JP2008164291A - Flow analysis system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flow analysis system capable of rapidly and automatically performing pretreatment, capable of minimizing an added pretreatment solution and capable of measuring trace amounts of an element in a sample solution, in real time. <P>SOLUTION: A pretreatment means has: a flow rate ratio changing means for changing the flow rate ratio of the flow rate of an analyzing target liquid and/or that of the pretreatment liquid with the elapse of time, by changing the flow rate ratio; a liquidity measuring means for measuring the liquidity of the mixed liquid of the analyzing target liquid and the pretreatment liquid and a liquidity determining means for determining whether the liquidity becomes a predetermined state. The flow rate ratio changing means functions so as to be able to change the flow rate ratio, even in a positive direction and a negative direction, corresponding to the liquidity, when the direction increasing the flow rate ratio of the pretreatment liquid with respect to the mixed liquid of the analyzing target liquid and the pretreatment liquid is set in the positive direction so as to guide the mixed liquid to an analysis means, when the liquidity goes into a predetermined state. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a flow analysis system capable of measuring trace elements in an analysis target liquid in real time using flow titration technology for pretreatment of the analysis target liquid (sample liquid).

Flow injection analysis (FIA) is an analysis technique that enables on-site analysis in real time. In particular, this method is effective for on-site analysis of trace elements contained as impurities in the chemicals in a semiconductor manufacturing process in which extremely high-purity chemicals are used. Here, FIA will be briefly explained. It is a kind of flow analysis. A reaction reagent in which a carrier (fluid carrying a sample) is allowed to flow through a flow path and the carrier is replaced with an analysis sample at appropriate times, and these detection elements develop color. And the element concentration is analyzed by detecting the difference Δ between the absorbance of the carrier and the absorbance of the analysis sample. That is, in FIA, a carrier and a reaction reagent are mixed and mixed well by stirring and dispersion, and then concentration detection (typically measurement of absorbance by absorbance analysis) is performed by a detector that detects the element concentration. However, the sample concentration is determined by measuring the difference in absorbance by replacing the carrier with the sample at some point. The contents of the prior patent 1 (Japanese Patent Application Laid-Open No. 2004-163191) are incorporated in this specification.
JP 2004-163191 A

  By the way, in the semiconductor manufacturing process, various chemicals such as acid and alkali are used. Here, when measuring trace elements in the chemical solution, it is necessary to prepare conditions suitable for the measurement. For example, when the metal in the sample solution is measured by a colorimetric method, if the optimum pH of the color former is within a predetermined range, the liquidity of the sample solution needs to be within the optimum pH range. As a specific example, when the sample solution is strongly acidic and the optimum pH of the color former is near neutral, after pre-treatment of adding a pre-treatment solution (alkaline solution) to the sample solution, a buffering agent is added. It is necessary to keep within the optimum pH range by adding it.

  Here, since there is no guarantee that the liquidity of the sample liquid is always constant, it is ideal to measure the pH of the sample liquid and determine the pretreatment conditions for each operation of the apparatus. However, operations such as collecting a sample solution and measuring the pH each time the operation is performed, and determining pretreatment conditions based on the pH are extremely troublesome and time consuming. In addition, basically, since humans perform these operations, there is a possibility that erroneous condition settings are made. As a result, an operator's wrong operation may cause the situation that the chemical solution is determined to be appropriate while being an inappropriate chemical solution, or it may take a long time to obtain a result. There is a risk that the chemical solution will continue to be used until the result is obtained, and in any case, the commercial value of the object to be processed (wafer or the like) using the inappropriate chemical solution may be lost. Furthermore, in order to analyze trace components in the sample liquid, it is necessary to reduce the amount of pretreatment liquid added to the sample liquid in order to increase sensitivity as much as possible. Therefore, the amount of pretreatment liquid added should be kept to the minimum necessary. Therefore, the present invention provides a flow analysis system capable of measuring trace elements in a sample liquid in real time, in which pretreatment is performed quickly and automatically and the pretreatment liquid to be added can be kept to a minimum. The primary purpose is to provide it.

  Further, when analyzing a trace component, even a slight contamination (contamination) affects the analysis result. For example, when analyzing a trace component (for example, iron) in an acid sample solution, it is necessary to make the color developer have a suitable pH range by neutralizing with an alkali as described above. It is measured with a pH detector. Then, the sample liquid that has been confirmed to be in a suitable pH range by the pH detector is subjected to the analysis. At this time, the alkali attached to the pH detector is transferred to the analyzer during the analysis. May flow in. Therefore, a second object of the present invention is to provide a flow analysis system that is optimal for analysis of trace components and that is free from the risk of contamination from a liquid property measuring means such as a pH detector.

  As a result of diligent research, the present inventors first found that the problem of achieving the first object can be solved by incorporating the flow titration technique into the flow analysis system, and the present invention (1 ) To (8) are completed.

