JP2011038977A - Separation analysis method and separation analysis apparatus for redox material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a separation analysis method and a separation analysis apparatus which are useful for separating a redox material in a sample solution by utilizing a redox reaction. <P>SOLUTION: The separation analysis apparatus is configured so that an eluent R (mobile phase) is fed to a separation-use flow type electrolytic cell 10 (separation column electrode 100) and a separation-use flow type electrolytic cell 20 (detection column electrode 200) successively through a sample injector 32 (injecting means) by using a pump 31 (liquid feeding means). When separating and analyzing the redox material in the sample solution, the sample solution is injected from the sample injector 32 and introduced into the separation column electrode 100, and then a pulse voltage is repeatedly applied while making the sample solution flow in the separation column electrode 100, thereby separating the redox material contained in the sample solution. Next, a pulse voltage is applied to the detection column electrode 200, and the concentration of the redox material in the sample solution is analyzed on the basis of a value of a current flowing at that time. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a separation analysis method and a separation analysis apparatus for separating and analyzing a redox substance in a sample solution.

  Conventionally, for example, in the field of component analysis and environmental measurement, a separation analysis technique called liquid chromatography (LC) has been used. For example, Patent Documents 1 to 4 propose a technique for separating and analyzing a target component in a sample solution by using a flow-type column electrode and applying a voltage to the column electrode.

  Non-Patent Document 1 proposes a separation analysis method called electrolytic chromatography using a flow-type electrolytic cell. This method uses an oxidation-reduction reaction for separation, and the principle will be described as follows. The potential of the working electrode material such as silver particles packed in the chromatographic column is kept constant by applying a potential gradient so that the outlet side becomes negative. A sample solution containing metal ions is allowed to flow through this electrode, and the deposition potential is deposited on the electrode in order from the positive metal. Next, when the potential gradient is gradually decreased while flowing the eluent (mobile phase) through the column electrode, the deposition potential is eluted (striped) from the electrode in order from the negative metal. Metal ions are separated by this stripping. The eluent is introduced into a polarographic cell, and the quantity is determined by measuring the area of the current peak in the current-time curve obtained by tracking the diffusion current (electrolysis current) at a constant potential, that is, the quantity of electricity. Do.

  The idea of electrolytic chromatography has since been developed into a multistage column electrode electrolysis method in which multistage column electrodes are connected in series.

  Non-Patent Document 2 proposes that the multiple sweep method is applied to the column electrode to use both the elution potential difference and the precipitation potential difference of the two components in the separation of metal ions. Specifically, the sample solution is introduced from the sample inlet of the column with a microsyringe. The separation column electrode is set to a constant potential when the sample is introduced, and the multiple sweep is started after the sample is electrodeposited (deposited) on the column electrode. After separation by multiple sweep, the components remaining in the column are eluted from the column by setting the electrode potential to ± 0.0V. And the elution component of a separation column is quantified with the detection column electrode set to -0.90V.

  Non-Patent Document 3 proposes a separation analysis method called electrochemical chromatography (EMLC) in which high performance liquid chromatography (HPLC) and electrochemistry are fused. This method involves changing the surface electric field of the stationary phase by applying an external potential to the HPLC column packed with a conductive substance (stationary phase). In other words, by changing the adsorptivity of the stationary phase, It changes the time during which the target component is captured (held) in the column. Component capture in this method is basically the same as HPLC (ionic interactions, size exclusion, etc.) and uses an electric field to alter the stationary phase. In this method, the target component is an electrochemically inactive substance (not a redox substance) and does not use a redox reaction.

  Non-Patent Document 4 proposes a separation analysis method using EMLC, which is an advanced form of HPLC as in Non-Patent Document 3. In this method, an external potential is applied to the HPLC column to cause an oxidation-reduction reaction of the target component in the stationary phase, thereby changing the capture time of the target component in the column. However, the applied potential is a constant potential.

