• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Procedure for measuring the concentration of chemical species of industrial, environmental or biomedical interest through the processing of the rgb values of a digital photograph taken together with a colorimetric sensor and a reference pattern system. It is possible for a user without specialization with a device with any type of camera, with data processing capacity, to carry out the analysis of any chemical species of interest, for example iron in blood. It allows the elimination of environmental noise, allowing the correct analysis from the chemical point of view from a photograph taken under any lighting condition and with any type of camera. Equally relevant is that the device used is commercial and does not require any adaptation, only the algorithm that executes the procedure in its part of extracting the data from the photograph and subsequent analysis. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2555161A1
    申请号:ES201400514
    申请日:2014-06-24
    公开日:2015-12-29
    发明作者:José Miguel GARCÍA PÉREZ；Félix Clemente GARCÍA GARCÍA；Saúl Vallejos Calzada；César REPRESA PEREZ；José María CÁMARA NEBREDA；Iván ROS SANTAOLALLA
    申请人:Universidad de Burgos；
    IPC主号:
    专利说明:

    Object of the invention
    The present invention relates to a method for measuring concentrations of chemical species by means of a chemical analysis to verify and control the concentration of chemical species of industrial, environmental or biomedical interest through the processing of RGB values of a digital photograph taken on sensors Colorimetric that have been brought into contact with solutions with a known concentration of a certain chemical species (a reference system of standard solutions) and with solutions with an unknown concentration (problem solutions), which you want to measure, of the same chemical species.
    Chemical colorimetric sensors, either as solid materials or in solution, have the characteristic of changing color in the presence of chemical species of interest.
    Said solid colorimetric sensors can be contacted with the solution containing the chemical species, either by immersion of the colorimetric sensor in the solution, or by deposition of a sample of the solution on the solid colorimetric sensor. In the case of colorimetric sensors in solution, a sample of the solution containing the chemical species to be analyzed is introduced into a vial or cuvette containing the colorimetric sensor solution.
    The automatic digital processing of the photograph taken on the colorimetric sensors that have been in contact with the standard solutions and with the problem solutions, offers as an output the concentration of the species of interest in the unit that the user defines, for example parts by million or molarity, as well as information on the limits in which the concentration is, whether legal or advisable, that is, if it is between, above or below these limits. Likewise, the present invention has provided for storing a record of the analyzes carried out for the subsequent study of the results or for their re-evaluation, together with the latitude and altitude coordinates that identify the physical place in which the analysis was performed.
    The photograph is taken directly, without specific lighting conditions or precautions, so that any user can carry it out, and is independent of the type of digital camera used. This is because the colorimetric sensor that has been in contact with the test solution sample and the colorimetric sensors that have been in contact with the standard solution samples are photographed at the same time, carrying out a calibration with each photograph.
    Also, the data processing is automatic, so no analytical experience or data processing is required. The digital processing recognizes the shape of the samples of standard solutions and problem solution in each colorimetric sensor, assigning the reference concentration to the first ones, to carry out a calibration using principal components of the RGB values of each standard solution; the three RGB variables of the color shown by each sample of standard solution in contact with colorimetric sensor material are transformed into a main component, as a way of agglutinating the RGB information into a single variable for each sample of standard solution, also reducing noise.
    The measuring system is thus calibrated by means of the corresponding adjustment of curves and subsequently the concentration of the chemical species to be analyzed in the problem solution is calculated, by extrapolation of the curve previously adjusted to the main component of the RGB values corresponding to the sample of problem dissolution. Alternatively, the calibration and extrapolation of the measurement can be carried out taking into account only one or two of the RGB parameters, or a mathematical combination of some or all of them.
    Technical problem to be solved and Background of the invention
    The use of chemical sensors or chemosensors in the determination of chemical species of interest is a mature technology for the assessment and quantification of chemical species in a laboratory of rapid technological evolution (José M. García,
    Félix C. García, Felipe Serna, José L. de la Peña, "Fluorogenic and Chromogenic Polymer Chemosensors", Polymer Reviews 2011, 51, 341-390; R. Martínez-Máñez, F. Sancenón, "Fluorogenic and chromogenic chemosensors and reagents for anions", Chemical Reviews 2003, 103,4419-4476).
    On the other hand, the novel development of solid polymeric colorimetric sensors, film-shaped, and easily manageable, by the Polymer Group of the University of Burgos has led to the design of sensor materials that allow the qualitative determination of the concentration of several chemical species visually and quantitatively through various analytical techniques, including color analysis of digital photographs through statistical and numerical data processing (S. Vallejos, A. Muñoz, S. Ibeas, F. Serna, FC García, JM García , "Sol id sensory polymer substrates for the quantification of iron in blood, wine and water by a scalable RGB technique", Journal of Materials Chemistry 2013,1, 15435-15441; JL Pablos, M. Trigo-López, F. Serna, FC García, JM García, "Water soluble polymers, solid polymer membranes, and coated fibers as smart sensory materials for the naked eye detection and quantification of TNT in aqueous media ", Chemical Communications 2014, 50, 2484-2487; Patent applied for J. L. Pablos, M. Trigo, S. Vallejos, M. A. Muñoz, L.A .. Sarabia, M.C Ortiz, A. Mendía, F.C. García, F. Serna, J.M. García, "Solid polymeric materials for the fluorogenic detection of nitro-derived explosives and their use", Application No.: P201400073, Application Year: 2014).