The present invention (1) includes a pretreatment means for pretreating an analysis target liquid prior to analysis, and an analysis means for analyzing the analysis target liquid pretreated by the pretreatment means. In the flow analysis system that can analyze the specified components in the target liquid,
The pretreatment means changes the flow rate ratio of the analysis target liquid and / or the pretreatment liquid, thereby changing the flow rate ratio with time, and the mixed liquid of the analysis target liquid and the pretreatment liquid. While having a liquid property measuring means for measuring the liquid property and a liquid property determining means for determining whether or not the liquid property is in a predetermined state,
The flow rate ratio changing means has either a positive direction or a negative direction depending on the liquidity when the direction in which the flow ratio of the pretreatment liquid to the mixed liquid of the analysis target liquid and the pretreatment liquid increases is a positive direction. Function to change the flow rate ratio,
The flow analysis system is configured such that when the liquid property is in the predetermined state, the mixed liquid when the liquid state is in the predetermined state is guided to the analysis means.

  The present invention (2) is the flow analysis system according to the invention (1), wherein the flow rate ratio changing means further includes variable width changing means when changing the flow rate ratio.

  According to the present invention (3), the variable means determines the change width when changing from one flow rate ratio to another flow rate ratio based on the measurement result of the liquid property at the certain flow rate ratio. ) Flow analysis system.

  In the present invention (4), the variable means sets the change width when changing from one flow rate ratio to another flow rate ratio smaller than the previous change width, and the liquidity at the certain flow rate ratio is set. It is the flow analysis system according to the invention (3) that determines whether the flow rate ratio is changed in the plus direction or the minus direction by the change width based on a measurement result.

  The present invention (5) is the flow analysis system according to any one of the inventions (1) to (4), which is a flow injection analysis system.

  The present invention (6) is the flow analysis system according to any one of the inventions (1) to (5), wherein the pretreatment is a neutralization treatment.

  The present invention (7) is the flow analysis system according to the invention (6), wherein the liquid property measured by the liquid property measuring means is pH.

  The present invention (8) is the flow analysis system according to any one of the inventions (1) to (7), wherein the analysis is an analysis of a trace component in the analysis target liquid.

  Next, as a result of intensive studies, the present inventors pay attention to the fact that the position of the liquid property measuring means is important with respect to the problem of achieving the second object, and the present inventions (9) to (13). It has been completed.

The present invention (9) includes pretreatment means for pretreating the analysis target liquid by adding the pretreatment liquid to the analysis target liquid prior to analysis, and the analysis target liquid pretreated by the pretreatment means. In a flow analysis system capable of analyzing a predetermined component in a liquid to be analyzed, comprising an analysis means for analyzing
The liquid measurement unit further includes a liquid property measurement unit that measures the liquid property of the analysis target solution that has been pretreated by the pretreatment unit, and the liquid measurement unit is configured so that the preprocessed analysis target solution is extracted from the pretreatment unit. The flow analysis system is arranged outside a line led to the analysis means.

  The present invention (10) is the flow analysis system of the invention (9), which is a flow injection analysis system.

  The present invention (11) is the flow analysis system according to the invention (9) or (10), wherein the pretreatment is a neutralization treatment.

  The present invention (12) is the flow analysis system according to the invention (11), wherein the liquid property measured by the liquid property measuring means is pH.

  The present invention (13) is the flow analysis system according to any one of the inventions (9) to (12), wherein the analysis is an analysis of a trace component in the analysis target liquid.

Here, the meaning of each term in this example will be described. “Analysis” includes any of quantitative analysis, semi-quantitative analysis, and qualitative analysis. “Pretreatment” refers to all treatments for obtaining suitable conditions when analyzing an analyte in a liquid to be analyzed. For example, when a response indicator is used, the environment is suitable for the analysis. (For example, setting the pH within a predetermined range) or removing an interfering substance. Here, the “response” can include, for example, discoloration (for example, color development or color reduction), an optical signal (for example, fluorescence), an electric signal, and the like, and is not particularly limited as long as it can be detected. “Analysis target liquid” refers to a liquid whose problem is whether or not it contains an analysis target component (element, compound, etc.). For example, a process liquid (cleaning liquid) used in each process (for example, a semiconductor cleaning process). And a stock solution (new solution) of the process solution. The “pretreatment liquid” refers to a liquid that substantially participates in the pretreatment when the analysis target liquid is pretreated. For example, a mixed liquid of an alkaline liquid and a diluted liquid is analyzed during the pretreatment. When combined with the target liquid, only the alkaline liquid corresponds to the “pretreatment liquid”. “Liquid” is not particularly limited as long as it is some physical property or state exhibited by the liquid, and examples thereof include pH. The “predetermined component” is a concept including not only a specific type of component but also a case where two or more types of components are included. “System” is a concept that encompasses not only devices but also plants, etc. In addition, each component is not physically integrated or aggregated, but each component is physically divided. Including those that are distributed or distributed. The “element” is not particularly limited, and is, for example, a metal element. “Flow analysis” means flow analysis including automatic analysis, and is a concept including flow injection analysis. The “trace amount” refers to a case where the content of the target element is 10 ⁻⁷ order (preferably ppb order) or less. Further, the following system is suitable for on-site analysis, but is not limited to on-site analysis, and other uses can be applied and belong to the scope of rights of the present invention.

