JPS6353448A - Coloring absorption analysis - Google Patents

Abstract

PURPOSE:To achieve a reduction in measuring time in a silica gauge for water quality inspection of boiler water at a thermal power plant, by making a coloring reaction tank serve as an absorption tank measuring cell concurrently to control the step movement monitoring the proceeding of a coloring reaction based on the results of detecting the quantity of transmission light. CONSTITUTION:Valves 7V and 9V are closed and a valve 8V is opened to inject a sample of boiler water or the like into a coloring reaction tank/absorbance measuring cell 3. A pump 10P is started to inject a first reagent such as ammonium molybdate by a specified amount into the reaction tank 3. Then, a coloring reaction is monitored with time through a light source 1 and a quantity of transmission light detector 4 and as an output value of the detector 4 reaches a specified value, a differentiated value is down to roughly zero. At this point, the completion of a coloring reaction is judged and a pump 11P or the like is started through an arithmetic control circuit 6 to automatically shift the operation to the next step by the subsequent reagent. The quantity of final transmission light as given at the end of the final step is taken in as measuring data. This enables a reduction in the coloring absorption analysis measuring time because not depending on fixed time unaboidably requiring a sufficient allowance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is a method for absorbance analysis of samples that involve a color reaction, such as in a siliometer used for testing the water quality of boiler water in thermal power plants. Concerning how to do.

[Traditional technique (nei)]

Recently, power and stem management at thermal power plants such as those mentioned above has been transitioning to a centralized computer-based management system, and as a result, efficient process management that meets power demand while minimizing unnecessary operations has become possible. In order to carry out rough process management such as the old annual startup/shutdown, WSS (weekly startup/shutdown) or D
More detailed management such as SS (day-to-day start-stop) is now possible, and in fact, process management based on such urgent start-up and stop is now the norm.

Accordingly, even more uniform responsiveness than ever has been required of the various measuring instruments that serve as the basis for such process management. There is no exception to this in measuring instruments such as the Siri dynamometer mentioned above, which utilize the chromogenic optical analysis method.

By the way, conventional color absorption spectrometry methods generally include
JIS designation method (J:S K-0101 or B-82
There is a 1 loaf method according to 24).

That is, in this JIS specified method, various predetermined reagents are sequentially introduced into the sample in the color reaction tank at predetermined time intervals while the reaction environment temperature in the color reaction tank is set and maintained at about 206C. After the coloring reaction has occurred sufficiently, the sample that has undergone the coloring reaction is guided to the absorbance measuring cell, the amount of transmitted light is measured by the i3 excess light amount detector, and a predetermined value is determined based on the result of the detected amount of transmitted light. A method of detecting absorbance by performing calculations is used.

For example, in the case of a silica force meter that uses all the standard methods prescribed by JISJ, as shown in Figure 3, first a predetermined amount of ammonium molybdate is introduced as reagent (2) into the sample in the color reaction tank, and then the silicon molybdate is After approximately 5 minutes, which is sufficient to ensure the progress of the yellow reaction, a predetermined amount of tartaric acid is introduced as a reagent (■) to hide phosphoric acid, which is a component that interferes with silica. After about 1 minute, which is sufficient to ensure that the reaction proceeds, a predetermined amount of 1-amino-2-naphthol-4-sulfonic acid as reagent (2) is added to cause a molybdenum blue reaction, and the molybdenum blue reaction is carried out in a manner sufficient to ensure that the molybdenum blue reaction proceeds. After about 10 minutes, the color-reacted sample is placed in the absorbance measurement cell, and the amount of transmitted light is measured using a transmitted light amount detector.

In other words, even if some safety factor is included, it takes a long time, about 16 minutes in total, from the start of measurement to the completion of measurement in the case of a silliform force meter that uses the conventional JIS specified method mentioned above. The problem has arisen that it is not possible to meet the recent demands for connectivity described above.

Therefore, through various experimental studies, the inventors of the present invention have found that no problem occurs in the reaction even if the reaction environment temperature is made higher than in the case of the JIS specified method, and as a result, the reaction environment temperature We have devised an improved method (prior art) in which a coloring reaction occurs while the temperature is set and maintained at about 40°C. According to this improved method of the prior art, in the case of a Siri force meter, for example, as shown in Figure 4, a sufficiently reliable color reaction can be achieved even if the time for the molybdenum blue reaction is shortened to about 4 minutes. Therefore, it was found that the time from the start of the measurement to the completion of the measurement could be shortened to about 10 minutes in total.

