JP7571554B2 - pH measuring device and liquid chromatograph - Google Patents

Description

The present invention relates to a pH measurement device that measures the pH of a liquid and a liquid chromatograph in which the pH of a mobile phase is measured by the pH measurement device.

A pH measurement device that measures the pH of a liquid flowing through a flow cell is known (see Patent Document 1). In addition to the flow cell, such a pH measurement device includes a pair of electrodes inserted into the flow cell, and a circuit section that detects the pH of the liquid flowing through the flow cell via the electrodes. Such a pH measurement device is sometimes introduced into a liquid chromatographic analysis system (hereinafter, LC system), and can be used as an online monitor of the pH of the mobile phase.

JP 2008-256488 A

When the pH measuring device is configured as one module to be mounted on an LC system, the flow cell, electrode, and circuit unit are mounted in the same housing. However, since the electrode is a consumable part that deteriorates, it needs to be replaced as necessary. When replacing the electrode, it is necessary to disconnect and connect the electrode to the circuit unit, but this is difficult to do when the connection between the electrode and the circuit unit is inside the housing. It is possible to provide a connector for connecting the electrode to the circuit unit on the front of the housing, but this would hinder the miniaturization of the housing, and there is also the problem that providing such a connector on the front of a miniaturized housing makes it difficult to work with.

The present invention was made in consideration of the above problems, and aims to make it easier to replace electrodes.

The pH measuring device according to the present invention comprises an electrode section having a measurement electrode and an electrode side connector integrally connected to the measurement electrode, a housing having a front section on which the electrode section is arranged, a circuit section stored inside the housing and including an electric circuit for measuring the pH of the liquid through the measurement electrode of the electrode section, a circuit side connector that is drawn out from the circuit section and electrically connects the circuit section to the measurement electrode by connecting the electrode side connector, and a moving section having an attachment section to which the electrode section is detachably attached and movable so that the electrode section attached to the attachment section can be in a first state in which the electrode section attached to the attachment section is arranged on the front section of the housing, and in a second state in which the attachment section is drawn forward from the front section of the housing, and the circuit side connector is mounted on the moving section so that it is stored inside the housing when the moving section is in the first state, and is drawn forward from the front section of the housing and exposed to the outside of the housing when the moving section is in the second state.

The pH measuring device according to the present invention is configured so that when the mounting section is pulled forward beyond the front surface of the housing, the circuit side connector pulled out from the circuit section is also pulled forward of the housing and exposed to the outside of the housing, so that the electrode section and the circuit section can be connected and disconnected outside the housing, making it easy to replace the electrode.

1 is a perspective view showing a first state of an embodiment of a pH measuring device, as viewed obliquely from the front. FIG. FIG. 2 is a perspective view showing the configuration of an electrode portion according to the embodiment. FIG. 2 is a view showing the top plate of the housing in a transparent state as viewed from above in the first state. 11 is a perspective view showing a second state in which the moving part is pulled forward in the embodiment, as seen obliquely from the front. FIG. 13 is a view showing the top plate of the housing in the second state as viewed from above in a transparent manner. FIG. FIG. 1 is a schematic diagram showing an embodiment of a liquid chromatograph incorporating a pH measuring device.

Below, we will explain one embodiment of the pH measuring device according to the present invention with reference to the drawings.

As shown in Figures 1 and 2, the pH measuring device of this embodiment includes a housing 2, an electrode unit 4, a moving unit 6, a circuit unit 8, and a circuit-side connector 10.

The housing 2 has a front and a back, and the electrode section 4 is disposed on the front section 14 of the housing 2. The electrode section 4 includes a flow cell 16, a measurement electrode 18, an electrode holder 20, wiring 22, and an electrode side connector 24. The flow cell 16 has an inlet and an outlet on the side for the inflow and outflow of liquid (e.g., the mobile phase of a liquid chromatograph), and liquid flows inside. The measurement electrode 18 has a pair of electrodes arranged with their tips facing vertically downward, and the tips of these electrodes are inserted into the flow cell 16 from above and sealed and fixed. The electrode holder 20 is a block-shaped member that holds the base end of the measurement electrode 18. Wiring 22 that is electrically connected to the measurement electrode 18 is drawn out from the electrode holder 20, and the electrode side connector 24 is provided at the tip of the wiring 22.

