A titration method using a portable microtitration analysis system

Abstract

The application relates to the field of on-site rapid detection technology, and provides a titration method using a portable microtitration analysis system.S1, a quantitative sample is placed in a liquid drop counting bottle;S2, an indicator in a plastic drop bottle is quantitatively added into the liquid drop counting bottle according to the sample volume;S3, a buffer solution or an auxiliary reagent in a plastic square bottle is quantitatively added into the liquid drop counting bottle according to the sample volume;S4, after titration liquid in an ampoule bottle is sucked by using the handheld microtitration device, titration is carried out on the liquid drop counting bottle, and the titration is stopped after the liquid in the liquid drop counting bottle is discolored.The beneficial effect lies in that the heteroscedasticity is used to judge the uniformity of the mixture of substances in the liquid, a miniature camera is used to collect liquid photos in the liquid drop counting bottle in real time, the heteroscedasticity of each pixel in the photos is calculated in real time, and whether the titration discoloring is completed or not can be accurately judged, and whether the titration is terminated or not.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of on-site rapid detection technology, and particularly relates to a titration method using a portable micro-titration analysis system. BACKGROUND

[0002] The titration analysis method is a quantitative chemical analysis method, which adds a standard solution with a known accurate concentration to a solution of a measured substance until the added solution is exactly reacted completely according to the stoichiometric relationship, and then calculates the content of the measured substance according to the concentration and the volume of the added standard solution. Since this determination method is based on the measurement of the volume of the solution, it is also called volumetric analysis. According to different chemical reactions used in the analysis, the titration analysis is divided into acid-base titration analysis, oxidation-reduction titration analysis, complex titration analysis, precipitation titration analysis and non-water titration analysis.

[0003] As one of the most classic and well-known chemical analysis methods, the titration analysis is widely used in quantitative analysis of various industries, including drinking water, automobile manufacturing, ceramics, chemical industry, cosmetic detergent, packaging raw materials, paint, pigment, papermaking industry, cement textile, tobacco, water and water treatment, etc., due to its fast detection speed, high measurement accuracy and low operation professional characteristics.

[0004] Most of the existing titration methods are determined by the human eye whether the titration color change is completed and whether the titration is terminated, and there is a certain human error. In view of this, the present application is proposed. SUMMARY

[0005] The present application aims to provide a titration method using a portable micro-titration analysis system to solve the technical problems existing in the prior art.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows: a titration method using a portable micro-titration analysis system, comprising:

[0007] S1, taking a quantitative sample into the liquid drop counting bottle;

[0008] S2, according to the sample volume, quantitatively adding an indicator in the plastic drop bottle to the liquid drop counting bottle;

[0009] S3, according to the sample volume, quantitatively adding a buffer solution or an auxiliary reagent in the plastic square bottle to the liquid drop counting bottle;

[0010] S4, using the handheld micro-titration device to suck the titration liquid in the ampoule bottle, then titrating the liquid drop counting bottle, stopping titration when the liquid in the liquid drop counting bottle changes color, and reading the titration volume of the handheld micro-titration device through the window;

[0011] S5、according to the titration volume, calculating the content of the measured substance in the sample;

[0012] Wherein, the liquid photo in the liquid drop counting bottle is collected by the micro camera in real time, and the sum of squares of deviations from the mean of each pixel in the photo is calculated in real time.

[0013] When the sum of squares of deviations from the mean is less than the first threshold value, it indicates that the substances in the liquid are mixed uniformly and the reaction is relatively sufficient at this time, and the color average of the whole image is compared with the color average of the image at the titration end point.

[0014] If the difference between the two color values is less than the second threshold value, it means that the titration end point is about to be reached, prompting the operator to slow down the titration speed.

[0015] When the difference between the two color values is less than the third threshold value, it indicates that the image at this time is similar enough to the standard image, prompting the operator that the titration end point has been reached and stopping titration.

[0016] In an optional embodiment, the third threshold value is less than the second threshold value.

