JP2016212028A - Concentration measurement device, concentration measurement method and control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concentration measurement device, concentration measurement method and control program that can automatically and sequentially measure samples broad in a content concentration range of measurement object elements with constant measurement accuracy maintained.SOLUTION: A concentration measurement device, which automatically and sequentially measures concentration of specific elements, comprises: a sample liquid sampling unit that discriminates between each of a plurality of sample liquids mutually different in a content concentration range of the specific element to sample the discriminated sample liquids; a measurement liquid preparation unit that performs control so as to be an amount of injection mutually different depending upon the content concentration range of the specific element to inject a reaction sample into the sample liquid, and prepares a measurement liquid; a plurality of measurement units of which any one is selected in accordance with a content concentration range of the specific element and which measures the content concentration of the specific element to be contained in the measurement liquid prepared by the measurement liquid preparation unit; and a control unit that causes the sample liquid sampling unit, measurement liquid preparation unit and measurement unit to operate in cooperation with each other.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a concentration measuring apparatus, a concentration measuring method, and a control program capable of automatically and continuously measuring a sample having a wide concentration range of an element to be measured.

  For example, the concentration of harmful elements contained in industrial wastewater, etc., and harmful elements contained in rivers and seawater are continuously monitored, and processing is performed so that the concentration of harmful elements is within the limits of regulatory values. Need to be released after a while.

  One of the harmful elements in the water quality is arsenic. Arsenic is an environmental pollutant, and Japanese Industrial Standards etc. stipulate a method for measuring the concentration of arsenic in wastewater. For example, the drainage standard is uniformly set to 0.1 mg / L or less for arsenic and its compounds. As a method for analyzing the concentration of arsenic, an absorptiometric method using a molybdenum blue complex has been conventionally shown as a standard method. In recent years, spectrophotometry with silver diethyldithiocarbamate, hydride generation atomic absorption, and hydride generation ICP emission spectroscopy have been shown as standard analytical methods.

  In order to constantly monitor the concentration of such arsenic, an automatic analysis method based on a flow injection analysis method based on arsenic molybdenum blue absorptiometry is known as a method for automatically performing concentration analysis (for example, Patent Document 1). , See Patent Document 2).

Japanese Patent No. 4075664 Japanese Patent No. 5567950 Japanese Patent Laying-Open No. 2015-042940

  Among the measurement elements of toxic element concentration, for example, factory effluent often has a wide concentration range of toxic elements, and it is necessary to continuously measure with a certain degree of accuracy from the low concentration range to the high concentration range. There is.

  However, the measuring devices described in Patent Document 1 and Patent Document 2 can perform measurement with a predetermined accuracy when measuring arsenic in a low concentration range (for example, about 0.01 to 1 mg / L). However, it is difficult to measure a wide concentration range from a low concentration region to a high concentration region (for example, 100 mg / L or more) with a certain accuracy with a single detector.

  In Patent Document 3, it is described that the sample collection amount is limited by controlling the opening time of the sample injection valve to be constant. However, in such a technique, when the concentration of harmful elements is high, it is constant. Measurement accuracy can be ensured. However, since the loop capacity of the sample injection valve is very small, measurement of harmful elements in the low concentration range cannot provide a certain measurement accuracy, and measurement is performed with a certain accuracy from the low concentration range to the high concentration range. It was difficult to do.

  The present invention has been made in view of the above-described situation, and is a concentration measuring device capable of automatically and continuously measuring a sample having a wide concentration range of the element to be measured while maintaining a certain measurement accuracy. An object is to provide a measurement method and a control program.

  In order to solve the above-mentioned problem, the concentration measuring apparatus of the present invention is a concentration measuring apparatus for automatically and continuously measuring the concentration of a specific element, and a plurality of types of samples having different concentration ranges of the specific element. A sample solution collecting unit for separately taking in the solution, and a measurement solution creating unit for injecting a reaction reagent into the sample solution and controlling the injection amount to be different depending on the concentration range of the specific element A plurality of measurement units that measure the content concentration of the specific element contained in the measurement liquid formed by the measurement liquid preparation unit, any one selected according to the content concentration range of the specific element, A sample solution collecting unit, the measurement solution creating unit, and a control unit for operating the measurement unit in cooperation with each other are provided.

