General dynamic titration optimization method applied to coulometry potentiometric titrator

Abstract

The invention discloses a general dynamic titration optimization method applied to a coulometry potentiometric titrator, which comprises the following steps: S101, in an initial stage, carrying out electrolysis by using small electrolytic current and medium electrolytic current, and monitoring potential change in real time; s102, when it is judged that the real-time potential is not larger than the control potential, entering an acceleration stage; s103, when it is judged that the real-time potential is smaller than the control potential, entering a speed reduction stage; and S104, judging whether to enter an end stage or not through a differential method. According to the present invention, a universal measurement method with both higher speed and higher precision is provided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coulometric potentiometric titrator, and particularly relates to a general dynamic titration optimization method applied to a coulometric potentiometric titrator. BACKGROUND

[0002] As a common and important technical means in the field of chemical analysis, the core principle of coulometric titration relies on electrochemical method to realize the determination of the content of the measured substance. Based on Coulomb's law, the consumed electric quantity is in a proportional relationship with the concentration of the substance in the electrolysis process. By calculating the consumed electric charge of the chemical reaction, the concentration of the measured substance can be calculated.

[0003] Coulometric titration has a series of significant advantages. Firstly, it does not need to perform complicated standard solution preparation work, and the operation process is simple and easy to implement, which greatly simplifies the analysis process. Secondly, in volumetric analysis, for substances such as I⁻, Br⁻, Cl⁻, which are difficult to directly serve as titrants, coulometric titration can achieve effective titration, thereby effectively expanding the analysis range. Thirdly, the electric quantity involved in the coulometric titration process is easy to accurately control and measure, which provides a solid guarantee for the reliability of the analysis result. Fourthly, the method has high sensitivity and accuracy, and can meet the demand of high-precision analysis.

[0004] At present, most of the coulometric titrators circulating in the market are special-purpose equipment, such as coulometric water meters focusing on water content determination and micro-coulometric sulfur determination instruments for sulfur content analysis. The existing titration method process is inefficient and slow. It has become a key problem to be solved in the current chemical analysis field, and it is of great significance to improve the overall performance and application value of coulometric titration technology.

[0005] Related parameter Set value Note Drift value 20 For balance waiting determination Minimum waiting time 2 Minimum waiting time after electrolysis end Maximum waiting time 10 Maximum waiting time after electrolysis end Large electrolysis current 400 mA Optional 400 mA, 300 mA, 200 mA, 100 mA. Medium electrolysis current 20 mA Optional 50 mA, 20 mA, 10 mA Small electrolysis current 10 mA Optional 20 mA, 10 mA, 1 mA Maximum electrolysis time 4 / Minimum electrolysis time 0.5 / Pre-control potential 250 / End point jump value 200 For end point determination SUMMARY

[0006] In view of the deficiencies in the prior art, the purpose of the present application is to provide a general dynamic titration optimization method applied to a coulometric potentiometric titrator, which has a general determination method with higher speed and higher precision. In order to achieve the above-mentioned purposes and other advantages according to the present application, a general dynamic titration optimization method applied to a coulometric potentiometric titrator is provided, comprising: S101, a starting stage: electrolysis is performed with a small electrolysis current and a medium electrolysis current, and the potential change is monitored in real time; S102, when it is judged that the real-time potential is not greater than the control potential, entering the acceleration stage; S103, when it is judged that the real-time potential is less than the control potential, entering the deceleration stage; S104, determining whether to enter the end stage by differential method.

[0007] Preferably, the step S101 is specifically using small electrolysis current for three times, and the electrolysis time is dynamically changed according to the rules, and then using medium electrolysis current for three times, and the electrolysis time is dynamically changed according to the rules.

[0008] Preferably, in the step S102, the electrolysis current uses large electrolysis current, and the electrolysis time is dynamically changed according to the rules.

[0009] Preferably, in the step S104, the instrument finds the differential dE jump peak meeting the condition, that is, the extreme value of the differential, and calculates the titration result.

[0010] Preferably, the judgment process of the jump peak is as follows: 1. After the titration operation is started, the differential values corresponding to the titration data need to be calculated in sequence.

[0011] 2. If the two consecutive differential values both exceed the preset end-point jump value, and the second differential value is not less than the previous one, it is determined that the titration end point is valid; 3. The titration is continuously performed until the titration data exceeds the maximum value of the end point by 5 points, and then the end point is determined to be established, and the end point value is recorded; 4. If the titration end-point jump amount is greater than 600, the maximum jump value is directly determined as the end point, without following the above regulation about the number of data points.

[0012] The beneficial effects of the present application relative to the prior art are: the control potential is set in advance, when the electrolysis system is outside the set control potential range, the maximum electrolysis current is used for electrolytic titration operation; and when the electrolysis system is within the set control potential range, small electrolysis current and medium electrolysis current are used for electrolytic titration, so as to ensure that the titration process can be completed in a fast and accurate manner. According to the pre-set control potential, the titration operation will adjust the electrolysis time according to a specific rule, so as to ensure that the titration process is completed quickly and accurately. According to the set drift value, the equilibrium waiting time is determined, so as to ensure that the titration operation is successfully completed in an efficient manner. In order to improve the titration speed, two different electrolysis currents are allowed to be selected for operation in the vicinity of the titration end point.

[0013] The method not only greatly leads in speed, but also improves accuracy.

[0014] An appropriate control potential can be reasonably set according to different titration requirements, so as to ensure that the titration process is successfully completed in a fast and accurate manner.

