JP7448090B2 - water quality analyzer - Google Patents

Description

The present invention relates to a water quality analysis device.

BACKGROUND ART Water quality analyzers that have both a fluorescence measurement function and a turbidity measurement function are conventionally known (for example, Patent Document 1).
Patent Document 1 Patent No. 6436266

The problem we are trying to solve

It is preferable that the water quality analyzer can be easily calibrated.

General disclosure

In order to solve the above problems, a first aspect of the present invention provides a water quality analysis device. The water quality analyzer may measure the concentration of a substance to be measured in sample water. The water quality analyzer may include a turbidity meter. The turbidity meter may measure the intensity of scattered or transmitted light from the sample water. The turbidity meter may measure the turbidity of the sample water. The water quality analyzer may include a fluorometer. The fluorometer may measure the fluorescence intensity of the substance to be measured. The water quality analyzer may include a fluorescence intensity correction section. The fluorescence intensity correction section may correct the fluorescence intensity of the substance to be measured based on the turbidity of the sample water. The water quality analyzer may include a concentration calculation section. The concentration calculation unit may set a concentration calibration coefficient for converting the fluorescence intensity of the substance to be measured into the concentration of the substance to be measured, based on the result of measuring the fluorescence intensity of the fluorescence intensity calibration aqueous solution. The fluorescence intensity calibration aqueous solution may include a fluorescence intensity calibration substance whose wavelength range to which the fluorescence intensity characteristics are sensitive overlaps with that of the substance to be measured and whose concentration is known.

The fluorescence intensity calibration aqueous solution may include formazin.

The turbidity meter may include a turbidity calculation section. The turbidity calculation unit performs turbidity calibration, which converts the intensity of scattered light or transmitted light from the sample water into the turbidity of the substance to be measured, based on the results of measuring the intensity of scattered light or transmitted light of the turbidity calibration aqueous solution. You may set a coefficient. The turbidity calibration aqueous solution may include a turbidity calibration substance with known turbidity.

The turbidity calibration aqueous solution may be used as the fluorescence intensity calibration aqueous solution.

The aqueous turbidity calibration solution may include two or more turbidity calibration substances.

The substance to be measured may be PAH.

The fluorometer may obtain the fluorescence intensity of the fluorescence intensity calibration aqueous solution in a specific wavelength range in which the wavelength ranges in which the fluorescence intensity characteristics of the measurement target substance and the fluorescence intensity calibration substance are sensitive overlap. The specific wavelength range may be 300 nm or more and 400 nm or less.

The fluorometer may irradiate the sample water or the fluorescence intensity calibration aqueous solution with excitation light in a wavelength range of 200 nm or more and 300 nm or less.

Note that the above summary of the invention does not list all the features of the invention. Furthermore, subcombinations of these features may also constitute inventions.

FIG. 1 is a diagram showing a water quality analysis device 100 according to an example. FIG. 1 is a diagram showing a water quality analysis device 100 according to an example. This is an example of the results of measuring the fluorescence intensity spectrum of formazin. 2 is a flowchart of an embodiment of a method for calibrating the water quality analyzer 100. It is a flow chart of an example of a measurement method of water quality analyzer 100. FIG. 3 is a diagram showing an example of the relationship between turbidity and fluorescence intensity.

Hereinafter, the present invention will be explained through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Furthermore, not all combinations of features described in the embodiments are essential to the solution of the invention.

FIG. 1 is a diagram showing a water quality analysis device 100 according to an example. In this example, the water quality analyzer 100 includes a flow path 1, a flow cell 2, a turbidity detection optical system 10, a fluorescence detection optical system 20, a turbidity detection signal processing section 13, and a fluorescence detection signal processing section 23. . In FIG. 1, an optical system of a water quality analyzer 100 is shown.

Sample water 3 is flowing inside the flow path 1 (indicated by the dashed line) and the flow cell 2 . The sample water 3 contains the substance to be measured. In this example, the substance to be measured is polycyclic aromatic hydrocarbons (hereinafter referred to as PAH). The flow cell 2 is provided in the turbidity detection optical system 10 and the fluorescence detection optical system 20, respectively. The flow cell 2 of the turbidity detection optical system 10 and the flow cell 2 of the fluorescence detection optical system 20 are arranged in series in the flow path 1. In FIG. 1, sample water 3 is introduced and led out in the direction of the arrow.

The water quality analyzer 100 measures the concentration of the substance to be measured in the sample water 3. The water quality analyzer 100 is a fluorescence detection type water quality analyzer. When the sample water 3 contains a fluorescent substance such as PAH, when the sample water 3 is irradiated with ultraviolet light (excitation light L3), fluorescence L4 having a wavelength unique to the substance is generated. Since the fluorescence intensity is proportional to the concentration of the fluorescent substance contained, the concentration of the fluorescent substance can be measured with high accuracy. In this example, the water quality analyzer 100 measures the concentration of the substance to be measured from the fluorescence intensity from the sample water 3. The fluorescence intensity is measured in the fluorescence detection optical system 20. The fluorescence intensity signal s2 is output from the fluorescence detection signal processing section 23. The fluorescence detection optical system 20 and the fluorescence detection signal processing section 23 are an example of a fluorometer that measures the fluorescence intensity of the sample water 3. In this specification, an "intensity signal" may be simply expressed as "intensity."