Taichiro Fujinaga, 3 others, “A new chromatographic method using electrolysis”, Nihon Kagaku Kabushiki, 1963, Vol. 84, No. 11, p.941-942 Yutaka Tomita and two others, “Separation of lead and tin by flow coulometric column electrode using multiple sweep method”, Analytical Chemistry (Bunseki Kagaku), 1977, Vol. 26, p.209-213 T. Nagaoka, 4 others, “Dynamic elution control in electrochemical ion chromatography using pulse perturbation of stationary phase potential”, Journal of Electroanalytical Chemistry, 1994, 371, p.283-286 Kazunori Saitoh, 5 others, “On-column electrochemical redox derivatization for enhancement of separation selectivity of liquid chromatography Use of redox reaction as secondary chemical equilibrium”, Journal of Chromatography A, 2008, 1180, p.66-72

  Among the non-patent documents, the separation analysis methods of Non-Patent Documents 1, 2, and 4 are those in which the component to be separated is a redox substance (metal ion or the like) and uses a redox reaction for separation. As a result of extensive studies by the inventors, it has been found that there are the following problems.

  In Non-Patent Document 1, it is difficult to apply a potential gradient to a single column electrode filled with metal particles such as silver particles, and this method results in insufficient separation of target components in a sample solution. Therefore, it developed into a multistage column electrode electrolysis method.

  Multi-stage column electrode electrolysis has made it possible to sufficiently separate multiple components of two or more components. However, since one component is captured in one column, at least the same number of column electrodes as the components to be separated are connected in series. It is necessary to connect to. For this reason, the multi-step process leads to complication of the apparatus. In addition, since it is necessary to increase the liquid feeding pressure of the mobile phase, problems such as damage to the column and the apparatus due to the increase in the internal pressure of the column frequently occur.

  Non-Patent Document 2 proposes that a multi-component is deposited on a single column electrode and that the multi-component is captured on a single column. When metal ions) are deposited, if these components continue for a certain period of time, these components undergo a chemical reaction (alloying), which causes a problem that they cannot be eluted thereafter. In Non-Patent Document 4, the applied potential is a constant potential, and the problem of alloying remains.

  The present invention has been made in view of the above circumstances, and one of its purposes is a separation analysis method and separation analysis apparatus useful for separating a redox substance in a sample solution using a redox reaction. Is to provide.

The separation analysis method of the present invention is a method for separating and analyzing a redox substance in a sample solution, and is characterized by comprising the following steps.
(1) Liquid feeding step for feeding the mobile phase to the separation column electrode (2) Injection step for injecting the sample solution to the mobile phase and flowing the sample solution to the separation column electrode (3) While flowing the sample solution to the separation column electrode Voltage application step of repeatedly applying a pulse voltage Note that the pulse voltage includes a pulse voltage including a deposition voltage for precipitating a specific redox material among redox materials and an elution voltage for re-eluting the deposited specific redox material. It is a voltage which has the following waveform. In the voltage application step, the specific oxidation-reduction substance is repeatedly trapped (held) on the electrode surface by repeatedly causing precipitation / re-elution on the separation column electrode, and the time for the substance to pass through the separation column electrode is determined. It is characterized in that the redox substance contained in the sample solution is separated by being delayed as compared with other substances not captured on the electrode surface.

  The separation analysis apparatus of the present invention is an apparatus for separating and analyzing a redox substance in a sample solution, a separation column electrode, a liquid feeding means for feeding a mobile phase to the separation column electrode, and a sample solution in the mobile phase. And a voltage applying means for repeatedly applying a pulse voltage to the separation column electrode. The pulse voltage is a voltage having a pulse-like waveform including a deposition voltage for depositing a specific redox substance among the redox substances and an elution voltage for re-eluting the deposited specific redox substance.

  The oxidation-reduction substance in the sample solution in the present invention typically includes metal ions, but is not limited to metal ions, and a substance whose adsorption ability to the electrode changes by causing an oxidation-reduction reaction. If available.

  According to the separation / analysis method and the separation / analysis apparatus of the present invention, it is possible to separate multiple components (multi-substances) using a single separation column electrode. For this reason, it is possible to avoid problems such as device complexity and liquid leakage due to increase in internal pressure due to multi-stage processing.