[0017] In an optional embodiment, the formula for calculating the sum of squares of deviations from the mean s is:

[0018]

[0019] Wherein, x i represents the color value of the i-th pixel in the image, n represents the number of pixels in the image, μ represents the average value of the color values of all pixels in the image; the size of the sum of squares of deviations from the mean represents the color uniformity of the whole image.

[0020] In an optional embodiment, during titration, if the sum of squares of deviations from the mean of the image is always greater than the first threshold value, and the sum of squares of deviations from the mean of the image suddenly increases when it is about to be less than the first threshold value, it indicates that new titration liquid is added immediately when the liquid is about to be mixed uniformly, prompting the operator to slow down the titration speed so as to determine the titration end point when the image is stable.

[0021] In an optional embodiment, in S3, the buffer solution or auxiliary reagent in the plastic square bottle is added to the liquid drop counting bottle by using the pipette.

[0022] The beneficial effects of the present application are:

[0023] (1) The present application uses the heteroscedasticity to judge the uniformity of the mixed substances in the liquid, wherein the smaller the heteroscedasticity, the more uniform the mixed substances, and vice versa, the larger the heteroscedasticity, the more non-uniform the mixed substances, through a miniature camera to collect the liquid photos in the drop counting bottle in real time (remove the non-liquid part), and calculate the heteroscedasticity of each pixel in the photo in real time, to accurately judge whether the titration color change is completed and whether the titration is terminated.

[0024] (2) The portable, anti-falling, anti-vibration micro-titrator (with titrator cover and glass syringe connection structure stable, can protect the glass syringe) replaces the laboratory glass burette (the burette in the laboratory is fixed on the iron stand and cannot be moved), and the pipette replaces the glass pipette in the laboratory, and the plastic drop counting bottle replaces the glass stoppered flask in the laboratory, and the above combination of instruments replaces the iron stand and related auxiliary devices in the laboratory, so that the titration detection can be carried out outside the laboratory. In addition, all reagents required for titration test are pre-prepared in plastic bottles and glass tubes, and the portable titration instrument, pre-prepared test reagents and all auxiliary devices required in the test are fixed in the shockproof box, so that the instruments will not be damaged during carrying, and the on-site rapid micro-detection of titration analysis experiment can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0026] Figure 1 The overall structure schematic diagram of a portable micro-titration analysis system provided by an embodiment of the present application.

[0027] Figure 2 The overall structure schematic diagram of a portable micro-titration analysis system provided by an embodiment of the present application. Figure One .

[0028] Figure 3 The image acquisition schematic diagram of a portable micro-titration analysis system provided by an embodiment of the present application.

[0029] In the figure, the reference signs are as follows: 1-handheld micro-titrator, 2-sample needle, 3-titrator cover, 4-inner core locking plug, 5-titrator pull rod, 6-titrator sample cavity, 7-drop counting bottle, 8-ampoule bottle, 9-pipette, 10-plastic drop bottle, 11-plastic square bottle, 12-darkroom, 13-light source, 14-miniature camera. DETAILED DESCRIPTION

[0030] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not intended to limit the present application.

[0031] It should be noted that when a component is referred to as "fixed to" or "disposed on" another component, it can be directly or indirectly on the other component. When a component is referred to as "connected to" another component, it can be directly or indirectly connected to the other component. The terms "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or position based on the orientation or position shown in the drawings, and are only for the convenience of description, and cannot be understood as a limitation on the technical solutions. The terms "first", "second" are only for the purpose of convenient description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. The meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0032] Embodiment one

[0033] Please refer to the accompanying Figures 1-2 The purpose of the present embodiment is to provide a portable microtitration analysis system, which comprises a portable shockproof box, a handheld microtitration device 1, a sample needle 2, a titration device sleeve 4, a droplet counting bottle 7, an ampoule 8, a pipette 9, a plastic dropper 10 and a plastic square bottle 11 placed in the portable shockproof box in sequence.