When suspended matter is contained in the sample water 3, the excitation light L3 and fluorescence L4 may be attenuated due to light scattering and absorption from the suspended matter (particles). This phenomenon is called the inner filter effect. Due to the inner filter effect, the accuracy of measuring fluorescence intensity may deteriorate in an environment with a high concentration of suspended solids (hereinafter referred to as turbidity). Therefore, in order to improve the measurement accuracy of fluorescence intensity, it is preferable to correct the fluorescence intensity by the turbidity of the sample water 3. In this example, the water quality analyzer 100 measures the turbidity of the sample water 3 along with the fluorescence intensity. The water quality analyzer 100 measures the turbidity of the sample water 3 based on the intensity of scattered light or transmitted light from the sample water 3. The intensity of the scattered light or transmitted light of the sample water 3 is measured by the turbidity detection optical system 10. The intensity signal s1 of the scattered light or transmitted light of the sample water 3 is output from the turbidity detection signal processing section 13.

First, measurement of the turbidity of the sample water 3 will be explained. The turbidity detection optical system 10 has a turbidity detection light emitting section 11 and a turbidity detection light receiving section 12 . The turbidity detection light emitting unit 11 emits infrared light L1. The turbidity detection light emitting unit 11 irradiates the sample water 3 inside the flow cell 2 with infrared light L1. The light emitting unit 11 for turbidity detection is, for example, an LED (Light Emitting Diode) or a laser irradiation device.

By irradiating the sample water 3 inside the flow cell 2 with the infrared light L1, scattered light or transmitted light (referred to as emitted light L2) is generated. The scattered light is generated by light scattering of the sample water 3. The transmitted light is light that is not absorbed by the suspended matter in the sample water 3. The turbidity detection light receiving section 12 receives the emitted light L2. The turbidity detection light receiving section 12 converts the emitted light L2 into an electrical intensity signal. The turbidity detection light receiving section 12 is, for example, a photodiode.

The turbidity detection signal processing section 13 processes the intensity signal from the turbidity detection light receiving section 12. The turbidity detection signal processing section 13 may amplify the intensity signal from the turbidity detection light receiving section 12. The turbidity detection signal processing section 13 may remove noise from the intensity signal from the turbidity detection light receiving section 12. The turbidity detection signal processing section 13 processes the intensity signal from the turbidity detection light receiving section 12 and outputs it as an intensity signal s1 of scattered light or transmitted light. The intensity signal s1 of the scattered light or the transmitted light may be an intensity signal according to at least one of the intensity of the scattered light and the intensity of the transmitted light.

When the turbidity is low, the intensity of scattered light is proportional to the turbidity. On the other hand, when the turbidity is high, the scattered light is attenuated by the inner filter effect, making it difficult to measure the turbidity based on the intensity of the scattered light. The turbidity detection signal processing unit 13 calculates a reference turbidity based on the intensity of the transmitted light, and determines whether to use the intensity of the scattered light or the intensity of the transmitted light in the turbidity measurement based on the reference turbidity. It's fine. The reference turbidity is a turbidity that is temporarily calculated. The reference turbidity may be calculated based on the intensity of scattered light. For example, when the reference turbidity is 0 to 40 FNU (low turbidity), the turbidity is calculated based on the intensity of scattered light. Furthermore, when the reference turbidity is 40 to 400 FNU (when the turbidity is high), the reference turbidity is used as the turbidity. Note that FNU is one of the units of turbidity. FNU is Formazin Nephelometric Unit. In addition, a turbidity calculation unit, which will be described later, calculates a reference turbidity based on the intensity of transmitted light, and based on the reference turbidity, determines whether to use the intensity of scattered light or the intensity of transmitted light in turbidity measurement. good.

Further, the turbidity detection signal processing unit 13 may output the intensity signal s1 of the scattered light or the transmitted light using both the intensity of the scattered light and the intensity of the transmitted light. For example, the intensity signal s1 of scattered light or transmitted light may be a ratio of the intensity of scattered light to the intensity of transmitted light (intensity of scattered light/intensity of transmitted light). By making the intensity signal s1 of the scattered light or transmitted light a ratio of the intensity of the scattered light and the intensity of the transmitted light, it is possible to cancel out the error in the intensity of the scattered light and the error in the intensity of the transmitted light. When the reference turbidity is 0 to 400 FNU, the turbidity detection signal processing unit 13 may output the ratio of the intensity of the scattered light and the intensity of the transmitted light as the intensity signal s1 of the scattered light or the transmitted light. Alternatively, the turbidity detection signal processing section 13 may output the intensity of scattered light and the intensity of transmitted light, and the turbidity calculation section may calculate the ratio of the intensity of scattered light and the intensity of transmitted light.

