KR102553384B1 - Method and apparatus for automatic measurement of total nitrogen, total phosphorus and phosphoric acid in water using multiple differential gain selection opitcal signal control processing algorithm technique - Google Patents

Abstract

The present invention relates to a method and an apparatus for automatically measuring total nitrogen, total phosphorus, and phosphoric acid using a photometric method, and more specifically, to a method and an apparatus for automatically measuring total nitrogen, total phosphorus, and phosphoric acid using a multiple differential gain selection optical signal amplification circuit, wherein light with the wavelength of 220 nm is extracted and radiated using a 220 nm band pass filter in the ultraviolet range emitted from a deuterium lamp in the case of the measurement of total nitrogen, light with the wavelength of 880 nm is radiated using a 880 nm LED in the case of the measurement of total phosphorus, light with the wavelength of 410 nm is radiated using a 410 nm LED in the case of the measurement of phosphoric acid, and a multiple differential gain selection optical signal control processing algorithm technique, to which a multiple differential gain selection optical signal amplification circuit and a control algorithm are applied, is introduced. Provided are a measurement method and apparatus capable of accurately measuring a sample and dilution water including a high-efficiency oxidizing reactor, and capable of securing measurement reproducibility by converting an optical signal into an electric signal using an efficient algorithm.

Description

METHOD AND APPARATUS FOR AUTOMATIC MEASUREMENT OF TOTAL NITROGEN, TOTAL PHOSPHORUS AND PHOSPHORIC ACID IN WATER USING MULTIPLE DIFFERENTIAL GAIN SELECTION OPITCAL SIGNAL CONTROL PROCESSING ALGORITHM TECHNIQUE}

The present invention is a method and apparatus for measuring nutrients such as total nitrogen, total phosphorus, phosphoric acid, etc. contained in water by a photometric method, which improves the reproducibility of measurement by processing an optical signal with a multi-differential gain selection optical signal control processing algorithm technique It relates to a method and apparatus for automatically measuring total nitrogen, total phosphorus and phosphoric acid in water.

When water in rivers and lakes contains excessive nutrients such as nitrogen and phosphorus, it causes eutrophication, and as a result, phenomena such as green and red tides occur, greatly affecting the quality of life of the people. Therefore, water quality items such as total nitrogen, total phosphorus, and phosphoric acid, which represent nutrients, are frequently measured and managed. In particular, in the case of Korea, the automatic measuring devices are applied to a water quality target management system (TMS) and river TMS, and water quality measurement data such as wastewater treatment plants and rivers are well managed.

For this reason, various types of automatic total nitrogen measuring instruments, automatic total phosphorus measuring instruments, automatic phosphoric acid measuring instruments, etc. have been developed and sold. The measurement principle of total nitrogen, total phosphorus and phosphoric acid is basically water pollution process test standard ES 04908. 1c (total nitrogen-continuous automatic measurement method), water pollution process test standard ES 04907. 1e (total phosphorus-continuous automatic measurement method), water quality Contamination Process Test Standard ES 04360.1d (phosphate-ultraviolet/visible ray spectroscopy-tin dichloride reduction method), Water Pollution Process Test Standard ES 04360.2c (phosphate-ultraviolet/visible ray spectrometry-ascorbic acid reduction method) there is. For total nitrogen, there are an ultraviolet absorbance measurement method and a cadmium-copper reduction method in the water pollution process test standard, but the ultraviolet absorbance measurement method is mainly used. In this method, nitrogen compounds contained in water samples are decomposed together with organic matter at 120 degrees Celsius in the presence of alkaline potassium persulfate, oxidized to nitrate ions, and then irradiated with 220 nm wavelength light in acidic conditions to measure absorbance. .

The total phosphorus measurement method of the water pollution process test standard decomposes all phosphorus compounds in the form of organic matter in water into phosphate ions, and then quantifies the phosphate ions by the ascorbic acid reduction method. quantify the phosphorus concentration. As a method of decomposition into phosphate ions, it is common to decompose at 120 degrees Celsius in the presence of potassium persulfate, as in the case of total nitrogen measurement.

In the case of phosphoric acid, phosphate ion is quantified by ascorbic acid reduction method or tin dichloride reduction method without decomposition process. Tin dichloride reduction method is quantified by measuring absorbance by irradiating light with a wavelength in the range of 400 to 450 nm.

An automatic nutrient salt measuring device using such a photometric method consists of a metering unit that measures the amount of sample, a reagent injection unit that measures and injects reagents, a heating reactor that performs a heating reaction, and an optical unit that irradiates light and measures transmittance. It can be said that this automatic measurement technology is a configuration made decades ago.

Japanese Unexamined Patent Publication No. 2-21261 discloses that a water quality sample is oxidized at 120 degrees Celsius for 30 minutes, and then the absorbance is measured to measure the nitrate nitrogen concentration. As described above, a sample weighing device, a heating reactor, a reagent injection device, an optical system, etc. , and a measurement method and principle similar to the above measurement method are described in Japanese Laid-Open Patent Publication No. 64-461, and the basic principle or configuration of the measurement device for measuring total nitrogen, total phosphorus, phosphoric acid, etc. from such a prior art It can be seen that is a common technique known for a long time.

For this reason, efforts have been made recently to increase the oxidizing power, increase the precision of metering, make the device compact, or stably process the optical signal. It is an attempt to make the device compact for a total phosphorus and total nitrogen measuring system equipped with a system. Korean Patent Registration 10-1761216 was intended to reduce metering injection errors using a syringe pump, but total nitrogen, total phosphorus and phosphoric acid are automatically Not only is the measuring device still not compact enough, but the error of quantitative injection of the sample is still large, the measurement error is large because the oxidizing agent is in contact with the sample after the oxidation reaction, the efficiency of the oxidation reactor is low, and the efficiency of the photometric analysis is large. There was a problem in that the measurement reproducibility was low because proper processing of the basic optical signal was not performed.

Patent Document 1: Korean Registered Patent No. 10-1194333 Patent Document 2: Korean Registered Patent No. 10-1761216 Patent Document 3: Korean Registered Patent No. 10-2092003 Patent Document 4: Korean Registered Patent No. 10-2216557

The present invention is to solve the problems of the prior art automatic measuring device for total nitrogen, total phosphorus, and phosphoric acid using a photometric method consisting of an oxidizing unit, a reagent injecting unit, a metering unit, an optical unit, etc., and is sufficiently compact, It solves the problem of low measurement reproducibility due to the small amount of sample injection error, low measurement error because the oxidizing agent does not come into contact with the oxidized sample, high efficiency of the oxidation reactor, and poor optical signal processing. It is to do.

That is, first, it is to provide a measuring method and a measuring device configured so that the oxidizing agent does not come into contact with the sample after the oxidation reaction while accurately weighing the sample and the dilution water.

Second, it is to provide a measuring method and a measuring device including a high-efficiency oxidation reactor capable of raising the temperature as quickly as possible and cooling it quickly without leaving a sample remaining in the reactor while having high chemical resistance, heat resistance, and thermal shock resistance.

Third, it is to provide a measuring method and a measuring device capable of securing measurement reproducibility by converting an optical signal into an electrical signal by applying an efficient algorithm when measuring transmittance by irradiating a sample with light of a specific wavelength.

In order to achieve the above object, the present inventors conducted research by applying various methods and found several improvements to increase the reproducibility and linearity of measurement.