[0034] The sample needle 2 is provided with a sample needle protective sleeve. The sample needle 2 is connected to a glass syringe in the handheld microtitration device 1 by removing the sample needle protective sleeve. The glass syringe is placed in the titration device sleeve 3, and the titration device sleeve 3 is fixedly connected with the glass syringe through an inner core locking plug 4. The push rod of the glass syringe is a titration device pull rod 5 of the handheld microtitration device 1, and the cavity of the glass syringe is a titration device sample cavity 6 of the handheld microtitration device 1. A window is provided on the titration device sleeve 3 for observing the titration amount. The sample needle 2, the titration device sample cavity and the titration device pull rod 5 are combined to realize the suction and titration of the titration solution. In order to realize the on-site operation of the titration experiment, the handheld microtitration device 1, the auxiliary accessories for titration experiment and the pre-prepared reagents are all fixed in the shockproof box, which is convenient for on-site detection and use, and avoids damage to the instruments during carrying.

[0035] In the present embodiment, the handheld microtitration device 1 is used to suck the titration solution in the ampoule 8; the plastic dropper 10 is used to store the titration indicator; and the plastic square bottle 11 is used to store the buffer solution or auxiliary reagent.

[0036] The portable, anti-falling and anti-vibration micro-titrator can replace the glass titration tube in the laboratory (the titration tube in the laboratory is fixed on the iron stand and cannot be moved), the pipette can replace the glass pipette in the laboratory, and the plastic drop counting bottle can replace the glass stoppered flask in the laboratory. The above-mentioned combination of instruments can replace the iron stand and related auxiliary devices in the laboratory, and the titration detection can be carried out outside the laboratory.

[0037] In addition, all reagents required for the titration test are pre-prepared in plastic bottles and glass tubes, the portable titration instrument, pre-prepared test reagents and all auxiliary devices required in the test are fixed in the anti-vibration box, the instruments will not be damaged during carrying, and the on-site rapid micro-detection of titration analysis experiments can be realized.

[0038] Embodiment two

[0039] Please refer to the accompanying Figures 1-3 The purpose of the embodiment is to provide a titration method using a portable micro-titrating analysis system, which comprises:

[0040] S1, placing a quantitative sample in the drop counting bottle 7;

[0041] S2, according to the sample volume, quantitatively adding the indicator in the plastic drop bottle 10 into the drop counting bottle 7;

[0042] S3, according to the sample volume, quantitatively adding the buffer solution or auxiliary reagent in the plastic square bottle 11 into the drop counting bottle 7; it should be noted that the buffer solution or auxiliary reagent in the plastic square bottle 11 is added into the drop counting bottle 7 by using the pipette 9;

[0043] S4, after the titration liquid in the ampoule bottle 8 is taken by using the handheld micro-titrator 1, the drop counting bottle 7 is titrated, and the titration is stopped when the liquid in the drop counting bottle 7 changes color; the titration volume of the handheld micro-titrator 1 is read through the window;

[0044] S5, calculating the content of the measured substance in the sample according to the titration volume.

[0045] It should be noted that, in order to realize the on-site operation of the titration experiment, all reagents are packaged and fixed in the container. The titration standard solution with calibrated concentration is packaged in the ampoule bottle 8. During the titration process, the indicator does not need to be accurately dosed in the plastic drop bottle 10; the buffer solution or auxiliary reagent needs to be accurately dosed in the plastic square bottle 11, and the pipette 11 is used.

[0046] During the titration process, the liquid in the liquid drop counting bottle 7 is collected by the miniature camera 14 in real time (non-liquid part is removed), and the sum of squares of deviations from the mean of each pixel in the photo is calculated in real time. The formula for calculating the sum of squares of deviations from the mean s is as follows:

[0047]

[0048] Wherein, x i represents the color value of the i-th pixel in the image, n represents the number of pixels in the image, and μ represents the average value of the color values of all pixels in the image. The size of the sum of squares of deviations from the mean represents the color uniformity of the entire image. In a uniform image, the sum of squares of deviations from the mean is very small; when the titration liquid is just dropped or the dropping speed is too fast, liquid flow marks are left in the image, and the sum of squares of deviations from the mean increases at this time. Therefore, the sum of squares of deviations from the mean is used to judge the uniformity of the mixing of substances in the liquid in the embodiment, and the smaller the sum of squares of deviations from the mean, the more uniform the mixing of substances, and vice versa. When the sum of squares of deviations from the mean is less than a first threshold value, it indicates that the substances in the liquid are mixed uniformly at this time, the reaction is relatively sufficient, and there is basically no liquid flow mark caused by too fast titration speed, etc. At this time, the color average of the entire image is compared with the color average of the image at the titration end point (i.e. the image when the color completely changes and the titration is completed, which is referred to as a standard image in the embodiment).