Next, measurement of the fluorescence intensity of the sample water 3 will be explained. The fluorescence detection optical system 20 has a fluorescence detection light emitting section 21 and a fluorescence detection light receiving section 22. The fluorescence detection light emitting unit 21 emits excitation light L3. The fluorescence detection light emitting unit 21 irradiates the sample water 3 inside the flow cell 2 with excitation light L3. The excitation light L3 is, for example, ultraviolet light. The fluorescence detection light emitting unit 21 may include an ultraviolet light source therein. The ultraviolet light source is, for example, a xenon flash lamp. The ultraviolet light source may be an LED or a laser irradiation device.

The fluorescence detection light emitting section 21 may include an optical filter therein. Since it includes an optical filter, the fluorescence detection light emitting unit 21 can irradiate the flow cell 2 with light in a predetermined wavelength range of the excitation light L3. In this example, the substance to be measured is PAH. PAH emits fluorescence most efficiently when the wavelength of excitation light is around 250 nm. Therefore, the transmission wavelength of the optical filter inside the fluorescence detection light emitting section 21 is set to, for example, 200 nm or more and 300 nm or less.

By irradiating the sample water 3 inside the flow cell 2 with the excitation light L3, fluorescence L4 is generated. The fluorescence detection light receiving section 22 receives the fluorescence L4. The fluorescence detection light receiving section 22 converts the fluorescence L4 into a fluorescence intensity signal. The fluorescence detection light receiving section 22 is, for example, a photodiode.

The fluorescence detection light receiving section 22 may include an optical filter therein. Since it includes an optical filter, the fluorescence detection light receiving section 22 can receive light in a predetermined wavelength range of the fluorescence L4. In this example, the substance to be measured is PAH. For PAH, when the wavelength of excitation light is around 250 nm, the fluorescence wavelength is around 350 nm. Therefore, the transmission wavelength of the optical filter inside the fluorescence detection light receiving section 22 is set to, for example, 300 nm or more and 400 nm or less.

The fluorescence detection signal processing section 23 processes the fluorescence intensity signal from the fluorescence detection light receiving section 22. The fluorescence detection signal processing section 23 may amplify the signal from the fluorescence detection light receiving section 22. The fluorescence detection signal processing section 23 may remove noise from the signal from the fluorescence detection light receiving section 22. The fluorescence detection signal processing section 23 processes the fluorescence intensity signal from the fluorescence detection light receiving section 22 and outputs it as a fluorescence intensity signal s2.

FIG. 2 is a diagram showing the water quality analysis device 100 according to the example. In this example, the water quality analyzer 100 includes the configuration shown in FIG. 1 and the control calculation section 30. The control calculation section 30 includes an infrared light lighting circuit 31, an excitation light lighting circuit 32, a turbidity calculation section 33, a fluorescence intensity correction section 34, and a concentration calculation section 35.

The infrared light lighting circuit 31 is connected to the turbidity detection light emitting section 11 of the turbidity detection optical system 10. The infrared light lighting circuit 31 is a circuit that controls the operation of the turbidity detection light emitting section 11. The excitation light lighting circuit 32 is connected to the fluorescence detection light emitting section 21 of the fluorescence detection optical system 20. The excitation light lighting circuit 32 is a circuit that controls the operation of the fluorescence detection light emitting section 21.

The turbidity calculation unit 33 calculates the turbidity D1 of the sample water 3. The turbidity calculation unit 33 calculates the turbidity D1 of the sample water 3 based on the signal from the turbidity detection signal processing unit 13. That is, the turbidity calculation unit 33 calculates the turbidity D1 of the sample water 3 based on the intensity signal s1 of scattered light or transmitted light. The turbidity calculation unit 33 may calculate the turbidity D1 of the sample water 3 by multiplying the intensity signal s1 of the scattered light or transmitted light by the turbidity calibration coefficient calculated by the turbidity calibration. Further, the turbidity detection optical system 10, the turbidity detection signal processing section 13, and the turbidity calculation section 33 are an example of a turbidity meter that measures the turbidity D1 of the sample water 3. The turbidity calculation unit 33 may output the turbidity D1 to an external device or the like.

The fluorescence intensity correction unit 34 corrects the fluorescence intensity. The fluorescence intensity correction section 34 corrects the fluorescence intensity signal s2 from the fluorescence detection signal processing section 23 based on the turbidity D1 of the sample water 3. For example, since the fluorescence intensity decreases as the turbidity D1 of the sample water 3 increases, the fluorescence intensity signal s2 is multiplied by a correction coefficient that increases as the turbidity D1 of the sample water 3 increases to calculate the fluorescence intensity signal s3 ( (See Figure 6). It is preferable to obtain the correction coefficient in advance.

