Aminophenol-Ag based + / Cu 2+ Organic acid small molecules, liquor identification method and visual sensor array

Abstract

The invention discloses a method based on aminophenol-Ag + / Cu 2+ The present invention provides an organic acid small molecule, liquor identification method and visual sensor array, which belongs to the technical field of organic identification and bionic sensor. + / Cu 2+ The present invention uses organic acid to identify 4-aminophenol and 2-aminophenol with Ag. + and Cu 2+ The redox reaction causes different degrees of inhibition. By collecting colorimetric data, drawing color difference diagrams, and combining chemometric analysis, we can achieve quantitative and qualitative analysis of single and mixed samples of organic acids, as well as identification of liquor and mixed liquors. We also used this method to design a series of visual sensor arrays.

Description

Technical Field

[0001] The invention belongs to the technical field of organic identification and bionic sensors, and specifically relates to an aminophenol-Ag-based + / Cu 2+ Organic acid small molecules, liquor identification method and visual sensor array. Background Art

[0002] Traditional organic acid detection methods such as chromatography and spectroscopy mostly have problems such as expensive instruments and long analysis time, making them difficult to be widely used in on-site detection and analysis. In recent years, a new cross-reaction array based on high color-sensitive material-analyte interaction has become increasingly popular among researchers. Unlike traditional instrumental analysis methods, visualization arrays have the advantages of simple equipment, fast analysis speed, and the ability to accurately identify the overall characteristics of the target through cross-response. Qualitative and quantitative analysis of the target can be achieved by relying solely on the color change effect of the sensor chip and using multivariate statistical data analysis methods. More importantly, the design and arrangement of the sensor units in the array can be completely guided by the properties of the target to be measured, and a variety of highly sensitive and highly selective color change sensor units are assembled on a sensor chip. Therefore, this method shows great potential for rapid identification and analysis of complex mixtures, especially highly similar complex mixtures. In existing studies, the visual sensor array element materials are mainly composed of chemical response inks, sensitive dyes, pH indicators, nano-level precious metals, and quantum dots. Redox materials are rarely used in visual sensor array systems.

[0003] Aminophenol has a certain reducing property and can undergo redox reactions with certain metal ions. However, there is currently no research on using the redox reaction of aminophenol with metal ions to detect flavor compounds in liquor. Summary of the invention

[0004] The present invention is to solve the technical gaps and defects existing in the above research background, and provides a kind of 4-aminophenol (PAP) and its isomer 2-aminophenol (OAP) and Ag + and Cu 2+ Under redox reactions, the identification of organic acid small molecules and substances rich in these small molecules, such as liquor, was constructed, and based on this principle, an organic acid-sensitive four-channel visual array sensor was designed. The sensor has the advantages of no need for synthesis, easy availability of raw materials, low cost and easy implementation. It can be widely used for the identification of a variety of organic acid small molecules and the visual online detection of samples rich in such compounds.

[0005] The present invention first provides a kind of aminophenol-Ag + / Cu 2+ A method for identifying small molecules of organic acids, comprising the following steps:

[0006] A, mixing solvent, 4-aminophenol and silver ions to obtain identification system A, mixing solvent, 4-aminophenol and copper ions to obtain identification system B, mixing solvent, 2-aminophenol and silver ions to obtain identification system C, mixing solvent, 2-aminophenol and copper ions to obtain identification system D;

[0007] B. Adding the organic acid small molecule solution to the identification system A to obtain sample group A, adding the organic acid small molecule solution to the identification system B to obtain sample group B, adding the organic acid small molecule solution to the identification system C to obtain sample group C, adding the organic acid small molecule solution to the identification system D to obtain sample group D, and using an equal volume of the solvent used for the organic acid small molecule solution as a control;

[0008] C. Extract the average values ​​of R, G and B of sample group A, sample group B, sample group C, sample group D and the control group, and subtract the average values ​​of R, G and B of the corresponding control group from the average values ​​of R, G and B of the sample group to obtain the difference values ​​of R, G and B of the organic acid small molecules;

[0009] Qualitative analysis: perform principal component analysis based on the R, G and B differences, and / or obtain a color difference map based on the R, G and B differences, and identify with the naked eye;

[0010] Quantitative analysis: According to the R, G and B differences, the variable weighted particle swarm optimization partial least squares support vector machine is used for quantitative analysis;

[0011] In step A, the solvent is at least one of water or ethanol;

[0012] In step B, the organic acid small molecule is at least one of benzoic acid, lactic acid, acetic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, caproic acid or octanoic acid;

[0013] When it is a qualitative analysis, in step B, the solvent used for the organic acid small molecule solution is at least one of water, ethanol or liquor;

[0014] When quantitative analysis is performed, in step B, the solvent used for the organic acid small molecule solution is at least one of water and ethanol.

