JPH0646187B2 - Analysis equipment - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an analyzer having a temperature correction mechanism.

[Technical background of the invention and its problems] Enzyme sensors have come to be used in analyzers such as chemical tests because they can easily measure component concentrations and the like by contacting the liquid to be measured. .

However, since the signal output of the enzyme sensor changes depending on the temperature, in the conventional analyzer, the sample liquid is held at a constant temperature for measurement, or the enzyme sensor and the sample liquid container are housed in the constant temperature unit and always kept constant. Measurement is performed while keeping the temperature.

Therefore, in such a device, it is necessary to incorporate a constant temperature part in the measuring device or to install an enzyme sensor in the constant temperature tank, and there are drawbacks such as the device becoming large, complicated, and difficult to use. Atsuta Further, it is inconvenient to measure a predetermined amount of the sample and inject it into the apparatus, or to maintain the sample at a constant temperature, so that it is not possible to carry out the measurement while the liquid to be measured is placed.

[Object of the Invention] The present invention has been made on the basis of such a problem, and an object of the present invention is to use an enzyme sensor without changing the sample solution to a constant temperature state by a heat-retaining means. An object of the present invention is to provide an analyzer capable of immediately measuring components.

[Summary of the Invention] The analysis apparatus of the present invention comprises a means for measuring the temperature of a sample solution in addition to the means constituting the conventional analysis apparatus, and a test substance in the sample solution using the measurement value by the temperature measurement means. It is characterized by comprising means for correcting the output signal from the enzyme sensor that measured It has been conventionally known that the output of an enzyme sensor and its first and second derivative values are proportional to the concentration of a test substance in a sample solution. However, since these measured values fluctuate depending on the temperature conditions, conventionally, a heat-retaining means such as a constant temperature bath was required. Since it is done, the measurement can be easily performed regardless of the sampled temperature. In particular, the inventors have found that the logarithm of the rate of change output (first derivative of the output from the sensor) with respect to each temperature of the enzyme sensor changes linearly with respect to temperature in the range of about 5 ° C to 40 ° C. . Therefore, when measuring based on the first derivative of the output from the enzyme sensor, simply use a constant relational expression (the relation where the logarithm of the first derivative changes linearly with temperature change). The temperature can be easily corrected. An example of the relationship between the logarithm of the change speed output of this enzyme sensor and the temperature is shown in the characteristic diagram of FIG. In the figure, the vertical axis shows the logarithmic ratio of the change speed output based on the output at 20 ° C, and the horizontal axis shows the temperature. It can be seen from this characteristic diagram that the temperature changes linearly in a wide temperature range.

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

Example 1 FIG. 1 shows an apparatus for measuring components of a sample solution 2 by an enzyme sensor 1. The enzyme sensor 1 is brought into contact with the sample solution 2, the output of the enzyme sensor 1 is amplified by the amplifier 4, and the A / D converter 6
The amount of change is converted from analog to digital and input to the signal processing circuit 8. In order to detect the temperature of the sample liquid 2, the temperature sensor 3 is brought into contact with the sample liquid 2 and the temperature measuring unit 5
The signal is converted into a digital signal by the A / D converter 7 and input to the signal processing circuit 8. A coefficient corresponding to the temperature is stored in the signal processing circuit 8, and the amount of change in the sensor output by the enzyme sensor 1 and the temperature of the sample solution 2 are measured and the respective data are captured. After the measurement of the change amount of the output of the enzyme sensor 1 is completed, the temperature coefficient stored in the memory is read from the measured temperature, and the result of temperature correction by multiplying the change amount of the sensor output by the temperature coefficient is displayed by the numerical display 9. I read the ingredients directly.