  According to the present invention (1) to (8), since the titration principle is adopted, it is possible to automatically perform an appropriate pretreatment according to the liquidity even for the liquid to be analyzed whose liquidity is not constant. When changing the flow rate ratio between the sample liquid and the pretreatment liquid during the pretreatment, the amount of change is too large, even if the liquidity exceeds the predetermined value or the predetermined range, Since the flow rate ratio can be changed in the opposite direction, compared to the gradient change mode, the pretreatment can be performed more quickly and as a result, inappropriate chemicals can be used for a long time. It is possible to minimize the loss caused by this. Furthermore, since the pretreatment liquid to be added can be kept to a minimum, there is also an effect that a highly sensitive analysis can be performed for a trace component. In addition, for the variable flow rate ratio variable type (variable step type), especially when the sample concentration is high, by increasing the flow rate of the pretreatment liquid at the initial stage and decreasing the flow rate of the pretreatment liquid as it approaches the equivalence point There is an effect that the liquid property can be brought closer to the vicinity of the equivalent point more quickly.

  According to the present invention (9) to (13), the liquid property measuring means for measuring the liquid property of the pretreated analysis target liquid is outside the analysis line (the line from which the analysis target liquid reaches the analysis means). As a result, it is possible to avoid contamination derived from the pretreatment liquid and the like attached to the liquid property measuring means. As a result, it is possible to perform analysis of trace components with higher accuracy.

  The best mode will be described below with reference to the drawings. Here, the best mode is a mode in which the flow rate ratio between the pretreatment liquid (alkaline liquid) and the sample liquid is quickly and within a suitable pH range by changing convolutionally (stepwise or stepwise). . Here, the first best mode is a mode in which the flow rate ratio change width is made constant and approaches a suitable pH range (hereinafter referred to as “constant step type”), and the second best mode is a flow rate ratio change. This is a mode in which the width is changed (for example, the change width is half of the previous time) to approach a suitable pH range (hereinafter referred to as “variable step type”). Hereinafter, the first best mode will be described first.

First, FIG. 1 is a system diagram of an FIA apparatus according to the best mode. First, each element will be described. The pipe A is a pipe through which the pretreatment liquid (alkaline liquid) is circulated, and communicates from the pretreatment liquid (alkaline liquid) reservoir N to the junction X. Next, the pipe C is a pipe through which the sample liquid is circulated and communicates from the sample liquid introduction part 2 to the junction part X. Next, the pipe D is a pipe through which the carrier liquid flows and communicates from the carrier liquid storage part C to the junction part Y. Next, the pipe E is a pipe through which the oxidant liquid flows and communicates from the oxidant liquid storage part O to the junction part Y. Next, the tube F is a tube through which the coloring reagent solution flows and communicates from the coloring reagent solution storage part R to the confluence part Y. Here, among the P _A to P _F for sending these liquid, P _A for flow rate change step it is not particularly limited as long as it is a pump capable of a step change, the plunger A pump or a syringe pump may be used.

And downstream of the merging portion X, pretreatment of the sample solution {neutralization reaction occurring in the mixed solution of the alkali solution from the tube A and the sample solution from the tube C (hereinafter referred to as “treatment solution”)} is performed. is provided with the preprocessing section MC1, on the downstream of the pre-processing unit, the carrier liquid Ya and the tube G for circulating the processing solution to the injection valve V ₂ to be described later, from the injection valve V ₂ to the merging portion Y A tube H for circulating the treatment liquid is provided.

Here, the tube G, the injection valve V ₂ is interposed. Here, the injection valve V ₂ is configured to be switched, in the position gamma (non-measurement mode), the flow path for guiding the treatment liquid from the upstream side tube G to the waste portion Z is formed, the tube A flow path for leading the carrier liquid from D to the pipe H is formed. Here, on the way to the waste liquid part Z, a pH detector for measuring the pH of the pretreated liquid is provided. By disposing the pH detector outside the line to the analyzer in this way, contamination by the pH detector at the time of analysis can be avoided and analysis with higher sensitivity becomes possible. Incidentally, when the process liquid is guided to the waste liquid portion Z, the process liquid is waste liquid through the injection loop provided in the injection valve V _2. Thereby, when the switching described later is executed, the processing liquid stored in the injection loop at the time of the switching is sent to the detection unit described later. On the other hand, in the position theta (time of measurement), a flow path for guiding a predetermined amount accommodated treating solution within the infusion loop connected to the injection valve V ₂ to the tube H is formed. As a result, a certain amount of processing liquid is sandwiched between the carrier liquid and the carrier liquid, and is sent to the junction Y.

  Finally, downstream of the merging portion Y, a reaction reaction of the processing liquid (a color reaction of the carrier liquid or the processing liquid from the pipe H, the oxidant liquid from the pipe E, and the color developing liquid from the pipe F) is performed. A part MC2 and a detection part D (absorption photometer) for detecting the response reaction are provided.

