JP2512623B2 - Detector - Google Patents

Description

The present invention relates to a detector, and more particularly to a detector that can measure the concentration of a substance to be electrolyzed with high accuracy and that can be easily downsized.

[Conventional technology]

In recent years, microarray electrodes (Chemical Society of Japan, 58th Annual Meeting, 4IG13, Kyoto (1988)) and carbon fiber electrodes (K. Kinoshita, “carbon” p.443-p.455 John Wil
Eych Sons, (1988)) and other microelectrodes have been developed, and the electrolysis technology (microelectrode technology) using these microelectrodes has been applied to in vivo sensors. In this in-vivo sensor, it is necessary to make the size as small as possible, and therefore, no attempt has been made to install accessories for improving analysis accuracy and expanding measurement species.

Generally, the output signal (current or voltage value) due to electrolysis of the substance to be electrolyzed is affected by the temperature and conductivity at the time of detection. Therefore, when highly accurate measurement is required, the temperature and conductivity are separately set. It was necessary to measure and correct the output signal due to electrolysis.

[Problems to be Solved by the Invention]

The present inventors previously proposed a water content measuring device and a water content measuring method capable of measuring the water content in a sample by direct electrolysis of water using an electrode in which a cathode and an anode are arranged at intervals of 1 mm or less ( Japanese Patent Application No. 1-321078 (JP-A-3-180747). A detector that directly electrolyzes a substance to be electrolyzed by setting the space between the negative and positive electrodes to 1 mm or less is not easily affected by the change in the conductivity of the sample.Therefore, the current value obtained by electrolysis should be corrected for temperature. Generally, good measurement can be performed.

An object of the present invention is to provide a detector that is easy to downsize and that can improve the accuracy of measurement values measured using the above electrodes and expand the types of measurement.

[Problems to be Solved by the Invention]

The present invention has at least one pair of a cathode and an anode, which are directly electrolyzed with a substance to be electrolyzed and are installed at intervals of 1 mm or less,
The present invention relates to a detector including an electrolytic detection unit that outputs a peak current signal that lasts for 0.1 second or more as an electrolytic current, and a temperature measurement unit that is installed close to the electrolytic detection unit.

[Action]

In the present invention, the sensor is left in the sample, fixed or fixed by hand, and the measurement values measured by the electrolytic detection section in the sensor are measured at the same time and at the same position by the temperature measurement section. Since the correction can be performed based on, it is possible to improve the accuracy of the measured value. As the measurement target of the sensor, in addition to quantification of general substances to be electrolyzed in a sample (water content, vitamin C concentration, etc.), acidity can also be measured by electrolysis of protons. Further, since the power supply unit and the measuring unit can be built in the sensor to form a small handy-type sensor, highly accurate measurement can be performed by a portable and simple device.

FIG. 1 is an explanatory diagram of a detector showing an embodiment of the present invention.

In the figure, a sensor-carrying rod 1 is installed at the tip of the sensor-carrying rod 1 for measuring an electrolysis current of an electrolyzed substance in a sample, and is installed near the electrolysis detecting unit. It comprises a temperature measuring unit 3 for measuring the temperature of the sample and a lead wire 5 for inputting a measured signal to the measuring unit 6.

In such a configuration, the tip measuring portion of the sensor-carrying rod 1 is immersed in the sample, and the voltage according to the measurement is applied to each measuring portion from the constant voltage power source portion 7 through the lead wire 5. In the electrolysis detection unit 2, among the currents measured by the direct electrolysis of the substance to be electrolyzed, at least the peak width on the time axis that lasts for 0.1 seconds or more is averaged to electrolyze the substance to be electrolyzed in the sample. Output as current. The respective measured values are input to the measuring unit 6 through the lead wire 5, are subjected to temperature-corrected data processing, and then displayed on the recorder 8. When the measurement of the next sample is started, the measurement unit 6 is provided.

FIG. 2 is an explanatory diagram of an example of the electrolytic detection unit sensor of FIG.

In this electrolytic detection section sensor 10, a plurality of anodes 20 and cathodes 21 are alternately arranged, and are connected to a power source and a measurement section via lead wires 23. The tips A of the anode 20 and the cathode 21
Except for the portion (which contacts the sample 25 and measures the electrolytic current value), it is covered and fixed with a resin 22 such as an epoxy resin. The tip A may be such that the electrodes are exposed as a surface, or the tip A protrudes to such an extent that the sample is not clogged between the electrodes. For example, a metal belonging to a white metal is used for the electrodes.

The magnitude of the voltage applied to the electrodes 20 and 21 is determined by the type of substance to be measured. For example, for water, 2.
A voltage of 5 V or more, preferably 3 to 10 V is applied, and a voltage of 2 V is applied when measuring vitamin C.