    In carrying out these developments, two facts became apparent: a) the potential of such materials in chemical analysis; b) the need for an automatic system to carry out a chemical analysis using the sensor materials from a simple photograph so that it could be used in situ, by any person, without specialization, therefore, and to offer finalist information for both this type of user as for other specialized; that is, in addition to providing a quantitative concentration, it will report on whether it is within the appropriate limits, which may be legal or recommended, depending on the scope of the measure. In this context, the advantage of automatic registration of all analyzes, together with the place of performance, for subsequent re-evaluation or preparation of chemical concentration maps in regions of interest would also be evident.
    Traditionally, optical chemical sensors have been used successfully, both based on fluorescence and color variations, on titration and quantification of chemical species of interest in the laboratory. The quantification requires a deep knowledge of the sensor system, as well as a high specialization of both the scientific equipment used to carry out the measurements, specifically ultraviolet / visible spectrophotometers and fluorimeters, as well as data processing by mathematical methods, and specifically statistical. A characteristic example of sensor products that require these characteristics for use is represented by the company Ursa Bioscience (www.ursabioscience.com).
    On the other hand, there are numerous commercialized colorimetric sensor kits, such as the "Test Kits" of the Hanna instruments company (http://www.hannainst.es/catalogo). which are based on a system of reagents that produce a color change depending on the concentration of, for example, iron, chlorine, copper, and others in water, and visual contrast with a color scale, or as the "Kits of Merime Millipore colorimetric test for Aquamerck®, Microquant® and Aquaquant® waters for hardness, nitrate, nitrite, phosphate analysis, etc. (http://www.merckmillipore.es/chemicals/ colorimetric-test-kits / spanish / c_JxWb.s10MaIAAAEdThBRbT5Y), or the test ones for water analysis such as quick kits and Visocolor® reagent cases, from Macherey- Nagel (http://www.mn-net.com/). The color change in these kits is visually contrasted with patterns so that the user has qualitative or semi-quantitative information on species concentrations or concentration ranges. The most widespread and characteristic example would be the strips of indicator paper for visual pH control.
    Therefore, the use of chemical sensors as a quantitative method of concentration determination currently requires, briefly, a chemical laboratory equipped with spectrophotometers, their maintenance, personnel specialized in chemical and / or clinical analysis, and sample collection and transfer to the laboratory, which implies a high cost in relation to the process and the time between sampling and results. Alternatively, the use of commercial kits entails a subjective assessment of the color by the user and the confrontation against a scale that will lead to a necessarily qualitative numerical value to be interpreted in the context of the analysis, so it also requires some specialization.
    Description of the invention
    The present invention relates to a method of measuring the concentration of chemical species.
    As a previous step to the procedure object of the present invention, the following actions are required:
    take samples of at least two standard solutions whose concentration of a certain chemical species to be measured is known; contacting said samples of standard solutions with at least one first colorimetric chemical sensor, capable of coloring in direct relation to the concentration of the chemical species to be measured, contained in each of the sample of standard solution; take at least one sample of at least one problem solution, whose concentration of the chemical species to be measured is unknown; contacting each problem solution sample with at least a second colorimetric sensor, of the same colorimetric characteristics as the first colorimetric chemical sensor, which can be colored directly in relation to the concentration of the chemical species to be measured, contained in the solution sample trouble.
    Next, the process of the present invention introduces the following novel phases:
    take at least one photograph of each first colorimetric sensor placed in contact with each of the samples of the standard solutions and at least one photograph of the second colorimetric sensor placed in contact with the test solution sample;
    extract, by means of a device capable of image processing, a representative color value, shown in the photographs, of each first calorimetric sensor brought into contact with each of the samples of the standard solutions and a representative value of the color of the second sensor calorimetric placed in contact with the test solution sample; associating to each representative value of the color of each first calorimetric sensor in contact with each of the samples of the standard solutions, the known concentration value of the chemical species to be measured in each of the standard solutions; statistically determine a mathematical expression that relates to each other the representative values of the color of each first calorimetric sensor brought into contact with each of the samples of the standard solutions, together with their corresponding concentration values of the chemical species to be measured; determine, by interpolation of the mathematical expression obtained in the previous step, the concentration value of the chemical species to be measured in the problem solution, corresponding to the representative value of the color of the second calorimetric sensor placed in contact with the sample of the problem solution .
    In a preferred embodiment of the present process, the extraction phase of a color-representative value, shown in the photographs, of each first calorimetric sensor contacted with each of the samples of the standard solutions and the second calorimetric sensor contacted With the sample of the problem solution, it includes:
    to. extract the RGB parameters related to the color, shown in the photographs, of each first calorimetric sensor in contact with each of the samples of the standard solutions and of the second calorimetric sensor in contact with the sample of the problem solution;
    b. determine, by means of a statistical analysis procedure, a representative value of the RGB parameters associated with the color, shown in
    the photographs of each first colorimetric sensor placed in contact with the samples of the standard solutions and of the second colorimetric sensor contacted with the sample of the problem solution.
