JPH0534621B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an electrochemical detector, and particularly to an electrochemical detector having a structure in which a working electrode thereof can be attached and detached with a single touch operation.

BACKGROUND TECHNOLOGY As is well known, an electrochemical detector is a detector that electrochemically measures substances based on the relationship between potential and current between a working electrode and a counter electrode placed in a cell flow path through which a test liquid flows. Generally, each electrode structure is inserted into a cell block that forms a cell flow path, and is integrally fixed with the cell block by screws or the like.

Problems to be Solved by the Invention On the other hand, in recent years, catecholamines and other biological substances have been increasingly used as measurement targets for electrochemical detectors.
In particular, since the working electrode is easily soiled, the cell structure must be disassembled and cleaned, and the assembly after disassembly and cleaning requires a great deal of effort and effort.
In addition, it is necessary to replace the electrodes depending on the type of sample to be measured, and in such cases, if you try to replace only the electrodes, it is necessary to completely separate the fixed and electrically connected electrodes, which are dimensionally finished as a single piece. However, a new electrode of the same shape made of a different electrode material must be attached, fixed, and connected in the same manner, which requires an extremely complicated operation.

An object of the present invention is to provide an electrochemical detector having a one-touch attachment/detachment structure for a working electrode and a cell disassembly structure, which eliminates the drawbacks of conventional fixed electrode electrochemical detectors as described above.

Means for Solving the Problems In order to achieve the above object, the present invention has a cell inlet flow path and an outlet flow path, and
a cell block equipped with a reference electrode and a counter electrode arranged so as to be in contact with the test liquid passing through the outlet channel; a gasket having an opening for forming a cell channel in cooperation with the cell block; a working electrode plate that is pressed from the opposite side of the cell block and has an exposed electrode surface for generating a potential difference with the counter electrode on a surface surrounding the cell flow path corresponding to the opening of the gasket; and the working electrode. a pressing operation mechanism having a tip that presses the back surface of the plate directly or indirectly through an intermediate member substantially in point contact; and a spring means that biases the tip in the pressing direction; An electrochemical detector comprising: an operating mechanism for producing a pressed position and a retracted position of the working electrode plate; and a clamp member for maintaining the pressed position of the pressing operation mechanism by the operating mechanism. It is composed of

Function In the electrochemical detector of the present invention, in the above configuration, when the user operates the operating mechanism to set the pressing mechanism to the backward position and releases the clamp member from the main body in this state, the cell block and gasket are removed. , and the working electrodes are released from the pressure exerted by the pressing mechanism and can be separated individually, making it easy to clean the inside of the cell flow path or replace working electrode plates of the same shape. It is something.

Embodiment FIGS. 1 and 2 show one side and a back view, respectively, of an electrochemical detector in an embodiment of the present invention. In Fig. 1, 1 is a metal block cover plate, and 2 is a screw 1a attached to the block cover plate 1.
3 is a block holding plate that holds the cell block from the opposite side of the block cover plate 1, preferably by the screw 1a inserted from the block cover plate 1 side. It is fixed on the back of 2. Further, numeral 4 denotes a mechanism section for integrally holding and separating the cell flow path and the electrode structure in cooperation with the block holding plate 3. The block holding plate 3 is a disc portion 2 that protrudes from the back surface of the cell block 2.
a flat plate portion having a central opening 3a that fits into the central opening 3a; and an upper bearing protrusion that projects rearward from the flat plate portion and engages with a pair of bearing protrusions 5 and 6 formed at the upper and lower front surfaces of the mechanism portion 4, respectively. 7 and a lower bearing protrusion 8. The main body case of the mechanism section 4 supports, at its rear end, a shaft 10 that supports an operating lever 9 along one side thereof, and accommodates a press operation mechanism 11 that is moved back and forth by a cam mechanism fixed to the shaft, which will be described later. This is what I did. The tip of the pressing mechanism 11 protrudes from the opening at the center of the tip of the mechanism section 4, and furthermore, the tip is a partial spherical surface of a metal ball 12 that partially protrudes from the main body case of the mechanism 11, and this is a bearing protrusion. The electrode holding plate 13 located between 5 and 6 is pressed by substantially point contact.