  For example, when applied to the separation of three substances, the deposition voltage may be set to a first deposition voltage at which the first substance is deposited and a second deposition voltage at which the first and second substances are deposited. . That is, when separating multiple substances, the deposition voltage may be controlled in accordance with the potential for causing each oxidation-reduction reaction. As the waveform of the pulse voltage, a rectangular wave, a sine wave, a triangular wave, a sawtooth wave, or the like can be selected. In addition, a set of waveforms such as a staircase or a slope may be used. Such a pulse waveform can be generated by, for example, an arbitrary waveform generator (function generator).

  In the present invention, the application of the pulse voltage causes the redox material to repeat deposition and re-elution. Therefore, even when different substances are deposited at the same position on the electrode surface, these substances (eg, metal ions) can be eluted before chemical reaction (alloying) and cannot be re-eluted. Is unlikely to occur. Furthermore, it is difficult to cause electrolysis of a solvent (for example, water) as a side reaction, and an improvement in accuracy can be expected.

  The application time (pulse width) of the deposition voltage in one pulse is desirably a short time, but within a range that does not cause a problem that these materials chemically react when different materials are deposited at the same position on the electrode surface. I just need it. For example, the pulse width of the deposition voltage is set in the range of 0.1 to 10 seconds. However, since the pulse width that does not cause the above-described problem is also affected by the electrolysis efficiency of the separation column electrode, it is desirable to set it according to, for example, the structure of the electrolytic cell used for the separation and the electrode material. In addition, by setting the pulse width of the deposition voltage within such a range, it is possible to suppress the chemical reaction between the deposited substance and the electrode material, and it is easy to avoid problems such as electrode deterioration and clogging. In addition, when the pulse voltage is composed of a deposition voltage and an elution voltage, the pulse width of the deposition voltage is, in other words, the time from when the elution voltage is applied until the next elution voltage is applied. is there.

In the separation and analysis method of the present invention, a more preferred form includes the following steps.
(4) Step of supplying the mobile phase that has passed through the separation column electrode to the detection column electrode connected in series to the separation column electrode (5) Applying a pulse voltage to the detection column electrode, and from the current value that flows when it is applied Analyzing the concentration of redox substances in the sample solution

  In the separation / analysis apparatus of the present invention, a more preferable form includes a detection column electrode to which a mobile phase that has passed through the separation column electrode is supplied, and an analysis means for analyzing the concentration of the redox substance in the sample solution. The detection column is connected in series to the separation column electrode. The analysis means applies a pulse voltage to the detection column electrode, and analyzes the concentration of the redox substance from the value of the current flowing when the pulse voltage is applied.

  According to these preferable methods and preferable apparatuses, separation and analysis can be performed in the same flow path. Specifically, in the separation process, a predetermined pulse voltage is applied to the separation column electrode, and a specific oxidation-reduction substance in the sample solution is intermittently captured, so that the movement time for each oxidation-reduction substance, that is, the separation column is determined. The time for passing through the electrode is changed to separate the redox material. In the analysis process, the mobile phase that has passed through the separation column electrode (separated for each oxidation-reduction substance at this time) is continuously supplied to the detection column electrode, and each of the oxidation-reduction substances separated in the detection column electrode. Qualitative and quantitative. Qualitative and quantitative determination is performed by applying a voltage to the detection column electrode to perform electrolysis, and measuring a current-time curve obtained by recording the relationship between the electrolytic current flowing at that time and time. For example, the passage time of each separated redox substance is obtained from the peak of the acquired current-time curve, and this is compared with the passage time of a specific redox substance (standard sample) obtained in advance under the same conditions. Can be identified. Further, for example, the concentration of the redox substance can be determined by determining the amount of electricity that has flowed during electrolysis, or by comparing the peak area of the acquired current-time curve with the peak area of the standard sample. .

  The separation column electrode in the present invention is preferably filled with a material mainly composed of carbon.