  According to the concentration measuring apparatus having such a configuration, the injection amount of the sample solution is increased / decreased according to the concentration range of the specific element contained in the sample solution, and a plurality of measurement units are added according to the concentration concentration range of the specific element. By selecting and measuring any one of them, it is possible to continuously and continuously perform measurement on samples in a wide concentration range of specific elements while maintaining a certain measurement accuracy.

  The specific element is at least one of As, Si, P, and Ge.

  The measurement unit is an absorptiometer, and the reaction reagent includes an oxidizing agent, a reducing agent, and a color former.

  The plurality of measuring units are composed of a plurality of absorptiometers each provided with sample cells having different optical path lengths arranged in parallel or in series.

  The apparatus further includes a cleaning unit that connects another infusion tube to the infusion tube that constitutes the measurement solution creating unit and supplies a cleaning solution.

  The control program of the present invention is a control program recorded in the control unit constituting the concentration measuring device according to each of the above items, wherein the measurement liquid preparation is performed according to the concentration concentration range of the specific element of the sample liquid A step of selecting an injection amount of the sample liquid with respect to the reaction reagent in a section, and a specific measurement section that performs concentration measurement from a plurality of the measurement sections according to a concentration concentration range of the specific element of the measurement liquid And a step.

  The concentration measurement method of the present invention is a concentration measurement method for automatically and continuously measuring the concentration of a specific element, wherein the sample solution contains a plurality of different sample solutions having different concentration ranges of the specific element. Included in the measurement liquid, a measurement liquid preparation process in which the sample liquid is injected into the reaction reagent by controlling the collection step, the injection amount to be different from each other depending on the content concentration range of the specific element, and a measurement liquid is formed And a measuring step for measuring the concentration of the specific element.

  According to the concentration measuring method having such a configuration, by changing the injection amount by increasing / decreasing the injection amount of the sample liquid according to the concentration range of the specific element contained in the sample liquid, A sample can be measured with a certain measurement accuracy.

  In the measurement step, the absorbance is measured with different optical path lengths according to the concentration range of the specific element in the measurement solution.

  The specific element is at least one of As, Si, P, and Ge.

  The specific element is As, and in the measurement liquid preparation step, the valence of As contained in the sample liquid is changed from III to V with an oxidizing agent and a reducing agent, and then an arsenic molybdenum blue complex is formed with a color former. In the measurement step, absorbance at a wavelength of around 840 nm is measured by absorptiometry.

  The concentration of As in the sample solution is in the range of 0.008 mg / L to 6000 mg / L.

  The oxidizing agent is potassium permanganate, the reducing agent is ascorbic acid, and the color former is sulfated ammonium molybdate and ascorbic acid.

  The method further comprises a cleaning step of removing potassium permanganate used as the oxidant in the measurement liquid preparation step from the infusion tube.

  According to the concentration measuring apparatus, the concentration measuring method, and the control program of the present invention, it is possible to automatically and continuously measure a sample having a wide concentration range of the element to be measured while maintaining a certain measurement accuracy.

It is a schematic block diagram which shows an example of the density | concentration measuring apparatus of this invention. It is a graph which shows the verification example of this invention. It is a graph which shows the verification example of this invention. It is a graph which shows the verification example of this invention. It is a graph which shows the verification example of this invention.

  Hereinafter, a concentration measuring device, a concentration measuring method, and a control program according to the present invention will be described with reference to the drawings. Each embodiment described below is specifically described for better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified. In addition, in the drawings used in the following description, in order to make the features of the present invention easier to understand, there is a case where a main part is shown in an enlarged manner for convenience, and the shape and dimensional ratio of each component are actually shown. Is not necessarily the same.

(Concentration measuring device)
FIG. 1 is a schematic configuration diagram showing an example of the concentration measuring apparatus of the present invention.
The concentration measuring device 10 of the present embodiment is a concentration measuring device (absorption photometer) that automatically and continuously measures the concentration of a specific element by an absorptiometry method. The concentration measuring apparatus 10 is roughly divided into a sample solution collecting unit 11, a measurement solution creating unit 12, a measuring unit 13, and a control unit 14 that operates the components of these units in cooperation with each other. The control unit 14 includes, for example, a personal computer and an interface, and executes a program that operates the components of each unit in cooperation.