(Problem to be Solved by the Invention) However, in the chromogenic absorption spectrometry method according to the prior art (improved method) by the present inventors, as well as in the case of the conventional JIS designated method described above, each step is Since the method of setting the reaction time in a fixed manner is adopted, when setting the fixed reaction time for each step, sufficient and reliable measures must be taken to ensure good measurement accuracy. In order to guarantee the color reaction, it is necessary to include a certain amount of safety time in each case, and therefore, if we take into account the If you reduce the amount of safety time added,
It can be considered that there is still room for shortening p″A during measurement. However, the end point of the color reaction is
-1/It is impossible to centrally predict and set the end point of the color reaction because it depends on conditions such as agricultural yield.

The present invention has been made in view of the above-mentioned conventional situation and the results of consideration thereof, and its purpose is to sufficiently achieve good absorbance measurement accuracy by developing a technology that can reliably detect the end point of a color reaction. It is an object of the present invention to provide a colorimetric absorption analysis method that can further shorten the measurement time while maintaining the same characteristics.

[Means for Solving the Problems] In order to achieve the above object, the chromogenic absorption spectrometry method according to the present invention uses a chromogenic reaction tank in which a sample and a reagent are introduced based on a measurement sequence consisting of a plurality of predetermined steps. In addition to sharing an absorbance measurement cell corresponding to the light amount detector, the progress state of the color reaction in the absorption light flood 11 constant cell ζ constituting the color reaction tank is determined based on the transmitted light amount detection result. It is characterized in that it is monitored over time and automatically moves from the current step to the next step when it is detected that the color reaction has reached a set standard level.

[Effect]

The effects achieved by using the above-mentioned characteristic means are as follows.

That is, according to the above-mentioned color absorption spectrometry method according to the present invention, as will become clearer from the description of the specific examples described below, each Instead of setting a fixed reaction time for each step, it is automatically determined when the color reaction reaches a set reference state (the end point of the color reaction) based on the results of monitoring changes in the amount of transmitted light detected by the transmitted light amount detector over time. By making a judgment based on the current step and moving from the current step to the next step at that point, each step does not include the long safety time required in the past, and the color reaction is fully ensured as desired. In addition, each step can be shortened to the minimum necessary time. Therefore, while ensuring good measurement accuracy, the time required for absorbance measurement is significantly reduced compared to conventional methods. (According to experiments, approximately 1
15. The process can now be reduced to about 1/3 of the improved method described above.

In addition, in the method of the present invention, the absorbance measurement cell corresponding to the transmitted light amount detector is shared as a coloring reaction tank, so the light source, measurement cell, and transmitted light amount detection that are originally required for absorbance measurement are The container can be used effectively as it is, and the number of special components to be added can be reduced as much as possible, and it is also possible to check whether various reagents have been put in 4 times blindly, whether there are any abnormalities in the data, etc. There is also an advantage that U'll UE can be performed by monitoring the amount of detected transmitted light over time.

〔Example〕

Hereinafter, specific examples of the colorimetric absorption analysis method according to the present invention will be described based on the drawings (FIGS. 1 and 2).

FIG. 1 schematically shows the structure of an automatic color-developing absorption analyzer constructed by applying the method of the present invention, and the case where it is used as a Siri force meter will be explained here as an example.

That is, as shown in the figure, a light source 1 for illuminating the toe. Interference filter 2. Absorption measurement cell 3. Transmitted light amount detector 4
are arranged in that order so that an optical linear relationship is established, and the detection output from the transmitted light amount detector 4 is sent to the preamplifier 5.
It is configured to be manually inputted to the 6in control circuit 6 via the 6in control circuit 6.

The absorbance measuring cell 3 is configured to include the arithmetic and control circuit 6.
The tank is configured to also be used as a color development tank into which wash water, samples, and reagents are automatically introduced based on a measurement sequence consisting of a predetermined number of steps determined by As shown in the figure, a cleaning water supply channel 7 equipped with a first electromagnetic closing valve 7■ and a sample supply channel 8 equipped with a second electromagnetic closing valve 8■ are introduced and connected, respectively. A first reagent supply channel 10.A first reagent supply channel 10.A first reagent supply channel 10.A first reagent supply channel 10.A first reagent supply channel 10.A first reagent supply channel 10.A first reagent supply channel 10.A first reagent supply channel 10.A first reagent supply channel 10.A first reagent supply channel 10.An iJF outlet channel 9 equipped with a third electromagnetic on-off valve 9. A second reagent supply channel 11 including a tank 11T and a second liquid feed pump I1.P, and a third reagent supply channel 12 including a third reagent tank 12T and a third liquid feed pump 12Pfc.
are connected to each other. In addition, the first electromagnetic on-off valve 7V, the second electromagnetic on-off valve 8V, the third electromagnetic on-off valve 9V, the first electromagnetic on-off valve
The liquid feed pump IOP, the second liquid feed pump IIP, the third liquid feed pump 12P, etc. are configured so that their operations are controlled by the calculation control circuit 6, respectively, in order to realize a predetermined measurement sequence. . Further, the absorbance measurement cell 3, which also serves as the color reaction tank, is placed in a thermostatic chamber 13 whose temperature is controlled by the arithmetic control circuit 6 so that the color reaction temperature is always set and maintained at about 40°C. .

