RU2110791C1 - Device for automatic determination of solution composition - Google Patents

Abstract

FIELD: examination and analysis of materials. SUBSTANCE: device has computer 1, unit of current-setting resistors 2, electrochemical transducer 3, amplitude detector 4 and digital voltmeter 5. Computer 1 includes AC voltage generator. It provides for programmed task and variation of AC voltage frequency, checking of transient process end on electrodes of electrochemical transducer, and processing of measurement results. EFFECT: higher results of analysis. 1 dwg

Description

 The invention relates to automatic, non-destructive and rapid control of the composition of solutions and may find application in the field of electroanalytical chemistry of fuels, environmental objects and technologies.

 A device for determining the composition of solutions, containing an alternating voltage generator, a frequency divider block, a multi-input switch, a block of current-setting resistors, an electrochemical sensor, a digital voltmeter, an automatic processing unit, a time relay, a trigger, a counter, a clock pulse generator and a converter (e.g., author. St. N 1818579, G 01 N 27/02).

 The disadvantages of this device are the probability of errors in the measurement results due to the lack of information about the end of the transient process on the electrodes of the electrochemical sensor, there is only a three-minute delay in recording the voltage of the sensor and only the first frequency of the polarization current, which does not guarantee the end of the transient process on the electrodes of the electrochemical sensor as at the first and subsequent frequencies; less ability to change measurement parameters due to the very wide spacing of the set frequencies when determining the composition of multicomponent solutions; hardware complexity.

 The objective of the invention is to improve the accuracy and reliability of determining the composition of solutions.

 The problem is solved in that the device for automatically determining the composition of the solutions contains an alternating voltage generator, a block of current-sensing resistors connected to an electrochemical sensor including electrodes, and a digital voltmeter connected to an electronic computer (computer) that provides measurement processing and calculation of the composition of the analyzed solution. Moreover, it additionally contains an amplitude detector connected between the electrodes of the electrochemical sensor and a digital voltmeter, and the generator used in the computer is used as an alternating voltage generator of the device, which makes it possible to program and change the frequency of the alternating voltage, as well as to control the end of the transient process on the electrochemical electrodes sensor, while the computer output is connected to a block of current-setting resistors.

 A device for automatically determining the composition of solutions (see drawing) contains a computer 1, a block of current-setting resistors 2, an electrochemical sensor 3, an amplitude detector 4, and a digital voltmeter 5.

 A device for automatically determining the composition of solutions works as follows.

 The analyzed solution is poured into the electrochemical sensor 3 and, after starting the computer program 1, it starts to produce a given alternating voltage of a fixed frequency through the block of current-setting resistors 2 to the electrochemical sensor 3. From the flowing current, the value of which is set by the current-setting resistors, a voltage drop is created on the electrochemical sensor, which is supplied to the amplitude detector 4 is rectified by it and then measured with a digital voltmeter 5. A digital voltmeter converts an analog signal to a digital and It stores information in a computer for memorization. The measurement cycle at a given frequency is periodically repeated until the difference between the previous and subsequent measurement results is less than the set tolerance. After storing the last voltage value, the computer according to the program proceeds to the measurement cycle at the second frequency. The number of frequencies is equal to the number of components. At the end of the full measurement cycle, based on the solution of the system of linear equations, the computer calculates the content of each component in the analyzed mixture.

 Calibration is reduced to determining the calibration coefficients of the system of equations for solutions of analytes with a known concentration. The minimum number of reference solutions should be equal to the number of analytes. At the end of the measurement cycle of all standard solutions, in accordance with the calibration algorithm, the computer calculates the coefficients of the system of linear equations (calibration coefficients).

 A device for automatically determining the composition of solutions can be implemented on the basis of personal computers (for example, Electronics BK 00101, PC 386/7), and a digital voltmeter (for example B721 A). Block of current-carrying resistors MLT 1 1,0; 4.7; 20; ten; 51; one hundred; 200 kOhm. The electrochemical sensor is a cylindrical glass with diameters: external 40 mm, internal 20 mm and a depth of 50 mm, which is closed by a lid, in which two electrodes are made of steel X18H10T with a length of 40 mm, a width of 10 mm and a thickness of 3 mm at a distance of 5 mm from each other . The lid and glass, made of fluoroplastic, have an annular groove for fixing the electrodes in depth. The amplitude detector contains a D20 diode, a capacitor with a capacity of 100 pF and a resistor MLT 2 180 kOhm.

The advantages of this device compared to the prototype are:
Accurate determination of the end of transients allows to significantly increase the reliability of the installation, and the accuracy of measurements increases by 1.5 - 2 times;
the ability to flexibly vary the frequencies of the polarizing voltage provides increased determination accuracy in the analysis of multicomponent systems;
simplified installation increases the reliability of measurements.

Claims (1)

 A device for automatically determining the composition of solutions, containing an alternating voltage generator, a block of current-setting resistors connected to an electrochemical sensor including electrodes, and a digital voltmeter connected to an electronic computer (PC), which provides measurement processing and calculation of the composition of the analyzed solution, characterized in that it additionally contains an amplitude detector connected between the electrodes of the electrochemical sensor and a digital voltmeter, moreover, as a gene The alternator voltage of the device used a generator, which is part of the computer, providing the ability to program and change the frequency of the alternating voltage, as well as control the end of the transient process on the electrodes of the electrochemical sensor, while the computer output is connected to a block of current-setting resistors.