That is, in the space formed between the bearing protrusions 5 and 6 of the mechanism part 4 and between the bearing protrusions 7 and 8 of the electrode holding plate, the back surface of the flat plate part of the block holding plate 3 and the end face of the disc part 2a of the cell block 2 are located. a gasket 14 in contact with the electrode holding plate 13;
There is a working electrode 15 located between them, which forms a cell flow path structure and a working electrode mounting structure that can be assembled and separated. Note that a counter electrode 16, its lead wire 17, and a cell inlet fitting 18 are protruded from the front center of the block cover plate.
Furthermore, a cell outlet fitting 19 is provided protruding from the upper side of the cell block 2. A clamp pin 20 is inserted into the mutually aligned bearing holes of the upper bearing protrusion 5 of the mechanism part 4 and the upper bearing protrusion 7 of the block holding plate, and the clamp pin 20 is inserted into the bearing hole of the upper bearing protrusion 5 of the mechanism part 4 and the upper bearing protrusion 7 of the block holding plate 3. A pivot pin 21 is inserted and fixed in the bearing hole in which the projections 8 are aligned.

As shown in FIG. 2, there is a knob 22 on the side of the electrochemical detector on the operating lever 9 side for inserting and removing the clamp pin 20, and a reference electrode insertion port 23 is provided on the same side of the cell block 2.
and a reference electrode structure 24 inserted into the cell block from here, and a horizontal protection rod 25 having a vertical groove for protecting the vertically bent end of this electrode structure 24.
is installed protrudingly.

Now, the state of the electrochemical detector shown in FIGS. 1 and 2 is in the clamp position where the clamp pin 20 is inserted and the operating lever 9 is held almost upright. 2
The gasket 14 and working electrode 15 are pressed into contact with each other in order to form a cell flow path and an electrode fixing structure.
When the operating lever 9 is rotated downward as shown by the arrow R in FIG. 1, the pressing mechanism 11 retreats and the ball 12 separates from the electrode holding plate 13, as shown in FIG. Until now, due to the pressing operation of the pressing operation mechanism 11, the frictional force acting on the clamp pin as the upper bearing projection 5 of the mechanism section 4 and the upper bearing projection 7 of the block holding plate 3 tend to separate from each other is released. As a result, the clamp pin 20 is in a state where it can be easily pulled out, and when the user pulls out the clamp pin 20 in this state, it is removed from the block cover plate 1, cell block 2, and block holding plate 3, as shown in FIG. The constructed block unit 26 rotates downward about the pivot pin 21 so as to be separated from the mechanism section 4, and the electrode holding plate 13, gasket 14, and working electrode 15 are in a state where they can be separated from this block unit 26. becomes. The stand 4a shown virtually in FIGS. 1 to 4 supports the mechanism section 4 by slightly lifting it from the workbench surface (not shown), and allows the block unit 26 to rotate downward. Next, before explaining the separation structure of the electrodes and the like, the internal structure of the pressing mechanism will be explained with reference to FIG. 3 again.

As shown in FIG. 3, the pressing mechanism 11 holds a metal ball 12 at the tip of its sleeve-like main body, and a coil spring 27 installed behind it.
The ball 12 is moved by a movable disk 28 supported at the tip of the
The ball 12 is pressed and supported from behind, and the ball 12 is restrained in a constant protruding state by a diaphragm opening 29 in the sleeve-like main body. A back support piece 30 of the spring 27 is fixed to the rear end of the pressing mechanism 11, and the rear end surface of this back support piece 30 is connected to the shaft 1.
The cam floor surface is driven by a cam 31 that is fixedly supported at 0. As a result, when the operating lever 9 is rotated from the near-horizontal tilted angle shown in FIG. 3 to the nearly upright angle shown in FIGS. 1 and 2, the pressing mechanism 11 moves to the position shown in FIG. At this time, the working electrode 15 and the like are attached as shown in the figure, and the clamp pin 20 is inserted into the bearing holes of the aligned bearing protrusions 5 and 7, and is subjected to tensile force from both sides. This results in a clamped state that can be used as an electrochemical detector.

