RU2705931C1 - Method of collecting and processing data during titration and a device that implements it - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: use: for volumetric titration. Summary of invention is that method of collecting and processing data during titration involves interface of recording device, made with possibility of measuring physical and chemical properties of analyzed solution, and data collection and processing device, voice input of visual volume measurement data with addition of each portion of titrant to solution for investigation after starting titration process, reading current readings of recording device, processing of volume data obtained by voice input, and data of parameters of physical and chemical state of solution obtained from recording device, with subsequent construction of their graphic dependence on each other, analysis of the plotted curve to determine inflection points on the titration curve and subsequent determination of the desired concentrations of the determined substances in the solution from the values of the volume at said points, processing of the obtained analysis data, preparation of the measurement protocol, storage and display thereof.

EFFECT: possibility of reducing time for titration with simultaneous increase in safety.

15 cl, 3 dwg

Description

This group of inventions relates to physico-chemical analysis, mainly to devices for volumetric titration, and can be used in the operational control of technological processes.

Titration (titrimetric analysis) is one of the most common methods in analytical chemistry, which consists in the fact that a liquid (titrant) is dosed to the test solution in certain portions (V, ml). At the same time, in solution using a sensor connected to a recording device (pH meter, ionomer or spectrophotometer), the pH / pX, electrochemical potential (E, mV) or optical density (D) of the solution is measured. The dependence E (V) or D (V) is built, the obtained curve is processed (after the end or in the titration process) and the inflection points are determined. The volume values at these points are used to calculate the desired concentrations of the substances to be determined.

Automatic and manual titrators are known.

In automatic titrators, the entire process (dosing using calibrated automatic burettes, data recording, recording and processing of the titration curve) is carried out in a fully automatic mode [Mettler Toledo (Switzerland). Product Catalog. Electronic resource. Resource access mode: https://www.mt.com/en/ru/home/products/Laboratory_Analitics_Brjwse/Produc t_Family_Browse_titrators_main.html - free; Metrohm (Switzerland). Product Catalog. Electronic resource. Resource access mode: http://www.metrohm.ru/Products/Titration/index.html?yclid=809281578786912 952 - free]. The main disadvantage of automatic titrators is the high cost and restrictions on the use of electronic burettes (each titrant needs its own burette).

Manual version of the titrator has the advantages of low cost and no restrictions on the number of titers used, since glass burettes are much cheaper than electronic burettes of automatic titrators. Manual titrator involves the use of a calibrated glass burette and a recording device, for example, an ionomer. Data is collected and then graphs of titration curves are built and calculated on them. In this case, data collection in the manual version is carried out only manually, i.e. readings are read at a certain point from the display of the recording device and recorded manually. If it is possible to connect the recording device to a personal computer (PC), the readings from the device at some point are transmitted to the PC on which the corresponding software is installed.

A device for collecting and processing data in the titration process [NPP "SEMIKO". Program for ionometric and potentiometric titration. Electronic resource. Access mode to the resource: http://multitest.semico.ru/titr.htm -free], including an electrode, a recording device based on a pH meter or ionomer of the MULTITEST IPL series manufactured by NPP Semiko, a personal computer based on Windows or Linux cable for communication between PC and recording device. Moreover, this device allows you to manually enter the values of the titrant volume, process the data received from the recording device, build and process the titration curve, and also display the results of measurements and calculations in the form of titrant volumes at the equivalence point.

The disadvantages of the known device include:

a narrow range of options for connecting recording devices;

- low security due to the fact that the registration device is connected to the PC using a cable (RS232 interface), and the location of the PC near the vessels with chemicals and a tripod with a burette is unsafe and clutters the workspace;

- if you need to get data from another recording device, you need to connect another PC or reconnect the cables and transfer the same PC;

- entering the volume of each portion of the titrant is performed from the keyboard, which complicates the process and stretches it in time.

The objective of this group of inventions is to develop a dynamic method for collecting and processing data during the titration process and an inexpensive small-sized device for its implementation, which cover the basic needs of users / laboratories performing titrimetric analyzes. The technical result of the claimed group of inventions is to reduce the time for the titration process while improving security.

The task in part of the method is solved due to the fact that the method of collecting and processing data in the titration process includes pairing a recording device configured to measure the physicochemical properties of the test solution, and a data collection and processing device, voice input of visual volume measurement data when adding each portion of the titrant to the study solution after starting the titration process, taking the current readings of the recording device, processing the volume data received by voice input, and data on the parameters of the physicochemical state of the solution obtained from the recording device, followed by constructing their graphical dependence on each other, analyzing the plot to determine the inflection points on the titration curve and then determining the desired concentrations of the substances to be determined from the values of the volume at these points in solution, processing the obtained analysis data, drawing up a measurement protocol, its storage and its display.