The concentration calculation unit 35 calculates the concentration C1. The concentration calculation unit 35 calculates the concentration C1 based on the fluorescence intensity signal s3. In this example, the concentration calculation section 35 calculates the concentration C1 based on the fluorescence intensity signal s3 corrected by the fluorescence intensity correction section 34. The concentration calculation unit 35 may calculate the concentration C1 by multiplying the fluorescence intensity signal s3 by the concentration calibration coefficient calculated by concentration calibration. The concentration calculation unit 35 may output the concentration C1 to an external device or the like.

Explain turbidity calibration. In this specification, in order to calculate the turbidity D1 of the sample water 3, the turbidity calculation unit 33 sets a turbidity calibration coefficient b1. The turbidity calibration coefficient b1 converts the intensity signal s1 of scattered light or transmitted light from the sample water 3 into the turbidity D1 of the sample water 3. The following equation 1 holds true for the turbidity calibration coefficient b1. In Equation 1, let the offset be e1. Offset e1 may be a fixed constant. Offset e1 may be 0. The turbidity calibration coefficient b1 may be a constant coefficient. The turbidity calibration coefficient b1 may be a variable. The turbidity calibration coefficient b1 may be a variable that changes depending on the intensity signal s1. When the turbidity calibration coefficient b1 is a variable, it is calibrated using turbidity standard samples having a plurality of different turbidities. Further, the turbidity calculation unit 33 may set a function f such that the turbidity D1 of the sample water 3 = f (intensity signal s1) instead of the turbidity calibration coefficient b1. In this case as well, calibrate using turbidity standard samples with different turbidities.
(Number 1)
D1=b1×s1+e1

A turbidity standard sample is used in turbidity calibration. A turbidity standard sample is a sample that serves as a reference for turbidity measurement. The turbidity of the turbidity standard sample is known. Therefore, in turbidity calibration, the turbidity calibration coefficient b1 can be calculated from Equation 1 by measuring the intensity signal of the turbidity standard sample. Formazin, kaolin, and polystyrene are generally used as turbidity standard samples. Formazin is a mixed aqueous solution prepared by polymerizing hydrazinium sulfate and hexamethylenetetramine. Kaolin is an aqueous solution prepared by refining kaolinite particles. Polystyrene is a polystyrene-based particle suspension.

Concentration calibration will be explained. In this specification, in order to calculate the concentration C1, the concentration calculation section 35 sets a concentration correction coefficient b2. The concentration calibration coefficient b2 converts the fluorescence intensity of the substance to be measured into the concentration C1 of the substance to be measured. The following equation 2 holds true for the concentration calibration coefficient b2. In Equation 2, let the offset be e2. Offset e2 may be a fixed constant. Offset e2 may be 0. The concentration calibration coefficient b2 may be a constant coefficient. The concentration calibration coefficient b2 may be a variable. The concentration calibration coefficient b2 may be a variable that changes depending on the fluorescence intensity signal s3. When the concentration calibration coefficient b2 is a variable, it is calibrated using a fluorescence intensity standard sample concentration having a plurality of different concentrations. Further, the concentration calculation unit 35 may set a function g such that concentration C1=g (fluorescence intensity signal s3) instead of the concentration calibration coefficient b2. In this case as well, calibration is performed using fluorescence intensity standard sample concentrations having a plurality of different concentrations.
(Number 2)
C1=b2×s3+e2

In the calibration of fluorescence intensity (concentration calibration), a fluorescence intensity standard sample is used. The concentration of the fluorescence intensity standard sample is known. Therefore, in calibrating the fluorescence intensity, the concentration calibration coefficient b2 can be calculated from Equation 2 by measuring the fluorescence intensity of the fluorescence intensity standard sample. Note that when the turbidity of the fluorescence intensity standard sample is known, the concentration calibration coefficient b2 may be calculated by correcting the fluorescence intensity using the turbidity of the standard sample. The fluorescence intensity standard sample differs depending on the substance to be measured. In this example, since the substance to be measured is PAH, a fluorescence intensity standard sample containing, for example, phenanthrene or amines is used. Further, the fluorescence intensity standard sample may be PAH.

In the water quality analyzer 100 in which the turbidity calibration coefficient b1 is not set, turbidity calibration is performed before concentration measurement. In the water quality analyzer 100 for which the concentration calibration coefficient b2 has not been set, concentration calibration is performed before concentration measurement. Further, the turbidity calibration coefficient b1 and the concentration calibration coefficient b2 may change due to dirt inside the flow cell 2 through which the sample water 3 flows or due to aging of optical components. It is preferable that the turbidity calibration coefficient b1 and the concentration calibration coefficient b2 be updated regularly in order to correct for the influence of dirt inside the flow cell 2 through which the sample water 3 flows and the aging of optical components.