Further, in FIG. 1, 14 is an output device connected to the calculation control circuit 6, which includes a CRT display and a recorder.

Next, as realized by the arithmetic control circuit 6,
A 1-measurement sequence consisting of a plurality of predetermined steps will be described with reference to the schematic time history example shown in FIG.

After the previous 1=measurement sequence is completed, first, as a pre-processing step, the first and second electromagnetic on-off valves 7V, 8
With V closed, the third electromagnetic on-off valve 9■ is opened to discharge the luminescence-reacted sample used for front measurement from the absorbance measurement cell 3 (color reaction tank), and then and with the third electromagnetic on-off valves 8V and 9V closed), ';
? Open the 111 on-off valve 7■, pour the cleaning liquid into the absorbance measurement cell 3 (color reaction), and then close the first and second electromagnetic on-off valves 7V and 8V! Check the third electromagnetic on-off valve 9v with a trowel and absorb the cleaning liquid.
The cleaning operation of discharging from +11 constant cell 3 (coloring reaction tank) is repeated 2 to 3 times. The time required for the above pretreatment step is usually about 2 to 3 minutes.

When the pre-processing step is completed, the arithmetic control circuit 6
Enter the measurement step.

That is, first, in the preprocessing step, pattern recognition is performed on all the monitor data of the change in the amount of transmitted light detected by the transmitted light amount detector 4, thereby confirming whether or not the preprocessing step has been performed normally. from,
With the first and third electromagnetic on-off valves 7V and 9V closed, the second electromagnetic on-off valve aV is opened to introduce test ghee I into the absorbance measurement cell 3 (coloring reaction tank). Then, after the differential value (rate of change) of the transmitted light amount change data being monitored at that time settles down to a predetermined value (0 or a minute setting value close to O), the initial transmitted light amount (to )
Measure and import as data.

The time required for this initial transmitted light N c + e ) data acquisition step is usually about 2 minutes.

Thereafter, with all the electromagnetic on-off valves 7V, 8V, and 9V closed, first, only the first liquid feeding pump IOP is operated by a predetermined amount, so that the absorbance measurement cell 3 ( A predetermined amount of the first reagent (1) (ammonium molybdate) is introduced into the coloring reaction tank (coloring reaction tank) to cause a silicon molybdenum yellow reaction. When it is detected that the differential value (rate of change) of the transmitted light amount change data monitored at that time has settled down to a predetermined value (0 or a minute setting value close to 0), the Assuming that the yellow reaction has progressed sufficiently and reached the end point, in order to move on to the next step, only the second liquid feed pump 11P is operated by a predetermined amount to increase the amount of light absorbed through the second reagent supply channel 11. Measurement cell 3 (into the coloring reaction tank, the second reagent ■
A predetermined amount of (fi-taric acid) is introduced to hide F4H, which is a component that interferes with silica. It is known that this reaction on phosphoric acid occurs almost instantaneously, so in this case, about 20 seconds later, in order to proceed to the next step, the third step is performed.
By operating only the liquid feed pump 1.2P by a predetermined amount, the absorbance measurement cell 3 (
A predetermined amount of the third reagent (1-amino-2-naphthol-4-sulfone fi) is introduced into the coloring reaction tank) to cause a molybdenum blue reaction, and the differential value of the l light intensity change data monitored at that time ( change rate) is set to a predetermined value (0
When it is detected that the molybdenum blue reaction has progressed sufficiently and reached the end point, the final transmitted light ■ (1
) and import it as data.

Finally, the arithmetic control circuit 6 receives the two transmitted light amount measurement data (■.>,
Based on (1), the following formula (% formula %) (where k is the molar extinction coefficient determined at the time of calibration, and I is the optical system dark determined at the time of calibration) is used to calculate the The absorbance C is calculated.

The monitor data of the change in the amount of transmitted light detected by the i3 excess light amount detector 4 is all outputted to the output device 414 through the 1-measurement sequence, and the two transmitted light data taken into the arithmetic control circuit 6 are It goes without saying that the light amount measurement data (10), (1) and the calculated absorbance C of the sample are also output to the output device 14.