  Note that a system configuration as shown in FIG. 2 may be employed instead of the system configuration as in the FIA apparatus according to FIG. Here, the features of the system will be described focusing on the differences from the FIA apparatus according to FIG. Note that when changing the system of the FIA apparatus according to FIG. 1, it is not always necessary that these differences exist at the same time, and only one of them may be present. Accordingly, these differences will be described. First, a pipe B in FIG. 2 is a pipe through which a diluted liquid of the pretreatment liquid (alkaline liquid) flows, and communicates from the diluted liquid storage part Di to the junction part X. As described above, the system adopts a configuration in which the diluent is mixed with the pretreatment liquid (alkaline liquid) before the pretreatment liquid (alkaline liquid) and the sample liquid are mixed. The reason for mixing this diluted solution is that the pH may not be measured with a pH detector when the conductivity of the solution is too low, so that the electrical conductivity of the entire solution can be measured even in such a case. This is to increase the degree.

Further, the system adopts a configuration in which the sample liquid is not always sent to the junction X, but is sent into the system only at the time of measurement. Specifically, first, the tubes C, unlike the case of FIG. 1, a tube for circulating the carrier liquid, and leads from the carrier liquid storage portion C ₂ to the joining portion X. Then, the tube C, the injection valve V ₁ is interposed. Here, the injection valve V ₁ was is configured to be switched, the position α in (non-measuring), while constructing a flow path for sending the carrier liquid from the tube C in the upstream side of the downstream pipe C, in the position beta (during measurement), to construct a flow path for sending the sample liquid which is a predetermined amount stored in the injection loop connected to the injection valve V ₁ to the downstream pipe C. As a result, a certain amount of sample liquid is sandwiched between the carrier liquid and the carrier liquid and sent to the junction X. Incidentally, the injection valve V ₁ in FIG. 2 is in a state of position beta.

  Next, the preprocessing procedure and the like in the best mode will be described more specifically with reference to FIGS. In this best mode (the second best mode is also the same), the amount of the sample liquid is always constant. For example, (1) the amount of the pretreatment liquid is constant and the amount of the sample liquid is changed. (2) A form in which any amount of the pretreatment liquid and the sample liquid is changed may be employed. Furthermore, with regard to (2), (2-1) the form in which the total amount of the pretreatment liquid and the sample liquid is always the same, (2-2) the total amount of the pretreatment liquid and the sample liquid is not always the same. (In the former case, the process for calculating the concentration of the analysis target can be simplified). In addition, this best mode (as well as the second best mode) is not only due to the use of a step pump, but also has the main effect of quickly reaching a suitable pH range, as well as pretreatment liquid and sample liquid. There is an additional effect that the defoaming can be performed. The additional effect will be described after the description of the best mode and the second best mode. Hereinafter, the best mode will be described by taking the mode (1) as an example.

  First, the first best mode will be described with reference to FIGS. In the first best mode, a method of performing neutralization titration by changing the amount of the pretreatment liquid (alkaline liquid) from the tube A stepwise (stepwise) is adopted. By changing stepwise in this way, it is possible to reach the preferred pH region in a shorter time than the gradient method. In particular, when a spectrophotometer is employed as a detector in FIA measurement, there is no problem even with the step method as in this embodiment because strict preprocessing that must reach the equivalence point is not necessary. .

Specifically, as shown in FIG. 3, increased by controlling the driving of the pump P _A and P _c, while maintaining the sample liquid in a predetermined amount, the pretreatment liquid the amount of (alkaline solution) in a stepwise manner By doing so, the ratio of both liquids is changed stepwise. On the other hand, the mixed liquid of the sample liquid and the pretreatment liquid (alkaline liquid) is combined with the sample liquid (hydrochloric acid) at the junction X and reaches the pH detector via the pretreatment part MC1. Then, when the pH value in the pH detector falls within a predetermined range, the processing liquid is sent to the detector D. In addition, when using the glass electrode for pH measurement as a pH detector, since the potential difference inside and outside the electrode is converted into pH, it may be directly determined whether or not it is within a predetermined range based on the potential difference. .

  Here, FIG. 4 shows an example of how the pH changes when the amount of the alkaline liquid is increased stepwise. Thus, since the sample solution is initially only the pH, the pH is around 3.5, which is the liquidity of the sample solution {(1) in the figure}, but the sample liquid / alkaline solution volume ratio is changed. In {2 in the figure}, the pH is around 3.75, and in the second step {3 in the figure} where the volume ratio of the sample solution / alkaline solution is further changed, the pH is around 7, and the sample solution / In the third step {4 in the figure} where the amount ratio of the alkaline solution is further changed, the pH becomes around 10.5, and the fourth step {5 in the figure (5 in the figure). )}, The pH is around 11.75. Here, in this example, since it entered between 5 and 9 which is a suitable pH range in the second step {(3)} in the figure, the liquid in this state is sent to the detector as the processing liquid. .