  The sample liquid collection unit 11 includes, for example, three liquid collection units 21 including a first liquid collection unit 21a, a second liquid collection unit 21b, and a third liquid collection unit 21c, and a sample selection valve 22. In the present embodiment, the liquid collection unit 21 exemplifies, for example, a case where three wastewaters (sample liquids) having different specific element content concentrations are collected, and measures the As concentration as the specific element.

  For example, the sample liquid collected by the first liquid collection part 21a (hereinafter sometimes referred to as the first sample liquid) has an As concentration range of about 1000 to 6000 mg / L. Further, the sample liquid collected by the second liquid collecting part 21b (hereinafter sometimes referred to as a second sample liquid) has an As concentration range of 5 to 30 mg / L. Further, the sample liquid collected by the third liquid collection part 21c (hereinafter sometimes referred to as a third sample liquid) has an As concentration range of about 0 to 1 mg / L.

  The measurement liquid preparation unit 12 includes sample injection valves 31, 32, solution flow path switching valves 33, 34, syringe pumps 35, 36, plunger pumps 37, 38, 39, 41, a reaction coil 42, a reaction tank 43, and these. Are provided with a plurality of infusion pipes (ducts) 45. In addition, a cleaning unit 46 that supplies a plurality of types of cleaning liquids to the infusion tube 45 that constitutes the measurement liquid preparation unit 12 is provided.

  The sample selection valve 22 automatically switches and selects feeding of the first sample solution, the second sample solution, and the third sample solution at the time of sample collection. Each sample is injected into the carrier liquid fed from the plunger pump 39 via the sample injection valve 31 or 32. As the carrier liquid, for example, ion exchange water is used.

  The solution flow path switching valve 34 functions as a switching valve when a plurality of types of cleaning liquids are introduced into the infusion tube 45 from the cleaning unit 46 by the syringe pump 35. For example, hydrochloric acid (concentrated hydrochloric acid 1: water 4) or ion-exchanged water is used as the cleaning liquid injected from the liquid flow path switching valve 34.

  The solution flow path switching valve 33 functions as a switching valve when introducing the oxidizing agent or the cleaning liquid into the infusion tube 45. As the oxidizing agent, potassium permanganate is used. The cleaning liquid is sent to the solution flow path switching valve 33 by the plunger pump 41. For example, ascorbic acid is used as the cleaning liquid fed through the solution flow path switching valve 33.

  The reaction coil 42 reacts the mixed liquid of the sample liquid and the carrier liquid sent from the sample injection valves 31 and 32 and the oxidizing agent (reaction reagent) sent from the plunger pump 38 and the solution flow path switching valve 33. The plunger pump 38 also injects a reducing agent (reaction reagent) into the sample liquid (carrier-liquid dilution) after reaction with the oxidizing agent. As the reducing agent, for example, ascorbic acid is used.

  The reaction tank 43 reacts the oxidant and the reducing agent with the sample liquid after reaction (carrier-liquid dilution) and the color former (reaction reagent) injected by the plunger pump 37 to form a measurement liquid. As the color former, for example, a plurality of kinds of color formers such as ammonium molybdate and ascorbic acid are used.

  The syringe pump 36 injects the cleaning liquid toward the plunger pumps 37, 38, and 41. As the cleaning liquid injected from the syringe pump 36, for example, ion exchange water is used.

  The measurement unit 13 includes a plurality of absorptiometers 51 and 52. As the absorptiometers 51 and 52, absorptiometers using various light sources such as infrared light, ultraviolet light, and visible light can be used. The absorptiometers 51 and 52 record calibration curve data using the standard solution injected from the sample selection valve 22 in advance, and are included in the sample solution by comparing the calibration curve data with the absorbance of the measurement solution. The concentration of As is calculated. The absorptiometer 51 and the absorptiometer 52 are provided with sample cells having different optical path lengths. For example, the absorptiometer 51 includes a sample cell having an optical path length of 20 mm, and the absorptiometer 52 includes a sample cell having an optical path length of 10 mm.

  The selection valve 53 is an absorptiometer 51 that measures the absorbance of the sample liquid to be measured, that is, the first sample liquid, the third sample liquid, and the third sample liquid, in which the content concentration range of the specific element is different from each other. The absorptiometer 52 is selected, and measurement liquids created from the respective sample liquids are injected toward the selected absorptiometer. The operation of the selection valve 53 is automatically performed based on the information on the type of sample liquid recorded in the control unit 14.