By the way, according to experiments, in the above measurement step, the time required from the introduction of reagent (black) to the introduction of reagent (2) (completion of the Keimolybdenum yellow reaction) is about 1 minute using a ladle, and the time required from the introduction of reagent (2) to the final The time required for the transmitted light i1 (+) to change (completion of the molybdenum blue reaction) was about 1 minute and 40 seconds.

Therefore, the total time required for the above measurement step is: [approximately 1 minute required for the molybdenum yellow reaction] + [approximately 20 seconds set for the phosphoric acid concealment reaction] + [approximately 1 minute required for the molybdenum blue reaction] 40 seconds] - 3 minutes per ladle, which is about 16 minutes compared to the conventional JI3 specified method, while still ensuring good measurement accuracy.15
It has been found that the absorbance detection time can be significantly shortened to about 1/10th of that in the case of the above-mentioned improved method, even when considering the pretreatment step.

By the way, in the above embodiment, the transition control from the current step to the next step in the 1-measurement sequence is performed using the rate of change of the monitor data itself of the amount of transmitted light detected by the amount of transmitted light detector 4. However, it is of course possible to use the rate of change of monitor data after converting the amount of transmitted light into absorbance.

In addition, the set value of the rate of change, which is the standard for the step transition control, should be set as low as possible when high measurement accuracy is required.
It can be arbitrarily determined depending on the situation, such as setting it to a small value close to , or setting it to a relatively large value if very high measurement accuracy is not required but quick measurement is required. .

C. Effects of the Invention] As is clear from the above detailed description, according to the colorimetric absorption analysis method of the present invention, a sample and a reagent are subjected to a colorimetric reaction if In addition to sharing the absorbance measurement cell corresponding to the transmitted light amount detector, the progress state of the color reaction in the absorbance measurement cell constituting the color reaction tank is monitored over time based on the detection result of the passing scene by the transmitted light amount detector. By adopting a method that automatically moves from the current step to the next step when it is detected that the color reaction has reached a set reference state, the conventional JIS specification mentioned above has been achieved. Instead of setting a fixed reaction time for each step as in the method and the improved method related to the prior art, the change in transmitted light detected by a transmitted light amount detector (or the change in absorbance calculated thereby) is
4+4 color reaction was set based on the results of monitoring over time.
It is possible to automatically and reliably determine when a state has been reached (towards the end of the color reaction), and to automatically move from the current step to the next step at that point, so that each step can be There is no need for wasted safety time such as (), the color reaction can be completed as desired, and each step can be shortened to the minimum necessary time. While ensuring good measurement accuracy, the time required for two absorbance measurements can be significantly shortened compared to conventional methods.Furthermore, the absorbance measurement cell corresponding to the transmitted light amount detector can be used as a coloring reaction tank. By sharing this feature, the light source, ATL constant cell, and transmitted light amount detector that are originally required for absorbance measurement can be used effectively as they are, and the number of special components that need to be added can be reduced. It has various excellent effects such as being able to reduce the amount of light as much as possible, as well as being able to check whether various reagents have been introduced reliably and whether there are any abnormalities in the data by monitoring the amount of detected transmitted light over time. It has come to pass.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are for explaining a specific example of the method for colorimetric absorption analysis according to the present invention, and FIG. 1 shows the colorimetric absorbance calibrated by applying the method of the present invention. A schematic configuration diagram of the automatic analyzer is shown, and FIG. 2 is a schematic time history showing an example of its operation in the 1-measurement sequence. Further, FIGS. 3 and 4 are for explaining the technical background of the present invention, and FIG. 3 is a diagram showing the time required for measurement according to the conventional JIS specified method. Further, FIG. 4 is a diagram showing the time required for measurement using the prior art (improved method). 3... Absorption measurement cell (shared as a coloring reaction tank), 4... Transmitted light amount detector, 6...
...Arithmetic control circuit. Applicant Horiba Manufacturing Co., Ltd. Representative Patent Attorney Hide Fujiki Hitogaki 1 Figure 1 Fee! ? m−δ Paulownia (8) bekaiso ← striped

Claims (1)

[Scope of Claims] [1] An absorbance measurement cell corresponding to a transmitted light amount detector is commonly used as a coloring reaction tank into which a sample and a reagent are introduced based on a measurement sequence consisting of a plurality of predetermined steps, and the amount of transmitted light is The progress state of the coloring reaction in the absorbance measuring cell constituting the coloring reaction tank is monitored over time based on the amount of transmitted light detected by the detector, and it is detected that the coloring reaction has reached a set reference state. A chromogenic absorption spectrometry method characterized by automatically shifting from the current step to the next step when the current step is detected. [2] The colorimetric absorption analysis method according to claim [1], wherein the colorimetric reaction temperature in the absorbance measuring cell constituting the colorimetric reaction tank is set and maintained at 40°C or approximately 40°C.