Next, FIG. 5 is a characteristic process in the best mode, a flow chart of the valve switching process of the injection valve V _2. Note that this processing can be executed by, for example, a personal computer. Specifically, the CPU in the personal computer executes the processing, the ROM in the computer stores the execution program for the processing, and the RAM of the computer stores information necessary for the processing (for example, set) The flow velocity and switching time Tx) are temporarily stored. Therefore, the processing will be described. First, in step 203, an instruction screen for inputting the flow velocity (V _c ) of the sample liquid is displayed on the display, and flow velocity information input by the operator via a keyboard or the like. Is temporarily stored in the RAM. Next, in step 205, an instruction screen for inputting the flow rate (V _d ) of the carrier liquid is displayed on the display, and flow rate information input by the operator via a keyboard or the like is temporarily stored in the RAM. Next, at step 207, an instruction screen for inputting the flow rate (V _e ) of the oxidant solution is displayed on the display, and flow rate information input by the operator via a keyboard or the like is temporarily stored in the RAM. . Next, at step 209, an instruction screen for inputting the flow rate (V _f ) of the color former solution is displayed on the display, and the flow rate information input by the operator via a keyboard or the like is temporarily stored in the RAM. . In this way, the flow rates of all liquids related to pretreatment, color reaction, etc. are set. Next, in step 211, various initialization processes are executed. Specifically, sets the default value (0) as the amount of the pretreatment liquid, and sets the step width to a predetermined value (e.g., 1/2 of the sample solution), and sets the injection valve V ₂ to the γ position , And so on. In step 213, various pumps are operated to start feeding all liquids. Here, the pump P _A is initially driven to the amount of the pretreatment liquid is zero. The other pumps P _{C to} P _F are independently driven so as to achieve the set flow rate. As described above, after the liquid supply of all the liquids is started, in step 217, the timer is started at the timing (T = 0).

  In step 219, it is determined whether or not the pH in the pH detector is within a predetermined range (for example, pH = 5 to 9). Here, in the case of No in Step 219, in Step 221, whether the pH is smaller than the lower limit value (for example, pH = 5) of the predetermined range, that is, whether the alkali amount as the pretreatment liquid is still small. Determine. In the case of Yes in step 221, the pretreatment liquid is increased by one step in step 223, and the process proceeds to step 219. On the other hand, in the case of No in Step 221, that is, when the amount of alkali as the pretreatment liquid is too large (in other words, when the step width is too large), the step width is decreased in Step 225 (for example, The sample liquid is restarted from the initial value (the amount of the pretreatment liquid is 0) together with ½ volume of the sample liquid → 1/3 volume of the sample liquid, and the process proceeds to Step 219.

On the other hand, in the case of Yes in step 219, in step 231, switching the injection valve _{V 2} which has been placed in the γ position to θ position. Thus, the processing liquid in the injection loop was connected to the injection valve V ₂ is, in a state sandwiched between the carrier and sent to the junction unit Y through line H. Here, the treatment liquid present in the injection loop is a treatment liquid having a pH within a predetermined range. By such processing, it becomes possible to send the sufficiently pretreated processing liquid to the junction Y.

  Next, the second best mode according to the variable step type will be described with reference to FIGS. In the second best mode, as in the first best mode, the amount of the pretreatment liquid (alkaline liquid) is changed stepwise (stepwise) while keeping the amount of the sample liquid from the tube C constant. The method of performing neutralization titration is adopted. However, in the first best mode, the step width is constant, but in this best mode, the step width is gradually reduced (in this example, it is reduced to a geometric progression (a half of the previous step)). }, It can be changed not only in one direction (the direction in which the pretreatment liquid increases) but also in both directions (the direction in which the pretreatment liquid increases and the direction in which the pretreatment liquid decreases) depending on the liquidity. Yes. That is, for example, if the acidic state is lower than the preferred pH range before a certain step and the acidic state is still maintained as a result of the step, the pretreatment liquid is increased in the next step. On the contrary, in the case where the pH was lower than the preferred pH range before a certain step, but the step resulted in an alkaline state greater than the preferred pH range, In the next step, a process for reducing the pretreatment liquid is performed. If the step width is initially increased and the step width is gradually decreased, the preferred pH region can be reached in a shorter time than the step method according to the first best mode.

Specifically, as shown in FIG. 6, by controlling the driving of the step pump P _A, the amount of the sample liquid (fixed amount: 100) starting from the pretreatment solution (alkaline solution) 100 with respect to (1 Second time). In the second time, the flow rate of the pretreatment liquid in the first time is set to ± 50. Here, if the pH at the first time is less than the predetermined range, it means that the amount of alkali is still insufficient, so the amount of the pretreatment liquid is increased by 50, while the pH at the first time exceeds the predetermined range. If there is, it means that the amount of alkali is excessive, so the amount of the pretreatment liquid is reduced by 50. In the third time, the flow rate of the pretreatment liquid in the second time is set to ± 25. Here, if the pH at the second time is less than the predetermined range, it means that the amount of alkali is still insufficient, so the amount of the pretreatment liquid is increased by 25, while the pH at the second time exceeds the predetermined range. If there is, it means that the amount of alkali is excessive, so the amount of the pretreatment liquid is decreased by 25. In the fourth time, the flow rate of the pretreatment liquid in the third time is set to ± 12.5. Here, if the pH at the third time is less than the predetermined range, it means that the amount of alkali is still insufficient, so the amount of the pretreatment liquid is increased by 12.5, while the pH at the third time exceeds the predetermined range. If it is, it means that the amount of alkali is excessive, so the amount of the pretreatment liquid is decreased by 12.5. In this best mode, the step width is set to be ½ of the previous step width. However, this ratio may not be ½, and the step width is changed in a geometric sequence. Even if it does not do, it may be a mode of decreasing in an arithmetic progression or non-sequence. Furthermore, at the time of the start, the pretreatment liquid: the amount of sample liquid = 100: 100 was set, but the numerical values in FIG. 6 are merely illustrative and are not limited to these, and the expected acid / alkali concentration is set. It is set accordingly.

