other on the same straight line, the portion where the optical path Er and the light receiving range Fr overlap is not a finite region. Therefore, the entire overlapping portion or the volume of 90% or more cannot be set below the water level of the minimum liquid level.
Therefore, in the present invention, it is not permissible for the optical axis Ex and the optical axis Fx to overlap or be parallel on the same straight line.

Further, in the multi-wavelength fluorescence analyzer 1 of the above embodiment, the optical axis Ex and the optical axis Fx are crossed, but the optical axis Ex and the optical axis Fx do not necessarily have to cross each other. The optical axis Ex and the optical axis Fx may be close to each other so that the optical path Er and the light receiving range Fr intersect.

Further, in the above embodiment, the overflow cylinder 6 which is a single cylinder is used, but a double pipe having an outer cylinder on the outside of the overflow cylinder 6 is used, and the sample liquid is used on the inner wall of the outer cylinder and the outer wall of the overflow cylinder 6. After lowering the space, it may flow into the inside of the overflow cylinder 6 from the lower opening of the overflow cylinder 6. In this case, air bubbles in the sample liquid can be removed while the sample liquid is lowered between the inner wall of the outer cylinder and the outer wall of the overflow cylinder 6.

Further, the overflow cylinder for overflowing the sample liquid is not essential, and the liquid level of the sample liquid may be the liquid level of the flowing liquid. Further, it may be a stationary liquid level of the sample liquid stored in the container.
Further, the factors of the liquid level fluctuation are not limited to the flow rate fluctuation at the time of overflow and the difference between the overflow and the stored water state. For example, it may be due to a measurement error when a certain amount is weighed in a measuring tub and sampled.

Further, in the above embodiment, the diffraction gratings are arranged in both the irradiation optical system and the detection optical system, but other spectroscopic means such as a prism may be used instead of the diffraction gratings. Further, a fixed wavelength may be used without providing each spectroscopic means. In that case, the irradiation optical system and the detection optical system can be simplified as compared with the above embodiments.

In the path from the sample liquid to the sample liquid inlet 6a, a member used in a known sampling system such as a water receiving tank and a flow rate control valve can be appropriately provided. Of course, an instruction operation unit for issuing an instruction to the arithmetic control device 90, a display device for displaying the measurement result, a recorder, a printer, and the like can be appropriately provided.
Further, although the above embodiment is a fluorescence analyzer, the present invention can also be applied to, for example, a turbidity meter using scattered light.

[Experimental Example 1]
Fluorescence measurement was performed with the same apparatus as in FIG. 1 except that the overflow cylinder 6 was not used and the measuring tub was used. The wavelength of the excitation light was 320 nm, and the wavelength of the fluorescence was 440 nm.
As the sample liquid, an aqueous solution of quinine sulfate was used, and the measurement was performed while changing the distance between the lens 62 of the light receiving unit 60 and the liquid surface. The results are shown in Table 1 and FIG.

As shown in Table 1, when the distance between the lens and the liquid surface was 36.6 mm, the measured output was close to 0. This is because the lens distance to the liquid surface was too far, and almost the entire overlapping portion W where the optical path Er and the light receiving range Fr overlap was present above the liquid surface.
Moreover, even when the distance was 34.6 mm, the measured output was as low as 132 mV. This is because the lens distance to the liquid surface is too long, and a considerable part of the overlapping portion W where the optical path Er and the light receiving range Fr overlap is present above the liquid surface.

On the other hand, when the distance was 32.6 mm or less, the measured output was high at around 450 mV. This is because the lens distance to the liquid surface is sufficiently close, and almost the entire overlapping portion W where the optical path Er and the light receiving range Fr overlap is present below the liquid surface.
From these results, it was confirmed that the ratio of the portion below the liquid level in the overlapping portion W where the optical path Er and the light receiving range Fr overlap greatly affects the measurement output.

Further, when the distance was 32.6 mm or less, the output tended to gradually decrease as the distance became shorter. It is considered that this is because the water depth of the overlapping portion W where the optical path Er and the light receiving range Fr overlap gradually increases, so that the light is attenuated by the sample liquid. Therefore, it was confirmed that the water depth of the overlapping portion W should not be excessively deep.
However, the degree of decrease in output as the distance became shorter was gradual as shown in FIG. Therefore, it was confirmed that a slight fluctuation in the water depth of the overlapping portion W does not cause a large measurement error.