    For this process, an algorithm for recognition of the edges of the images of the samples of standard solutions and problem solutions in contact with the sensor materials of each colorimetric sensor is previously used.
    An algorithm of this type (conventional in the state of the art of image recognition), allows to analyze the color of each one of the zones delimited by the recognized edges.
    For its part, the determination of a representative value of the RGB parameters associated with the color, shown in the photographs, of each first colorimetric sensor placed in contact with each of the samples of the standard solutions and of the second calorimetric sensor contacted with The sample of the problem solution includes:
    calculate the mutual covariance between the RGB parameters associated with the color, shown in the photographs, of each first calorimetric sensor contacted with each of the samples of the standard solutions and of the second colorimetric sensor contacted with the sample of the problem solution ;
    calculate the eigenvalues and eigenvectors associated with the covariance matrix whose values are the cavariances calculated in the previous phase;
    determine the representative eigenvector, such as that eigenvector associated with the autovalue of greater absolute value calculated in the previous phase;
    calculate, for each first colorimetric sensor contacted with each of the samples of the standard solutions and for the second colorimetric sensor contacted with the sample of the problem solution, the absolute values of the projections of their associated autovectors, calculated in the previous phase, on the representative autovector determined in the previous phase;
    determine, for each sample of standard solution and problem solution, the highest of the absolute values calculated in the previous phase;
    establish each greater of the absolute values determined in the previous phase, respectively as the representative value of the RGB parameters associated with the color, shown in the photographs, of each first colorimetric sensor brought into contact with each of the samples of the standard solutions and the Second colorimetric sensor placed in contact with the sample of the problem solution.
    In turn, in a preferred embodiment of the present invention, the phase of statistical determination of a mathematical expression that relates to each other the representative color values of each first colorimetric sensor brought into contact with each of the samples of the standard solutions, together with their corresponding known concentration values of the chemical species (to be measured in the problem solution), it comprises:
    Obtain an experimental curve resulting from joining points associated with each sample of standard dissolution, where the values of the coordinates of each of these points in some coordinate axes are respectively the representative value of the color, shown in the photographs, of the first colorimetric sensor placed in contact with the sample of the standard solution associated with said point and the known value of the concentration of the chemical species to be measured in said sample of standard solution;
    determine, through an assimilation procedure for least squares
    or linear regression, a mathematical expression that represents a curve that closely resembles the experimental curve obtained in the previous phase.
    According to a first embodiment, the first colorimetric sensor and the second colorimetric sensor are composed of discs comprising solid chromogenic reactive materials.
    According to a second embodiment, the first colorimetric sensor and the second colorimetric sensor are composed of solutions of chromogenic reactive materials that are introduced into vials or cuvettes of transparent or translucent material.
    The method object of the present invention provides that the taking of at least one photograph of the first colorimetric sensor and the second colorimetric sensor is carried out by means of a mobile device with an integrated image processor, which is responsible for taking the photograph of the first colorimetric sensor set in contact with the samples of the standard solutions and the second colorimetric sensor placed in contact with the sample of the test solution and determine the concentration value of the chemical species to be measured in the test solution.
    Said mobile device can be a smart mobile phone (Smartphone) or a tablet.
    In this way, the procedure can be executed automatically by means of said mobile device, so that a user without knowledge of chemistry or practice in the measurement of dissolved chemical species can carry out the measurement in any type of environmental conditions and lighting of the environment , without more than photographing the colorimetric sensors after having put them in contact with the samples of standard solutions and problem solutions.
    In a preferred embodiment of the invention, in the phase of taking pictures, the mobile device records together with the concentration values of the chemical species to be measured in the problem solutions, also the data relating to the date, time, latitude , the length and altitude of the moment and the place where the test is performed.
    Alternatively, if the measurement of the concentration of a chemical species is made on the body of a patient, the mobile device records together with the concentration values of the chemical species to be measured in the problem solutions, also the data related to the date, the time and anatomical region in which the test is performed.
    In any of the cases mentioned above, the mobile device is expected to offer a representation of a concentration map on a surface
    or given geographical or anatomical region, together with the variation of concentrations of the chemical species to be measured in a given period.
    The process object of the present invention typically comprises comparing the results obtained from the concentration value of a certain chemical species in a problem solution with characteristic limit values contained in a database, where, as a result of the previous comparison, it is determined if the concentration of a certain chemical species in a problem solution is above or below said characteristic limits. In this way it can be determined if a detected concentration is within the legal and / or advisable limits.
    The present invention has as key characteristics that the analysis is carried out through the evaluation of color variations by taking a photograph, and that interference of the type and characteristics of the camera, the light environment and the user is eliminated by taking the photograph together with the reference system of samples of standard solutions and with the samples of problem solutions, together with the calculation of the calibration curve for each measurement, that is, with each photograph.
    Likewise, the invention consists in the treatment of the analysis data and its confrontation against relevant tabulated concentration data to indicate if the measured concentration exceeds, is lower, or is among these reference data, which may well be legal or recommended limits. for certain industrial, environmental or biomedical applications.