  An example of the structure of the separation column electrode is a structure in which a porous glass tube is filled with an electrode material. Here, as the electrode material, a carbon-based material such as glassy carbon (GC) or porous graphite carbon (PGC), or a metal-based material such as platinum, copper, silver, or gold can be used. It is preferable in that a chemical reaction with a deposited substance is difficult to occur as compared with a metal-based material. In addition, examples of the shape of the electrode material include a granular shape and a fibrous shape, but a granular shape is preferable from the viewpoint of electrolytic efficiency. For the glass tube, for example, a porous Vycor glass tube can be used. Similarly to the separation column electrode, the detection column electrode is preferably filled with a material mainly composed of carbon.

  The separation analysis method and separation analysis apparatus of the present invention can separate redox substances contained in a sample solution by using a single separation column electrode, and can suppress alteration due to a chemical reaction of the sample solution during voltage application. So it is very useful.

  Furthermore, since the present invention performs separation for each substance depending on the oxidation-reduction potential of the oxidation-reduction substance, for example, separation by the valence of the same metal ion (eg, Cr (III) ion and Cr (VI) ions) are considered possible.

It is a figure explaining an example of the composition of the separation analyzer concerning the present invention. It is a schematic diagram explaining the structure of a flow type electrolytic cell. (A) is a figure explaining the separation process in a separation column electrode, (B) is an example of the current-time curve obtained by a separation analyzer. It is a figure explaining the pulse voltage applied to a separation column electrode. 4 is a diagram showing a current-time curve obtained in Experimental Example 1. FIG. (A) shows the current-time curves of the solution in which Cd (II) ions are dissolved and the solution in which Cu (II) ions are dissolved. (B) is the solution in which Cd (II) ions and Cu (II) ions are dissolved. Shows the current-time curve of the solution.

  Embodiments of the present invention will be described with reference to the drawings. In addition, in the figure, the same code | symbol is attached | subjected to the same member.

(Separation analyzer)
The separation analyzer illustrated in FIG. 1 includes a separation flow type electrolytic cell 10 and an analysis flow type electrolytic cell 20, and the separation column electrode 100 and the detection column electrode 200 of these electrolytic cells are connected in series. ing. In this separation and analysis apparatus, an eluent R (mobile phase) is separated by a pump 31 (liquid feeding means) through a sample injector 32 (injection means), a flow type electrolytic cell 10 (separation column electrode 100) for separation, and an analysis The flow type electrolysis cell 20 (detection column electrode 200) is fed in order and drained. In addition, electrochemical measuring devices 41 and 42 (voltage applying means) are connected to the electrolysis cells 10 and 20, respectively, and a function generator 45 is connected to one electrochemical measuring device 41 and the other electrochemical cell is connected. A PC 50 for data recording is connected to the measuring device 42. This PC 50 controls the entire apparatus.

  When the redox substance in the sample solution is separated and analyzed, the sample solution is injected from the sample injector 32 using the syringe while the eluent R is fed and introduced into the separation column electrode 100. Also, data recording is started simultaneously with the injection of the sample solution. While flowing the sample solution to the separation column electrode 100, a pulse voltage is repeatedly applied from the electrochemical measuring device 41 to intermittently capture a specific redox substance on the electrode surface and separate the redox substance contained in the sample solution. To do. Next, the eluent R that has passed through the separation column electrode 100 is continuously supplied to the detection column electrode 200. A pulse voltage is applied to the detection column electrode 200 from the electrochemical measuring device 42, and the concentration of the redox substance in the sample solution is analyzed from the current value flowing at that time. Specifically, the electrolysis is performed by applying a voltage to the detection column electrode 200, and the current-time curve obtained by recording the time change of the current flowing at that time in the PC 50 is measured.

(Flow-type electrolytic cell)
The structure of the flow type electrolysis cell 10 for separation will be described with reference to FIG. In the electrolytic cell 10, a separation column electrode 100 is accommodated, and the outer side of the column electrode 100 is filled with an electrolytic solution. The column electrode 100 is configured by filling a porous Vycor glass tube 102 with glassy carbon (GC) particles 101 as an electrode material, and the GC particles 101 and the porous glass tube 102 function as a working electrode and an electrolytic diaphragm, respectively. A GC rod 103 serving as a lead is inserted into the column electrode 100 filled with GC grains. In addition, a liquid inlet 106 and a liquid outlet 107 are provided so that the eluent R moves from one end side to the other end side of the space filled with the GC particles 101 in the porous glass tube 102. Yes.