In this clamped state, the cross-sectional structures of the disk portion 2a of the cell block, the gasket 14, the working electrode 15, and the electrode holding plate 13 are as shown in FIG. In FIG. 5, the cell channel chamber itself of the electrochemical detector is defined by the space S between the end face of the block disk portion 2a and the corresponding end face of the working electrode 15.
formed within. The space, that is, the cell channel chamber S, is limited by an opening punched in a gasket 14 made of a Teflon sheet or the like, and its thickness, that is, the distance between the end surface of the disk portion 2a and the working electrode 15, is limited by the compression of the gasket 14. It is regulated by thickness. The working electrode 15 is fixedly supported within the central opening of a plastic supporting plate 15a that is slightly thinner than the electrode body, and the front end surface of the electrode 15 is connected to a liquid outlet slit 32 provided in the disk portion 2a. It faces the tip 16a of the counter electrode 16. In the disc portion 2a, a small hole 33 provided below the liquid outlet slit 32 is an end of the inlet flow path communicating with the inlet flow path fitting 18 shown in FIG. The aforementioned liquid outlet slit 32 and small hole 33 are located within the confines of the flow chamber S bounded by the gasket 14. An electrode contact plate 13a made of a conductive metal is inserted into the front surface of the electrode holding plate 13 so as to slightly protrude from the front. The lead wire 13b serves to connect the working electrode 15 to an external circuit. The electrode holding plate 13 itself is made of a suitable plastic material, and a metal lining 13c is inserted into the back surface of the plate so as to slightly protrude, and this exposed surface is pressed into contact with the ball 12 of the pressing mechanism. There is.

FIG. 6 is a sectional view showing a state in which the gasket 14, the working electrode 15, and the holding plate 13 are separated from the block unit 26, and the flow path structure within the cell block 2. In FIG. 6, the gasket 14, the working electrode 15 and the holding plate 13 are connected to the block unit 2.
The cell block 2 has a guide hole that aligns with a pair of guide pins 34 projecting rearward from the block holding plate 3 at 6, so that the cell block 2 is aligned and held with the disc portion 2a of the cell block 2. From the front of the cell block 2, within the range of the opening 1b formed in the electrode cover plate 1, there are formed a counter electrode insertion hole 35 that corresponds to and communicates with the liquid outlet slit 32, and a cell inlet channel 36 that communicates directly with the small hole 33. has been done. Further, an exit hole 37 extending upward from the middle portion of the counter electrode insertion hole and a reference electrode insertion hole 38 extending to one side of the cell block 2 are formed. The gasket 14 attached to the end face of the disk portion 2a of the cell block is provided with a relatively thin reinforcing lining sheet 14a having an opening sufficiently larger than the opening forming the flow path chamber S.
has been installed. FIG. 7 shows the back side of such a gasket 14, where 39 is an opening having a semicircular or U-shaped outline forming the flow path chamber S, 40 is an opening formed in the backing sheet, Furthermore, 41a and 41b are guide holes corresponding to the guide pins 34.

Channel chamber forming opening 39 and cell block disc portion 2
The positional relationship between a and the slit 32 and the small hole 33 is as shown in FIG. That is, the horizontal upper edge 39a of the U-shaped opening 39 is located parallel to the slit 32 and slightly outside, and the lower end of the U-shaped curved edge 39b is located slightly below the small hole 33. Therefore, the test liquid flowing in from the small hole 33 diffuses and flows into the cell flow path chamber in the opening 39, rises, and flows out from the liquid outlet slit 32 at the upper end, as shown in FIGS. 6 and 9.
It will be discharged through the outlet channel 37 shown in the figure. In the cell flow path chamber S, the working electrode 15 is fully exposed on the opposite side of the cell block, so the entire liquid phase of the test liquid is in contact with the working electrode 15 very efficiently, ensuring accuracy and reproducibility. This allows for highly sensitive analysis.