    Likewise, the invention consists in the automatic registration of the altitude and latitude at which the analysis has been carried out so that together with the results of the analysis, the data of the place where they were obtained are also taken, to complete the analysis and develop concentration maps on physical maps.
    The analysis of the color variations in each photo containing the reference of standard solutions and the sample of problem solution is carried out by processing the RGB values of the colorimetric sensor material brought into contact
    with the solutions, both of the sample of problem solution and of the reference system of samples of standard solutions.
    Preferably, and not limitation to other mathematical treatments, the analysis of the three RGB data (red, green and blue) of each of the colorimetric chemical sensors included in each photograph (which include the sample of problem solution and the system of reference of samples of standard solutions) is done by reducing the three RGB variables of each sensor point to a single variable, by means of main components. With the main component and the concentration of the chemical species of interest in the different sensor materials that include the reference, the XY calibration line is constructed, by linear or non-linear adjustment, which allows the concentration information of the chemical species to be extracted in the Sample of dissolution problem deposited in the colorimetric sensor. This information can also be obtained with calibrations directly using one of the RGB parameters, or a combination of them.
    Once the concentration information is obtained, it is recorded, preferably automatically by a mobile device, together with the altitude and latitude coordinates at which the analysis was carried out. In addition, this concentration can be automatically compared with the relevant concentration data for the chemical species of interest and the medium, resulting in qualitative information thereof, which, by way of example, may be pass / fail, meet / does not comply, outside / within range, within / outside the legal limit, within / outside the advisable limit, etc.
    The method object of the present invention is capable of being implemented by means of an application in a mobile device, which can be connected to a remote database in which relevant concentration data for new chemical species are available, as well as possible updates of existing ones. to new values or to different places in the world.
    Likewise, the procedure allows the remote analysis of the photographs taken by a mobile device, so that the analysis takes place in a different device and / or located at a certain distance from the place where the photographs of the colorimetric sensors have been taken that have contacted the standard solutions and / or the problem solutions.
    The present invention has the advantage, compared to the aforementioned state of the art, in that the analysis can be carried out automatically from the taking of a photograph taken on a colorimetric sensor that has been brought into contact with the sample of the chemical species in solution to be measured, or problem solution, and in a reference system consisting of colorimetric sensors placed in contact with standard solutions of the chemical species in question; that is, for the measurement of each chemical species, a standard reference system specifically designed for said chemical species is necessary.
    In addition, the reference system of samples of standard solutions brought into contact with the first colorimetric sensor may be previously prepared, so that the measurement of the problem solution sample is performed simply by contacting this problem solution sample with the second colorimetric sensor. and taking the picture on both colorimetric sensors.
    Therefore, preferably the user intervenes only in the contact of the sensor system with the problem solution and in the taking of that photograph, and this taking can be carried out by anyone without knowledge of chemistry, or analysis, or even of photography / optics.
    The influence of the type of camera, lighting conditions, user, etc., are eliminated by automatically performing the calibration curve with each photo to be analyzed, which includes both the reference system of samples of standard solutions brought into contact with the First colorimetric sensor as the second colorimetric sensor placed in contact with the sample of problem solution, which represents the key to the democratization of the analysis system. In addition, the result of the analysis is offered in quantitative terms, which is recorded and is useful for further evaluation, as well as for a more specialized person, and for a study of maps and maps, and qualitatively indicating whether the result, for example, It is within the legal limits, if a certain water is potable in relation to the chemical species to be assessed, or if it is within the conventional limits in a biological analysis.
    On the other hand, the results are recorded for subsequent evaluations, reassessments or monitoring of evolution, or establishment of concentration maps through the indication of the anatomical or geographical region by latitude and altitude coordinates of each pair of photography / analysis.
    In summary, the advantages it presents over existing solutions are:
    • It allows measurements of chemical species in situ and without user intervention in the analysis of the data. Said analysis can be carried out in a fully automated way;
    • the introduction of errors in the measurement is avoided due to the existing environmental conditions and due to the photographic device itself, since the captured image encompasses both the reference system formed by the first colorimetric sensor placed in contact with the samples of standard solutions, as with the second colorimetric sensor placed in contact with the sample of the problem solution, so that any error or deviation introduced affects the reference system and the second colorimetric sensor placed in contact with the sample of the solution solution, as the analysis is It is carried out by comparing the RGB parameters of the second colorimetric sensor in contact with the sample of dissolution problem against the first colorimetric sensor in contact with the samples of the standard solutions. Therefore, these deviations or errors do not affect the final result of the analysis;
    • the analysis of the chemical species is allowed in real time;
    • This analysis is allowed to be carried out by any person who has a photographic device without the need for specialized personnel, when performed digitally and automatically, and;
    • a large cost reduction is allowed in relation to conventional photometric quantification techniques. Brief description of the figures
    As part of the explanation of the embodiment of the invention, a series of figures are included, the explanation of which is as follows:
    Figure 1.- Shows a flow chart of an embodiment of the measurement procedure of the concentration of chemical species object of the present invention.