First, it was found that the measurement of sample and dilution water should be reproducible. In addition, it was found that reproducibility of measurement is lowered if the oxidizing agent added when oxidizing the sample is not completely decomposed during the oxidation reaction or if even a small amount of oxidizing agent is injected into the sample after the reaction. Therefore, it is necessary to configure a measuring method and a measuring device so that the oxidizing agent does not come into contact with the sample after the oxidation reaction while measuring the sample and dilution water accurately.

Second, it was confirmed that the efficiency of the oxidation reactor is very important when an oxidation reaction is required, such as total nitrogen and total phosphorus analysis. Therefore, the oxidation reactor must have high chemical resistance, heat resistance, and thermal shock resistance, and must be able to raise the temperature as quickly as possible and cool quickly, while leaving no sample residue in the reactor.

Thirdly, it was revealed that proper processing of optical signals, which is the basis of photometry analysis, is very important. When light of a specific wavelength is irradiated to a sample to measure transmittance, measurement reproducibility can be secured only when the optical signal is converted into an electrical signal by applying an efficient algorithm.

The present inventors arrived at the present invention by discovering the above improvements for improving the reproducibility and linearity of measurement, and the method for automatically measuring total nitrogen, total phosphorus, and phosphoric acid according to the present invention consists of the following steps.

1) Injecting the measurement sample into the reagent reaction/optical chamber;

2) first dilution by injecting dilution water into the reagent reaction/optical chamber;

3) weighing the first diluted sample and injecting it into the reagent reaction/optical chamber;

4) secondary dilution by injecting dilution water into the reagent reaction/optical chamber;

5) injecting and mixing the oxidizing agent into the reagent reaction/optical chamber;

6) transferring the sample injected with the oxidizing agent to an oxidation reactor;

7) heating the oxidation reactor to oxidize the sample;

8) transferring the oxidized sample to the reagent reaction/optical chamber;

9) injecting the color former into the reagent reaction/optical chamber;

10) irradiating light to the reagent reaction/optical chamber to measure transmittance;

11) cleaning the reagent reaction/optical chamber and oxidation reactor; and

12) Calculating absorbance using the measured transmittance and converting it into concentration; It is an automatic measurement method for total nitrogen, total phosphorus, and phosphoric acid using a multiple differential gain selection optical signal amplification circuit comprising:

And the method for measuring phosphoric acid not accompanied by an oxidation reaction is,

1) Injecting the measurement sample into the reagent reaction/optical chamber;

2) injecting dilution water into the reagent reaction/optical chamber;

3) weighing the first diluted sample and injecting it into the reagent reaction/optical chamber;

4) secondary dilution by injecting dilution water into the reagent reaction/optical chamber;

5) injecting the color former into the reagent reaction/optical chamber;

6) measuring the transmittance by irradiating light to the reagent reaction/optical chamber;

7) cleaning the reagent reaction/optical chamber and oxidation reactor; and

8) Calculating absorbance using the measured transmittance and converting it into concentration; It is an automatic measurement method for total nitrogen, total phosphorus, and phosphoric acid using a multiple differential gain selection optical signal amplification circuit comprising the steps of:

Here, '1) injecting the measurement sample into the reagent reaction/optical chamber; 9), and after sufficiently transporting and discharging the initial intake sample containing excessive floating matter to the water collection tank 9, the sample to be measured is collected in the sample tank 30 and the two three-way electric valves (3, 8) ), the two 3-way valves (3, 8) switch the valve opening direction, and the air pump (4) is operated to transfer the measurement sample filled in the pipe to the reagent reaction/optical chamber. It is characterized by transport.

In addition, '2) first dilution by injecting dilution water into the reagent reaction/optical chamber;' measures the residual in the pipe between the ultrapure water bottle 29 and the transfer pump 1 by operating the transfer pump 1 The sample is transferred to the collecting tank (9), and the measurement sample remaining in the pipe between the two three-way electric valves (3, 8) and the metering coil (7) is transferred to the collecting tank (9) and discharged, and then the ultrapure water bottle ( 29), fill the pipe between the two 3-way electric valves (3, 8) and the measurement coil (7) with ultrapure water, change the valve opening direction of the two 3-way valves (3, 8) and air It is characterized in that the ultrapure water filled in the pipe is transferred to the reagent reaction/optical chamber by operating the pump 4.

And, '5) injecting and mixing the oxidizing agent into the reagent reaction/optical chamber;' is characterized in that the oxidizing agent is transferred to the reagent reaction/optical chamber 18 by operating the oxidizing agent injection pump 11.

In addition, '6) transferring the sample injected with the oxidizing agent to the oxidation reactor;' is characterized in that the transfer pump 19 is operated to transfer the sample injected with the oxidizing agent to the oxidation reactor 26.

And, '7) oxidizing the sample by heating the oxidation reactor;' is characterized by heating to 110 to 130 ° C.

In addition, '8) transferring the oxidized sample to the reagent reaction/optical chamber;' is characterized in that the transfer pump 19 is reversely operated to transfer the sample to the reagent reaction/optical chamber 18. .

And, '9) injecting the color reagent into the reagent reaction/optical chamber;' is characterized in that the color reagent injection pump 15 is operated to inject the color reagent.

In addition, '10) measuring the transmittance by irradiating light to the reagent reaction/optical chamber;' extracts light with a wavelength of 220 nm using a 220 nm band pass filter in the ultraviolet region emitted from the deuterium lamp in the case of total nitrogen measurement. In the case of phosphorus measurement, 880nm wavelength light is irradiated using only 880nm LED for total phosphorus measurement, and 410nm wavelength light is irradiated using 410nm LED for phosphorus measurement, multiple differential gain selection optical signal amplification circuit and control algorithm The applied multiple differential gain selection optical signal control processing algorithm technique is introduced, where the 'multiple differential gain selection optical signal control processing algorithm technique' is a current-to-voltage conversion inverting amplifier in which the output of the photodetector for the incident light intensity is converted into a current signal. Circuit, rail-to-rail type dual operational amplifier to distinguish the difference between maximum current output and dark current, 3 types of differential gain control feedback resistors connected to the operational amplifier to convert the light-receiving current of the photodetector into voltage, optical In order to prevent the oscillation phenomenon caused by the difference in capacitance between the terminals of the detector, a capacitor element for oscillation compensation connected in parallel with three types of feedback resistors for differential gain control, and for preventing and removing noise signals from external light sources A Sallen-Key Active Filter circuit that removes frequencies in a specific band including an R-C filter, a control device including an input/output interface centered on a microprocessor, an operational amplifier, and an I2C type ADC to control multiple differential gain selection optical signal amplification circuits, It includes a control program based on an optical signal control algorithm built into the control device to automatically select three types of feedback resistors for differential gain amplification according to the change in optical signal strength, where 'optical signal built into the control device Sigma-Delta oversampling technique, which increases the resolution of the ADC by sampling 2 to 4 times more than the number of sampling required when converting the input optical signal to digital to compensate for the measurement error. The Kalman filter technique, which reduces errors stochastically by outputting a value when the difference is minimized while feeding back the difference between the input value of the photodetector containing noise and the value expected by the prediction model, included in the converted voltage signal It is characterized in that it further includes a Savitzky-Golay filter technique for smoothing the voltage signal with a weighted polynomial to remove some peak noise components in the present invention.

On the other hand, the apparatus for automatically measuring total nitrogen, total phosphorus, and phosphoric acid using the photometric method according to the present invention consists of the following configuration.