  Here, FIG. 7 shows an example of how the pH changes when the amount of the alkaline liquid is increased stepwise. Thus, since the sample solution is initially only the pH, the pH shows around 3.5, which is the liquidity of the sample solution, but the first step (“first time” in the figure) where sample solution / alkaline solution = 100: 100 ), The pH approaches 3.75 and approaches the range of 5 to 9 which is a preferable pH range. Then, in the second step (“second time” in the figure) where the sample liquid / alkaline liquid = 100: 150, the pH is in the vicinity of 10.5 and exceeds the range of 5 to 9 which is the preferred pH range. Therefore, in the third step, the sample solution / alkaline solution = 100: 125, and as a result of reducing the amount of the alkali solution, it again becomes less than the preferred pH range. However, it approaches the preferred pH range more than the first time. In the fourth step, the sample liquid / alkaline liquid = 100: 137.5 and the amount of the alkaline liquid are slightly increased. As a result, the pH of the liquid falls within the preferable pH range of 5-9.

Next, FIG. 8 is a characteristic process in the best mode, a flow chart of the valve switching process of the injection valve V _2. Note that this processing can be executed by, for example, a personal computer. Specifically, the CPU in the personal computer executes the processing, the ROM in the computer stores the execution program for the processing, and the RAM of the computer stores information necessary for the processing (for example, set) The flow velocity and switching time Tx) are temporarily stored. Therefore, the processing will be described. First, in step 303, an instruction screen for inputting the flow velocity (V _c ) of the sample liquid is displayed on the display, and flow velocity information input by the operator via a keyboard or the like. Is temporarily stored in the RAM. In step 305, an instruction screen for inputting the flow rate (V _d ) of the carrier liquid is displayed on the display, and flow rate information input by the operator via a keyboard or the like is temporarily stored in the RAM. Next, in step 307, an instruction screen for inputting the flow rate (V _e ) of the oxidant solution is displayed on the display, and flow rate information input by the operator via a keyboard or the like is temporarily stored in the RAM. . Next, in step 309, an instruction screen for inputting the flow rate (V _f ) of the color former is displayed on the display, and the flow rate information input by the operator via a keyboard or the like is temporarily stored in the RAM. . In this way, the flow rates of all liquids related to pretreatment, color reaction, etc. are set. Next, in step 311, various initialization processes are executed. Specifically, a default value (for example, pretreatment liquid: sample liquid = 100: 100) is set as the initial amount of the pretreatment liquid, the step width is set to 1/2 (the step width of a certain number of times is set to the previous amount). It is set to 1/2 of the step size), and sets the injection valve V ₂ to the γ position, executes such processing. In step 313, various pumps are operated to start feeding all the liquids. Here, the step pump P _A, initially pretreatment liquid and the sample liquid quantities the default value (i.e., 100: 100) and a are driven. The other pumps P _{C to} P _F are independently driven so as to achieve the set flow rate. In this way, after the liquid supply of all the liquids is started, in step 317 and step 321, the timer is started at the timing (T = 0), and 1 is set as the initial value of k.

  In step 323, it is determined whether or not the pH in the pH detector is within a predetermined range (for example, pH = 5 to 9). Here, in the case of No in Step 323, in Step 325, whether or not the pH is lower than the lower limit value (for example, pH = 5) of the predetermined range, that is, whether or not the amount of alkali as the pretreatment liquid is still small. Determine. In the case of Yes in step 325, in step 327, the pretreatment liquid is increased by one step (1/2 of the increase / decrease amount of the previous pretreatment liquid), and the process proceeds to step 331. On the other hand, in the case of No in step 325, that is, when the amount of alkali as the pretreatment liquid is excessive, in step 329, the pretreatment liquid is one step (1/2 of the increase / decrease amount of the previous pretreatment liquid). Decrease and go to step 331. In step 331, 1 is added to k, and the process proceeds to step 323.

On the other hand, in the case of Yes in step 323, in step 337, switching the injection valve _{V 2} which has been placed in the γ position to θ position. Thus, the processing liquid in the injection loop was connected to the injection valve V ₂ is, in a state of being sandwiched between the carrier and sent to the junction unit Y through line H. Here, the treatment liquid present in the injection loop is a treatment liquid having a pH within a predetermined range. By such processing, it becomes possible to send the sufficiently pretreated processing liquid to the junction Y.