    Figure 2.- Shows an example of an embodiment with the reference system formed by the first colorimetric sensor placed in contact with five samples of standard solutions (P1 to P5) and the second colorimetric sensor placed in contact with a sample to be analyzed for problem solution. (P) inserted perpendicular to it.
    Figure 3.- It shows a mobile device with integrated camera, showing the image of the reference system with the samples of standard solutions, and the sample of problem solution (P).
    Figure 4.- Shows the resulting recognized forms during the edge detection phase of the process object of the present invention.
    Figure 5.- Shows the graphs resulting from a least squares adjustment of the points whose coordinates correspond to the known concentrations of the chemical species to be measured in the reference system of standard solutions, and with the main component of the RGB parameters of each of the samples of standard solutions, obtained from the analysis of an image of the first colorimetric sensor captured by the mobile device. This adjustment can be linear or quadratic, the one with the least error being the one used to obtain the value of the problem concentration. Likewise, the point corresponding to the problem solution sample in contact with the second colorimetric sensor is observed; The coordinate of this point relative to the concentration of the chemical species to be measured in the problem solution is obtained by interpolation of the graph obtained by least squares or linear regression.
    Figure 6.- Shows the graphs resulting from a least squares adjustment of the points whose coordinates correspond to the known concentrations of the chemical species to be measured in the reference system of standard solutions, and with the main component of the RGB parameters of each of the samples of standard solutions, obtained from the analysis of an image of the first colorimetric sensor captured by the mobile device under different lighting conditions than those used for Figure 5. This adjustment can be linear or quadratic, being that of minor error is used to obtain the value of the problem concentration. Likewise, the point corresponding to the problem solution sample in contact with the second colorimetric sensor is observed; The coordinate of this point relative to the concentration of the chemical species to be measured in the problem solution is obtained by interpolation of the graph obtained by least squares or linear regression.
    Figure 7.- Shows a table representing data of the RGB parameters (and their main components) of the first colorimetric sensor, put in contact with each of the samples of standard solutions. It also shows the RGB parameters (and its main component) of the second colorimetric sensor placed in contact with the sample of the solution solution, as well as the result of the calculation of the concentration of the chemical species to be measured in said problem solution, obtained by interpolation of the graph obtained by linear regression or by least squares, from the representative points of the samples of standard solutions.
    Figure 8.-Sample, for the same samples used in the example of Figure 7, but taking the photograph of the samples under other environmental conditions, a table representing data of the RGB parameters (and their main components) of the first colorimetric sensor, placed in contact with each of the samples of standard solutions. It also shows the RGB parameters (and its main component) of the second colorimetric sensor placed in contact with the sample of the solution solution, as well as the result of the calculation of the concentration of the chemical species to be measured in said problem solution, obtained by interpolation of the graph obtained by linear regression or by least squares, from the representative points of the samples of standard solutions.
    Detailed description
    The flow chart of Figure 1 shows the different stages in which the procedure for measuring the concentration of chemical species of biomedical, environmental and industrial interest is divided.
    Initially, the image containing a second colorimetric sensor (2) is captured, which has been contacted with the problem solution, a solution that contains an unknown concentration of a specific chemical species whose concentration is to be measured. Preferably, a photograph of said second colorimetric sensor (2) (in contact with the problem solution) is taken, superimposed on a first colorimetric sensor (1) in contact with at least two samples of standard solutions, which contain a known concentration of the mentioned chemical species to measure.
    In the exemplary embodiment shown in Figure 2, the first colorimetric sensor (1) contains five circular plates, discs or sample holders, with colorimetric sensor material that has come into contact with standard solutions with known concentration of a chemical species whose concentration it is desired to measure in the problem solution.
    This operation is performed by default with the camera integrated in the mobile device (3), although it is also possible to incorporate an image taken with another imported photographic device with standard RGB color format. The result of this operation is seen in Figure 3.
    The samples are then recognized, which includes both the samples of standard solutions in contact with the first colorimetric sensor (1), which in the example illustrating the invention are 5, and the sample of problem solution in contact with the sensor material of the second colorimetric sensor (2), as seen in Figures 2 to 4. For this purpose, an edge detection algorithm is used that delimits the circles corresponding to each sample in circular samples. In the same way it would be done in samples of another format or in liquid samples in vials or cuvettes.
    Then, once the regions in which the relevant information is found, a representative value of the color of each of the sensor materials that have come into contact with the standard solutions and problem solution is extracted.
    Said process is preferably carried out by extracting the RGB parameters or components corresponding to the color of each sample in contact with the corresponding sensor material. Since the color is not uniform in each sample, an average value is calculated in each sample for each component R, G or B.
    Next, a representative value of the RGB parameters associated with the color of each of the samples of standard solution and problem solution in contact with its corresponding colorimetric sensor is sought.
    The representative value of each color, hereinafter referred to as the main component of that color, is obtained by a standard statistical procedure known as principal component analysis. This analysis is based on the standardized covariance matrix, which is the result of the calculation of the correlations between the RGB channels of each sample of standard dissolution. Following this statistical procedure, the eigenvalues of the covariance matrix are calculated and the eigenvector associated with the eigenvalue of higher value is extracted. This proprietary vector is used to obtain the main component of each standard color sample by simply calculating the scalar product between said own vector and the RGB values of each sample.