Implementation options for the main technical solution:

- pairing of the recording device and the data collection and processing device is performed using wireless technologies such as Bluetooth or Wi-Fi;

- before the start of the titration process, input data are manually entered;

- before the start of the titration process, the corresponding measurement template is started, and the corresponding titration template is launched from the list of templates created previously or in the current process;

- the data collection process is stopped automatically after reaching the equivalence point specified previously in the launched template;

- determination of the inflection point on the titration curve is carried out using the algorithm of smoothing by the method of moving average, polynomial interpolation and subsequent processing by numerical differentiation or the Gran method.

The problem in part of the device is solved due to the fact that the device for collecting and processing data in the titration process includes a manual data input and correction unit, an interface unit with external devices, a power supply unit, a memory unit connected to a processing and control unit that is connected to a voice unit and an information display unit, while the interface unit with external devices is configured to connect to at least one recording device for measuring physicochemical properties solution, the voice unit is configured to voice input data, speech recognition and converting audio data to digital, and the processing and control unit is configured to control the on and off of the remaining units, construct and process the titration curve, output to the information display unit the measurement results and / or computing.

Implementation options for the main technical solution:

- the unit for interfacing with external devices is made with the possibility of wired connection to it of at least one recording device for measuring the physicochemical properties of the test solution;

- the unit for interfacing with external devices is configured to wirelessly connect to it at least one recording device for measuring the physicochemical properties of the test solution;

- the voice unit registers sound using a microphone;

- the processing and control unit is configured to generate and adjust at least one measurement pattern;

- the processing and control unit is configured to generate a report on the measurements taken;

- the processing and control unit is configured to transmit the generated report on the measurements using, for example, Wi-Fi, Bluetooth, or via GSM communication to other devices;

- all blocks are implemented on the basis of a smartphone or tablet.

Thus, thanks to the claimed group of inventions, it became possible to create a semi-automatic device that allows to speed up and secure the process of collecting and processing data during the titration process while maintaining fully automated data processing. Voice input is by far the fastest data entry method. According to studies, the number of characters entered using voice input over the same period of time is three to four times the number of characters entered manually [see http://readmultiplex.com/2017/03/27/stanford-university-voice-first-is-3x-faster-than-typing/]. Thus, in the absence of a limit on establishing equilibrium in the titration process, the speed of analysis also increases by 3-4 times. The use of voice data entry frees up the hands of the laboratory assistant and allows him not to be distracted from the dosing process, which is especially important near volumes corresponding to equivalence points.

At the same time, the wireless connection of the recording device additionally significantly simplifies the claimed device and reduces the required workspace, since there is no need to use wires and connect them, and also allows you to work with several recording devices, since there is no limit on the number of paired devices, which increases functionality and area application of the device as a whole. The ability to implement a device based on a smartphone or a compact portable tablet allows you to make the device more compact and can be mounted directly on a tripod with a burette, which will significantly save the workplace on the laboratory assistant’s table.

The essence of the claimed group of inventions is illustrated using the figures and the following description.

In FIG. 1 presents a block diagram of the inventive device.

In FIG. 2 and 3 are graphical results of measurements according to Example 1.

A device for collecting and processing data during the titration process (Fig. 1) includes a block 1 for manual data input and correction, a block 2 for interfacing with external devices, a memory block 3, a power block 4 connected to the processing and control block 5. The processing and control unit 5 is connected to the voice block bis by the information display unit 7.

Block 1 of manual data input and correction (keyboard, touch screen, etc.) is configured to manually fill in the proposed forms with data, for example, initial data at the start of the process, as well as adjusting voice values during the titration process.

Initial data refers to the variables required to perform the final calculations and draw up protocols, for example, the mass of the added weights, units of measure, solution titers, dilution factors, etc. However, the input of input data can also be carried out by voice using the voice unit 6.

Block 2 pairing with external devices is made with the possibility of a wired or wireless connection to at least one recording device (not shown) to measure the physicochemical properties of the test solution. In the case of wireless pairing, unit 2 comprises a wireless connection module 8 based on technologies such as Bluetooth or Wi-Fi. The benefits of wireless pairing will be to free up work space and increase the security of the titration process.