  Alternatively, as shown in (another example) in the upper right part of FIG. 1, the spectrophotometers 51 and 52 are connected in series with the selection valve 53 excluded, and the absorptiometers 51 and 52 are connected by the control unit 14. It is also possible to select which one of the response signals is adopted. In an embodiment in such a case, the spectrophotometer 51 or the spectrophotometer 52 for measuring the absorbance is selected according to the first sample liquid, the second sample liquid, and the third sample liquid having different concentration ranges of the specific element, Only the response signal of the selected absorptiometer is recorded by the control unit 14. The selection of the absorptiometer is automatically performed based on the information on the type of the sample liquid recorded in the control unit 14.

  According to the concentration measuring apparatus having such a configuration, by adjusting the opening time of the sample injection valves 31 and 32 according to the concentration range of As contained in the sample solution, the amount of sample solution injected can be increased or decreased. It is possible to continuously and continuously measure a sample in the As concentration range while maintaining a certain measurement accuracy.

  Further, by selecting and measuring any one of a plurality of absorptiometers provided with sample cells having different optical path lengths according to the concentration range of As contained in the sample solution, the concentration of As in the sample solution is measured. It is possible to measure the concentration of As with appropriate accuracy according to the area.

(Concentration measurement method)
The concentration measuring method of the present invention using the concentration measuring apparatus shown in FIG. 1 will be described.
In the present embodiment, an example of a concentration measurement method for collecting three wastewaters (sample solutions) each having a different concentration range of As as a specific element and measuring the As concentration in each sample solution will be described. .
First, sample liquids having different As concentration ranges are collected from the first liquid collection part 21a, the second liquid collection part 21b, and the third liquid collection part 21c constituting the sample liquid collection part 11, respectively. The first sample liquid collected from the first liquid collection unit 21a has, for example, an As concentration range of about 1000 to 6000 mg / L. The second sample liquid collected from the second liquid collection part 21b has, for example, an As concentration range of about 5 to 30 mg / L. Further, the third sample liquid collected from the third liquid collection part 21c has, for example, an As concentration range of about 0 to 1 mg / L.

  The collected sample liquid is sent to the measurement liquid preparation section 12 and injected into ion exchange water as a carrier liquid by the sample injection valves 31 and 32. For example, the carrier liquid is flowed at a flow rate of 1 mL / min. In the case of the first sample liquid, the sample liquid injection amount is set to 1 second by setting the opening time of the sample injection valve 31 to this carrier liquid. Control and inject to 20 μL. In the case of the second sample solution, 0.24 mL of the sample solution is injected into this carrier solution. In the case of the third sample solution, 2.4 mL of the sample solution is injected into the carrier solution.

  Next, an oxidizing agent and a reducing agent are sequentially injected into the mixed solution of the sample solution and the carrier solution to perform an oxidation-reduction reaction, thereby changing the valence of arsenic from III to V. For example, about 0.5 g / L of potassium permanganate as an oxidizing agent is mixed with each mixed solution at a flow rate of 1 ml / min. As a reducing agent, ascorbic acid is mixed at about 5 g / L at a flow rate of 1 ml / min.

  Next, two kinds of color formers are injected into the mixed solution in which the arsenic valence is changed to the V valence, and the reaction is performed in the reaction tank 43 at a temperature of about 100 ° C. As the color former, for example, about 16 g / L of ammonium molybdate dissolved in sulfuric acid and about 0.4 g / L of ascorbic acid are respectively injected and reacted. As a result, a measurement liquid in which an amount of arsenic molybdenum blue complex corresponding to the concentration of arsenic is generated is obtained.

  In the measurement liquid preparation unit 12, the carrier liquid, the oxidizing agent, the reducing agent, and the two color formers are always sent to the infusion tube 45 by the plunger pumps 37, 38, and 39, for example, at a flow rate of 1 mL / min. Yes. As a result, the measurement liquid is always generated continuously from the sample liquid collected continuously.

  Next, the obtained measurement liquid is sent to the measurement unit 13 to measure the arsenic concentration. In measurement, the absorbance of the measurement liquid obtained from the third sample liquid in the low concentration region is measured by an absorptiometer 51 including a sample cell having an optical path length of 20 mm. Further, the absorbance of the measurement liquid obtained from the second sample liquid in the medium concentration range and the first sample liquid in the high concentration range is measured by the absorptiometer 52 including a sample cell having an optical path length of 10 mm. In the measurement, the absorbance near the wavelength of 840 nm, which is an absorption peak of As, is measured.