[0015] Among them, the above-mentioned aminophenol-Ag + / Cu 2+ In the organic acid sub-step A, the silver ions are derived from silver nitrate.

[0016] Among them, the above-mentioned aminophenol-Ag + / Cu 2+ In the organic acid sub-step A, the copper ions are derived from at least one of copper nitrate, copper sulfate or copper chloride.

[0017] Among them, the above-mentioned aminophenol-Ag + / Cu 2+ The organic acid small molecule identification method comprises the following steps: in step B, adding the organic acid small molecule solution to the identification system A and reacting for 2 to 5 minutes.

[0018] Among them, the above-mentioned aminophenol-Ag + / Cu 2+ The organic acid small molecule identification method comprises the following steps: in step B, adding the organic acid small molecule solution to the identification system B and reacting for 2 to 5 minutes.

[0019] Among them, the above-mentioned aminophenol-Ag + / Cu 2+ The organic acid small molecule identification method comprises the following steps: in step B, adding the organic acid small molecule solution to the identification system C and reacting for 2 to 5 minutes.

[0020] Among them, the above-mentioned aminophenol-Ag + / Cu 2+ The organic acid small molecule identification method comprises the following steps: in step B, adding the organic acid small molecule solution to the identification system D and reacting for 2 to 5 minutes.

[0021] Among them, the above-mentioned aminophenol-Ag + / Cu 2+ The method for identifying organic acid small molecules, in step B, the concentration of organic acid small molecules in sample group A, sample group B, sample group C and sample group D is 0.001 to 25 mmol / L.

[0022] Among them, the above-mentioned aminophenol-Ag + / Cu 2+ The method for identifying small molecules of organic acids, in step B, the concentration of 4-aminophenol in the sample group A is 10 to 50 mmol / L.

[0023] Among them, the above-mentioned aminophenol-Ag + / Cu 2+ The method for identifying small molecules of organic acids, in step B, the silver ion concentration in the sample group A is 10 to 50 mmol / L.

[0024] Among them, the above-mentioned aminophenol-Ag + / Cu 2+ The method for identifying small molecules of organic acids, in step B, the concentration of 4-aminophenol in the sample group B is 10 to 50 mmol / L.

[0025] Among them, the above-mentioned aminophenol-Ag + / Cu 2+The method for identifying small molecules of organic acids, in step B, the copper ion concentration in the sample group B is 10 to 50 mmol / L.

[0026] Among them, the above-mentioned aminophenol-Ag + / Cu 2+ The method for identifying small molecules of organic acids, in step B, the concentration of 2-aminophenol in the sample group C is 10 to 50 mmol / L.

[0027] Among them, the above-mentioned aminophenol-Ag + / Cu 2+ The method for identifying small molecules of organic acids, in step B, the silver ion concentration in the sample group C is 10 to 50 mmol / L.

[0028] Among them, the above-mentioned aminophenol-Ag + / Cu 2+ The organic acid small molecule identification method is as follows: in step B, the concentration of 2-aminophenol in the sample group D is 10 to 50 mmol / L.

[0029] Among them, the above-mentioned aminophenol-Ag + / Cu 2+ The organic acid small molecule identification method is as follows: in step B, the copper ion concentration in the sample group D is 10 to 50 mmol / L.

[0030] Among them, the above-mentioned aminophenol-Ag + / Cu 2+ In the identification method of small molecules of organic acids, when qualitative analysis is performed and the color difference diagram is obtained, the difference between R, G and B is magnified by 2 to 6 times.