By a recording device (not shown in the drawing) is meant a primary information signal converter configured to determine the response of a titrated solution to the addition of a dosed substance. As a recording device (not shown in the drawing), a pH meter, an ionomer, a conductometer, an ammeter, a spectrometric cell, a polarograph, etc. can be used.

The voice unit 6 includes a sound recording module 9 for enabling voice input of data, for example, a microphone, a speech recognition module 10 configured to extract human speech from the total voice data stream from the microphone, and a voice to digital conversion module 11 (digitization), for example using a combination of the pattern matching method and the function combination method.

Block 5 processing and control is configured to control internal processes, primary processing of incoming data from other blocks and processing the results of the analysis, as well as providing power to the remaining blocks. The processing and control unit 5 controls the remaining units using the control unit 12; constructing and processing a titration curve using module 13 for constructing a graph of E (V) and module 14 for processing a titration curve E (V); output to the block 7 display information of the results of measurements and / or calculations using module 15 calculations. The concentration is determined using formulas for calculations, which include symbols that correspond to the found values of volumes at equivalence points, as well as to variables and constant values specified in the templates or when starting the methods [https://studfiles.net/preview/2180060/page: 3 /; https://studopedia.info/1-57948.html; A.B. Yuryev ANALYTICAL CHEMISTRY Textbook Omsk - 2006 UDC 543 (075) LBC 24.4 y73 Yu 85]:

c1 = m1 / V1 - concentration expressed in g / l

c2 = m1 / M1 / V1 - concentration expressed in mol / l

etc.

Block 5 determines the inflection point on the titration curve, for example, using a moving average smoothing algorithm, polynomial interpolation, and subsequent processing using numerical differentiation methods or the Gran method.

The processing and control unit 5 may be configured to form and adjust at least one measurement pattern using the pattern module 16. The template is a fillable form and can be made in the form of a set of algorithms for performing analysis using one or another titration technique, indicating all the necessary variables and constants for automatic calculation, processing parameters of the titration curve in each case, units of measure, texts for protocols and instructions for the operator. Templates are needed so that the operator, depending on the analysis of which sample he needs to perform, can select the corresponding pre-created template with all the necessary parameters. This greatly speeds up the routine laboratory tests.

Block 5 processing and control can be performed with the possibility of statistical processing of the obtained results (average value, standard deviation, repeatability, etc.), as well as with the possibility of generating a report on the measurements using module 17 of the report, which allows you to structure the results in compliance with internal laboratory requirements, as well as the requirements of international standards GMP and GLP.

The processing and control unit 5 can be configured to transmit the generated report using the module 18 for transmitting the report on measurements using, for example, Wi-Fi, Bluetooth technology or via GSM communication to other devices, including LIMS (laboratory information system).

The memory unit 3 is a data storage (hard disk) in which all device data is stored.

The power supply unit 4 is configured to provide operability of the remaining units and can operate both from a stationary network and from rechargeable batteries.

The information display unit 7 (screen) is configured to visualize information both in the titration process and at the end of it.

Blocks can be implemented in the form of various software modules, each of which is embodied on a material storage medium for storing data readable by a computer, as well as in the form of a device including a memory and at least one processor that is connected to the memory and configured to performing the steps of the method. The device can be implemented on the basis of a general purpose computer, laptop, smartphone or tablet. Such an implementation may use, for example, a processor, a storage device, and an input / output interface, formed, for example, using a display and keyboard. Implementation on the basis of a smartphone will save maximum space on the title table, while ensuring maximum speed and operator safety when entering and displaying information.

The operator can be a person with special knowledge in the field of chemistry, namely titration processes.

The described device implements the following method of collecting and processing data in the titration process, which includes:

1) pairing a recording device (not shown), configured to measure the physicochemical properties of the test solution, and a data acquisition and processing device through its unit 2 for pairing with external devices;

2) subsequent voice input of visual volume measurement data when each portion of titrant is added to the study solution after starting the titration process using voice unit 6 of the data acquisition and processing device;

3) taking the current readings of the recording device using the unit 2 for interfacing with external devices and transmitting data to the processing unit 5 of the data acquisition and processing device;

4) the processing of volume data obtained by voice input and data of the parameters of the physicochemical state of the solution received from the recording device, followed by constructing their graphical dependence on each other using the processing and control unit 5 of the data collection and processing device;

5) analysis of the constructed graph to determine the inflection points on the titration curve and the subsequent determination by the volume values at these points of the desired concentrations of the analytes in solution, as well as processing the obtained analysis data and compiling the measurement protocol, storing and displaying it using processing unit 5 and control devices for collecting and processing data.