The electrode holder 20 of the electrode unit 4 is detachably attached to the attachment unit 12 provided at one end of the moving unit 6. In this embodiment, in order to easily attach and detach the electrode unit 4 to and from the attachment unit 12, a structure is adopted in which a convex protrusion provided on the electrode holder 20 is fitted into a groove provided on the attachment unit 12 to engage the electrode unit 4. The attachment unit 12 is a plate-like member and is provided so as to form part of the front panel of the housing 2. Note that these structures are merely examples, and any structure for attaching and detaching the electrode unit 4 to the attachment unit 12 may be used, and the attachment unit 12 does not have to be a plate-like member that forms part of the front panel of the housing 2. The housing 2 may be provided with an openable or removable cover that covers the front part 14.

As shown in FIG. 3, the electrode unit 4 includes a flow cell 16, a measurement electrode 18, an electrode holder 20, wiring 22, and an electrode side connector 24, and the entire electrode unit 4 can be replaced by attaching and detaching the electrode holder 20 to the mounting portion 12.

The circuit unit 8 and the circuit side connector 10 are mounted on the moving unit 6. The circuit side connector 10 is provided at the tip of the wiring 28 drawn out from the circuit unit 8, and the circuit unit 8 and the measurement electrode 18 of the electrode unit 4 are electrically connected by connecting the electrode side connector 24 of the electrode unit 4. The circuit unit 8 includes an electric circuit for measuring the pH of the liquid flowing in the flow cell 16 via the measurement electrode 18 of the electrode unit 4. The circuit unit 8 is connected to wiring 30 for receiving power and communicating with external devices.

The moving part 6 has a longitudinal direction, and is arranged so that the tip where the mounting part 12 is provided faces the front side of the housing 2. The moving part 6 is arranged so that it can move in one axial direction parallel to the longitudinal direction (left and right direction in FIG. 2) along a linear guide rail 26 provided inside the housing 2.

In Figures 1 and 2, the moving part 6 is in a state (first state) when the pH measuring device is in use, that is, when a liquid is flowing through the flow cell 16 to measure the pH. In this first state, the electrode part 4 attached to the mounting part 12 is placed on the front part 14 of the housing 2, and the circuit part 8 and the circuit side connector 10 are stored inside the housing 2.

Figures 4 and 5 show a state (second state) in which the moving part 6 is pulled out to the front of the housing 2 (left side in Figure 5) in order to replace the electrode part 4. In this second state, as the moving part 6 is pulled out to the front of the housing 2, the circuit side connector 10 mounted on the moving part 6 is also pulled out to the front of the housing 2 and exposed to the outside.

When replacing the electrode unit 4, it is necessary not only to attach and detach the electrode holder 20 to and from the mounting portion 12, but also to electrically connect and disconnect the electrode unit 4 and the circuit unit 8. In this embodiment, as described above, the circuit side connector 10 for electrically accessing the circuit unit 8 is pulled forward of the housing 2 and exposed to the outside of the housing 2 when the moving portion 6 is pulled forward of the housing 2, so that the operation of electrically connecting and disconnecting the electrode unit 4 to the circuit unit 8 is easy.

In the above embodiment, the circuit unit 8 is mounted on the moving unit 6 together with the circuit side connector 10 and is configured to move with the movement of the moving unit 6, but the present invention is not limited to this. The circuit unit 8 may be fixed at a specific position within the housing 2, and only the circuit side connector 10 may be mounted on the moving unit 6.

In addition, in the above embodiment, the flow cell 16 is integrated with the measurement electrode 18 to form a single electrode unit 4, but the present invention is not limited to this, and the electrode unit 4 does not necessarily have to include the flow cell 16.