[0049] If the difference between the two color values is less than a second threshold value, it indicates that the titration end point is about to be reached, prompting the operator to slow down the titration speed (for example, to one drop per second), and to continue titration at a slower speed. When the difference between the two color values is less than a third threshold value, it indicates that the image at this time is similar enough to the standard image, prompting the operator to stop titration when the titration end point is reached. The third threshold value is less than the second threshold value. In actual application, the above-mentioned threshold values can be pre-marked by experiment, and the embodiment does not make specific limitations.

[0050] During the process, if the sum of squares of deviations from the mean of the image is always greater than the first threshold value, for example, the sum of squares of deviations from the mean of the image suddenly increases when it is about to be less than the first threshold value, it indicates that new titration liquid is dropped immediately when the liquid is about to be mixed uniformly, at which time the operator is reminded that the titration speed is too fast, which is not conducive to comparison with the standard image, so as to slow down the titration speed, so as to determine the titration end point when the image is stable.

[0051] The above is only a preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A titration method using a portable micro-titer analysis system, characterized in that, include: S1. Take a quantitative sample and place it in a drop counting bottle (7); S2. Add the indicator from the plastic dropper bottle (10) to the dropper counting bottle (7) in a quantitative manner according to the sample volume; S3. Add a quantitative amount of buffer solution or auxiliary reagent from plastic square bottle (11) to the drop counting bottle (7) according to the sample volume; S4. After using a handheld micro-titrator (1) to draw the titrant from the ampoule (8), titrate the drop counting bottle (7). Stop titrating when the liquid in the drop counting bottle (7) changes color. Read the titration volume of the handheld micro-titrator (1) through the window. S5. Calculate the content of the analyte in the sample based on the titration volume; Among them, a miniature camera (14) is used to collect photos of the liquid in the drop counting bottle (7) in real time, and the sum of squares of the deviations from the mean of each pixel in the photo is calculated in real time. When the sum of squared deviations from the mean is less than the first threshold, it indicates that the substances in the liquid are mixed evenly and the reaction is relatively complete. At this time, the color mean of the entire image is compared with the color mean of the image at the titration endpoint. If the difference between the average color value of the entire image and the average color value of the image at the titration endpoint is less than the second threshold, it means that the titration endpoint is about to be reached, and the operator is prompted to slow down the titration speed. When the difference between the color mean of the entire image and the color mean of the image at the titration endpoint is less than the third threshold, it indicates that the image at this point is sufficiently similar to the standard image, prompting the operator that the titration endpoint has been reached and the titration should be stopped.

2. The titration method using a portable micro-titration analysis system as described in claim 1, characterized in that, The third threshold is less than the second threshold.

3. The titration method using a portable micro-titration analysis system as described in claim 1, characterized in that, The formula for calculating the sum of squared deviations s from the mean is: ， Where, x i Let represent the color value of the i-th pixel in the image, n represent the number of pixels in the image, and μ represent the average color value of all pixels in the image; the sum of squared deviations from the mean represents the color uniformity of the entire image.

4. The titration method using a portable micro-titration analysis system as described in claim 1, characterized in that, During titration, if the sum of squares of the deviations from the mean in the image is consistently greater than the first threshold, and then suddenly increases again just before it is about to fall below the first threshold, it indicates that new titrant was added just as the liquid was about to be evenly mixed. In this case, the operator should be reminded to slow down the titration speed so that the endpoint can be determined when the image stabilizes.

5. The titration method using a portable micro-titration analysis system as described in claim 4, characterized in that, In S3, a pipette (9) is used to draw buffer solution or auxiliary reagent from the plastic square bottle (11) and add it to the drop counting bottle (7).

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