Before the titration process can begin, manually or using the voice unit 6 to enter the source data.

Before starting the titration process, they can start the corresponding measurement template, for example, based on templates created previously or in the current process. At the same time, the data collection process can be stopped automatically after reaching the equivalence point previously set in the running template.

In the absence of templates, the criterion for stopping the data collection process is to achieve the required amount of collected data to ensure reliable processing. So, for example, in order to reliably calculate the inflection, it is necessary that after passing it there should be at least five points on the curve. The operator must visually determine the moment of stop.

The determination of the inflection point on the titration curve can be carried out using the smoothing algorithm according to the moving average method, polynomial interpolation and subsequent processing by numerical differentiation methods or the Gran method.

The operation of the method and device is illustrated using examples.

Example 1. Determination of tartaric acid fault

Materials and equipment used: NaOH 1M reagent; 10 ml burette; burette tripod; glass for titration per 100 ml; magnetic stirrer; a recording device — a company’s pH meter (for example, Semiko model IPL-301); Bluetooth adapter for pH meters manufactured by Semiko; pH electrode ESK-10603; device for collecting and processing data in the process of titration.

The burette is fixed on a tripod and filled with NaOH 1M reagent. A 50 ml sample of wine is poured into the titration beaker and the beaker is mounted on a magnetic stirrer. Connect the electrode and Bluetooth adapter to the pH meter. Immerse the electrode in a sample of wine in a glass. Mixing is started.

Turn on the device for collecting and processing data during the titration. Perform pairing with a recording device 6 (pH meter). The template "Determination of tartaric acid in wine" is launched. In advance, the constant k1 value (correction factor for NaOH 1M solution) 0.988 is introduced into the template. All other parameters in the template are set during its creation: name, signal stabilization parameter, processing method, calculation formula “V1 * 1 * k * 150.09 / 2 / m” (150.92 - molar mass of tartaric acid, 2 - equivalent) , the unit of measurement for the final result is “g / l”. After the start, the device will prompt you to enter the variable "m" (sample volume, ml). Enter a value of 50. Start adding titrant in portions. After the signal, a portion of the titrant is added and the value of the added volume is pronounced in voice in the following format: “One point fourteen.” When the next signal from the device sounds (meaning the pH has stabilized), add the next portion and say again: “One point seventy one.” Etc. The device writes to the memory (using memory unit 3) a table of measured values in the following format:

During the process, a titration curve is displayed on the screen (Fig. 2).

At the same time, processing is performed according to the method laid down (search for an extremum on the curve of the first derivative). The curve of the first derivative can be superimposed on the graph (Fig. 3). Then an extremum is found and it is proposed to stop the process.

The operator confirms the stop.

Based on the found volume value at the extremum point (3.54 ml), the calculation is performed using the formula specified in the template, and the result is displayed on the screen:

C = 5.257 g / l

In memory block 3, the protocol is stored in the form:

Example 2. Determination of water hardness

Materials and equipment used: reagent EDTA 0, 1M; black Eriochrome solution 0.1%; 5 ml burette; burette tripod; 100 ml titration cell; magnetic stirrer; a recording device — a spectrophotometer with a wavelength of 550 nm; device for collecting and processing data in the process of titration.

The burette is fixed on a tripod and filled with EDTA 0, 1M reagent. A 50 ml sample of water is poured into the titration beaker. Add 1 ml of a solution of the indicator Eriochrome black 0.1%. Set the beaker into the cell of the spectrophotometer. Mixing is started.

Turn on the device for collecting and processing data during the titration. Perform pairing with a recording device 6 (spectrophotometer). The template "Determination of water hardness" is launched. Start adding titrant in portions. After the signal, a portion of the titrant is added and the value of the added volume is pronounced in voice in the following format: “One point fourteen.” When the next signal from the device sounds (meaning the optical density in mV has stabilized), add the next portion and say again: “One point seventy-one”. Etc.

The device writes to the memory a table of measured values in the following format:

As the process progresses, a titration curve is displayed on the screen. At the same time, processing is performed according to the method laid down (search for an extremum on the curve of the first derivative). The curve of the first derivative can be superimposed on the graph. One extremum is detected and the process stops automatically. Based on the found volume value at the extremum point (1.2 ml), the calculation is performed using the formula specified in the template and displays the result:

C = 214.6 ppm

The protocol is saved in memory as:

Example 3. Determination of citric acid in orange juice

Used materials and equipment: 0.1 M NaOH reagent; 10 ml burette; burette tripod; glass for titration per 100 ml; magnetic stirrer; a recording device - a pH meter of a company (for example, “Hanna Instruments)) HI5522-01); Bluetooth adapter for pH meters from Hanna Instruments)); pH electrode HI1048B; a device for collecting and processing data in the process of titration, implemented on the basis of a personal computer, including a microphone.