The water quality analyzer 100 of this example includes both a fluorescence measurement function and a turbidity measurement function. Therefore, turbidity calibration and fluorescence intensity calibration (concentration calibration) are performed respectively. Turbidity standard samples are safe and highly stable substances, and samples with predetermined concentrations are commercially available, making them highly convenient and requiring no specialized knowledge or specialized equipment for use.

On the other hand, the fluorescence intensity standard sample differs depending on the substance to be measured. If the substance to be measured is difficult to handle or hazardous, reagents must be prepared for calibration. Additionally, drug preparation is generally complex and requires specialized knowledge. Additionally, if the substance to be measured is a hazardous substance, specialized equipment is required. Therefore, it is necessary to move the relevant water quality analyzer from the measurement location to a location with specialized equipment, which poses a problem in that calibration work is time-consuming and costly. Therefore, in calibrating the fluorescence intensity, it is preferable that the calibration can be performed easily.

FIG. 3 is an example of the results of measuring the fluorescence intensity spectrum of formazin. The fluorescence intensity spectrum is measured using, for example, a fluorescence spectrophotometer. The fluorescence intensity spectrum may be measured by the fluorescence detection optical system 20. In FIG. 3, the wavelength of the excitation light is 254 nm.

In the fluorescence intensity spectrum of FIG. 3, the fluorescence intensity characteristics have sensitivity in the wavelength range from 350 nm to 370 nm. When the fluorescence intensity characteristic has sensitivity, it means that the fluorescence intensity is higher than in other wavelength ranges. The fluorescence intensity characteristics may have a peak in the wavelength range of 350 nm to 370 nm. The present inventors have found that the fluorescence intensity characteristics of formazin are almost equivalent to PAH, which is the substance to be measured. Therefore, formazin can be used instead of PAH in the calibration of fluorescence intensity. PAH is a volatile substance and is also toxic, making it extremely difficult to handle. On the other hand, since formazin is easy to handle, solutions of predetermined concentrations are commercially available and are readily available. Therefore, the water quality analyzer 100 can be easily calibrated.

FIG. 4 is a flowchart of an embodiment of a method for calibrating the water quality analyzer 100. The calibration method of the water quality analyzer 100 includes a calibration aqueous solution injection step S101, a fluorescence detection step S102, a fluorescence correction step S103, a concentration calibration coefficient calculation step S104, a scattered light transmitted light detection step S105, a turbidity calibration coefficient calculation step S106, and a calibration completion step. The method includes step S107. Each stage will be explained below.

In the calibration aqueous solution injection step S101, a calibration aqueous solution is injected into the flow cell 2. The calibration aqueous solution may be a fluorescence intensity calibration aqueous solution. That is, the calibration aqueous solution may include a fluorescence intensity calibration substance whose wavelength range, in which the fluorescence intensity characteristics are sensitive, overlaps with that of PAH, which is the substance to be measured. Further, the calibration aqueous solution may contain a fluorescence intensity calibration substance whose concentration is known. The fluorescence intensity calibration substance is, for example, the above-mentioned formazin. The aqueous calibration solution may include formazin. By using formazin as a fluorescence intensity calibration substance, measurement reproducibility can be improved. The fluorescence intensity calibration substance is not limited to formazin. The calibration aqueous solution may also contain kaolin. The calibration aqueous solution may include polystyrene.

Moreover, the calibration aqueous solution may be a turbidity calibration aqueous solution. That is, the calibration aqueous solution may contain a turbidity calibration substance whose turbidity is known. The turbidity calibrator is, for example, the above-mentioned formazin. Turbidity calibrators are not limited to formazin.

The aqueous calibration solution may include more than one turbidity calibrator. The calibration aqueous solution includes formazin and kaolin, for example. Even if two or more turbidity calibration substances are included, the calibration work can be easily performed.

In the fluorescence detection step S102, the fluorometer (fluorescence detection optical system 20 and fluorescence detection signal processing unit 23) detects (measures) the fluorescence intensity signal of the calibration aqueous solution. The fluorescence intensity of the calibration aqueous solution is output to the fluorescence intensity correction section 34.

The fluorometer measures the fluorescence intensity of a calibration aqueous solution in a specific wavelength range where the wavelength ranges in which the fluorescence intensity characteristics of the substance to be measured (in this example, PAH) and the fluorescence intensity calibration substance (in this example, formazin) are sensitive overlap. You may obtain it. The specific wavelength range may be 300 nm or more and 400 nm or less. Further, the fluorometer may irradiate the calibration aqueous solution with excitation light in a wavelength range of 200 nm or more and 300 nm or less.