Embodiment 2 In FIG. 2, a primary differentiating circuit is added to the measuring circuit of FIG. After the enzyme sensor 1 is brought into contact with the sample liquid 2 and the output of the oxygen sensor 1 is amplified by the amplifier 4, it is input to the primary differentiating circuit 10 to measure the changing speed of the sensor output, and the primary differential value is A / D. The signal is digitally converted via the converter 6 and input to the signal processing circuit 8. On the other hand, the temperature information of the sample liquid 3 is converted into a digital signal through the temperature measuring unit 5 and the A / D converter 7 by the temperature sensor 3 which is in contact with the sample liquid 3, and is input to the signal processing unit 8.

The signal processing unit 8 uses the relationship that the logarithm of the first-order differential value of the signal from the enzyme sensor 1 changes linearly with respect to temperature change to obtain the result of performing temperature correction on the information from the enzyme sensor 1 as a numeral. It is displayed on the display unit 9.

In addition, in this Example 2, since the measurement is performed using the first-order differential value (change rate of the enzyme reaction), the measurement result can be displayed even during the enzyme reaction, and the measurement is shorter than that in Example 1. It has the feature that it can be done in time.

Table 1 shows the measurement results obtained by actually using the above apparatus.

As a measurement condition, a glucose solution having a concentration of 45 mg / dl was used as a test sample, and the temperature of the sample solution was changed variously to measure,
The output value after correction was examined. As a result, the measurement results were satisfactory and good results were obtained.

Third Embodiment FIG. 3 shows that the thermistor 11 is used as a temperature sensor and the temperature characteristic of the thermistor is used to correct the temperature of the enzyme sensor 1. It is input to the primary differentiating circuit 10 after the amplifier 4 in order to obtain the change speed of the output of the enzyme sensor 1.

Now, the resistance-temperature characteristic of the thermistor of the temperature sensor 11 is
The change rate output of the enzyme sensor is inversely related to the straight line of the temperature characteristic, and the resistance value increases as the temperature decreases. Therefore, if the change speed output of the enzyme sensor 1 and the resistance change of the temperature sensor 11 are converted into voltage signals and added, a flat output with respect to temperature can be obtained. The resistance change of the temperature sensor 11 is converted into a voltage, and the change speed output of the enzyme sensor 1 and the adder 13 are used to calculate the change speed output of the enzyme sensor 1 via a gain adjusting unit 12 that adjusts the gain to be a straight line that is completely opposite. , A flat output signal is always obtained with respect to temperature. The components are read by the numerical display 9 by the A / D converter 6 and the arithmetic processing circuit 14.

According to the respective devices of the above examples, good measurement results were obtained in the practical temperature range of the enzyme sensor.

EFFECTS OF THE INVENTION According to the present invention, since the first derivative of the output from the enzyme sensor is subjected to temperature correction for measurement, the concentration of the test substance in the sample solution can be accurately measured without being affected by the ambient temperature. It is good and can be measured in a short time. Further, it suffices to simply add a temperature measurement system and a correction circuit, and a constant temperature unit and the like are not required, so that a compact and simplified device can be provided.

[Brief description of drawings]

FIGS. 1, 2, and 3 are block diagrams of an embodiment according to the present invention, and FIG. 4 is a characteristic diagram showing the relationship between the logarithmic ratio of the change rate output of the enzyme sensor output and the temperature. 1 ... Enzyme sensor, 2 ... Sample solution 3,11 ... Temperature sensor, 4 ... Amplifier 5 ... Temperature measurement circuit, 6,7 ... A / D converter 8 ... Signal processing circuit, 9 ... Number Display 10 …… Primary differentiation circuit, 12 …… Gain adjusting circuit 13 …… Adding circuit, 14 …… Calculation processing circuit

Claims (1)

[Claims] 1. An enzyme sensor for measuring the concentration of a test substance in a sample solution using an enzymatic reaction, a temperature measuring unit for measuring the temperature of the sample solution, and an output signal from the enzyme sensor. A differential calculating means for performing primary differentiation and outputting the differentiated value; and a correction calculating means for performing a predetermined correction on the output signal from the differentiating means according to the output signal from the temperature measuring means and outputting the corrected signal. An analyzer characterized by.