[0015] Multiple parameters can be set to adapt to and complete different types of titration tasks, and the versatility is stronger. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 Flow chart for general dynamic titration optimization method applied to coulometric potentiometric titrator according to the present application. DETAILED DESCRIPTION The technical solutions in the embodiments of the present application will be apparently and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the present application.

[0017] Reference Figure 1 A general dynamic titration optimization method applied to coulometric potentiometric titrator, comprising the following steps: Step S101: initial stage, using small electrolysis current three times, electrolysis time changes dynamically according to rules, then using medium electrolysis current to electrolyze three times, electrolysis time changes dynamically according to rules, and then coming to the acceleration stage after electrolysis. If the real-time potential E is not greater than the control potential CE in the whole process, then the electrolysis directly jumps to the deceleration stage S103.

[0018] Step S102: acceleration stage, using large electrolysis current, electrolysis time changes dynamically according to rules. If the real-time potential E is less than the control potential CE in the whole process, then the electrolysis enters the deceleration stage S103.

[0019] Step S103: deceleration stage, small electrolysis current and medium electrolysis current are switched according to rules, and electrolysis time changes dynamically according to rules.

[0020] Decceleration stage current transformation rules: ; ; Wherein, I mid Medium electrolysis current, unit: microampere (mA); I min Small electrolysis current, unit: microampere (mA); dE — Titration curve differential value, unit: millivolt / millicoulomb (mV / mC) Potential change amount after adjacent two electrolyses, unit: millivolt (mV); Coulomb change amount of adjacent two electrolyses, unit: millicoulomb (mC); Electrolysis time change rules:

[0021] wherein T —— electrolysis time, unit: second (s); T max — maximum electrolysis time, unit: second (s); T min — minimum electrolysis time, unit: second (s); dE —— titration curve differential value, unit: millivolt per milliliter (mV / mC).

[0022] Equilibrium waiting time rule: The instrument will calculate the drift value of the potential in unit time in real time. When the real-time drift value is lower than the set drift value, the equilibrium waiting is over. When the waiting time is too small, the set minimum waiting time is automatically selected. When the waiting time is too large, the set maximum waiting time is automatically selected.

[0023] ; wherein — potential change in a period of time, unit: millivolt (mV); — time interval, unit: second (s); generally default is 1 s.

[0024] Step S104: end stage, which is the end point determination end, the instrument finds the differential dE jump peak (extreme value of differential) that meets the condition, and calculates the titration result. The determination process of the jump peak is as follows: 1. After the titration operation is started, the differential value corresponding to the titration data needs to be calculated in sequence.

[0025] 2. If both of the two consecutive differential values exceed the preset end point jump value, and the second differential value is not less than the previous one, it is determined that the titration end point is valid.

[0026] 3. Continue titration until the titration data exceeds the maximum value of the end point by 5 points, that is, the end point is established, and the end point value is recorded.

[0027] 4. If the titration end point jump amount is greater than 600, the maximum jump value is directly determined as the end point, without following the above provisions about the number of data points.

[0028] The number of devices and processing stages described herein are intended to simplify the description of the application and are not intended to limit the application to the embodiments described. Although embodiments of the application have been disclosed in connection with the specified materials and procedures, it is to be understood that the application is not limited to the disclosed materials and procedures, but rather, the intended application is to suggest that the application is broadly applicable to the pertinent art. Various modifications and alterations of this application will become apparent to those skilled in the art from the disclosure herein, and it is intended that the application shall be limited only by the scope of the claims appended hereto and equivalents thereof.

Claims

1. A general dynamic titration optimization method applied to a coulometric titration apparatus, characterized in that, The method comprises the following steps: S101, initial stage: electrolysis is carried out with small electrolysis current and medium electrolysis current, and the potential change is monitored in real time; S102, when it is judged that the real-time potential is not greater than the control potential, entering the acceleration stage; S103, when it is judged that the real-time potential is less than the control potential, entering the deceleration stage; S104, judging whether to enter the end stage by differential method.

2. A general dynamic titration optimization method for coulometric titration apparatus as claimed in claim 1, wherein, The step S101 is specifically that small electrolysis current is used for three times, the electrolysis time is dynamically changed according to the rule, then medium electrolysis current is used for three times, and the electrolysis time is dynamically changed according to the rule.

3. A general dynamic titration optimization method for coulometric titration apparatus as claimed in claim 1, wherein, In the step S102, when the real-time potential is greater than the control potential, directly entering the deceleration stage in the step S103.

4. A general dynamic titration optimization method for coulometric titration apparatus as claimed in claim 1, wherein, In the step S102, large electrolysis current is used, and the electrolysis time is dynamically changed according to the rule.

5. A general dynamic titration optimization method for coulometric titration apparatus as claimed in claim 1, wherein, In the step S104, the differential dE jump peak meeting the condition is found by the instrument, that is, the extreme value of the differential, and the titration result is calculated.

6. A general dynamic titration optimization method for coulometric titration apparatus as claimed in claim 5, characterized in that, The judgment process of the jump peak is as follows:

1. After the titration operation is started, the differential values corresponding to the titration data are calculated in sequence; 2. If the two continuous differential values are both greater than the preset end jump value, and the second differential value is not less than the previous one, it is judged that the titration end point is valid; 3. The titration is continuously carried out, and when the titration data exceeds the maximum value of the end point by 5 points, it is determined that the end point is established, and the end point value is recorded; 4. If the titration end point jump amount is greater than 600, the maximum jump value is directly determined as the end point, and the above-mentioned regulation about the number of data points does not need to be followed.

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