  In the electrolyte solution outside the column electrode 100, a coiled platinum wire 104 and an Ag / AgCl electrode 105 are disposed, and the platinum wire 104 and the Ag / AgCl electrode 105 function as a counter electrode and a reference electrode, respectively. One end of each of the GC rod 103 (working electrode), the platinum wire 104 (counter electrode) and the Ag / AgCl electrode 105 (reference electrode) is drawn out.

  The structure of the flow type electrolytic cell 20 for analysis is the same as the structure of the flow type electrolytic cell 10 for separation. In addition, a commercial item can be used for such a three-electrode flow type electrolysis cell.

  In the separation analyzer shown in FIG. 1, the liquid outlet of the separation column electrode 100 and the liquid inlet of the detection column electrode 200 are connected in series, and the eluent R that has passed through the separation column electrode 100 is directly applied to the detection column electrode 200. It is configured to be supplied. Thereby, separation and analysis can be performed in the same flow path. Further, the working electrode, the counter electrode, and the end of the reference electrode drawn out of the electrolysis cells 10 and 20 are connected to the electrochemical measuring devices 41 and 42, and a predetermined voltage is supplied from the electrochemical measuring devices 41 and 42 to the column electrodes 100 and 200. It is comprised so that it may be applied to. For example, in the electrochemical measurement device 41, the voltage applied to the separation column electrode 100 by the function generator 45 can be changed to a voltage having an arbitrary pulse waveform. When a voltage is applied to the column electrodes 100 and 200, a voltage is applied between both the working electrode and the counter electrode, and the potential between the two electrodes is regulated by the reference electrode.

(Separation process)
A separation process in the separation column electrode 100 will be described in detail with reference to FIG. Here, a case where three kinds of redox substances A to C in the sample solution are separated will be described as an example. The waveform of the pulse voltage applied to the separation column electrode 100 is shown on the left side of the figure, and the behavior of the three types of redox substances when the pulse voltage is applied to the separation column electrode 100 is shown on the right side of the figure. Shown in In the figure, the pulse voltage E is composed of a deposition voltage Ed for depositing a specific redox substance among the redox substances and an elution voltage Ee for re-eluting the deposited specific redox substance. In the figure, redox substance A is indicated by ◯, redox substance B is indicated by □, redox substance C is indicated by Δ, and the flow direction of eluent R is from the left to the right of the page.

The relationship between the redox potentials of the redox substances A to C is A>B> C. In FIG. 3 (A), the waveform of the pulse voltage E is shown in a simplified manner. Actually, the deposition voltage Ed is the first deposition voltage Ed _{A at} which the substance A is deposited, the first deposition voltage Ed _{A at} which the substance A and the substance B are deposited. It consists of two pulse voltages with a double deposition voltage Ed _B. The elution voltage Ee is a voltage at which the substance A and the substance B are eluted again.

  First, the redox substances A to C in the sample solution introduced into the separation column electrode 100 move in the flow direction of the eluent R. Further, while the elution voltage Ee is applied to the separation column electrode 100, the substances A to C continue to move together with the eluent R (see (a) of FIG. 3A).

When the first deposition voltage Ed _A of the deposition voltage Ed is applied to the separation column electrode 100, the substance A is deposited on the electrode surface, and the substance A is captured by the separation column electrode 100. During this time, substance B and substance C are not captured and continue to move. Thereafter, by applying an elution voltage Ee to the separation column electrode 100, the substance A is eluted again, and the substance A starts to move again after being delayed by the substances B and C. Next, when the second deposition voltage Ed _B of the deposition voltage Ed is applied to the separation column electrode 100, the substance A and the substance B are deposited on the electrode surface, and the substance A and the substance B are captured by the separation column electrode 100. become. During this time, substance C is not captured and continues to move. After that, by applying the elution voltage Ee to the separation column electrode 100 again, the substance A and the substance B are eluted again, and the substance A and the substance B begin to move again after the substance C (((A) in FIG. 3A) see b)).