The burette is fixed on a tripod and filled with 0.1 M NaOH reagent. A 5 ml sample of juice is poured into the titration beaker, 50 ml of deionized water is added, and the beaker is placed on a magnetic stirrer. A data acquisition and processing device is connected to a pH meter. Immerse the electrode in a sample of juice in a glass. Mixing is started.

Turn on the microphone.

Portions of titrant are added and the value of the added volume read from the burette scale into the microphone is simultaneously pronounced. Watching the progress of the titration curve on the computer display, interrupt the process after adding at least 1 ml following the bend site.

Then it is stored in the computer memory and then processed in a suitable mathematical processing program (Excel, MathCad or otherwise) in order to determine the value of the volume at the inflection point. A value of 5.7 ml is obtained.

According to the value of the volume at the inflection point, the content of citric acid in the juice, expressed in g / l, is calculated.

C = 5.7 * 0.1 * 192.13 / 3/5

7.3 g / l are obtained.

Claims (15)

1. The method of collecting and processing data in the titration process includes pairing a recording device configured to measure the physicochemical properties of the test solution and a data collection and processing device, voice input of visual volume measurement data when each portion of the titrant is added to the study solution after launch titration process, taking current readings of a recording device, processing volume data obtained by voice input, and physicochemical state parameter data the solution obtained from the recording device, with the subsequent construction of their graphical dependence on each other, the analysis of the constructed graph to determine the inflection points on the titration curve and the subsequent determination by the values of the volume at these points of the desired concentrations of the substances to be determined in the solution, processing the obtained analysis data, compiling measurement protocol, its storage and its display. 2. The method of collecting and processing data in the titration process according to claim 1, characterized in that the pairing of the recording device and the device for collecting and processing data is performed using wireless technologies such as Bluetooth or Wi-Fi. 3. The method of collecting and processing data in the titration process according to claim 1, characterized in that the initial data are manually entered before the titration process begins. 4. The method of collecting and processing data in the titration process according to claim 1, characterized in that before starting the titration process, the corresponding measurement template is started. 5. The method of collecting and processing data in the titration process according to claim 4, characterized in that the launch of the corresponding titration template is performed from the list of templates created previously or in the current process. 6. The method of collecting and processing data in the titration process according to claim 4, characterized in that the data collection process is stopped automatically after reaching the equivalence point specified previously in the launched template. 7. The method of collecting and processing data in the titration process according to claim 1, characterized in that the determination of the inflection point on the titration curve is carried out using a smoothing algorithm using the moving average method, polynomial interpolation and subsequent processing by numerical differentiation methods or the Gran method. 8. A device for collecting and processing data in the titration process includes a block for manual input and correction of data, a unit for interfacing with external devices, a power unit, a memory unit connected to a processing and control unit that is connected to the voice unit and to the information display unit, when this unit interfacing with external devices is configured to connect to at least one recording device for measuring the physico-chemical properties of the test solution, the voice unit is made with the possibility of naked ovogo data input, speech recognition and conversion into digital audio data, and the processing and control unit configured to control on and off of the other blocks, construction and processing of the titration curve output unit displaying information on measurements and / or calculations. 9. A device for collecting and processing data in the titration process according to claim 8, characterized in that the unit for interfacing with external devices is capable of wiring at least one recording device for measuring the physicochemical properties of the test solution. 10. A device for collecting and processing data in the titration process according to claim 8, characterized in that the interface unit with external devices is configured to wirelessly connect at least one recording device to it for measuring the physicochemical properties of the test solution. 11. A device for collecting and processing data in the titration process according to claim 8, characterized in that the voice unit registers sound with a microphone. 12. A device for collecting and processing data in the titration process according to claim 8, characterized in that the processing and control unit is configured to generate and adjust at least one measurement pattern. 13. A device for collecting and processing data in the titration process according to claim 8, characterized in that the processing and control unit is configured to generate a report on the measurements taken. 14. A device for collecting and processing data in the titration process according to claim 8, characterized in that the processing and control unit is configured to transmit the generated report on the measurements made, for example, using Wi-Fi, Bluetooth technology or via GSM communication to other devices. 15. A device for collecting and processing data in the titration process according to claim 8, characterized in that all the blocks are implemented on the basis of a smartphone or tablet.

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