In the fluorescence correction step S103, the fluorescence intensity correction unit 34 corrects the fluorescence intensity of the calibration aqueous solution. When the calibration aqueous solution is a turbidity calibration aqueous solution, the known turbidity of the calibration aqueous solution may be input to the fluorescence intensity correction section 34. The fluorescence intensity correction unit 34 may correct the fluorescence intensity of the calibration aqueous solution based on the known turbidity of the calibration aqueous solution. For example, the fluorescence intensity correction unit 34 calculates a correction coefficient based on the known turbidity, multiplies the fluorescence intensity by the correction coefficient, and corrects the fluorescence intensity. Further, when the turbidity calibration coefficient b1 is set in the turbidity calculation unit 33, the turbidity may be calculated from the intensity of scattered light or transmitted light of the calibration aqueous solution. The turbidity may be calculated from the turbidity calibration coefficient b1 and the intensity of scattered light or transmitted light of the calibration aqueous solution, and the fluorescence intensity of the calibration aqueous solution may be corrected. That is, the fluorescence intensity correction unit 34 may correct the fluorescence intensity by multiplying the fluorescence intensity by a correction coefficient determined by the turbidity calibration coefficient b1 and the turbidity calculated from the intensity of scattered light or transmitted light of the calibration aqueous solution.

In the concentration calibration coefficient calculation step S104, the concentration calculation section 35 calculates the concentration calibration coefficient b2. The concentration calculation unit 35 calculates a concentration calibration coefficient b2 based on the result of measuring the fluorescence intensity of the calibration aqueous solution. As a result of measuring the fluorescence intensity of the calibration aqueous solution, the concentration calibration coefficient b2 can be calculated from the concentration (known) of the calibration aqueous solution and Equation 2. The concentration calculation unit 35 sets the calculated concentration correction coefficient b2. By setting the concentration calibration coefficient b2, the concentration of the substance to be measured can be measured from the fluorescence intensity.

In the scattered light transmitted light detection step S105, the turbidity meter (turbidity detection optical system 10, turbidity detection signal processing unit 13, and turbidity calculation unit 33) detects the intensity of scattered light or transmitted light of the calibration aqueous solution. (Measure. The turbidity detection signal processing unit 13 outputs the intensity of scattered light or transmitted light of the calibration aqueous solution to the turbidity calculation unit 33.

In the turbidity calibration coefficient calculation step S106, the turbidity calculation unit 33 calculates the turbidity calibration coefficient b1. A turbidity calibration coefficient b1 is calculated based on the result of measuring the intensity of scattered light or transmitted light of the calibration aqueous solution. As a result of measuring the intensity of scattered light or transmitted light of the calibration aqueous solution, the turbidity calibration coefficient b1 can be calculated from the turbidity (known) of the calibration aqueous solution and Equation 1. The turbidity calculation unit 33 sets the calculated turbidity calibration coefficient b1. By setting the turbidity calibration coefficient b1, the turbidity of the substance to be measured can be measured from the intensity of scattered light or transmitted light.

In the calibration completion step S107, the turbidity calibration coefficient b1 and the concentration calibration coefficient b2 are set in the turbidity calculation section 33 and the concentration calculation section 35, respectively, thereby completing the calibration. Note that when the calibration is completed, the calibration aqueous solution is removed. In addition, when performing calibration using a different concentration of a turbidity or fluorescence intensity calibration substance, a calibration aqueous solution having a different concentration of a turbidity or fluorescence intensity calibration substance is injected into the flow cell 2, and the calibration operation is repeated in the same manner.

In FIG. 4, a calibration aqueous solution is used as a fluorescence intensity calibration aqueous solution. Further, the calibration aqueous solution is used as a turbidity calibration aqueous solution. That is, a turbidity calibration aqueous solution containing formazin is used as a fluorescence intensity calibration aqueous solution. In other words, the fluorescence intensity calibration aqueous solution and the turbidity calibration aqueous solution are the same. By using the turbidity calibration aqueous solution as the fluorescence intensity calibration aqueous solution, there is no need to separately inject the fluorescence intensity calibration aqueous solution, and the calibration work can be carried out quickly.

Note that the turbidity calibration aqueous solution and the fluorescence intensity calibration aqueous solution may be different. That is, in each of the turbidity calibration and fluorescence intensity calibration, the calibration aqueous solution is replaced. When the turbidity calibration aqueous solution and the fluorescence intensity calibration aqueous solution are different, the turbidity calibration aqueous solution contains kaolin, as an example, and the fluorescence intensity calibration aqueous solution contains formazin, as an example. Even when the turbidity calibration aqueous solution and the fluorescence intensity calibration aqueous solution are different, the calibration work can be easily carried out.

FIG. 5 is a flowchart of an embodiment of the measurement method of the water quality analyzer 100. The measurement method of the water quality analyzer 100 includes a sample water injection step S201, a fluorescence detection step S202, a scattered light transmitted light detection step S203, a turbidity calculation step S204, a fluorescence correction step S205, a concentration calculation step S206, and a measurement completion step S207. . Each stage will be explained below using the reference numerals in FIG.

In sample water injection step S201, sample water 3 is injected into flow cell 2. In this example, the sample water 3 contains PAH, which is a substance to be measured.