  As described above, while the substances A to C are moving on the separation column electrode 100, the pulse voltage E is repeatedly applied to the separation column electrode 100, so that the substances A and B are repeatedly precipitated and re-eluted. Thus, substance A and substance B are intermittently trapped on the electrode surface. As a result, the moving speeds of the substances A, B and C change, so that the substances A to C are gradually separated (see (c) to (f) in FIG. 3A). .

Here, the moving speed of the substance A and the substance B depends on the time captured by the respective separation column electrodes 100, that is, the application time (pulse width) of the first deposition voltage Ed _A and the second deposition voltage Ed _B. Therefore, each pulse width is set so that the separation is sufficiently performed. Further, the pulse width is set within a range in which when the substances A and B are deposited at the same position on the electrode surface, these substances do not cause a chemical reaction.

  FIG. 3 (B) shows that the eluent R obtained by separating the substances A to C by passing the redox substances A to C in the sample solution through the separation column electrode is supplied to the detection column electrode. It is an example of the current-time curve obtained by recording the time change of the electrolysis current. Peak A, peak B, and peak C in the figure correspond to substance A, substance B, and substance C, respectively.

[Experimental Example 1]
The separation / analysis apparatus of FIG. 1 as described above was used to separate and analyze the redox material contained in the sample solution. The sample solution and separation analysis conditions were as follows.

<Sample solution>
The following solutions 1 to 3 were prepared as sample solutions.
Solution 1: 0.1 mol / dm ³ nitric acid solution to the Cd (II) ions is 100ppm lysis solution 2: 0.1 mol / dm ³ nitric acid solution to the Cu (II) ions 10ppm lysis solution 3: a 0.1 mol / dm ³ nitric acid 50ppm Cd (II) ion and 5ppm Cu (II) ion dissolved in the solution

<Eluent>
As the eluent, a 0.1 mol / dm ³ nitric acid solution was used, and the liquid feeding amount was set to 150 μL / min. The amount of liquid fed was controlled by a pump.

<Electrolysis cell>
The column electrode used was filled with GC particles having a particle diameter of 80 to 200 μm, and the same 0.1 mol / dm ³ nitric acid solution as the eluent was used as the electrolyte.

<Pulse voltage applied to the separation column electrode>
The pulse voltage applied to the separation column electrode had the waveform shown in FIG. 4, and was set to the deposition voltage Ed: −200 mV (pulse width td: 5.0 sec) and the elution voltage Ee: +800 mV (pulse width te: 0.8 sec). At -200 mV, Cu (II) ions are deposited on the separation column electrode, but Cd (II) ions are not deposited. On the other hand, +800 mV is a voltage at which Cu (II) ions deposited on the separation column electrode are re-eluted.

<Pulse voltage applied to detection column electrode>
The pulse voltage applied to the detection column electrode is the same as the pulse voltage applied to the separation column electrode as shown in FIG. 4, and the deposition voltage Ed: -800 mV (pulse width td: 0.25 sec), elution voltage Ee: +800 mV (pulse Width te: 0.75 sec).

  Under the above conditions, 20 μL of each of Solutions 1 to 3 was injected from the sample injector, and current-time curves in each case were measured. The result is shown in FIG. In FIG. 5 (A), the current-time curve (thick line) of solution 1 in which Cd (II) ions are dissolved and the current-time curve (thin line) of solution 2 in which Cu (II) ions are dissolved are shown in one figure. Shown together. FIG. 5B further shows a current-time curve (extremely thick line) of the solution 3 in which Cd (II) ions and Cu (II) ions are dissolved.

  As shown in FIG. 5A, it can be seen that the peak of the solution 2 appears with a delay compared to the peak of the solution 1. Therefore, in the case of Cd (II) ions, it is not captured by the separation column electrode and the time for passing through the separation column electrode is short, whereas in the case of Cu (II) ions, the separation column electrode is intermittently formed. It can be seen that the time taken and passed through the separation column electrode can be controlled. Therefore, according to the present invention, it is considered that a plurality of redox substances in the sample solution can be sufficiently separated.