[0031] The present invention also realizes the identification of complex systems such as liquor, and provides a method for identifying a complex system based on aminophenol-Ag + / Cu 2+ The identification method of liquor. The qualitative identification of liquor is the same as that of the qualitative identification of organic acid small molecules. On the basis of the above-mentioned qualitative analysis steps of organic acid small molecules, the organic acid small molecule solution is replaced with liquor (the liquor does not need to be diluted or other additional operations, and the original liquor sample can be directly detected), and an equal volume of Vol40-70% ethanol aqueous solution is used as a control; the quantitative identification of organic acid small molecules in liquor is the same as that of the quantitative identification of organic acid small molecules (pure organic acid or mixed organic acid). On the basis of the above-mentioned quantitative analysis steps of organic acid small molecules, the organic acid small molecule solution is replaced with liquor (the liquor does not need to be diluted or other additional operations, and the original liquor sample can be directly detected), and an equal volume of Vol40-70% ethanol aqueous solution is used as a control.

[0032] Based on the above-mentioned qualitative and quantitative identification methods for organic acid small molecules and liquor, the present invention also provides a method based on aminophenol-Ag + / Cu 2+ A visual sensor array, the detection principle of which is the same as the above identification method, so it includes N sensor units S1, N sensor units S2, N sensor units S3 and N sensor units S4, the substance in S1 is the identification system A in the above identification method, the substance in S2 is the identification system B in the above identification method, the substance in S3 is the identification system C in the above identification method, and the substance in S4 is the identification system D in the above identification method; N is an integer greater than 0.

[0033] Among them, the above-mentioned aminophenol-Ag + / Cu 2+ In the visual sensor array, each sensor unit is controlled so that after adding the analyte, the total amount of the final system added is 90 to 150 μL.

[0034] Among them, the above-mentioned aminophenol-Ag + / Cu 2+ In the visual sensor array, after the analyte is added, the 4-aminophenol concentration, silver ion concentration and total volume in each sensor unit S1 are controlled to be the same; after the analyte is added, the 4-aminophenol concentration, copper ion concentration and total volume in each sensor unit S2 are controlled to be the same; after the analyte is added, the 2-aminophenol concentration, copper ion concentration and total volume in each sensor unit S3 are controlled to be the same; after the analyte is added, the 2-aminophenol concentration, copper ion concentration and total volume in each sensor unit S4 are controlled to be the same.

[0035] The beneficial effects of the present invention are:

[0036] The present invention constructs a novel aminophenol-Ag + / Cu 2+ The present invention uses organic acid to identify 4-aminophenol (PAP) and its isomer 2-aminophenol (OAP) with Ag. + and Cu 2+The redox reaction causes different degrees of inhibition. By collecting colorimetric data and drawing color difference diagrams, the fingerprints of 9 organic acids are obtained. Combined with chemometric analysis, in addition to the accurate quantification of single organic acid samples, mixed organic acid samples can also be accurately quantified. In addition, there are certain differences in the types and contents of organic acids contained in liquors of different brands, grades and origins, which leads to differentiated results. Based on the same principle, the present invention can ultimately achieve qualitative identification of liquors and mixed liquors from different origins, flavors, brands, grades and years, and quantitative analysis of the organic acids they contain.

[0037] Compared with traditional sensors, the sensor based on the above principle has many advantages such as easy availability of raw materials and low cost. It does not require complex synthesis methods and can be applied to the qualitative and quantitative identification of various organic acids and the identification of complex samples such as liquor rich in such compounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The present invention utilizes 4-aminophenol and 2-aminophenol to react with metal ions Ag + and Cu 2+ Schematic diagram of an organic acid-sensitive four-channel visual array sensor constructed by reduction reaction for identifying organic acid small molecules and liquor; wherein A is the structural formula of 9 kinds of organic acid small molecules, B is the four channel materials, C is the visual color difference diagram, and D is the PCA analysis result diagram.

[0039] Figure 2 This is a visualized color difference diagram of the four-channel visualized array sensor in Example 1 for 9 organic acids at 11 concentrations.

[0040] Figure 3 This is a graph showing the PCA analysis results of 9 organic acids at 11 concentrations in Example 1; wherein the AK concentrations are 0.001mmol / L, 0.005mmol / L, 0.010mmol / L, 0.025mmol / L, 0.05mmol / L, 0.1mmol / L, 0.5mmol / L, 1mmol / L, 5mmol / L, 10mmol / L, and 25mmol / L.

[0041] Figure 4 This is a diagram showing the quantitative analysis results of nine organic acids by the four-channel visual array sensor in Example 1; wherein AJ are benzoic acid, lactic acid, acetic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, caproic acid and octanoic acid, respectively, the number of detections n=24, and the images are repeated 6 times in each detection.