  The absorbance data of each sample solution thus measured is sent to the control unit 14 and compared with calibration curve data using a standard solution measured in advance, and the As concentration of each measurement solution is calculated. The obtained As concentration data is recorded and accumulated in the control unit 14.

  The As concentration of each measurement liquid obtained in this way is fed back to, for example, a drainage treatment facility connected to the first liquid collection part 21a, the second liquid collection part 21b, and the third liquid collection part 21c. It can also be reflected in the control of the process wastewater treatment equipment so that the concentration falls within the standard.

  On the other hand, the cleaning unit 46 automatically cleans the residual sample of the sample selection valve 22, the sample injection valves 31 and 32, and the infusion tube 45 connected to the sample selection valve 22, and the infusion tube 45 connected thereto by the syringe pump 35 every time measurement is completed. For example, as a specific cleaning method, hydrochloric acid (concentrated hydrochloric acid 1: water 4) is injected by a syringe pump 35 to perform cleaning, and then the solution flow path switching valve 34 is switched to perform water cleaning with ion exchange water. Such cleaning prevents clogging of the infusion tube and each valve with suspended particulate matter (SS), which is often contained when using process wastewater from factories as a sample solution, and automatically and continuously measures the As concentration. Make it possible to do.

  In addition, the cleaning unit 46 automatically performs the infusion tube 45 through the solution flow path switching valve 33 by the plunger pump 41 every time one measurement is completed. Specifically, the feeding of potassium permanganate, which is an oxidant, and ascorbic acid, which is a cleaning liquid, is automatically switched by the solution flow path switching valve 33, and the inside of the infusion tube 45 is automatically switched each time one measurement is completed. Wash with. That is, the solution flow path switching valve 33 is set so that potassium permanganate, which is an oxidizing agent, flows into the infusion pipe 45 during measurement, and the solution flow path is switched so that ascorbic acid, which is a cleaning liquid, flows into the infusion pipe 45, during cleaning. Valve 33 is set. Thereby, in the infusion tube 45 in which potassium permanganate is mixed with the sample solution, it is prevented that the potassium permanganate is changed to manganese dioxide and the infusion tube 45 is clogged. Manganese dioxide can be reliably removed from the infusion tube 45 by using reducing ascorbic acid as a cleaning agent.

  On the other hand, the cleaning unit 46 automatically performs the pump heads of the plunger pumps 37, 38, and 41 each time one measurement is completed by the syringe pump 36. In order to protect the plunger seal, the liquid is fed to prevent salt precipitation. Water is used as the cleaning liquid.

  As described above, according to the concentration measurement method of the present invention, the open time of the sample injection valves 31 and 32 is adjusted according to the concentration range of As contained in the sample solution to increase or decrease the injection amount of the sample solution, By changing the injection amount into the carrier liquid, it is possible to perform measurement with a certain measurement accuracy on a sample having a wide As concentration range.

  In addition, each part of the concentration measuring apparatus 10 is controlled by executing a control program recorded in the control unit 14, and the process from measuring the concentration of As in the sample liquid to cleaning the infusion tube and each valve is automatically performed as one routine. By carrying out the measurement, the concentration of As contained in the sample solution can be continuously and automatically measured.

  Furthermore, if the measurement is performed by switching a plurality of absorptiometers provided with sample cells having different optical path lengths according to the concentration range of As contained in the sample solution, the measurement solution corresponds to the As concentration range of the sample solution. It makes it possible to measure the concentration of As with appropriate accuracy.

(Control program)
The control program of the present invention is stored, for example, in a storage device of a personal computer constituting the control unit 14 of the concentration measuring device 10 and is executed during the operation of the concentration measuring device 10. The control program selects the injection amount of the sample liquid into the reaction reagent in the measurement liquid preparation unit 13 according to the specific element of the sample liquid, for example, the As content concentration area, and the content concentration area of the specific element of the measurement liquid And a step of selecting a specific absorptiometer (measuring unit) that performs concentration measurement from a plurality of absorptiometers (measuring units) arranged in parallel or in series.

  The control program also includes a control program for switching each valve of the concentration measuring apparatus 10 and controlling the absorptiometers (measurement units) 51 and 52 in order to execute these steps.