The pH measuring device described above can be incorporated into a liquid chromatograph and used to measure the pH of the mobile phase of the liquid chromatograph. FIG. 6 shows an example of a liquid chromatograph incorporating the pH measuring device 1. The liquid chromatograph is provided with a liquid delivery pump 102, an injector 104, a separation column 106, and a detector 108, in that order from the upstream side, on an analysis flow path 100 for separating and analyzing samples, and a flow cell 16 of the pH measuring device 1 is connected downstream of the detector 108. The mobile phase is delivered through the analysis flow path 100 by the liquid delivery pump 102, the sample is injected into the mobile phase by the injector 104, the components in the injected sample are separated by the separation column 106, and each separated component is detected based on the detection signal of the detector 108. The mobile phase flowing out from the outlet of the detector 108 flows through the flow cell 16 of the pH measuring device 1, and the pH of the mobile phase is measured via the measurement electrode 18.

The above-described embodiment is merely one example of an embodiment of the pH measurement device according to the present invention. The embodiment of the pH measurement device according to the present invention is as follows.

In one embodiment of the pH measuring device according to the present invention, the device includes an electrode section having a measurement electrode and an electrode side connector drawn from the measurement electrode to make electrical contact with the measurement electrode, a housing having a front surface on which the electrode section is disposed, a circuit section stored inside the housing and including an electric circuit for measuring the pH of the liquid through the measurement electrode of the electrode section, a circuit side connector drawn from the circuit section and for electrically connecting the circuit section to the measurement electrode by connecting the electrode side connector, and a moving section having an attachment section to which the electrode section is detachably attached and movable so that the electrode section attached to the attachment section can be in a first state in which the electrode section attached to the attachment section is disposed on the front surface of the housing, and in a second state in which the attachment section is drawn forward from the front surface of the housing, and the circuit side connector is mounted on the moving section so that it is stored inside the housing when the moving section is in the first state, and is drawn forward from the front surface of the housing and exposed to the outside of the housing when the moving section is in the second state.

In the first aspect of the above embodiment, the moving part is arranged to slide in one axial direction along a linear guide rail provided inside the housing. This aspect allows the moving part to be easily moved.

In the second aspect of the above embodiment, the circuit unit is mounted on the moving part. With this aspect, the relative positional relationship between the circuit unit and the circuit-side connector does not change even when the moving part is moved, so the wiring length can be shortened. This has the effect of simplifying the wiring, reducing noise, and preventing the wiring from being pinched by the slide rail. This second aspect can be combined with the above first aspect.

In a third aspect of the above embodiment, the electrode unit includes a flow cell into which the tip of the measurement electrode is inserted. With this aspect, it is not necessary to remove the measurement electrode from the flow cell when replacing the measurement electrode, which makes it easier to replace the measurement electrode and prevents cross-contamination. This third aspect can be combined with the above first aspect and/or second aspect.

In a fourth aspect of the above embodiment, the electrode unit includes a block-shaped electrode holder that is attached to the attachment unit while holding the measurement electrode, and the attachment unit includes a groove that engages with the electrode holder by fitting a protrusion provided on a side of the electrode holder, and the electrode unit is attached to the attachment unit by fitting the protrusion of the electrode holder into the groove of the attachment unit. This aspect makes it easy to attach and detach the electrode unit to and from the attachment unit. This fourth aspect can be combined with the above first aspect and/or second aspect and/or third aspect.

In a fifth aspect of the above embodiment, the mounting portion of the moving portion is a plate-like member that constitutes a part of the front panel of the housing when in the first state. This fifth aspect can be combined with the first aspect and/or the second aspect and/or the third aspect and/or the fourth aspect.

One embodiment of the liquid chromatograph according to the present invention includes an analysis flow path for separating and analyzing samples, and the above-mentioned pH measurement device having a flow cell through which the mobile phase flowing in the analysis flow path flows and measuring the pH of the mobile phase flowing in the flow cell.