    The main component of each of the standard dissolution samples is associated with their respective concentration of known value, which allows establishing a functional relationship. This relationship is obtained from a linear regression or a quadratic adjustment, as shown in Figure 5, finally taking the one that provides the least error.
    In the last step, with the main component of the problem or problem sample, the estimated concentration is obtained from the interpolation of the functional relationship provided by the previous adjustment. This is a preferred but not limiting calculation for the calculation of concentrations from the RGB data.
    The following example is illustrative of the invention, is not intended to be limiting, and describes
    the determination of the concentration of iron in aqueous medium of a sample
    problem using patterns of known concentration for the elaboration of
    s calibrated.
    Example 1. Calculation of the concentration of Fe (lIl) in aqueous media using a
    5 pattern system.
    10 It is based on a system of 6 Fe (lIl) sensor discs prepared according to
    published procedure (S. Vallejos, A. Muñoz, S. Ibeas, F. Serna, F. C. García, J. M.
    García, "Solid sensory polymer substrates for the quantification of iron in blood, wine
    and water by a scalable RGB technique ", Journal of Materials Chemistry 2013, 1,
    15435-15441).
    lS
    Of the 6 discs, 5 discs make up the first colorimetric sensor (1), and are
    arranged on a support labeled P1 to P5 (see Figure 2 and table in Figure
    7) and 30 mL of a Fe solution (lI) are added on the surface of each disk
    known, between 0 and 6 ppm, (see table shown in Figure 7), buffered at pH = 2. A
    twenty 30 mL of a test solution are then added, with concentration
    Fe (III) unknown, buffered at pH = 2 on a sensor disk on a support
    separated, constituting the second colorimetric sensor (2), which after adding the
    solution is inserted perpendicularly in the support of the patterns, as
    schematically shown in Figure 2.
    2S
    In this example the preparation of the standard is indicated, which once prepared serves to
    the realization of multiple measures. This pattern can also be marketed.
    Figure 2 corresponds to the image to be photographed by the camera. In it you can
    30 distinguish the reference pattern and the sample to be analyzed perpendicularly
    to the. After a border detection process, the standard samples are recognized and
    problem (Figure 3). The RGB values are extracted from the detected samples
    shown in the table shown in Figure 7.
    By means of an analysis in main components, the number of variables from 3 (R, G and B) is reduced to a single variable (CP1) of each sample. The analysis is carried out in conjunction with the samples of standard solutions and with the sample of problem solution. The reduction of variables to a single one fulfills two functions, on the one hand it simplifies the subsequent adjustment and extrapolation for the calculation of the concentration of the test sample and, on the other and more important, it supposes an important reduction of noise with a minimum loss of information. Through an adjustment by least squares we can establish a functional relationship between the concentrations of the chemical species in the samples of standard solutions and the corresponding main component of its RGB parameters. The adjustment that provides a lower error allows us to know the value of the concentration of the chemical species in the problem solution, by extrapolation.
    The result indicates that the concentration of the test solution sample was
    50.5 ppm, with an error of less than 2% with respect to the concentration estimated by atomic absorption spectroscopy, proven analytical technique.
    It is especially relevant to indicate that this procedure, when calculating the calibration curve in each measurement with the RGB data treated from the samples of standard solutions, and extrapolating with those of the sample of problem solution, offers the same result in different devices, conditions environmental and users, eliminating these interferences and allowing the use of commercial electronic devices, without any adaptation or support. That is, the RGB data of each sample will vary from one analysis to another depending on the conditions mentioned, but the valuation curve of these data with the known concentrations of the samples of standard solutions will result in the same concentration value of the Sample dissolution problem.
    Example 2. Calculation of the concentration of the test solution sample of Example 1 by taking the picture in different environmental conditions.
    To illustrate the independence of the result with the environmental conditions, a photograph is taken with a conventional camera in other conditions to the analysis system described in Example 1; it is imported into the mobile analysis device (3) used in Example 1, and processed, resulting in the one shown in the table of Figure 8.
    In the tables of Figures 7 and 8, the concentration value of the test solution sample is measured by atomic absorption spectroscopy to verify the goodness of the calculated result.
    The result indicates that the concentration of the test solution sample was
    49.96 ppm, with an error of less than 1% with respect to the concentration estimated by 10 atomic absorption spectroscopy, proven analytical technique.
    Concordance with the result of Example 1 is appreciated.