In other words, total nitrogen, total phosphorus, and phosphoric acid automatic measuring devices are broadly classified,

A storage unit filled with measurement samples, reagents, and dilution water (ultrapure water);

A transfer unit for transferring measurement samples, reagents, and dilution water;

A metering unit for measuring the amount of sample, reagent and dilution water;

A reagent reaction unit for reacting a sample with a reagent; Optical unit for optical measurement; and a control unit.

Specifically, the storage unit is a device filled with measurement samples, standard solutions, reagents, ultrapure water as dilution water, washing liquid, waste liquid, etc. ), waste tank (25), ultrapure water bottle (27), washing solution bottle (28), standard solution bottle (29), sample tank (30), color reagent tank 1, 2 (39, 40), ultrapure water bottle (50) , It includes a sample tank 51 and the like.

In addition, the transfer unit is a device for transferring samples, reagents, and dilution water, and transfer pumps (1, 19, 44), air pump (4), 2-way electric valves (20, 21, 22, 23, 24), 3-way It includes solenoid valves (32, 33, 35, 49), pipes, and the like.

In addition, the metering unit includes a buffer coil 5, a metering coil 7, and the like as a device for measuring the amount of reagent and dilution water.

The reagent reaction unit is a device for reacting the sample with the reagent, and includes a reagent reaction/optical chamber 18, an oxidant injection pump 11, an oxidation reactor 26, and the like.

In addition, the optical part is a device for measuring light, and includes a lamp 16, a light detection sensor 17, a light detector, a dual operational amplifier, a feedback resistor for controlling multiple differential gains, an R-C filter, and a Sallen-Key Active Filter circuit. .

In addition, the control unit includes a microprocessor, control program, input/output interface, operational amplifier, ADC Sigma-Delta Over sampling, Kalman Filter, Savitzky-Golay filter, etc. will be.

On the other hand, the oxidation reactor 26 of the reagent reaction unit includes a reaction tube 56 made of quartz, a metal hot wire 58 wound in direct contact with the reaction tube made of quartz, and a temperature sensor mounting groove formed on the outer wall of the reaction tube 56. (60), including a temperature sensor inserted into the temperature sensor mounting groove (60). Here, the metal heating wire 58 includes an upper heating wire hook 57, a lower heating wire hook 59, a lower heating wire lead groove 61, a lower heating wire ring 67, an upper heating wire lead groove 69, and an upper heating wire hook 70 ), which is mounted so as to come into close contact with the surface of the quartz reaction tube 56, is placed on the reaction tube cover 66 between the upper adapter 53 and the lower adapter 62, and the lower adapter 62 ) and the reactor cover 66 to tighten the lower adapter 62 so that the shape of the oxidation reactor 26 is maintained, and the sample is introduced into the reaction tube 56 using the tube fitting 64 The cooling fan 68 is mounted on the reaction tube cover 66 of the oxidation reactor.

The automatic measurement method and device according to the present invention exhibits the effect of measuring total nitrogen, total phosphorus, and phosphoric acid in water more precisely, and when used for analysis of rivers, sewage treatment plant effluent, wastewater treatment plant effluent, and factory process water It shows the effect of efficient process water and effluent management by accurately and stably measuring the quality of process water and effluent water, and also shows the effect that efficient optical signal processing technology can be used in other optical measurement fields. Invar, the specific effects of the present invention are as follows.

First, it shows the effect of providing a measuring method and apparatus configured so that the oxidizing agent does not come into contact with the sample after the oxidation reaction while the measurement of the sample and the dilution water is accurate.

Second, it shows the effect of providing a measurement method and apparatus including a high-efficiency oxidation reactor that has high chemical resistance, heat resistance, and thermal shock resistance, does not leave a sample residue in the reactor, and can increase the temperature as quickly as possible and cool it quickly.

Third, when light of a specific wavelength is irradiated to a sample to measure transmittance, an optical signal is converted into an electrical signal by applying an efficient algorithm, thereby showing the effect of providing a measurement method and apparatus capable of securing measurement reproducibility.

1 is a schematic diagram of a measuring device for explaining the total nitrogen and total phosphorus measuring method of the present invention.
Figure 2 is a schematic diagram of a measuring device for explaining the phosphoric acid measuring method of the present invention.
3 is a structural diagram for explaining the oxidation reactor of the present invention.
4 is a schematic diagram of an algorithm of a single-gain optical signal amplifying circuit.
5 is a schematic diagram of an algorithm of a multiple differential gain selection optical signal amplification circuit.
6 is a schematic diagram of a multiple differential gain selection optical signal control processing algorithm technique.
7 is a graph showing linearity using the measured values of Example 1.
8 is a graph showing linearity using the measured values of Example 2.
9 is a graph showing linearity using the measured values of Example 3.
10 is a graph showing the linearity of the photocurrent-voltage conversion relationship in Example 4.
11 is a graph showing optical signal values before and after noise removal in Example 5;
12a, 12b, and 12c are graphs showing the linearity of measured values of Comparative Example 1.

A method and apparatus for automatically measuring total nitrogen, total phosphorus, and phosphoric acid will be described in detail with reference to the drawings.

The drawings introduced below are provided as examples to sufficiently convey the spirit of the present invention to those skilled in the art. Therefore, the present invention may be embodied in other forms without being limited to the drawings presented below, and the drawings presented below may be exaggerated to clarify the spirit of the present invention. At this time, if there is no other definition in the technical terms and scientific terms used, they have meanings commonly understood by those of ordinary skill in the art to which this invention belongs, and the gist of the present invention is unnecessary in the following description and accompanying drawings. Descriptions of well-known functions and configurations that may be obscure are omitted.

First, a method for automatically measuring total nitrogen, total phosphorus, and phosphoric acid using a photometric method according to an embodiment of the present invention will be described.

That is, the method for automatically measuring total nitrogen, total phosphorus, and phosphoric acid using the photometric method,

1) Injecting the measurement sample into the reagent reaction/optical chamber;

2) injecting dilution water into the reagent reaction/optical chamber;

3) weighing the first diluted sample and injecting it into the reagent reaction/optical chamber;

4) secondary dilution by injecting dilution water into the reagent reaction/optical chamber;

5) injecting and mixing the oxidizing agent into the reagent reaction/optical chamber;

6) transferring the sample injected with the oxidizing agent to an oxidation reactor;

7) heating the oxidation reactor to oxidize the sample;

8) transferring the oxidized sample to the reagent reaction/optical chamber;

9) injecting the color former into the reagent reaction/optical chamber;

10) measuring transmittance by irradiating light into the reagent reaction/optical chamber;

11) cleaning the reagent reaction/optical chamber and oxidation reactor; and

12) Calculating the absorbance using the measured transmittance and converting it into a concentration. The above method is used when measuring total nitrogen and total phosphorus, which are essentially required for oxidation.

And, how to measure phosphoric acid that does not require an oxidation reaction

1) Injecting the measurement sample into the reagent reaction/optical chamber;

2) injecting dilution water into the reagent reaction/optical chamber;

3) weighing the first diluted sample and injecting it into the reagent reaction/optical chamber;

4) secondary dilution by injecting dilution water into the reagent reaction/optical chamber;

5) injecting the color former into the reagent reaction/optical chamber;

6) measuring transmittance by irradiating light into the reagent reaction/optical chamber;

7) cleaning the reagent reaction/optical chamber and oxidation reactor; and

8) Calculating the absorbance using the measured transmittance and converting it into a concentration; It is an automatic phosphoric acid measurement method using a multiple differential gain selection optical signal amplification circuit. This method is used to measure phosphoric acid that does not require oxidation.