  In the second best mode, the increase / decrease amount of the pretreatment liquid is gradually reduced by the number of steps, but under a predetermined condition (for example, when the liquidity does not change), You may comprise so that increase / decrease amount may not be changed (namely, combination with the 1st best form). That is, for example, even if the acid concentration of the sample liquid is very high, if the amount of the pretreatment liquid set by default is too small, the liquidity of the mixed liquid will not fall within the predetermined range. A situation is assumed. In such a case, in each step until the liquidity of the liquid mixture becomes alkaline, for example, the initial step width (50 in the above example) may be maintained.

Next, a modified example of the best mode will be described with reference to FIGS. In the above-mentioned best mode, the location where the pH detector is installed is out of the line to the analysis unit in order to avoid contamination based on ultra-trace analysis. The installation location may be within the line. For example, FIGS. 12 and 13 show a modification of the first best mode (FIG. 12 is a modification of FIG. 1 and FIG. 13 is a modification of FIG. 2). As shown in these figures, downstream of the merging section X, sample liquid pretreatment occurs in the mixed liquid of the alkali liquid from the tube A and the sample liquid from the tube C (hereinafter referred to as “treatment liquid”). A pretreatment unit MC1 in which the neutralization reaction} is performed, and a pH detector that measures the pH of the pretreated treatment solution. Further, downstream of the pH detector, a pipe G for circulating the processing liquid to an injection valve V ₂ described later, and a pipe H for circulating the carrier liquid and the processing liquid from the injection valve V ₂ to the junction Y And are provided.

Next, with reference to the flowchart of FIG. 14, according to a modified example of the first best mode, it will be described a valve switching process of the injection valve V _2. Here, the difference from FIG. 5 according to the first best mode is the presence of step 227 and step 229. More specifically, in the case of Yes in step 219, in step 227, the value obtained by dividing the distance from the pH detector to the valve V ₂ by the flow rate of the processing liquid is added to the current time (T). A switching time (T _x ) of V ₂ is determined. In other words, pH present in the detector processing liquid is a predetermined value (the pre-treatment liquid + sample liquid) to determine the time to reach the valve V _2. In step 229, it is determined whether or not the switching time _Tx has been reached. If Yes at step 229, in step 231, switching the injection valve _{V 2} which has been placed in the γ position to θ position. Thus, the processing liquid in the injection loop was connected to the injection valve V ₂ is, in a state sandwiched between the carrier and sent to the junction unit Y through line H.

Next, with reference to the flowchart of FIG. 15, according to a modification of the second best mode, illustrating the valve switch processing of the injection valve V _2. Here, the difference from FIG. 8 according to the second best mode is the presence of step 333 and step 335. In detail these, in the case of Yes in step 323, in step 333, by adding the value obtained by dividing the flow rate of the distance of the treatment liquid from the pH sensor to the valve V ₂ to the current time (T) The switching time (T _x ) of the valve V ₂ is determined. In other words, pH present in the detector processing liquid is a predetermined value (the pre-treatment liquid + sample liquid) to determine the time to reach the valve V _2. In step 335, it is determined whether or not the switching time _Tx has been reached. If Yes at step 335, in step 337, switching the injection valve _{V 2} which has been placed in the γ position to θ position. Thus, the processing liquid in the injection loop was connected to the injection valve V ₂ is, in a state of being sandwiched between the carrier and sent to the junction unit Y through line H. Here, the treatment liquid present in the injection loop is a treatment liquid having a pH within a predetermined range. By such processing, it becomes possible to send the sufficiently pretreated processing liquid to the junction Y.

  Hereinafter, the present invention will be specifically described with reference to Examples relating to measurement of iron concentration in an acidic sample solution. In the above-described best mode, the case where the flow rate of the sample liquid is fixed has been described as an example. However, in the present embodiment, both the sample liquid and the pretreatment liquid are changed in steps. First, FIG. 9 shows a system according to the present embodiment. The basic configuration is the same as in FIG. As shown in the figure, the pretreatment liquid (neutralization liquid: ammonium hydroxide aqueous solution) and the sample liquid are driven by independent step pumps. Hereinafter, various conditions other than those described in FIG. 9 are listed.

DPD (0.01M hydrochloric acid) = 0.024M
Ammonium hydroxide = 0.01M
Hydrogen peroxide = 0.5M (4M ammonium acetate pH 5.7)
Sample solution = iron ion concentration: 1 ppb, 5 ppb, 10 ppb

<Constant step type example>
Under the condition that the total amount of the sample liquid flow rate and the neutralization liquid flow rate is constant (1 ml / min), the flow rates of the sample liquid and the neutralization liquid are changed stepwise with time (see Table 2). In this example, 40 seconds per step was used, and the time lag between steps was about 20 seconds. In addition, in the measurement system, in consideration of the fact that the sample liquid does not need to be pretreated at the equivalence point, “pretreatment is completed” when it falls within the range of −0.2 to +0.2 V. The sample liquid that had been pretreated (more precisely, a mixed liquid of the sample liquid and the pretreatment liquid) was sent to the measurement system. As a result, in this example, “measurement OK” was obtained at the third step, and the sample liquid at this step was sent to the measurement system (measurement time about 100 seconds). Thus, as a result of measuring about three types of sample liquids from which iron ion concentration differs, the calibration curve in which a correlation coefficient exceeds 0.95 was obtained. FIG. 10 shows how the voltage of the pH detector changes with time.