[0042] Figure 5This is a PCA analysis result diagram of a mixture of 25 organic acids measured by the organic acid-sensitive four-channel visual array sensor in Example 2. The number of detections n=24, and the images were taken 6 times in each detection.

[0043] Figure 6 This is the identification result diagram of 12 kinds of Luzhou-flavor liquors by the organic acid-sensitive four-channel visual array sensor in Example 3; wherein A is the colorimetric diagram (left) and color difference diagram (right) of the 12 kinds of liquors, and B is the PCA analysis result diagram. DETAILED DESCRIPTION

[0044] The present invention found that 4-aminophenol (PAP) and its isomer 2-aminophenol (OAP) can react with Ag + and Cu 2+ Oxidation-reduction reaction occurs. This reaction is accompanied by obvious color change. Under appropriate reaction concentration conditions, PAP reacts with Ag. + After the reaction, the whole system is yellow, and PAP and Cu 2+ After the reaction, it turns light yellow. OAP and Ag + After the reaction, it turns purple. OAP and Cu 2+ After the reaction, it turns dark yellow-brown. When organic acids such as acetic acid, caproic acid, lactic acid, and butyric acid are present in the system, the reaction will be disturbed to a certain extent, and its reaction color will also change, presenting a unique color development pattern. Different types of organic acids will produce different colors and color differences after interference. The higher the concentration of organic acid, the greater the color difference. This provides feasibility for the qualitative and quantitative detection of organic acids using the redox reaction of aminophenol and metals.

[0045] In addition, there are certain differences in the types and contents of organic acids contained in liquors of different brands, grades and origins, which leads to differentiated results. Ultimately, it is possible to identify liquors and / or mixed liquors from different origins, flavors, brands, grades and years.

[0046] Specifically, based on aminophenol-Ag + / Cu 2+ A method for identifying small molecules of organic acids, comprising the following steps:

[0047] A, mixing solvent, 4-aminophenol and silver ions to obtain identification system A, mixing solvent, 4-aminophenol and copper ions to obtain identification system B, mixing solvent, 2-aminophenol and silver ions to obtain identification system C, mixing solvent, 2-aminophenol and copper ions to obtain identification system D;

[0048] B. Adding the organic acid small molecule solution to the identification system A to obtain sample group A, adding the organic acid small molecule solution to the identification system B to obtain sample group B, adding the organic acid small molecule solution to the identification system C to obtain sample group C, adding the organic acid small molecule solution to the identification system D to obtain sample group D, and using an equal volume of the solvent used for the organic acid small molecule solution as a control;

[0049] C. Extract the average values ​​of R, G and B of sample group A, sample group B, sample group C, sample group D and the control group (generally using software such as Adobe Photoshop), and subtract the average values ​​of R, G and B of the corresponding control group from the average values ​​of R, G and B of the sample group to obtain the difference values ​​of R, G and B of the organic acid small molecule;

[0050] Qualitative analysis: perform principal component analysis based on the R, G and B differences, and / or obtain a color difference map based on the R, G and B differences, and identify with the naked eye;

[0051] Quantitative analysis: According to the R, G and B differences, the variable weighted particle swarm optimization partial least squares support vector machine is used for quantitative analysis;

[0052] In step A, the solvent is at least one of water or ethanol;

[0053] In step B, the organic acid small molecule is at least one of benzoic acid, lactic acid, acetic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, caproic acid or octanoic acid;

[0054] When it is a qualitative analysis, in step B, the solvent used for the organic acid small molecule solution is at least one of water, ethanol or liquor;

[0055] When quantitative analysis is performed, in step B, the solvent used for the organic acid small molecule solution is at least one of water and ethanol.

[0056] In the method of the present invention, silver ions and copper ions can be derived from soluble salts commonly used in the art, for example, silver ions are derived from silver nitrate, and copper ions are derived from at least one of copper nitrate, copper sulfate or copper chloride.

[0057] In step B of the method of the present invention, after adding the organic acid small molecule solution to the identification system A, react for 2 to 5 minutes; after adding the organic acid small molecule solution to the identification system B, react for 2 to 5 minutes; after adding the organic acid small molecule solution to the identification system C, react for 2 to 5 minutes; after adding the organic acid small molecule solution to the identification system D, react for 2 to 5 minutes.

[0058] In step B of the method of the present invention, the concentration of the organic acid small molecules in the sample group A, the sample group B, the sample group C and the sample group D is 0.001-25 mmol / L.