For example, the measurement of the electrolytic current value (water content) in the dehydrated sludge 25 is performed using the sensor 10 as follows. First, the entire electrode tip portion A is pressed so as to be completely immersed in the sludge 25, and a voltage of 2.5 V or more is applied to the electrodes 20 and 21.

When a voltage is applied, the reaction of 2H ₂ O + 2e ⁻ → H ₂ ↑ + 20H ⁻ occurs at the cathode 21, and the reaction of 2H ₂ O → O ₂ ↑ + 4H ⁺ + 4e ⁻ occurs at the anode 20 to measure the water content of the dehydrated sludge. In the case of, an electrolytic current based on the water content up to the electroosmotic dehydration region and the heat treatment region can be obtained.

FIG. 3 is a perspective view of a detector showing another embodiment of the present invention, FIG. 4A is an enlarged view of the detector tip portion of FIG. 3, and FIG. 4B is a bottom view of FIG. 4A. .

In FIG. 3, the difference from FIG.
As the sensor of the sensor, either the anode or the cathode is arranged in the center (detection electrode 31), and the electrode having the other pole (counter electrode 32) circularly provided at intervals of 1 mm or less is used, and the sensor The carrier rod 1 is equipped with the measuring unit 6 and the constant voltage power supply unit 7 shown in FIG.
And the reset button 35 is attached to make it a handy type. According to such a detector, it is possible to carry and easily measure various samples.

In the present invention, the output signal (current or voltage signal) from the electrolysis detection unit is stably obtained when the electrodes of the electrolysis detection unit are in sufficient contact with the sample. As described above, it is preferable to stably measure the sample by dipping or inserting it.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to Examples.

Example 1 Using the sensor-supporting rod 1 of FIG. 1 in which a platinum electrode pair having a width of 0.5 mm, a length of 5 mm, and an interval of 0.1 mm as an electrode for electrolysis and a platinum side temperature body as a temperature sensor were installed, different concentrations were used. The water content of each slurry was measured. The tip of the sensor-carrying rod 1 was held in the hand and inserted into the slurry, and a constant voltage of 4 V was applied to the electrodes. At first, an irregular current signal was obtained, but when it was held for 3 to 5 seconds or longer, a peak current lasting 0.1 seconds or more was obtained as a signal. The water content obtained by multiplying this peak current by a coefficient was displayed on the recorder 8. When measuring another sample, the same measurement was performed after pressing the reset button to remove the data. The temperature-corrected water content obtained at this time was compared with the water content obtained by the dry weight method, and the results are shown in FIG. 6. The water content after temperature correction is shown by the dry weight method. In agreement with the rate. In addition, the water content calculated by simply using the average value of the output current of the sensor as the electrolysis current value is shown by a cross in FIG. 6, but in this case, an accurate water content cannot be obtained even if the temperature is corrected. I understand.

〔The invention's effect〕

According to the detector of the present invention, an electrode having a cathode and an anode arranged at a distance of 1 mm or less, which is obtained by directly electrolyzing a substance to be electrolyzed, has a peak current signal of 0.1 second or more as an electrolytic current, which is almost the same. By making corrections based on the temperatures measured at the same time and at the same position, it is possible to improve the accuracy of the measured values. Furthermore, by incorporating a measuring unit and a power supply unit into a small, handy-type detector, it is possible to perform easy measurement.

[Brief description of drawings]

FIG. 1 is an explanatory view of a detector showing an embodiment of the present invention, FIG. 2 is an illustration of an example of the electrolytic detection sensor of FIG. 1, and FIG. 3 is another embodiment of the present invention. A perspective view of the detector shown,
FIG. 4A is an enlarged view of the detector tip of FIG. 3, and FIG.
FIG. 4A is a bottom view and FIG. 5 is a diagram showing the relationship between the water content after temperature correction obtained by the detector of the present invention and the water content by the dry weight method. 1 ... Sensor carrying rod, 2,30 ... Electrolytic detection part, 3,33
...... Temperature measuring unit, 5,23 ...... Lead wire, 6 …… Measuring unit,
7: Constant voltage power supply, 8: Recorder, 9, 35 ... Reset button, 10 ... Electrolysis detector sensor, 20 ... Anode, 21
…… Cathode, 22 …… Resin, 23 …… Lead wire, 25 …… Sludge,
31 …… Detection pole, 32 …… Counter pole, liquid crystal display 36.

Claims (1)

(57) [Claims] 1. An electrolytic detector which has at least one pair of a cathode and an anode installed at intervals of 1 mm or less for directly electrolyzing a substance to be electrolyzed, and which outputs a peak current signal lasting 0.1 seconds or more as an electrolytic current. A detector comprising a temperature measuring unit installed in the vicinity of the electrolytic detecting unit.