  By executing such a control program in the control unit 14 of the concentration measuring apparatus 10, the process from the measurement of the concentration of As in the sample solution to the cleaning of the infusion tube and each valve is automatically performed as a single routine. It becomes possible to automatically and continuously measure the concentration of As contained.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to this, It can change suitably in the range which does not deviate from the technical idea of the invention.
In the above-described embodiment, the example in which As is given as the specific element and the concentration is measured has been described. However, the specific element is not limited to As. For example, at least one of Si, P, and Ge can be selected as the specific element other than As.

  As an example, when measuring the Si concentration in a sample solution using Si as a specific element, after sulfating the sample solution containing Si, an ammonium molybdate and a reducing agent are added to prepare a measurement solution. And it can apply to the measurement of the density | concentration of Si by measuring the peak whose wavelength is 830 nm vicinity using an absorptiometer.

  As another example, when measuring the Ge concentration in a sample solution using Ge as a specific element, after sulfating the sample solution containing Ge, ammonium molybdate and a reducing agent are added to the measurement solution. Create And it can apply to the measurement of the density | concentration of Ge by measuring the peak whose wavelength is about 830 nm using an absorptiometer.

  In the above-described embodiment, the sample liquid is divided into three content concentration ranges, and the injection amount to the carrier liquid is adjusted respectively. However, the classification of the specific element content concentration ranges is not limited to three. . For example, the measurement liquid can be prepared with two specific element content concentration regions, or the measurement liquid can be prepared with four or more specific element content concentration regions.

  In the embodiment described above, two absorptiometers (measuring units) each provided with sample cells having different optical path lengths are arranged in parallel or in series. For example, the optical path length is divided into three or more and 3 Even in a configuration in which two or more absorptiometers are arranged in parallel or in series, and one of these three or more absorptiometers is selected according to the content concentration range of the specific element and the absorbance is measured. Good.

The effect of the concentration measuring method of the present invention was verified.
The measurement results of the sample solution containing 0 to 30 mg / L of As using the concentration measuring device shown in FIG. 1 are shown below.
2.4 mL of a sample solution having an As concentration range of 0 to 1 mg / L is collected from the sample injection valve 32. Further, 0.24 mL of a sample solution having an As concentration range of 0.2 to 30 mg / L is collected from the sample injection valve 31. Each sample solution was combined with a carrier solution having a flow rate of 1 mL / min and reacted with potassium permanganate 0.5 g / L and ascorbic acid 5 g / L.
Next, 16 g (2M H ₂ SO ₄ ) of ammonium molybdate and 0.4 g / L of ascorbic acid were combined to form an arsenic molybdenum blue complex in a reaction vessel at 100 ° C. to obtain a measurement solution.

  A measurement liquid prepared from a sample liquid having an As concentration range of 0 to 1 mg / L using the measurement liquid thus obtained is an absorptiometer 51 provided with a sample cell having an optical path length of 20 mm. A measurement solution prepared from a sample solution of 0.2 to 30 mg / L was measured for absorbance at a wavelength of 840 nm with an absorptiometer 52 equipped with a sample cell having an optical path length of 10 mm, and the As concentration was quantified.

  The calibration curve measurement results are shown in FIGS. 2 and 3, respectively. The correlation coefficient of the calibration curve results obtained by measuring As standard solution 0.05, 0.1, 0.5, 1 (mg / L) and As standard solution 5, 10, 20, 30 (mg / L) is Good results were obtained with r = 0.9996 and 0.9999, respectively. As (III) standard solution was used as the As standard solution. FIG. 4 and Table 1 show the results of measuring the above-described sample solution with the concentration measuring apparatus of the present invention and the results of measuring with the ICP-emission spectroscopic analysis method of the comparative example, respectively. From these results, it was confirmed that the As concentration can be accurately measured according to the concentration measuring apparatus and the concentration measuring method of the present invention.

The measurement results of the sample solution containing As of 1000 to 6000 mg / L using the concentration measuring apparatus shown in FIG. 1 are shown below.
A sample solution with an As concentration range of 1000 to 6000 mg / L was controlled to 20 μL by opening the sample injection valve 31 for 1 second, and joined with a carrier solution having a flow rate of 1 mL / min. Reaction was performed with 5 g / L and ascorbic acid 5 g / L.
Next, 16 g (2M H ₂ SO ₄ ) of ammonium molybdate and 0.4 g / L of ascorbic acid were combined to form an arsenic molybdenum blue complex in a reaction vessel at 100 ° C. to obtain a measurement solution.