Next, an apparatus for automatically measuring total nitrogen, total phosphorus, and phosphoric acid using a photometric method according to an embodiment of the present invention will be described with reference to the drawings.

That is, the total nitrogen, total phosphorus, and phosphoric acid automatic measuring device largely includes a storage unit filled with measurement samples, reagents, and dilution water (ultrapure water); A transfer unit for transferring measurement samples, reagents, and dilution water; A metering unit for measuring the amount of sample, reagent and dilution water; A reagent reaction unit for reacting a sample with a reagent; Optical unit for optical measurement; and a control unit.

Here, the storage unit is a device filled with measurement samples, standard solutions, reagents, ultrapure water as dilution water, washing liquid, waste liquid, etc. Waste tank (25), ultrapure water bottle (27), washing solution bottle (28), standard solution bottle (29), sample tank (30), color reagent tank 1, 2 (39, 40), ultrapure water bottle (50), sample It includes a water tank 51 and the like.

In addition, the transfer unit is a device for transferring samples, reagents, and dilution water, and transfer pumps (1, 19, 44), air pump (4), 2-way electric valves (20, 21, 22, 23, 24), 3-way It includes solenoid valves (32, 33, 35, 49), pipes, and the like.

In addition, the metering unit includes a buffer coil 5, a metering coil 7, and the like as a device for measuring the amount of reagent and dilution water.

The reagent reaction unit is a device for reacting the sample with the reagent, and includes a reagent reaction/optical chamber 18, an oxidant injection pump 11, an oxidation reactor 26, and the like.

In addition, the optical part is a device for measuring light, and includes a lamp 16, a light detection sensor 17, a light detector, a dual operational amplifier, a feedback resistor for controlling multiple differential gains, an R-C filter, and a Sallen-Key Active Filter circuit. .

In addition, the control unit includes a microprocessor, control program, input/output interface, operational amplifier, ADC Sigma-Delta Over sampling, Kalman Filter, Savitzky-Golay filter, etc. will be.

On the other hand, the oxidation reactor 26 of the reagent reaction unit includes a reaction tube 56 made of quartz, a metal hot wire 58 wound in direct contact with the reaction tube made of quartz, and a temperature sensor mounting groove formed on the outer wall of the reaction tube 56. (60), including a temperature sensor inserted into the temperature sensor mounting groove (60).

Here, the metal heating wire 58 includes an upper heating wire hook 57, a lower heating wire hook 59, a lower heating wire lead groove 61, a lower heating wire ring 67, an upper heating wire lead groove 69, and an upper heating wire hook 70 ), which is mounted so as to come into close contact with the surface of the quartz reaction tube 56, is placed on the reaction tube cover 66 between the upper adapter 53 and the lower adapter 62, and the lower adapter 62 ) and the reactor cover 66 to tighten the lower adapter 62 so that the shape of the oxidation reactor 26 is maintained, and the sample is introduced into the reaction tube 56 using the tube fitting 64 In addition, a cooling fan 68 is mounted on the reaction tube cover 66 of the oxidation reactor.

Hereinafter, a method for measuring total nitrogen and total phosphorus using a total nitrogen, total phosphorus, and phosphorus measuring device will be described in more detail with reference to FIG. 1 .

The transfer pump 1 is operated to collect samples. When collecting a sample in the sample tank 30, the pipe between the sample tank 30 and the transfer pump 1 is filled with the previous sample, and excessive suspended matter may be sucked in at the beginning of the water collection, so the sample is sufficiently sent to the collection tank 9. transported and discharged.

After draining the previous sample, the sample is filled in the pipe between the two three-way motorized valves (3, 8). Then, when the valve opening direction of the two three-way valves 3 and 8 is changed and the air pump 4 is operated, the sample filled in the pipe is transferred to the reagent reaction/optical chamber. In this way, the sample can be weighed and sampled by a predetermined amount. If you want to change the amount of sample to be weighed, just change the length of the weighing coil (7).

By operating the transfer pump 1, ultrapure water can be metered and transferred to the reagent reaction/optical chamber 18 in the same way as when collecting samples from the ultrapure water bottle 29. The concentration of the sample can be diluted by 2 times for 1 transfer and 3 times for 2 transfers.

In the case of diluting the measured sample to a lower concentration, the first diluted sample weighed in the reagent reaction/optical chamber 8 is transferred to the buffer coil 5 by operating the transfer pump 19. After cleaning the reagent reaction/optical chamber 18 with ultrapure water, the transfer pump 19 is operated to fill the pipe between the two 3-way electric valves 3 and 8 with the first diluted sample. When the valve opening direction of the two 3-way valves 3 and 8 is changed and the air pump 4 is operated, the sample filled in the pipe is transferred to the reagent reaction/optical valve. Secondary dilution is possible by measuring ultrapure water again and injecting it into the reagent reaction/optical chamber 18 .

The oxidizing agent injection pump 11 is operated to inject the oxidizing agent into the reagent reaction/optical chamber 18 . The sample injected with the oxidizing agent is transferred to the oxidation reactor 26 by operating the transfer pump 19 to undergo an oxidation reaction. The oxidation temperature is 110 to 130 degrees Celsius in accordance with the water pollution process test standard, and 120 degrees is preferable. As described above, even a small amount of the oxidizing agent is brought into contact with the sample after the oxidation reaction, affecting the measured value. In the present invention, when the oxidation reaction proceeds after the sample into which the oxidizing agent is injected is transferred from the reagent reaction/optical chamber 18 to the oxidation reactor 26, the reagent reaction/optical chamber is washed with ultrapure water to remove the oxidizing agent from the sample after the oxidation reaction. was prevented from contacting.

After sufficiently cleaning the reagent reaction/optical chamber 18, ultrapure water is finally injected and light is irradiated to measure the transmittance of the ultrapure water.

After the oxidation reaction is completed, the transfer pump 19 is operated in reverse to transfer the sample to the reagent reaction/optical chamber 18. Thereafter, the color reagent injection pump 15 is operated to inject the color reagent. Thereafter, light is irradiated to measure transmittance. The absorbance is calculated using the transmittance of ultrapure water and the transmittance after color development, and finally converted into concentration.

The waste liquid measured by operating the transfer pump 19 is transferred to the waste liquid tank. Thereafter, the oxidation reactor 26, the reagent reaction/optical chamber 18, and pipes are cleaned using the sample and ultrapure water, and then discharged into the water collection tank 9.

Next, the method of measuring phosphoric acid using a total nitrogen, total phosphorus, and phosphoric acid measuring device will be described with reference to FIG. It is the same as the nitrogen and total phosphorus measurement method.

At this time, there is no thermal reaction, but the temperature of the sample is often low, so in order to increase the accuracy and reproducibility of the measurement, the reagent reaction/optical chamber 43 has a hot wire such as the oxidation reactor 26 for total nitrogen and total phosphorus measurement. this is fitted If the temperature of the sample is lower than room temperature, the temperature of the sample is heated to adjust to room temperature before analysis.

On the other hand, since the efficiency of the oxidation reaction is very important in measuring total nitrogen and total phosphorus, the oxidation reaction method using the oxidation reactor 26 proposed in the present invention will be described in detail with reference to FIG. 3 .