In the fluorescence detection step S202, the fluorometer (fluorescence detection optical system 20 and fluorescence detection signal processing unit 23) detects (measures) the fluorescence intensity of the sample water 3. The fluorescence intensity signal s2 of the sample water 3 is output to the fluorescence intensity correction section 34.

The fluorometer measures the fluorescence intensity of sample water 3 in a specific wavelength range in which the wavelength ranges in which the fluorescence intensity characteristics of the measurement target substance (in this example, PAH) and the fluorescence intensity calibration substance (in this example, formazin) overlap overlap. may be obtained. The specific wavelength range may be 300 nm or more and 400 nm or less. The fluorometer may irradiate the sample water 3 with excitation light in a wavelength range of 200 nm or more and 300 nm or less.

In the scattered light transmitted light detection step S203, the turbidity meter (turbidity detection optical system 10, turbidity detection signal processing section 13, and turbidity calculation section 33) detects the intensity signal of the scattered light or transmitted light of the sample water 3. Detect (measure) s1. The turbidity detection signal processing unit 13 outputs an intensity signal s1 of scattered light or transmitted light of the sample water 3 to the turbidity calculation unit 33.

In the turbidity calculation step S204, the turbidity meter measures the turbidity D1 of the sample water 3. The turbidity calculation unit 33 calculates the turbidity D1 of the sample water 3 based on the signal from the turbidity detection signal processing unit 13. The turbidity calculation unit 33 calculates the turbidity D1 of the sample water 3 based on the intensity signal s1 of the scattered light or transmitted light of the sample water 3. The turbidity calculation unit 33 may calculate the turbidity D1 of the sample water 3 by multiplying the intensity signal s1 of the scattered light or transmitted light of the sample water 3 by the turbidity calibration coefficient b1 calculated by turbidity calibration. . The turbidity D1 of the sample water 3 is output to the fluorescence intensity correction section 34.

In the fluorescence correction step S205, the fluorescence intensity correction unit 34 corrects the fluorescence intensity. The fluorescence intensity correction section 34 corrects the fluorescence intensity signal s2 from the fluorescence detection signal processing section 23 based on the turbidity D1 of the sample water 3. For example, since the fluorescence intensity decreases as the turbidity D1 of the sample water 3 increases, the fluorescence intensity signal s2 is multiplied by a correction coefficient that increases as the turbidity D1 of the sample water 3 increases to calculate the fluorescence intensity signal s3 ( (See Figure 6).

In the concentration calculation step S206, the concentration calculation section 35 calculates the concentration C1 based on the signal from the fluorescence intensity correction section 34. The concentration calculation unit 35 calculates the concentration C1 based on the fluorescence intensity signal s3. The concentration calculation unit 35 may calculate the concentration C1 by multiplying the fluorescence intensity signal s3 by a concentration correction coefficient b2 calculated by fluorescence intensity calibration.

At the measurement completion step S207, the concentration C1 is output to another device and recorded. Further, the turbidity D1 of the sample water 3 may be output to another device and recorded. Note that when the measurement is completed, the sample water 3 is removed.

FIG. 6 is a diagram showing an example of the relationship between turbidity and fluorescence intensity. In FIG. 6, solid lines indicate ideal values, and dotted lines indicate measured values.

As shown in FIG. 6, due to the inner filter effect, as the turbidity increases, the difference between the ideal value and the measured value of fluorescence intensity increases. Therefore, it is preferable that the fluorescence intensity correction unit 34 corrects the fluorescence intensity so as to bring it closer to the ideal value. In the example of FIG. 6, the fluorescence intensity correction unit 34 multiplies the fluorescence intensity by a correction coefficient that increases as the turbidity increases, thereby correcting the fluorescence intensity. The correction coefficient is expressed as, for example, ideal value of fluorescence intensity/measured value of fluorescence intensity.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the range described in the above embodiments. It will be apparent to those skilled in the art that various changes or improvements can be made to the embodiments described above. It is clear from the claims that such modifications or improvements may be included within the technical scope of the present invention.