2 Housing 4 Electrode section 6 Moving section 8 Circuit section 10 Circuit side connector 12 Mounting section 14 Front section 16 Flow cell 18 Measurement electrode 20 Electrode holder 22, 28, 30 Wiring 24 Electrode side connector 26 Guide rail

Claims (7)

an electrode portion having a measurement electrode and an electrode side connector drawn from the measurement electrode for making electrical contact with the measurement electrode;
a housing having a front surface on which the electrode portion is disposed;
a circuit section that is housed inside the housing and includes an electric circuit for measuring the pH of a liquid through the measurement electrode of the electrode section;
a circuit-side connector that is pulled out from the circuit unit and that electrically connects the circuit unit to the measurement electrodes by connecting the electrode-side connector;
a moving section provided movably so as to be capable of taking a first state in which the electrode section attached to the mounting section is disposed on the front surface of the housing, and a second state in which the mounting section is pulled forward beyond the front surface of the housing,
A pH measuring device, wherein the circuit side connector is mounted on the movable part so that it is stored inside the housing rearward of the front portion when the movable part is in the first state, and is pulled forward of the front portion of the housing and exposed to the outside of the housing when the movable part is in the second state. The pH measuring device according to claim 1, wherein the moving part is arranged to slide in one axial direction along a linear guide rail provided inside the housing. an electrode portion having a measurement electrode and an electrode side connector drawn from the measurement electrode for making electrical contact with the measurement electrode;
a housing having a front surface on which the electrode portion is disposed;
a circuit section that is housed inside the housing and includes an electric circuit for measuring the pH of a liquid through the measurement electrode of the electrode section;
a circuit-side connector that is pulled out from the circuit unit and that electrically connects the circuit unit to the measurement electrodes by connecting the electrode-side connector;
a moving section provided movably so as to be capable of taking a first state in which the electrode section attached to the mounting section is disposed on the front surface of the housing, and a second state in which the mounting section is pulled forward beyond the front surface of the housing,
the circuit-side connector is mounted on the moving part so as to be stored inside the housing when the moving part is in the first state, and to be pulled forward beyond the front part of the housing and exposed to the outside of the housing when the moving part is in the second state;
The circuit unit is mounted on the moving unit, the pH measuring device. The pH measurement device according to any one of claims 1 to 3, wherein the electrode unit includes a flow cell into which the tip of the measurement electrode is inserted. an electrode portion having a measurement electrode and an electrode side connector drawn from the measurement electrode for making electrical contact with the measurement electrode;
a housing having a front surface on which the electrode portion is disposed;
a circuit section that is housed inside the housing and includes an electric circuit for measuring the pH of a liquid through the measurement electrode of the electrode section;
a circuit-side connector that is pulled out from the circuit unit and that electrically connects the circuit unit to the measurement electrodes by connecting the electrode-side connector;
a moving section provided movably so as to be capable of taking a first state in which the electrode section attached to the mounting section is disposed on the front surface of the housing, and a second state in which the mounting section is pulled forward beyond the front surface of the housing,
the circuit-side connector is mounted on the moving part so as to be stored inside the housing when the moving part is in the first state, and to be pulled forward beyond the front part of the housing and exposed to the outside of the housing when the moving part is in the second state;
The electrode unit includes a block-shaped electrode holder that is attached to the attachment unit while holding the measurement electrode,
the mounting portion includes a groove into which a protrusion provided on a side surface of the electrode holder is fitted to engage with the electrode holder,
A pH measuring device, wherein the electrode portion is attached to the mounting portion by fitting a protrusion of the electrode holder into the groove of the mounting portion. The pH measuring device according to any one of claims 1 to 5, wherein the mounting portion of the moving portion is a plate-like member that constitutes part of the front panel of the housing when in the first state. an analysis flow path for separating and analyzing a sample;
A liquid chromatograph comprising: a flow cell through which a mobile phase flows in the analysis flow path; and a pH measurement device according to any one of claims 1 to 6, which measures a pH of the mobile phase flowing in the flow cell.

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