In order to rapidly increase the temperature of the oxidation reactor 26, a direct heating method was applied instead of an indirect heating method. The metal hot wire 58 was wound while directly contacting the reaction tube 56 made of quartz. In addition, a temperature sensor mounting groove 60 was made on the outer wall of the reaction tube 56, and the temperature sensor was inserted and fixed. The hot wire is a reaction tube using an upper hot wire hanger 57, a lower hot wire hanger 59, a lower hot wire lead groove 61, a lower hot wire hook 67, an upper hot wire lead groove 69, and an upper hot wire hook 70. (56) Install it so that it adheres to the surface. It is placed on the reaction tube cover 66 between the upper adapter 53 and the lower adapter 62. The shape of the oxidation reactor 26 is maintained by screwing the lower adapter 62 and the reactor cover 66 to tighten the lower adapter 62 . The tube fitting 64 was used to allow the sample to be introduced into or discharged from the inside of the reaction tube 56.

After the oxidation reaction, the sample must be cooled to room temperature to continue the next analysis process. In the present invention, a cooling fan (68) was mounted on the reaction tube cover (66) and cooled in an air-cooled manner. When the cooling fan 68 is installed, there is an advantage in that the cooling time can be greatly shortened compared to natural cooling. In general, when the temperature of the reactor is raised by heating the heater, an overshoot in which the temperature rises higher than the set temperature occurs. When the overshoot temperature is lower than the set temperature, the power is supplied again and the process of raising the temperature is repeated, and the overshoot decreases and converges to the set temperature. Therefore, it takes time for the temperature to stably adjust to the set temperature. In the present invention, when the temperature rises and overshoot starts, a fan is operated to apply cooling air to the reaction tube 56. By doing this, the overshoot temperature could be lowered and it was confirmed that the temperature was quickly stabilized at the set temperature. In addition, when cooling without using the cooling fan 68 after the oxidation reaction at 120 ° C., the cooling time was 15 minutes or more when cooling to 40 ° C. It was confirmed that it cooled below.

In addition, as described above, the absorbance should be calculated by measuring transmittance with light of 220 nm for total nitrogen and 400 nm to 250 nm or 800 nm to 900 nm for total phosphorus and phosphoric acid. Therefore, light must be used after being monochromated into a specific wavelength. A general monochrome process is to extract only light of a specific wavelength after dispersing light using a prism or grating. However, such a monochromator has disadvantages in that the device is complex, large, and expensive. Therefore, it is common to use a deuterium lamp or a tungsten lamp as a light source for monochromatic light by using a band-pass filter or to use an LED emitting a specific wavelength in an automatic water quality analyzer. However, when monochromating using a band pass filter, the band gap width of light has a wide characteristic of 10 to 20 nm. The inventors of the present invention confirmed that when light was monochromated using a band pass filter, the reproducibility and linearity of the measurement values were lower because the band gap was larger than when the light was monochromated using a prism or grating. Therefore, the algorithm applied to the optical signal processing unit designed to efficiently measure the optical signal of a specific wavelength band was implemented, and the corresponding electronic circuit unit and algorithm control program were constructed. The absorbance of the sample responds linearly to the intensity of the light signal passing through, and the higher the absorbance, the lower the light signal. Noise that is measured higher than the intensity of and electrically introduced also acts as a factor in not ensuring linearity for absorbance, so that the measurable concentration range is inevitably limited.

4 shows a unity-gain optical signal amplifying circuit used in a general optical signal measurement circuit. As described above, it is difficult to overcome the limitations of the measurement range caused by optical characteristics and electrical characteristics with such a general circuit. In the present invention, in order to measure high absorbance by expanding the detection range for minute optical signals, a multiple differential gain selection optical signal amplification circuit is constructed as shown in FIG. 5 . When using a general single-gain signal amplification circuit, the optical signal for the absorbance of the high-concentration sample is measured at a relatively very low voltage through current-voltage conversion, and the optical signal conversion voltage for the absorbance of the low-concentration sample is measured at a relatively high voltage. The voltage difference between the concentrations exceeds the voltage range that can be processed by the circuit, and when high absorbance is measured, the voltage value converted to the optical signal is measured relatively very low, so the signal is distorted out of the linear relationship, resulting in minute differences. The discriminative power for high-concentration samples tends to be low. Therefore, when a very low voltage is measured, the gain amplification factor must be set high to ensure discrimination against high-concentration samples, and the resolution of an AD converter that converts an analog voltage signal to a digital signal must also increase. In order to realize this, a multiple differential gain selection optical signal amplification circuit is configured by applying three kinds of power-of-10 gain amplification factors differentially according to the intensity of the optical signal, and the optical signal amplification rate of the sample measured at low absorbance is It is configured to be relatively very low, and the amplification rate of the light signal of the sample measured at high absorbance is configured to be amplified relatively very high. The optical signal of the sample to be measured was measured in the voltage signal range of 0 ~ 2.048V, and the selection of the differential gain was performed by comparing and analyzing the voltage change value of the optical signal input by the algorithm control program with the maximum amplification range of the amplification circuit. was automatically selected.

The multiple differential gain selection optical signal control processing algorithm scheme to which the multiple differential gain selection optical signal amplification circuit and control algorithm devised in the present invention are applied is illustrated in FIG. 6 and will be described in detail. Since the output of the photodetector for the incident light intensity is converted into a current signal, the optical signal processing circuit constitutes a current-voltage conversion inverting amplifier circuit. was adopted. In order to convert the light-receiving current of the photodetector into voltage, three types of feedback resistors for differential gain control are connected to the operational amplifier. In order to prevent and remove noise signals from external light sources, a Sallen-Key Active Filter circuit was constructed to remove frequencies in a specific band, including an R-C filter. Control of multiple differential gain selection optical signal amplification circuits is performed according to changes in optical signal intensity by an optical signal control algorithm-based control program embedded in a control device composed of an input/output interface, an operational amplifier, and an I2C ADC based on a microprocessor. Three types of feedback resistors for differential gain amplification were automatically selected. Ultra-precision analysis equipment that requires high precision when connecting three or more kinds of feedback resistors for gain control by applying 'multiple differential gain selection optical signal control processing algorithm technique applying multiple differential gain selection optical signal amplification circuit and control algorithm' can be applied to

The control program consists of a function to automatically select three types of feedback resistors for differential gain amplification according to the change in optical signal intensity and a function to compensate measurement errors caused by noise included in the input optical signal. The measurement error compensation function built into the control program of the present invention is a Sigma-Delta oversampling technique that increases the resolution of the ADC by sampling 2 to 4 times more than the number of sampling required when converting the input optical signal to digital. , a Kalman filter that stochastically reduces errors by outputting a value when the difference is minimized while feeding back the difference between the input value of the photodetector containing noise and the value expected by the prediction model, and the converted voltage signal It consists of a Savitzky-Golay filter that smooths the voltage signal with a weighted polynomial to remove some peak noise components. Three algorithm logics are designed and implemented as a program to reduce the noise of the measured optical signal, resulting in a straight line in the absorbance measurement range. castle was secured.

