JPH0664001B2 - Automatic chemical analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention comprises an electrolyte measuring unit consisting of an ion-selective electrode and a reference electrode that are alternately in contact with a sample solution such as serum and a calibration solution. The present invention relates to an automatic chemical analyzer.

(Prior Art) For example, an electrolyte solution such as serum or urine collected from a human body is used as a sample, and the ion concentration (ion activity) of this electrolyte solution is measured using an electrolyte measurement unit. Chemical analyzers are known. FIG. 4 is a side view showing a conventional configuration of such an analyzer, in which a sample liquid 1 whose ion concentration is to be measured is stored in a sample container 2 and is kept constant by a carrier plate 3 driven by a belt conveyor or the like. Is arranged so as to be intermittently moved in a desired direction. Further, a calibration solution container 4 is arranged adjacent to the sample container 2, and the calibration solution 5 for calibrating the characteristics of the ion-selective electrode of the electrolyte measuring unit as described later is stored in the sample container 2 Like the above, it is configured to be intermittently moved in a constant cycle. The diluting liquid storage 6 holds a diluting liquid for diluting the sample liquid to a desired magnification, and is configured so that it can be supplied to the sample container 2 via the flow path 8 by driving a pump as needed. The calibration solution storage 9 holds the calibration solution, and like the diluting solution, can be supplied to the calibration solution container 4 via the flow path 11 as needed. An electrolyte measuring unit is provided above the transport plate 3 at a midpoint of the transport path.
12 is provided so that the ion concentration of the sample liquid or the calibration liquid can be measured by descending alternately into the containers 2 and 4 at a predetermined timing.

FIG. 5 is a sectional view showing the structure of the electrolyte measuring unit 12,
A desired ion-selective electrode 15 and a reference electrode 16 are arranged around an insulating substrate 14 provided with a supply path 13 for an electrolyte solution such as a sample solution and a calibration solution. An ion-sensitive layer 15A that is sensitive to desired ions is provided on the contact surface of the ion-selective electrode 15 with the electrolyte solution, and the inner solution 15B is filled so as to come into contact with the ion-sensitive layer 15A and come into contact with the inner solution 15B. An internal electrode 15C is provided. On the other hand, a liquid junction member 16A is provided on the contact surface of the reference electrode 16 with the electrolyte liquid, and an internal electrode 16C is provided so as to be filled with the internal liquid 16B so as to come into contact with the liquid junction member 16A. Has been. The internal solutions 15B and 16B are used to keep the potential of the electrolyte solution to be measured stable.

Using such an electrolyte measurement unit, first, the sample solution 1 diluted 10 times with a diluent, for example, is sucked and supplied to the supply path 13, and the ion sensitive layer 15A of the ion selective electrode 15 causes the sample solution 1 to flow. Since it is sensitive to a specific ion in the inside, such as sodium ion (Na ⁺ ), potassium ion (K ⁺ ), chlorine ion (Cl ⁻ ), etc.
A unique electromotive force corresponding to a desired ion is generated between 5 and 16, and a desired ion concentration can be measured by detecting the response electromotive force. When the measurement of one sample liquid is completed, a calibration liquid having a known concentration is supplied to the measurement ions diluted 10 times similarly to the sample liquid, and the potential of the ion selective electrode 15 is calibrated. By thus calibrating the electrode 15 each time the sample solution is measured using the calibration solution having almost the same concentration as that of the sample solution, it is possible to prevent a measurement error when the sample solution is continuously measured.

The containers 2 and 4 filled with the sample solution and the calibration solution measured in this way are placed in the constant temperature water 18 in the constant temperature tank 17 so that each solution is kept at a constant temperature and stable measurement is performed. It is configured to be transported while being immersed. The constant temperature water 18 is circulated by a pump (not shown) so that the constant temperature water 18 is always kept at a constant temperature.

(Problems to be solved by the invention) By the way, in the conventional analyzer, a constant temperature bath for keeping the electrolyte solution to be measured at a constant temperature must be prepared, and a space for installing the constant temperature bath is required and the cost is increased. There is a problem that is inevitable.

The present invention has been made to address the above problems,
It is an object of the present invention to provide an automatic chemical analyzer capable of stable measurement of an electrolyte solution without requiring a constant temperature bath.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the invention according to claim 1 measures the concentration of a specific ion in a diluted sample liquid by an electrolyte measuring unit, and In an automatic chemical analyzer for calibrating the electrolyte measurement unit using a calibration liquid containing the specific ions, the electrolyte measurement unit,
An ion-selective electrode and a reference electrode are provided, each electrode is provided with an internal solution containing the specific ion and the concentration of the specific ion is the same as the calibration solution, and is in contact with the diluted sample solution and calibration solution. It is characterized in that the concentration of a specific ion of each liquid is measured.