    权利要求:
    Claims (12)
    [1]
    1. Procedure for measuring the concentration of chemical species comprising:
    take samples of at least two standard solutions whose concentration of a certain chemical species to be measured is known; respectively contacting each of said samples of standard solutions with at least one first colorimetric sensor (1), which can be colored directly in relation to the concentration of the chemical species to be measured, contained in each sample of standard solution; take at least one sample of at least one problem solution, whose concentration of the chemical species to be measured is unknown; contact each test solution sample with at least a second colorimetric sensor (2), of the same colorimetric characteristics as the first colorimetric sensor (1), which can be colored directly in relation to the concentration of the chemical species to be measured, contained in the sample of dissolution problem;
    characterized in that it additionally comprises:
    take at least one photograph of each first colorimetric sensor (1),
    contacted each of the standard solutions, and at least
    a photograph of the second colorimetric sensor (2), brought into contact
    with the problem solution;
    extract, through a device capable of processing
    images, a representative value of the color, shown in the photographs,
    of each first colorimetric sensor (1) contacted with each
    one of the samples of the standard solutions, and of the second sensor
    colorimetric (2) contacted the problem solution;
    associate each representative color value of each first sensor
    colorimetric (1) brought into contact with each of the samples of standard solutions, the known concentration value of the species
    chemistry to be measured in each of the standard solutions;
    statistically determine a mathematical expression that relates
    each other the representative values of the color, shown in the
    photographs of each first colorimetric sensor (1) contacted
    with each of the samples of standard solutions, together with their
    corresponding values of known concentration of the species
    chemistry to be measured;
    determine, by interpolation of the mathematical expression obtained
    in the previous step, the concentration value of the chemical species a
    measure in the problem solution, corresponding to the value
    representative of the color of the second colorimetric sensor (2) set to
    Contact with the sample of problem solution.
    [2]
    2. Method for measuring the concentration of chemical species according to claim 1, characterized in that the extraction phase of a color-representative value of each first colorimetric sensor (1) brought into contact with each of the samples of the standard solutions and of the second colorimetric sensor (2) placed in contact with the sample of the problem solution comprises:
    to. extract the RGB parameters related to the color, shown in the photographs, of each first colorimetric sensor (1) placed in contact with each of the samples of the standard solutions and of the second colorimetric sensor (2) contacted with the dissolution sample trouble;
    b. determine, by means of a statistical analysis procedure, a representative value of the RGB parameters associated with the color, shown in the photographs, of each first colorimetric sensor (1) brought into contact with each of the samples of the standard solutions and the second sensor Colorimetric (2) placed in contact with the sample of problem solution.
    [3]
    3. Method for measuring the concentration of chemical species according to claim 2, characterized in that the determination of a representative value of the RGB parameters associated with the color, shown in the photographs, of each first colorimetric sensor (1) contacted with each of the samples of the standard solutions and of the second colorimetric sensor (2) put in contact with the sample of problem solution comprises:
    a) calculate the mutual covariance between the RGB parameters associated with the color, shown in the photographs, of each first colorimetric sensor
    (1) contacted each of the samples of the standard solutions and the second colorimetric sensor (2) contacted the sample of the test solution;
    b) calculate the eigenvalues and eigenvectors associated with the covariance matrix whose values are the covariances calculated in the previous phase;
    c) determine a representative eigenvector, such as that eigenvector associated with the autovalue of greater absolute value calculated in the previous phase;
    d) calculate, for each first colorimetric sensor contacted with each of the samples of the standard solutions and for the second colorimetric sensor contacted with the sample of the solution solution, the absolute values of the projections of their associated autovectors, calculated in the previous phase, on the representative autovector determined in the previous phase;
    e) determine, for each first colorimetric sensor contacted with each of the samples of the standard solutions and for the second colorimetric sensor contacted with the test solution sample, the highest of the absolute values calculated in the previous phase;
    f) establish each of the highest absolute values determined in the previous phase, respectively as a representative value of the RGB parameters associated with the color, shown in the photographs, of each first colorimetric sensor (1) contacted with each of the samples of the standard solutions and the second colorimetric sensor (2) put in contact with the sample of problem solution.
    [4]
    4. Method for measuring the concentration of chemical species according to claim 1, characterized in that the phase of statistical determination of a mathematical expression that relates to each other the representative values of the color, shown in the photographs, of each first colorimetric sensor (1 ) placed in contact with each of the samples of the standard solutions, together with their corresponding concentration values of the chemical species to be measured, comprises:
    to. Obtain an experimental curve resulting from joining points associated with each sample of standard dissolution, where the values of the coordinates of each of these points in some coordinate axes are respectively the representative value of the color, shown in the photographs, of the first colorimetric sensor (1) placed in contact with the sample of the standard solution associated with said point and the known value of the concentration of the chemical species to be measured in said standard solution;
    b. determine, through a method of assimilation by least squares or linear regression, a mathematical expression that represents a curve that closely resembles the experimental curve obtained in the previous phase.
    [5]
    5. Method for measuring the concentration of chemical species according to claim 1, characterized in that the first colorimetric sensor (1) and the second colorimetric sensor (2) are composed of disks comprising solid chromogenic reactive materials.
    [6]
    6. Method for measuring the concentration of chemical species according to claim 1, characterized in that the first colorimetric sensor (1) and the second colorimetric sensor (2) are composed of solutions of chromogenic reactive materials that are introduced into vials or cuvettes of translucent material .
    [7]
    7. Method for measuring the concentration of chemical species according to claim 1, characterized in that the taking of at least one photograph of the first colorimetric sensor (1) and the second colorimetric sensor (2) is carried out by means of a mobile device (3) with processor integrated image, which is responsible for taking the picture of the first colorimetric sensor (1) put in contact with the samples of the standard solutions and the second colorimetric sensor (2) contacted with the sample of the problem solution, and determine the concentration value of the chemical species to be measured in the problem solution.