[0059] In step B of the method of the present invention, the concentration of 4-aminophenol in sample group A is 10-50 mmol / L, and the concentration of silver ions in sample group A is 10-50 mmol / L; the concentration of 4-aminophenol in sample group B is 10-50 mmol / L, and the concentration of copper ions in sample group B is 10-50 mmol / L; the concentration of 2-aminophenol in sample group C is 10-50 mmol / L, and the concentration of silver ions in sample group C is 10-50 mmol / L; the concentration of 2-aminophenol in sample group D is 10-50 mmol / L, and the concentration of copper ions in sample group D is 10-50 mmol / L. In each identification system, the concentrations of the three materials can be appropriately adjusted according to the concentration of the organic small molecule to be detected.

[0060] In the embodiment of the present invention, in the laboratory stage, in order to ensure the accuracy of the amount, 4-aminophenol, 2-aminophenol, silver ion salt, and copper ion salt are first prepared into an initial solution, and then a certain amount is taken to prepare a final concentration identification system. However, in actual application, it is not necessary to follow the operation of the embodiment of the present invention, as long as the final concentration of each material meets the requirements.

[0061] For example, the above method can be specifically operated as follows: all colorimetric reactions are completed in a sterilized 96-well plate, and the sensor array is composed of aminophenol (4-aminophenol, 2-aminophenol) with a concentration of 50mmol / L and metal ions (water-soluble silver salts such as silver nitrate, water-soluble copper salts such as copper nitrate / copper chloride / copper sulfate, etc.) with a concentration of 25mmol / L. The specific order of adding samples can be metal ion solution (30μL, 25mmol / L), organic acid solution or wine sample (30μL), aminophenol (30μL, 50mmol / L), which respectively constitute 4 sensor elements S1, S2, S3 and S4, and the total system of each sensor element is 90μL. The organic acid solution in the experiment can be prepared by 52% anhydrous ethanol. The blank control group is a 52% ethanol aqueous solution.

[0062] Images were captured in the dark by a Canon EOS 750D digital camera 2 min after the reaction. A 15W LED panel was covered with an opaque black cloth, and an area close to the size of the 96-well plate was cut out from the center of the panel, with only this area having a uniform white backlight. The 96-well plate was placed in this area, and images were captured in the dark using a Canon EOS 750D digital camera. The camera was equipped with a Canon EFS 18-135 mm zoom lens and fixed on a tripod. The photos were taken at a constant shutter speed of 1 / 125s, an aperture setting of f / 11, and a sensitivity of ISO 400. During the capture of all photos, the camera parameters, distance from the LED panel, panel light power, and darkness of the room environment were kept constant to avoid color differences in various photos. To avoid uneven colors and edge shadows, the RGB averages of all pixels in each reaction well (25 pixels in diameter) were extracted using Adobe Photoshop. The color vector matrix (ΔRGB) was determined by subtracting the R, G, B values ​​of the control group from the R, G, B values ​​of the reaction group. In addition, for visualization purposes only, the R, G, and B ranges were expanded and magnified 2 to 6 times to obtain more significant color difference maps. The RGB values ​​used in data analysis are the original RGB differences without magnification. All the above experiments were repeated six times in parallel, and four sets of images were taken during the measurement process. Therefore, there are 24 sets of parallel RGB data for each well point for color difference mapping and chemometric analysis.

[0063] The method of the present invention adopts principal component analysis for qualitative identification. Principal component analysis is a supervised classification method. This method defines the sample categories in advance and realizes the distinction between samples of different categories; it generally analyzes the data through software such as matlab. In principal component analysis, for different samples of the same series, it is necessary to keep the conditions of the reaction system of two different samples as consistent as possible. For a single sample in the same series, the conditions in the four channels are not required to be exactly the same; and between different series, since they are not distinguished as references to each other, the conditions can be different. For example, for the detection of different samples of the same series (or batch), it is not necessary to strictly control the reaction time, concentration, etc. in the identification system A~D when a certain sample is detected. Generally, it is only necessary to ensure the consistency of the identification system of different samples (such as reaction time, concentration, etc.).