Further, the invention according to claim 2 is characterized by comprising storage means for storing a diluting liquid for diluting the sample liquid and a calibration liquid used for the concentration measurement under the same temperature condition. .

(Operation) According to the invention of claim 1, when the concentration of the specific ions in the internal liquid is changed, the isothermal intersection of the electrodes moves, so that the concentration of the specific ions in the internal liquid should be the same as that of the calibration liquid. Causes the isothermal intersection to move to the measurement range. Therefore, even if a temperature difference occurs between the diluted sample liquid and the calibration liquid, the measurement can be performed in a state in which the temperature difference is unlikely to be affected. As a result, stable measurement can be performed without using a constant temperature bath.

According to the second aspect of the present invention, the temperature difference between the diluted sample liquid and the calibration liquid is reduced by storing the dilution liquid and the calibration liquid under the same temperature condition. This allows
More stable measurement can be performed.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an automatic chemical analyzer according to the present invention. A sampler section 19 is composed of, for example, a circular rotary table 20, and a plurality of sample containers 21 containing desired samples are arranged in a concentric circle. Has been done. The rotary table 20 is intermittently moved by a drive source (not shown) in a constant cycle. Sample dispensing arm 22 around the rotary table 20
Is provided, and the sample in the sample container 21 is sucked by the arm 22 and dispensed into the sample container 2 in the transport system 23.

The transport system 23 has a plurality of transport plates 3 driven by a belt conveyor or the like, and these transport plates 3 each have a pair of adjacent two plates to which a sample container 2 and a calibration liquid container 4 are attached. It is configured to be intermittently moved in the cycle. The common storage 24 stores the diluting liquid storage 6 and the calibration liquid storage 9 and is configured to be maintained at the same temperature condition. The diluting solution is supplied from the diluting solution storage 6 to the sample container 2 via the flow path 8 by the nozzle 25, and the diluting solution is supplied from the calibration solution storage 9 to the flow path 11.
The calibration liquid can be supplied to the calibration liquid container 4 via the nozzle by the nozzle 26. Usually, the diluted solution is supplied to the sample container 2 so that the sample solution is diluted about 10 times.
The sample solution is not kept at the same temperature as the diluent or calibration solution, but since the sample solution is usually diluted about 10 times, the diluted sample solution can be regarded as almost the same temperature as the diluent. it can.

An electrolyte measurement unit 12 is provided above the transport plate 3 at a midway position of the transport path, and the unit 12 alternately descends into the sample container 2 and the calibration solution container 4 at a predetermined timing to collect the sample solution and the calibration solution. It is configured to aspirate and measure the concentration of these ions. Electrolyte measuring unit
The data measured in 12 is output to the arithmetic processing unit 27 where the desired arithmetic processing of the data is performed.

FIG. 2 is a cross-sectional view showing the structure of the electrolyte measuring unit 12 of FIG. 1, and is a supply path 13 for the electrolyte solution such as the sample solution and the calibration solution.
A plurality of ion-selective electrodes 15 (15 ₁ , 15 ₂ , 15 ₃ ) and a reference electrode 16 are arranged around the insulating substrate 14 provided with.

For example, ion-selective electrodes 15 ₁ sodium ions (N
a ⁺ ) sensitive layer 15 _{1 A} , and the ion selective electrode 15 ₂ is sensitive layer 15 ₂ sensitive to potassium ions (K ⁺ ).
_A ion-selective electrode 15 ₃ has a sensitive layer 15 _{3 A} sensitive to chlorine ions (Cl ⁻ ). The respective electrodes 15 _1, 1
5 ₂ and 15 ₃ have internal liquids 15 _{1 B} , 15 _{2 B} and 15 _{3 B} , respectively, and internal electrodes 15 _{1 C} , 15 _{2 C} and 15 _{3 C} , respectively. On the other hand, the reference electrode 16 is a liquid junction member 16A, an internal liquid 16B, an internal electrode 16C.
have.

Here, the internal liquid 15 ₁ of each of the ion-selective electrodes 15 ₁ , 15 ₂ , 15 ₃
The internal solutions 16B of _B , 15 _{2 B} , 15 _{3 B} and the reference electrode 16 are almost the same as the calibration solution, that is, they contain the specific ions to be measured, and the concentration of the specific ions is almost the same as the calibration solution. The same one is used. By using the foregoing as the internal solution in 10 m mol / Thus, ^- as the calibration fluid such as those of the composition containing the components such as: ^{Na + 14m mol / K + 0.4m} mol / Cl When measuring the ion concentration of an electrolyte solution such as a sample solution and a calibration solution, the measurement can be performed in a state in which it is hardly affected by temperature.