  In fact, as shown in FIG. 5 (B), the two peaks of solution 3 are almost coincident with the peak of solution 1 and the peak of solution 2, and Cd (II) ions and Cu (II) ions are It is well separated and well possible to identify. Further, since the two peaks of the solution 3 are almost half of the peak of the solution 1 and the peak of the solution 2, respectively, it is possible to analyze the concentration of each redox substance in the sample solution.

[Modification 1]
In the separation / analysis apparatus illustrated in FIG. 1, the redox material in the sample solution is separated by the separation electrolytic cell 10 (separation column electrode 100) and then analyzed using the analysis electrolytic cell 20 (detection column electrode 200). However, various known detectors may be used for the analysis. For example, a UV detector, a mass spectrometer, an ICP emission spectrometer, an ICP mass spectrometer, or the like can be used. Moreover, when using such a detector, you may provide a deaeration apparatus, a mixing pump, etc. as needed.

  In addition, this invention is not limited to the above-mentioned Example, It can change suitably in the range which does not deviate from the summary of this invention. For example, in addition to changing the pulse voltage according to the redox material to be separated, the structure of the electrolytic cell and the electrode material may be changed as appropriate.

  The separation analysis method and separation analysis apparatus of the present invention are useful for separating redox substances in a sample solution. For example, as a more specific example such as component analysis or environmental measurement, it can be suitably used for measurement of metal ion concentration in the plating solution.

10 Flow electrolysis cell for separation 20 Flow electrolysis cell for analysis
31 Pump (liquid feeding means) 32 Sample injector (injecting means)
41,42 Electrochemical measurement device (voltage application means)
45 Function generator
50 PC (electronic computer)
R Eluent (mobile phase)
100 Separation column electrode 200 Detection column electrode
101 GC grains (working electrode)
102 Porous Vycor glass tube (electrolytic diaphragm)
103 GC bar
104 Platinum wire (counter electrode)
105 Ag / AgCl electrode (reference electrode)
106 Liquid inlet 107 Liquid outlet

Claims (5)

A method for separating and analyzing a redox substance in a sample solution,
A liquid feeding step of feeding a mobile phase to the separation column electrode;
Injecting a sample solution into the mobile phase and flowing the sample solution through the separation column electrode;
A voltage application step of repeatedly applying a pulse voltage while flowing the sample solution to the separation column electrode,
The pulse voltage is a voltage having a pulse-like waveform including a deposition voltage for precipitating a specific redox substance among the redox substances and an elution voltage for re-eluting the deposited specific redox substance,
In the voltage application step, the specific oxidation-reduction substance is intermittently trapped on the electrode surface by repeatedly causing precipitation / re-elution on the separation column electrode, and the time during which the substance passes through the separation column electrode A method for separating and analyzing a redox substance, characterized in that a redox substance contained in a sample solution is separated by being delayed as compared with other substances not captured on the surface. Supplying the mobile phase that has passed through the separation column electrode to a detection column electrode connected in series to the separation column electrode;
The method of claim 1, further comprising: applying a pulse voltage to the detection column electrode, and analyzing a concentration of the redox material in the sample solution from a current value flowing when the pulse voltage is applied. Separation analysis method.   The method for separating and analyzing a redox substance according to claim 1 or 2, wherein the separation column electrode is filled with a material mainly composed of carbon.   The method for separating and analyzing a redox substance according to any one of claims 1 to 3, wherein the redox substance is a metal ion. An apparatus for separating and analyzing a redox substance in a sample solution,
A separation column electrode;
A liquid feeding means for feeding a mobile phase to the separation column electrode;
Injection means for injecting a sample solution into the mobile phase;
Voltage application means for repeatedly applying a pulse voltage to the separation column electrode,
The pulse voltage is a voltage having a pulse-like waveform including a deposition voltage for depositing a specific redox substance among the redox substances and an elution voltage for re-eluting the deposited specific redox substance. A device for separating and analyzing redox substances.

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