<Example of variable step type>
Under the condition that the total amount of the sample solution flow rate and the neutralization solution flow rate is constant (1 ml / min), the flow rates of the sample solution and the neutralization solution are changed stepwise with time (see Table 3). The step width was set to ½ of the previous step width, and the increase / decrease direction was determined based on the positive / negative of the previous voltage. As a result, in this example, “measurement OK” was obtained at the third step, and the sample liquid at this step was sent to the measurement system (measurement time about 100 seconds). Thus, as a result of measuring about three types of sample liquids from which iron ion concentration differs, the calibration curve in which a correlation coefficient exceeds 0.97 was obtained. FIG. 11 shows how the voltage of the pH detector changes with time.

FIG. 1 is an overview of the FIA system according to the best mode. FIG. 2 is an overview (modified example) of the FIA system according to the best mode. FIG. 3 shows how the pretreatment liquid amount and the sample liquid amount change with time (first best mode). FIG. 4 shows how the pH of the treatment liquid changes as the quantity ratio between the pretreatment liquid and the sample liquid changes (first best mode). FIG. 5 is a flowchart of the valve switching process in the first best mode. FIG. 6 shows how the pretreatment liquid amount and the sample liquid amount change with time (second best mode). FIG. 7 shows how the pH of the treatment liquid changes as the quantity ratio between the pretreatment liquid and the sample liquid changes (second best mode). FIG. 8 is a flowchart of the valve switching process in the second best mode. FIG. 9 is an overview of the FIA system according to the embodiment. FIG. 10 shows how the voltage changes with time in the pH detector according to the example (constant step type). FIG. 11 shows how the voltage of the pH detector according to the example changes with time (variable step type). FIG. 12 is an overview of an FIA system according to a modified example of the best mode (FIG. 1). FIG. 13 is an overview of an FIA system according to a modification of the best mode (FIG. 2). FIG. 14 is a flowchart of valve switching processing in a modification of the first best mode. FIG. 15 is a flowchart of valve switching processing in a modification of the second best mode.

Claims (13)

Pretreatment means for pretreating the analysis target liquid by adding the pretreatment liquid to the analysis target liquid prior to analysis, and analysis means for analyzing the analysis target liquid pretreated by the pretreatment means In a flow analysis system capable of analyzing a predetermined component in an analysis target liquid,
The pretreatment means changes the flow rate ratio of the analysis target liquid and / or the pretreatment liquid, thereby changing the flow rate ratio with time, and the mixed liquid of the analysis target liquid and the pretreatment liquid. Liquid measurement means for measuring the liquid property, and liquid property determination means for determining whether or not the liquid property is in a predetermined state,
The flow rate ratio changing means has either a positive direction or a negative direction depending on the liquidity when the direction in which the flow ratio of the pretreatment liquid to the mixed liquid of the analysis target liquid and the pretreatment liquid increases is a positive direction. Function to change the flow rate ratio,
The flow analysis system is configured such that when the liquid property is in the predetermined state, the liquid mixture at the time of the predetermined state is guided to the analysis means.   The flow analysis system according to claim 1, wherein the flow rate ratio changing unit further includes a variable unit for changing the flow rate when changing the flow rate ratio.   The flow analysis system according to claim 2, wherein the variable means determines the change width when changing from one flow rate ratio to another flow rate ratio based on the measurement result of the liquid property at the certain flow rate ratio.   The variable means sets the change width when changing from one flow rate ratio to another flow rate ratio smaller than the previous change width, and based on the measurement result of the liquid property at the certain flow rate ratio, the flow rate The flow analysis system according to claim 3, wherein it is determined whether the ratio is changed in the positive direction or the negative direction by the change width.   The flow analysis system according to any one of claims 1 to 4, which is a flow injection analysis system.   The flow analysis system according to claim 1, wherein the pretreatment is a neutralization treatment.   The flow analysis system according to claim 6, wherein the liquid property measured by the liquid property measuring means is pH.   The flow analysis system according to claim 1, wherein the analysis is an analysis of a trace component in the analysis target liquid. Pretreatment means for pretreating the analysis target liquid by adding the pretreatment liquid to the analysis target liquid prior to analysis, and analysis means for analyzing the analysis target liquid pretreated by the pretreatment means In a flow analysis system capable of analyzing a predetermined component in an analysis target liquid,
The liquid measurement unit further includes a liquid property measurement unit that measures the liquid property of the analysis target solution that has been pretreated by the pretreatment unit, and the liquid measurement unit is configured so that the preprocessed analysis target solution is extracted from the pretreatment unit. A flow analysis system, wherein the flow analysis system is arranged outside a line led to the analysis means.   The flow analysis system according to claim 9, which is a flow injection analysis system.   The flow analysis system according to claim 9 or 10, wherein the pretreatment is a neutralization treatment.   The flow analysis system according to claim 11, wherein the liquid property measured by the liquid property measuring means is pH.   The flow analysis system according to any one of claims 9 to 12, wherein the analysis is an analysis of a trace component in a liquid to be analyzed.

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