FIG. 3 is a characteristic diagram for explaining such a situation. The vertical axis shows the response electromotive force V, and the horizontal axis shows the ion concentration C of the electrolyte solution in logarithm. The corresponding electromotive force V of the electrolyte solutions a and b having different liquid temperatures differs depending on the ion concentration C, but at the isothermal intersection P, the response electromotive force V is constant regardless of the liquid temperature. By measuring the electrolyte measuring unit under the conditions as described above, the isothermal intersection P can be moved to the measurement range W, and the measurement can be performed in a state where it is hardly affected by temperature. The effective range of the measurement range W is previously determined by experiments.

Next, the operation of this embodiment will be described.

At the position where the sample container 2 and the calibration solution container 4 which are intermittently moved by the transfer plate 3 of the transfer system 23 have been transferred directly below the nozzles 25 and 26, first, the diluent is stored in the sample container 2 from the diluent storage container 6. The sample liquid previously stored by being supplied through the flow path 8 and the nozzle 25 is diluted about 10 times, for example. Next, the calibration solution is supplied from the calibration solution storage 9 to the calibration solution container 4 through the flow path 11 and the nozzle 26. The sample container 2 and the calibration solution container 4 diluted in this way are intermittently moved further ahead, and the electrolyte measuring unit
The ion concentration of each sample solution and the calibration solution is measured at the position where the sample solution and the calibration solution are transported directly below 12.

For example, the unit 12 descends into the sample container 2, sucks the sample solution, and then ascends to measure the ion concentration of the sample solution. Subsequently, the unit 12 descends into the calibration solution container 4, sucks the calibration solution, and then ascends to measure the ion concentration of the calibration solution, whereby the ion-selective electrode is calibrated. The measurement data obtained by the electrolyte measuring unit 12 is output to the arithmetic processing unit 27 so that desired processing is performed.

According to the present embodiment as described above, since the diluent and the calibration solution are held in the common storage 24, they are always kept under the same temperature condition, and the sample solution and the calibration solution diluted with such a diluent are used. Are transported under substantially the same temperature condition. Further, in such a sample liquid and the calibration liquid, the internal liquids of the ion selective electrode 15 and the reference electrode 16 are substantially the same as the calibration liquid at a predetermined position, that is, containing the specific ion to be measured, and The ion concentration is measured by an electrolyte measuring unit whose concentration is almost the same as that of the calibration solution.
With such a configuration, the diluted sample solution and calibration solution are always measured under almost the same temperature conditions, and the electrolyte measurement unit, which is not easily affected by temperature, performs the measurement. Stable measurement can be performed. Therefore, the space for installing the thermostatic chamber can be saved, so that the apparatus can be downsized and the cost increase can be avoided.

EFFECTS OF THE INVENTION As described above, according to the present invention, the electrolyte solution is measured without using the constant temperature bath, so that the device can be downsized and the cost can be reduced. By storing the solution under the same temperature condition, the temperature difference between the diluted sample solution and the calibration solution can be reduced, and more stable measurement can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the automatic chemical analyzer of the present invention, FIG. 2 is a sectional view showing the main part of the apparatus of this embodiment, and FIG.
FIG. 4 is a characteristic diagram for explaining an embodiment of the present invention, and FIGS. 4 and 5 are a side view and a sectional view showing a conventional example. 2 ... sample liquid container, 4 ...... diluent container, 12 ... electrolyte measurement unit, 15 (15 _1, 15 _2, 15 ₃₎ ...... ion-selective electrode, 16 ... reference electrode, 23 ... transport system , 27 …… Arithmetic processing section.

Claims (2)

[Claims] 1. An automatic chemical analyzer for measuring the concentration of a specific ion in a diluted sample liquid by an electrolyte measuring unit and calibrating the electrolyte measuring unit using a calibration liquid containing the specific ion. The electrolyte measurement unit has an ion-selective electrode and a reference electrode, each electrode includes an internal liquid containing the specific ion and the concentration of the specific ion is the same as the calibration liquid, and the diluted sample liquid And an automatic chemical analyzer characterized by being in contact with a calibration solution to measure the concentration of a specific ion in each solution. 2. The automatic chemical analysis according to claim 1, further comprising storage means for storing a diluting solution for diluting the sample solution and a calibration solution used for the concentration measurement under the same temperature condition. apparatus.