Examples and Comparative Examples

The internal capacity of the pipe between the three-way electric valves 2 and 3 was set to 1 mL. Standard solutions having total nitrogen concentrations of 1, 5, 10, 30, 50, 80, and 100 mg/L were prepared as samples. After filling the sample between the three-way electric valves 2 and 3 by operating the transfer pump 1, the sample was transferred to the reagent reaction/optical chamber 18 by operating the air pump 4. After the ultrapure water was filled between the three-way electric valves, the ultrapure water was transferred to the reagent reaction/optical chamber 18 four times in the same manner as above. This will result in a first 5-fold dilution of the sample. After mixing the sample and ultrapure water, the firstly diluted sample is filled in the buffer coil (5) by operating the transfer pump (19). After cleaning the reagent reaction/optical chamber with ultrapure water, the transfer pump 19 is operated to fill the pipe between the three-way valves 2 and 3 with the first diluted sample. The first diluted sample is transferred to the reagent reaction/optical chamber 18 by operating the air pump 4. Again, ultrapure water is transferred to the reagent reaction/optical chamber 18 4 times and mixed to perform secondary dilution, resulting in a total of 25-fold dilution. The secondary diluted sample is filled in the buffer coil (5) by operating the transfer pump (19). After cleaning the reagent reaction/optical chamber with ultrapure water, the transfer pump 19 is operated to fill the pipe between the 3-way valves 2 and 3 with the second diluted sample. The air pump 4 is operated to transfer the secondary diluted sample to the reagent reaction/optical chamber 18. When this process is performed twice, 2 mL of the second diluted sample is injected into the reagent reaction/optical chamber. Again, ultrapure water is transported twice to the reagent reaction/optical chamber 18 and mixed to perform a third dilution and finally a 50-fold dilution.

An oxidizing agent is added to the final diluted sample by operating the oxidizing agent injection pump 11. The final diluted sample to which the oxidizing agent is added is transferred to the oxidation reactor 26 by operating the transfer pump 19. The oxidation reactor 26 is operated to heat and oxidize at 120 degrees Celsius for 30 minutes. During the oxidation reaction, ultrapure water is injected into the reagent reaction/optical chamber 18 to perform cleaning. In the process of washing with ultrapure water, the lamp 16 is turned on during the final washing and the optical signal of the ultrapure water is read by the light detection sensor 17. The lamp is a deuterium lamp and a 220 nm band pass filter is used to extract and irradiate light with a wavelength of 220 nm. After the oxidation reaction is completed, the transfer pump 19 is operated to transfer the sample to the reagent reaction/optical chamber 18. The color reagent injection pump 15 is operated to inject the color reagent, and then an optical signal is read. Oxidation reagents and coloring reagents are injected to meet the water pollution process test standards. Calculate the transmittance and absorbance using ultrapure water and the light signal of the sample. Signal value with noise removed by using ADC Sigma-Delta Over sampling, Kalman Filter and Savitzky-Golay filter implemented in the program to which the optical signal control algorithm technique is applied to select multiple differential gains for the optical signal containing noise ( filtering) was processed to show a similar trend without distortion of the actual measured signal value (original). It is obtained by converting the concentration using the absorbance. An optical signal detector that can directly read the light of a lamp is installed in the optical system, and the optical signal obtained during measurement can be corrected with the obtained optical signal. It can be seen that the reproducibility of the measured value is within CV 1% and the accuracy is also high. It can be seen that the linearity also has a correlation coefficient of 0.999 or more. The results are shown in Tables 1 and 2 and FIG. 7 .

The concentration of total phosphorus was set to 0.5, 1, 5, 10, and 20 mg/L, and the test was performed in the same manner as in Example 1 except that the first dilution was 5 times and the second dilution was 4 times, and an 880 nm LED was used as a light source. It can be seen that the reproducibility of the measured value is within CV 1% and the accuracy is also high. It can be seen that the linearity also has a correlation coefficient of 0.999 or more. The results are shown in Tables 3 and 4 and FIG. 8 .

The concentration of phosphoric acid was set to 0.5, 1, 4, 8, 12, and 15 mg/L, and the test was performed in the same manner as in Example 1 except that dilution was not performed and a 410 nm LED was used as a light source. The reproducibility of the measured values was in the range of CV 0.4 to 0.8%, and the accuracy was very high. It can be seen that the linearity also has a correlation coefficient of 0.999 or more. The results are shown in Tables 5, 6 and 9.

Linearity was tested by measuring the optical signal in the device fabricated with the multi-differential gain selection optical signal control algorithm technique by varying step-by-step between 0.0uA and 5.0uA using a photocurrent generator. The photocurrent is divided into sections of 0.0~0.05uA, 0.05~0.5uA, and 0.5~5uA, and the converted voltage value is measured by changing the gain amplification resistor in each corresponding section, and the converted voltage value is converted into a digital value with an AD converter to generate a signal according to the change in the photocurrent. It was confirmed that the value increased, and the differential gain amplification resistor was automatically converted according to the photocurrent increase, maintaining a linear correlation without distortion of the voltage signal even in the lowest photocurrent section, and as a result of the first regression analysis, the correlation coefficient approached 1.000. can know that The results are shown in FIG. 10 .

Signal value with noise removed by using ADC Sigma-Delta Over sampling, Kalman Filter and Savitzky-Golay filter implemented in the program to which the optical signal control algorithm technique is applied to select multiple differential gains for the optical signal containing noise ( It is shown in FIG. 11 that filtering) exhibits a similar trend without distortion of the actual measured signal value (original).

[Comparative Example 1]

The test was performed in the same manner as in Example 1, Example 2, and Example 3, except that the optical signal was not processed using the multiple differential gain selection optical signal control processing algorithm technique. The reproducibility of the measured values was in the range of CV 1.3 to 2.3%, and the accuracy was relatively low. The correlation coefficient meaning linearity was also lower than that of the examples. In FIGS. 12a, 12b, and 12c, the correlation coefficients representing the correlation are 0.9973, 0.9976, and 0.9969, which may not seem low, but the accuracy of having this degree of correlation is lowered. The results are shown in Tables 7 and 8 and Figures 12a, 12b and 12c.

measured concentration
(mg/L)


standard concentration
(mg/L) number of measurements average
(mg/L) standard
Deviation CV% One 2 3 4 5 One 0.95 0.98 0.97 0.98 0.98 0.972 0.013 1.34 5 5.12 5.06 5.14 5.08 5.04 5.088 0.041 0.82 10 9.94 9.92 9.86 9.96 9.88 9.912 0.041 0.42 30 31.12 30.85 30.72 30.94 31.24 30.97 0.208 0.67 50 52.41 51.68 51.97 51.56 52.35 51.99 0.383 0.74 80 81.58 81.45 82.38 82.19 81.57 81.83 0.420 0.51 100 101.5 102.4 101.6 101.7 102.5 101.93 0.456 0.45

accuracy(%)


standard concentration
(mg/L) number of measurements One 2 3 4 5 One 5.00 2.00 3.00 2.00 2.00 5 -2.40 -1.20 -2.80 -1.60 -0.80 10 0.60 0.80 1.40 0.40 1.20 30 -3.73 -2.83 -2.40 -3.13 -4.13 50 -4.82 -3.36 -3.94 -3.12 -4.70 80 -1.98 -1.81 -2.97 -2.74 -1.96 100 -1.52 -2.38 -1.58 -1.69 -2.46

measured concentration
(mg/L)


standard concentration
(mg/L) number of measurements average
(mg/L) standard
Deviation CV% One 2 3 4 5 0.5 0.486 0.497 0.486 0.491 0.488 0.490 0.005 0.94 One 0.994 0.997 0.986 0.989 0.995 0.992 0.005 0.46 5 4.897 4.892 4.925 4.957 4.985 4.931 0.040 0.81 10 10.15 10.21 10.18 10.27 10.16 10.19 0.048 0.47 20 20.14 20.08 20.07 20.17 20.13 20.12 0.042 0.21

accuracy(%)


standard concentration
(mg/L) number of measurements One 2 3 4 5 0.5 2.80 0.60 2.80 1.80 2.40 One 0.60 0.30 1.40 1.10 0.50 5 2.06 2.16 1.50 0.86 0.30 10 -1.50 -2.10 -1.80 -2.70 -1.60 20 -0.70 -0.40 -0.35 -0.85 -0.65