The execution order of each process such as operation, procedure, step, and stage in the apparatus, system, program, and method shown in the claims, specification, and drawings specifically refers to "before" and "prior to". It should be noted that they can be implemented in any order unless explicitly stated as such, and unless the output of a previous process is used in a subsequent process. With regard to the claims, specification, and operational flows in the drawings, even if the terms "first,""next," etc. are used for convenience, this does not mean that the operations must be carried out in this order. isn't it.
[Item 1]
A water quality analyzer that measures the concentration of a substance to be measured in sample water,
a turbidity meter that measures the intensity of scattered light or transmitted light from the sample water to measure the turbidity of the sample water;
a fluorometer that measures the fluorescence intensity of the substance to be measured;
a fluorescence intensity correction unit that corrects the fluorescence intensity of the substance to be measured based on the turbidity of the sample water;
Based on the results of measuring the fluorescence intensity of a fluorescence intensity calibration aqueous solution containing a fluorescence intensity calibration substance whose wavelength range to which the fluorescence intensity characteristics are sensitive overlaps with that of the measurement target substance and whose concentration is known, the measurement target substance is determined. a concentration calculation unit that sets a concentration calibration coefficient for converting the fluorescence intensity of the sample into the concentration of the substance to be measured;
A water quality analyzer equipped with
[Item 2]
The water quality analyzer according to item 1, wherein the fluorescence intensity calibration aqueous solution contains formazin.
[Item 3]
The turbidimeter measures the intensity of scattered light or transmitted light from the sample water based on the results of measuring the intensity of scattered light or transmitted light of a turbidity calibration aqueous solution containing a turbidity calibration substance with known turbidity. The water quality analysis device according to item 1 or 2, further comprising a turbidity calculation unit that sets a turbidity calibration coefficient that is converted into turbidity of the sample water.
[Item 4]
The water quality analyzer according to item 3, wherein the turbidity calibration aqueous solution is used as the fluorescence intensity calibration aqueous solution.
[Item 5]
The water quality analysis device according to item 3 or 4, wherein the turbidity calibration aqueous solution contains two or more of the turbidity calibration substances.
[Item 6]
The water quality analyzer according to any one of items 1 to 5, wherein the substance to be measured is PAH.
[Item 7]
Items 1 to 6, wherein the fluorometer obtains the fluorescence intensity of the fluorescence intensity calibration aqueous solution in a specific wavelength range in which wavelength ranges in which the fluorescence intensity characteristics of the measurement target substance and the fluorescence intensity calibration substance are sensitive overlap. The water quality analyzer according to any one of the items.
[Item 8]
The water quality analyzer according to item 7, wherein the specific wavelength range is 300 nm or more and 400 nm or less.
[Item 9]
9. The water quality analyzer according to any one of items 1 to 8, wherein the fluorometer irradiates the sample water or the fluorescence intensity calibration aqueous solution with excitation light in a wavelength range of 200 nm or more and 300 nm or less.

1. Channel, 2. Flow cell, 3. Sample water, 10. Optical system for turbidity detection, 11. Light emitting section for turbidity detection, 12. Light receiving section for turbidity detection, 13.. Signal processing unit for turbidity detection, 20. Optical system for fluorescence detection, 21. Light emitting unit for fluorescence detection, 22. Light receiving unit for fluorescence detection, 23. Signal processing unit for fluorescence detection, 30. Control calculation. Parts, 31...Infrared light lighting circuit, 32...Excitation light lighting circuit, 33...Turbidity calculation unit, 34...Fluorescence intensity correction unit, 35...Concentration calculation unit, 100...Water quality analysis device

Claims (8)

A water quality analyzer that measures the concentration of a substance to be measured in sample water,
a turbidity meter that measures the intensity of scattered light or transmitted light from the sample water to measure the turbidity of the sample water;
a fluorometer that measures the fluorescence intensity of the substance to be measured;
a fluorescence intensity correction unit that corrects the fluorescence intensity of the substance to be measured based on the turbidity of the sample water;
Based on the results of measuring the fluorescence intensity of a fluorescence intensity calibration aqueous solution containing a fluorescence intensity calibration substance whose wavelength range to which the fluorescence intensity characteristics are sensitive overlaps with that of the measurement target substance and whose concentration is known, the measurement target substance is determined. a concentration calculation unit that sets a concentration calibration coefficient for converting the fluorescence intensity of the substance into the concentration of the substance to be measured ;
The measurement target substance and the fluorescence intensity calibration substance are different substances,
Water quality analyzer. The water quality analyzer according to claim 1, wherein the toxicity of the fluorescence intensity calibration substance is lower than the toxicity of the substance to be measured. The substance to be measured is PAH,
The fluorescence intensity calibration substance is at least one of formazin, kaolin, and polystyrene.
The water quality analysis device according to claim 1 or 2. The turbidimeter measures the intensity of scattered light or transmitted light from the sample water based on the results of measuring the intensity of scattered light or transmitted light of a turbidity calibration aqueous solution containing a turbidity calibration substance with known turbidity. The water quality analyzer according to any one of claims 1 to 3, further comprising a turbidity calculation unit that sets a turbidity calibration coefficient to be converted into the turbidity of the sample water. The water quality analysis device according to claim 4 , wherein the turbidity calibration aqueous solution includes two or more of the turbidity calibration substances. The fluorometer obtains the fluorescence intensity of the fluorescence intensity calibration aqueous solution in a specific wavelength range in which wavelength ranges in which the fluorescence intensity characteristics of the measurement target substance and the fluorescence intensity calibration substance are sensitive overlap . The water quality analyzer according to any one of the items. The water quality analysis device according to claim 6 , wherein the specific wavelength range is 300 nm or more and 400 nm or less. The water quality analysis device according to any one of claims 1 to 7 , wherein the fluorometer irradiates the sample water or the fluorescence intensity calibration aqueous solution with excitation light in a wavelength range of 200 nm or more and 300 nm or less.

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