    [8]
    8. Method for measuring the concentration of chemical species according to claim 7, characterized in that the mobile device (3) is a smartphone or a tablet.
    [9]
    9. Method for measuring the concentration of chemical species according to claim 7, characterized in that the mobile device (3) records the concentration values of the chemical species to be measured in the test solutions, together with the data relating to the date, time , latitude, longitude and altitude of the moment and the place where the test is performed.
    [10]
    10. Method for measuring the concentration of chemical species according to claim 7, characterized in that the mobile device (3) records the concentration values of the chemical species to be measured in the test solutions, together with the data relating to the date, time and the anatomical region in which the test is performed.
    [11]
    eleven. Method for measuring the concentration of chemical species according to claims 9 and 10, characterized in that the mobile device (3) offers a representation of a map of concentrations on a given surface or region, together with the variation of species concentrations
    5 chemicals to be measured in a given period.
    [12]
    12. Method for measuring the concentration of chemical species according to claims 1, characterized in that it comprises comparing the results obtained from the concentration value of a particular chemical species
    10 in a problem solution with characteristic limit values contained in a database, where, as a result of the previous comparison, it is determined whether the concentration of a certain chemical species in a problem solution is above or below said limits characteristic.
    类似技术:
    公开号 | 公开日 | 专利标题
    Levin et al.2016|Monitoring of fluoride in water samples using a smartphone
    Hussain et al.2017|Low-cost, robust, and field portable smartphone platform photometric sensor for fluoride level detection in drinking water
    KR101954783B1|2019-03-06|Testing apparatus
    Luka et al.2017|Portable device for the detection of colorimetric assays
    Sumriddetchkajorn et al.2014|Mobile-platform based colorimeter for monitoring chlorine concentration in water
    Knutson et al.2015|A fresh look at the crystal violet lab with handheld camera colorimetry
    CN109312280A|2019-02-05|Reagent test strip comprising the reference area for measuring colorimetric test platform
    Gee et al.2017|Quantifying protein concentrations using smartphone colorimetry: a new method for an established test
    Bond et al.2013|Chromatography paper as a low-cost medium for accurate spectrophotometric assessment of blood hemoglobin concentration
    Dutta et al.2015|Dye-assisted pH sensing using a smartphone
    CN105372195B|2018-02-13|A kind of micro ultraviolet specrophotometer quality determining method and detection kit
    Zilberman et al.2014|Dissolved ammonia sensing in complex mixtures using metalloporphyrin-based optoelectronic sensor and spectroscopic detection
    ES2890884T3|2022-01-24|Methods and devices for performing an analytical measurement based on a color-forming reaction
    Ahuja et al.2014|Minimizing color interference from biological samples in optode-based measurements
    Gavrilenko et al.2014|Polymethacrylate optodes: A potential for chemical digital color analysis
    ES2555161B1|2016-10-07|Procedure for measuring the concentration of chemical species
    CN107807093A|2018-03-16|Fluid sensor equipment
    KR20200025687A|2020-03-10|System and method for measuring environmental pollutants or disease tracers using smart device
    Martinez-Hurtado et al.2017|Multiplex smartphone diagnostics
    CN107966435A|2018-04-27|Colorimetric gas detects
    Shariati-Rad et al.2016|Multivariate analysis of digital images of a paper sensor by partial least squares for determination of nitrite
    Muravyov et al.2019|Polymethacrylate sensors for rapid digital colorimetric analysis of toxicants in natural and anthropogenic objects
    WO2020037252A1|2020-02-20|Methods, apparatuses, and kits for detection of lead and other materials in water
    CN110226085B|2022-02-01|Urine test paper comprising timer, and urine test paper detection and analysis method
    CN107817244A|2018-03-20|Fluid sensor card
    同族专利:
    公开号 | 公开日
    ES2555161B1|2016-10-07|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US6952263B2|1997-10-31|2005-10-04|Jack L. Aronowitz|Reflectometer|
    EP1022550A2|1999-01-25|2000-07-26|Aquacheck Systems Inc.|Colorimeter apparatus and related process|
    US7077064B1|2005-04-19|2006-07-18|Sun Chemical Corporation|Methods for measurement and control of ink concentration and film thickness|
    US20070092975A1|2005-10-26|2007-04-26|General Electric Company|Methods and systems for delivery of fluidic samples to sensor arrays|ES2696228A1|2018-05-25|2019-01-14|Bioquochem Sl|METHOD FOR THE DETERMINATION OF TOTAL ANTIOXIDANT CAPACITY IN LIQUID SAMPLES USING A MOBILE DEVICE |
    法律状态:
    2016-10-07| FG2A| Definitive protection|Ref document number: 2555161 Country of ref document: ES Kind code of ref document: B1 Effective date: 20161007 |
    优先权:
    申请号 | 申请日 | 专利标题
    ES201400514A|ES2555161B1|2014-06-24|2014-06-24|Procedure for measuring the concentration of chemical species|ES201400514A| ES2555161B1|2014-06-24|2014-06-24|Procedure for measuring the concentration of chemical species|
    [返回顶部]