measured concentration
(mg/L)


standard concentration
(mg/L) number of measurements average
(mg/L) standard
Deviation CV% One 2 3 4 5 0.5 0.504 0.509 0.498 0.495 0.502 0.502 0.005 1.08 One 0.995 1.005 0.995 0.995 0.994 0.997 0.005 0.46 4 4.013 4.014 4.012 3.995 4.012 4.009 0.008 0.20 8 7.986 8.024 7.954 8.014 8.031 8.002 0.031 0.40 12 12.15 12.18 12.09 12.17 12.16 12.15 0.035 0.29

accuracy(%)


standard concentration
(mg/L) number of measurements One 2 3 4 5 0.5 -0.80 -1.80 0.40 1.00 -0.40 One 0.50 -0.50 0.50 0.50 0.60 4 -0.32 -0.35 -0.30 0.12 -0.30 8 0.18 -0.30 0.58 -0.17 -0.39 12 -1.25 -1.50 -0.75 -1.42 -1.33

item measured concentration
(mg/L)


standard concentration
(mg/L) number of measurements average
(mg/L) standard
Deviation CV% One 2 3 4 5 total nitrogen One 0.87 1.12 1.05 0.86 1.06 0.992 0.119 12.0 5 4.88 4.82 5.18 5.23 5.27 5.076 0.210 4.13 10 9.82 9.75 9.67 10.35 10.59 10.04 0.409 4.07 30 27.82 26.78 28.67 27.84 25.94 27.41 1.060 3.87 50 48.67 49.58 46.78 46.28 45.79 47.42 1.627 3.43 80 82.98 93.45 81.29 80.54 82.92 84.24 5.257 6.24 100 103.4 98.6 97.64 103.7 104.6 101.6 3.214 3.16 total person 0.5 0.465 0.527 0.542 0.531 0.477 0.508 0.035 6.86 One 1.094 1.127 1.025 1.085 1.069 1.08 0.037 3.46 4 4.766 4.752 4.628 5.367 5.423 4.987 0.377 7.55 8 9.846 9.549 9.637 9.267 9.564 9.573 0.208 2.17 12 20.26 20.04 20.59 22.46 21.89 21.05 1.066 5.07 phosphoric acid 0.5 0.467 0.488 0.526 0.546 0.548 0.515 0.036 7.00 One 1.056 1.046 1.254 1.116 1.189 1.132 0.089 7.85 4 3.856 3.927 3.648 3.782 3.843 3.811 0.105 2.75 8 7.895 7.825 7.695 7.895 7.459 7.754 0.184 2.37 12 12.12 12.85 12.77 12.06 12.79 12.52 0.392 3.13

item accuracy(%)


standard concentration
(mg/L) number of measurements One 2 3 4 5 total nitrogen One 13.00 -12.00 -5.00 14.00 -6.00 5 2.40 3.60 -3.60 -4.60 -5.40 10 1.80 2.50 3.30 -3.50 -5.90 30 7.27 10.73 4.43 7.20 13.53 50 2.66 0.84 6.44 7.44 8.42 80 -3.73 -16.81 -1.61 -0.68 -3.65 100 -3.40 1.40 2.36 -3.70 -4.60 total person 0.5 7.00 -5.40 -8.40 -6.28 4.60 One -9.40 -12.70 -2.50 -8.50 -6.90 4 4.68 4.96 7.44 -7.34 -8.46 8 1.54 4.51 3.63 7.33 4.36 12 -1.30 -0.20 -2.95 -12.30 -9.45 phosphoric acid 0.5 6.60 2.40 -5.20 -9.20 -9.60 One -5.60 -4.60 -25.40 -11.60 -18.90 4 3.60 1.83 8.80 5.45 3.93 8 1.31 2.19 3.81 1.31 6.76 12 -1.00 -7.08 -6.42 -0.50 -6.58

One transfer pump 2 3-way motorized valve 3 3-way motorized valve 4 air pump 5 buffer coil 6 vent valve 7 metering coil 8 3-way motorized valve 9 catchment tank 10 vent valve 11 Oxidant injection pump 12 Oxidant Reagent Vial 13 Color Reagent Bottle 1 14 Color reagent bottle 2 15 Color Reagent Injection Pump 16 lamp 17 light detection sensor 18 Reagent reaction/optical chamber 19 transfer pump 20 2-way motorized valve 21 2-way motorized valve 22 2-way motorized valve 23 2-way motorized valve 24 2-way motorized valve 25 waste tank 26 oxidation reactor 27 ultra pure water bottle 28 cleaning liquid bottle 29 standard solution bottle 30 sample tank 31 transfer pump 32 3 way solenoid valve 33 3 way solenoid valve 34 buffer coil 35 3 way solenoid valve 36 catchment tank 37 air pump 38 Bent 39 Color Reagent Tank 1 40 Color Reagent Tank 2 41 reagent injection pump 42 photodetector sensor 43 Reagent reaction/optical chamber 44 transfer pump 45 3 way solenoid valve 46 waste tank 47 lamp 48 buffer coil 49 3 way solenoid valve 50 ultra pure water bottle 51 sample tank 52 3 way solenoid valve 53 upper adapter 54 upper fitting holder 55 upper o-ring 56 reaction tube 57 Upper heated wire hanger 58 thermic rays 59 Lower heating wire hanger 60 Temperature sensor mounting groove 61 Bottom heated lead groove 62 lower adapter 63 lower fitting holder 64 tube fittings 65 lower o-ring 66 reaction tube cover 67 lower heating loop 68 cooling fan 69 Upper heated lid groove 70 upper heating loop

Claims (13)