In addition, the noise generated by the elastic deformation of air bubbles generated and accumulated in the cell chamber of the conventional electrochemical detector or in the insertion hole of each electrode according to the pressurized state of the test liquid can be eliminated by the above-mentioned embodiment. can be completely eliminated in the structure. That is,
This is because the bubbles generated in the cell chamber S move from the slit 32 at the upper end to the outlet flow path 37, float through this flow path, and disappear immediately.

Effects of the Invention As described above, the present invention allows these cells and electrode assembly structures to be disassembled with a single touch in order to clean the cell chamber and the electrode surface or to replace the working electrode, and when replacing the working electrode, simply separate It can be assembled immediately by simply placing the working electrode unit in place. In addition, since the cell chamber is formed within the opening of the gasket and is extremely thin, it has excellent effects in use and measurement, such as allowing the working electrode exposed in this opening to work extremely efficiently. It is something that can be demonstrated.

[Brief explanation of the drawing]

FIG. 1 is a side view of an electrochemical detector according to an embodiment of the present invention, FIG. 2 is a rear view thereof, FIG. 3 is a partially cutaway plan view thereof, and FIG. 4 is a diagram of an electrochemical detector according to an embodiment. FIG. 5 is a side view showing the block unit separated from the mechanical part, FIG. 5 is a cross-sectional view of essential parts showing the cell flow path and working electrode holding structure, and FIG. 6 is a side view showing the cell flow path components separated from the block unit. 7 is a rear view of the gasket forming the cell flow path chamber, FIG. 8 is a plan view showing the correspondence between the cell block end face and the gasket, and FIG. 9 is a flow path configuration of the cell block. It is an AA sectional view of. 2...Cell block, 11...Press operation mechanism,
12... Ball, 13... Electrode holding plate, 14...
Gasket, 15... working electrode, 18... cell inlet fitting, 19... cell outlet fitting, 20... crank pin, 21... pivot pin, 23... reference electrode insertion port, 24... reference electrode structure, 26...Block unit, 32...Liquid outlet slit, 33...
Small hole, 34... Guide pin, 35... Counter electrode insertion hole, 36... Cell inlet channel, 37... Outlet hole, 3
8... Reference electrode insertion hole, 39... Gasket opening.

Claims (1)

[Scope of Claims] 1. A cell block having a cell inlet channel and an outlet channel, and equipped with a reference electrode and a counter electrode arranged so as to be in contact with a test liquid passing through the outlet channel; and a cell block that cooperates with the cell block. a gasket having an opening for forming a cell flow path; and a gasket that is pressed against the gasket from the opposite side of the cell block, and has a potential difference with the opposite electrode on a surface surrounding the cell flow path corresponding to the opening of the gasket. a working electrode plate having an exposed electrode surface for producing the same; a tip portion that presses the back surface of the working electrode plate directly or indirectly through an intermediate member with substantially point contact; a push actuation mechanism having a spring means for biasing the push actuation mechanism in the direction; an actuation mechanism for producing the working electrode plate of the push actuation mechanism in a pressed position and a retracted position; An electrochemical detector comprising: a clamp member for maintaining the electrochemical detector. 2. As an intermediate member interposed between the working electrode plate and the pressing operation mechanism, a backing whose front surface is made of a surface of a conductive plate that is in pressure contact with and electrically contacts the back surface of the working electrode plate, and whose back surface has substantial rigidity. 2. The electrochemical detector according to claim 1, characterized in that the electrode holding plate is made up of two parts.