[Experimental Example 2]
Fluorescence measurement was performed with the same device as in FIG. The wavelength of the excitation light was 320 nm, and the wavelength of the fluorescence was 440 nm. The crossover angle between the optical axis Fx and the optical axis Ex was set to 45 degrees.
Further, the focal length of the lens 62 of the light receiving unit 60 was set to 35 mm, and the lens 46 of the excitation light unit focused on the position 31.6 mm from the lens 62 of the optical axis Fx. In this device, the highest position of the overlapping portion W where the optical path Er and the light receiving range Fr overlap was the position 29.4 mm from the lens 62.

As the sample liquid, an aqueous solution of quinine sulfate was used, and the distance d between the lens 62 of the light receiving unit 60 and the upper opening 6b of the overflow cylinder 6 was set to 31.6 mm, and the measurement output at the time of passing water and at the time of storing water was obtained. The area of the upper opening 6b of the overflow cylinder 6 was 3390 mm ² , and the flow rate during water flow was 1 L / min. The liquid level at the time of storing water is substantially equal to the position of the upper opening 6b of the overflow cylinder 6.
Similarly, the distance d between the lens 62 of the light receiving unit 60 and the upper opening 6b of the overflow cylinder 6 was set to 28.1 mm, and the measured outputs at the time of passing water and at the time of storing water were obtained. The results are shown in Table 2.

As shown in Table 2, when the distance d was 31.6 mm, the measured output was larger when the water was passed than when the water was stored. This is because the liquid level 7 rises due to the passage of water, and the proportion of the portion below the liquid level in the overlapping portion W where the optical path Er and the light receiving range Fr overlap increases.
Further, when the distance d was 28.1 mm, the measured outputs at the time of passing water and at the time of storing water were almost the same. This is because the entire overlapping portion W where the optical path Er and the light receiving range Fr overlap was already below the liquid level 7 at the time of storing water, so even if the liquid level 7 rises due to water flow, it is below the liquid level 7. This is because the ratio of the overlapping portion W where the optical path Er and the light receiving range Fr overlap in the above direction does not change significantly.

1 ... Multi-wavelength fluorescence analyzer, 2 ... Partition plate, 3 ... Detection unit case, 4 ... Sample case,
6 ... overflow cylinder, 6b ... upper opening, 7 ... liquid level, 7a ... lowest liquid level,
10 ... Light source unit, 20 ... Optical path unit, 30 ... Light source side spectroscopic unit,
33 ... Diffraction grating, 40 ... Excitation light unit, 60 ... Light receiving unit,
70 ... Detection side spectroscopic unit, 73 ... Diffraction grating, 80 ... Detector unit,
90 ... Arithmetic control device, S ... Sample solution, E ... Excitation light, F ... Fluorescence, R ... Reference light Er ... Optical path, Ex ... Optical axis, Fr ... Light receiving range, Fx ... Optical axis, W ... Overlapping part

Claims (4)

An overflow cylinder whose upper end is an opening and which allows the sample liquid to overflow from the opening.
Light source and
An irradiation optical system that guides the light emitted from the light source to the liquid surface of the sample liquid located near the opening of the overflow cylinder as irradiation light.
A detector that detects the response light emitted from the sample liquid near the liquid surface by the irradiation light, and
It is equipped with a detection optical system that receives the response light and guides it to the detector.
The overflow cylinder, the light source, the irradiation optical system, and the detection optical system have a fixed positional relationship with each other.
The optical axis of the optical path of the irradiation light by the irradiation optical system and the optical axis of the light receiving range of the response light by the detection optical system do not overlap and are not parallel on the same straight line.
The optical path of the irradiation light by the irradiation optical system and the light receiving range of the response light by the detection optical system intersect.
An optical measuring device, characterized in that 90% or more of the volume of a portion where the optical path of the irradiation light and the light receiving range of the response light overlap is present below the opening . The optical measuring device according to claim 1, wherein the response light is fluorescent. The optical measuring device according to claim 1, wherein the response light is scattered light. The method for calibrating an optical measuring device according to any one of claims 1 to 3.
Sensitivity calibration of an optical measuring device that calibrates based on the response light when the calibration solution is stored in the overflow cylinder until it overflows from the opening instead of continuously overflowing the sample solution. Method.

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