A method for automatically measuring total nitrogen, total phosphorus, and phosphoric acid in one device using a photometric method, and a method for measuring total nitrogen and total phosphorus accompanied by an oxidation reaction,
1) Injecting the measurement sample into the reagent reaction/optical chamber;
2) first dilution by injecting dilution water into the reagent reaction/optical chamber;
3) weighing the first diluted sample and injecting it into the reagent reaction/optical chamber;
4) secondary dilution by injecting dilution water into the reagent reaction/optical chamber;
5) injecting and mixing the oxidizing agent into the reagent reaction/optical chamber;
6) transferring the sample injected with the oxidizing agent to an oxidation reactor;
7) heating the oxidation reactor to oxidize the sample;
8) transferring the oxidized sample to the reagent reaction/optical chamber;
9) injecting the color former into the reagent reaction/optical chamber;
10) irradiating light to the reagent reaction/optical chamber to measure transmittance;
11) cleaning the reagent reaction/optical chamber and oxidation reactor; and
12) calculating the absorbance using the measured transmittance and converting it into a concentration;
A method for measuring phosphoric acid not accompanied by an oxidation reaction is,
1) Injecting the measurement sample into the reagent reaction/optical chamber;
2) injecting dilution water into the reagent reaction/optical chamber;
3) weighing the first diluted sample and injecting it into the reagent reaction/optical chamber;
4) secondary dilution by injecting dilution water into the reagent reaction/optical chamber;
5) injecting the color former into the reagent reaction/optical chamber;
6) measuring the transmittance by irradiating light to the reagent reaction/optical chamber;
7) cleaning the reagent reaction/optical chamber and oxidation reactor; and
8) Calculating the absorbance using the measured transmittance and converting it into a concentration; Total nitrogen, total phosphorus, and phosphorus automatic measurement method using a multiple differential gain selection optical signal amplification circuit comprising:
According to claim 1,
In '1) injecting the measurement sample into the reagent reaction/optical chamber; After transferring and discharging the initial intake sample containing excessive floating matter to the collection tank 9, the measurement sample is collected in the sample tank 30 and between the two 3-way electric valves 3 and 8 Filling the measurement sample in the pipe, switching the valve opening direction of the two three-way valves (3, 8) and operating the air pump (4) to transfer the measurement sample filled in the pipe to the reagent reaction / optical chamber A method for automatically measuring total nitrogen, total phosphorus, and phosphoric acid using a multiple differential gain selection optical signal amplification circuit.
According to claim 2,
'2) Primary dilution by injecting dilution water into the reagent reaction/optical chamber; It is transferred to the collecting tank (9), and the measurement sample remaining in the pipe between the two 3-way electric valves (3, 8) and the metering coil (7) is transferred to the collecting tank (9) and discharged, and then the ultrapure water bottle (29) The ultrapure water from the two 3-way electric valves (3, 8) and the measurement coil (7) are filled with measurement samples, the two 3-way valves (3, 8) are switched to the valve opening direction, and the air pump ( 4) is operated to transfer the ultrapure water filled in the pipe to the reagent reaction/optical chamber. A method for automatically measuring total nitrogen, total phosphorus, and phosphoric acid using a multiple differential gain selective optical signal amplification circuit.
According to claim 3,
'5) Injecting and mixing the oxidizing agent into the reagent reaction/optical chamber;' is a multi-differential gain selection light characterized in that the oxidizing agent injection pump 11 is operated to transfer the oxidizing agent to the reagent reaction/optical chamber 18 A method for automatic measurement of total nitrogen, total phosphorus and phosphoric acid using a signal amplification circuit.
According to claim 4,
'6) Transferring the sample injected with the oxidizing agent to the oxidation reactor;' is a multiple differential gain selection optical signal characterized by operating the transfer pump 19 to transfer the sample injected with the oxidizing agent to the oxidation reactor 26 Method for automatic measurement of total nitrogen, total phosphorus and phosphoric acid using an amplification circuit.
According to claim 5,
'7) Heating the oxidation reactor to oxidize the sample;' is a method for automatically measuring total nitrogen, total phosphorus, and phosphoric acid using a multiple differential gain selection optical signal amplification circuit, characterized in that heating to 110 to 130 ℃.
According to claim 6,
'8) Transferring the oxidized sample to the reagent reaction/optical chamber;' is a multiple differential gain characterized in that the transfer pump 19 is operated in reverse to transfer the sample to the reagent reaction/optical chamber 18 A method for automatic measurement of total nitrogen, total phosphorus and phosphoric acid using a selective optical signal amplification circuit.
According to claim 7,
'9) Injecting the colorant into the reagent reaction/optical chamber;' is total nitrogen and total phosphorus using a multiple differential gain selection optical signal amplifier circuit, characterized in that the colorant injection pump 15 is operated to inject the colorant. and a phosphoric acid automatic measurement method.
According to claim 1,
'10) Measuring the transmittance by irradiating light into the reagent reaction/optical chamber;' is irradiated by extracting light of a wavelength of 220 nm using a band pass filter of 220 nm from the ultraviolet region emitted from the deuterium lamp in the case of total nitrogen measurement. In the case of total phosphorus measurement, light of 880 nm wavelength is irradiated using 880 nm LED, and in case of phosphoric acid measurement, light of 410 nm wavelength is irradiated using 410 nm LED, and multiple differential gain selection optical signal amplification circuit and control algorithm are applied. A method for automatically measuring total nitrogen, total phosphorus, and phosphoric acid using a multiple differential gain selection optical signal amplification circuit, characterized in that a differential gain selection optical signal control processing algorithm technique is introduced.
According to claim 9,
'Multiple differential gain selection optical signal control processing algorithm technique' is a current-to-voltage conversion inverting amplifier circuit in which the output of the photodetector for the incident light intensity is converted into a current signal, and a rail-to-voltage conversion amplifier circuit for distinguishing the difference between the maximum current output and the dark current. Rail-type dual operational amplifier, 3 feedback resistors for differential gain control connected to the operational amplifier to convert the light-receiving current of the photodetector into voltage, 3 to prevent oscillation caused by the difference in capacitance between the terminals of the photodetector Sallen-Key Active Filter circuit that removes frequencies in a specific band, including a capacitor element for oscillation compensation connected in parallel with feedback resistors for differential gain control of species, and an RC filter to prevent and remove noise signals from external light sources , In order to control the multiple differential gain selection optical signal amplification circuit, a control device including an input/output interface, an operational amplifier, and an I2C type ADC centered on a microprocessor, feedback resistors for automatically amplifying three types of differential gain according to the change in optical signal strength A method for automatically measuring total nitrogen, total phosphorus, and phosphoric acid using a multiple differential gain selection optical signal amplification circuit, characterized in that it includes a control program based on an optical signal control algorithm built into a control device for selecting.
delete In the total nitrogen, total phosphorus and phosphoric acid automatic measuring device,
Collecting tank (9), oxidizing agent reagent bottle (12), color reagent bottle 1, 2 (13, 14), waste liquid tank (25), ultrapure water bottle (27), washing liquid bottle (28), standard solution bottle (29), sample tank ( 30);
Including transfer pump (1, 19, 44), air pump (4), 2-way electric valve (20, 21, 22, 23, 24), 3-way solenoid valve (32, 33, 35, 49), piping, etc. A transfer unit for transferring a measurement sample, a reagent, and dilution water to be measured;
a metering unit for measuring an amount of a sample, a reagent, and dilution water including a buffer coil 5 and a metering coil 7;
a reagent reaction unit including a reagent reaction/optical chamber 18, an oxidizing agent injection pump 11, an oxidation reactor 26, etc., and reacting a sample with a reagent;
An optical unit including a lamp 16, an optical sensor 17, a photodetector, a dual operational amplifier, a feedback resistor for controlling multiple differential gains, an RC filter, and a Sallen-Key Active Filter circuit and performing optical measurement; and
Microprocessor, control program, input/output interface, operational amplifier, control unit including ADC Sigma-Delta Over sampling, Kalman Filter, Savitzky-Golay filter, etc. implemented in the program to which multiple differential gain selection optical signal control algorithm techniques are applied. An automatic measuring device for total nitrogen, total phosphorus, and phosphoric acid using multiple differential gain selection optical signal amplification circuits.
13. The method of claim 12, wherein the oxidation reactor 26 of the reagent reaction unit comprises a reaction tube 56 made of quartz, a metal hot wire 58 wound in direct contact with the reaction tube made of quartz, and formed on the outer wall of the reaction tube 56. It includes a temperature sensor mounting groove 60 and a temperature sensor inserted into the temperature sensor mounting groove 60; The metal heating wire 58 includes an upper heating wire hook 57, a lower heating wire hook 59, a lower heating wire lead groove 61, a lower heating wire hook 67, an upper heating wire lead groove 69, and an upper heating wire hook 70. It is mounted so as to be in close contact with the surface of the quartz reaction tube 56, and is placed on the reaction tube cover 66 between the upper adapter 53 and the lower adapter 62, and the lower adapter 62 and the reactor threading the cover 66 to tighten the lower adapter 62 so that the rigid shape is maintained; A sample can be introduced into or discharged from the inside of the reaction tube 56 using the tube fitting 64; A cooling fan (68) is mounted on the reaction tube cover (66) of the oxidation reactor.

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