Using the measurement solution thus obtained, a measurement solution prepared from a sample solution with an As concentration range of 1000 to 6000 mg / L was measured for absorbance at a wavelength of 840 nm with an absorptiometer 52 equipped with a sample cell with an optical path length of 10 mm. The As concentration was quantified.
FIG. 5 and Table 2 show the results of measuring the above-described sample solution with the concentration measuring apparatus of the present invention and the results of measuring with the ICP-emission spectroscopic analysis method of the comparative example, respectively. From these results, it was confirmed that the As concentration can be accurately measured according to the concentration measuring apparatus and the concentration measuring method of the present invention.

DESCRIPTION OF SYMBOLS 10 Concentration measuring device 11 Sample liquid collection part 12 Measurement part 13 Control part 51,52 Absorptiometer

Claims (13)

A concentration measuring device that automatically and continuously measures the concentration of a specific element,
A sample liquid collecting unit that distinguishes and takes in plural types of sample liquids having different concentration ranges of the specific element, and
A measurement liquid preparation unit that controls the injection amount to be different from each other depending on the concentration range of the specific element, injects a reaction reagent into the sample liquid, and forms a measurement liquid;
A plurality of measurement units that measure the content concentration of the specific element contained in the measurement liquid formed by the measurement liquid preparation unit, any one selected according to the content concentration range of the specific element,
A concentration measuring apparatus comprising: the sample solution collecting unit, the measuring solution creating unit, and a control unit that operates the measuring unit in cooperation with each other.   The concentration measuring apparatus according to claim 1, wherein the specific element is at least one of As, Si, P, and Ge.   The concentration measuring apparatus according to claim 1, wherein the measurement unit is an absorptiometer, and the reaction reagent includes an oxidizing agent, a reducing agent, and a color former.   4. The plurality of measuring units are each composed of a plurality of absorptiometers each provided with sample cells having different optical path lengths arranged in parallel or in series. 5. Concentration measuring device.   5. The concentration measuring apparatus according to claim 1, further comprising a cleaning section that connects another infusion pipe to the infusion pipe constituting the measurement liquid preparation section and supplies a cleaning liquid. 6. A control program recorded in the control unit constituting the concentration measuring device according to any one of claims 1 to 5,
Selecting an injection amount of the sample liquid with respect to the reaction reagent in the measurement liquid preparation unit according to a concentration range of the specific element of the sample liquid;
Selecting a specific measurement unit that performs concentration measurement from a plurality of the measurement units according to the concentration concentration range of the specific element of the measurement liquid; and
A control program comprising: A concentration measurement method for automatically and continuously measuring the concentration of a specific element,
A sample liquid collecting step for distinguishing and taking in plural types of sample liquids having different concentration ranges of the specific element from each other;
A measurement liquid preparation step of controlling the injection amount to be different from each other depending on the concentration range of the specific element, injecting the sample liquid into a reaction reagent, and forming a measurement liquid;
And a measuring step for measuring the concentration of the specific element contained in the measuring solution.   The concentration measurement method according to claim 7, wherein in the measurement step, the absorbance is measured with different optical path lengths according to a concentration range of the specific element in the measurement solution.   9. The concentration measuring method according to claim 7, wherein the specific element is at least one of As, Si, P, and Ge. The specific element is As;
In the measurement liquid preparation step, the valence of As contained in the sample liquid is changed from III to V with an oxidizing agent and a reducing agent, and then an arsenic molybdenum blue complex is formed with a color former.
10. The concentration measuring method according to claim 9, wherein, in the measuring step, absorbance at a wavelength of around 840 nm is measured by absorptiometry.   The concentration measurement method according to claim 10, wherein the concentration of As in the sample solution is in a range of 0.008 mg / L to 6000 mg / L.   The concentration measuring method according to claim 10 or 11, wherein the oxidizing agent is potassium permanganate, the reducing agent is ascorbic acid, and the color former is sulfated ammonium molybdate and ascorbic acid.   13. The concentration measuring method according to claim 12, further comprising a washing step of removing potassium permanganate used as the oxidizing agent in the measuring solution preparation step from the infusion tube.

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