[0064] In the present invention, a color difference diagram can be directly obtained by the difference between R, G and B, and the small molecule solution can be distinguished to a certain extent by the color difference diagram (such as Example 1); in addition, in order to make the naked eye observation relatively more obvious, the present invention can amplify the difference between R, G and B by 2 to 6 times, and then obtain a color difference diagram, which can also be distinguished by the naked eye. When the detection requirements are relatively loose, the discrimination can be achieved more efficiently.

[0065] When the method of the present invention is used for quantitative identification, a variable weighted particle swarm optimization partial least squares support vector machine analysis (PSO-VWLS-SVM) is performed according to the R, G and B differences. This chemometric model can accurately quantify not only a single sample of organic acid, but also a mixed sample of organic acid (such as Example 2).

[0066] The present invention also realizes the identification of complex systems such as liquor, and provides a method for identifying a complex system based on aminophenol-Ag + / Cu 2+ Method for identifying liquor. The qualitative identification of liquor is the same as the qualitative identification principle of organic acid small molecules. On the basis of the above-mentioned qualitative analysis steps of organic acid small molecules, the organic acid small molecule solution sample is replaced with the liquor sample, and because the ethanol solution has little effect on U1 and U2, an equal volume of Vol40-70% ethanol aqueous solution (this range includes the alcohol content range of most liquors) is used as a control. In addition, based on the principle that the present invention can realize the quantitative identification of mixed organic acids, on the basis of the above-mentioned quantitative analysis steps of organic acid small molecules, the organic acid small molecule solution is replaced with liquor (liquor does not need additional operations such as dilution, and the original liquor sample can be directly detected), and an equal volume of Vol40-70% ethanol aqueous solution is used as a control, which can also realize the quantitative identification of organic acids in liquor or mixed liquor.

[0067] Based on the above-mentioned qualitative and quantitative identification methods for organic acid small molecules and liquor, the present invention also provides a method based on aminophenol-Ag + / Cu 2+ The visual sensor array has the same detection principle as the above identification method, so it includes N sensor units S1, N sensor units S2, N sensor units S3 and N sensor units S4, the substance in S1 is the identification system A in the above identification method, the substance in S2 is the identification system B in the above identification method, the substance in S3 is the identification system C in the above identification method, and the substance in S4 is the identification system D in the above identification method; N is an integer greater than 0. The principle of the sensor is the principle of the above identification method, so when using the colorimetric array sensor, it can be operated according to the above identification method.

[0068] Among them, the above-mentioned aminophenol-Ag + / Cu 2+ In the visual sensor array, each sensor unit is controlled so that after adding the analyte, the total amount of the final system added is 90 to 150 μL.

[0069] Among them, the above-mentioned aminophenol-Ag + / Cu 2+In the visual sensor array, after adding the object to be tested, each sensor unit S1 (i.e. S1 1 、S1 2 、S1 3 After adding the analyte, the 4-aminophenol concentration, the copper ion concentration and the total volume in each sensing unit S2 are controlled to be the same; after adding the analyte, the 2-aminophenol concentration, the copper ion concentration and the total volume in each sensing unit S3 are controlled to be the same; after adding the analyte, the 2-aminophenol concentration, the copper ion concentration and the total volume in each sensing unit S4 are controlled to be the same; thereby ensuring that the reaction conditions are the same between the same series or batches of samples, and ensuring the accuracy of the results.

[0070] In the present invention, in order to make the text description clearer, each sensor unit in the visual sensor array is numbered, and the substance in each sensor unit is limited. However, in actual application, as long as the detection conditions of samples in the same series (or batch) can be the same, it is not necessary to follow the sensor unit number and the corresponding substance of the present invention.

[0071] The present invention is further described in detail below by way of examples, but the protection scope of the present invention is not limited to the scope of the examples.

[0072] Example 1

[0073] The four-channel visual array sensor constructed in this embodiment can be used to distinguish 9 kinds of organic acid compounds. It should be specifically explained that the identification system A of the first sensor unit (S1) is: OAP (50mmol / L) + Ag + (25mmol / L); the second sensor unit (S2) identification system B is: OAP (50mmol / L) + Cu 2+ (25mmol / L), the third sensor unit (S3) identification system C is: PAP (50mmol / L) + Ag + (25mmol / L); the second sensor unit (S4) identification system D is: PAP (50mmol / L) + Cu 2+ (25mmol / L).

[0074] In this embodiment, 4-aminophenol and 2-aminophenol are first prepared into 150mmol / L initial solutions respectively, so as to ensure that when 30μL of the aforementioned solutions are added to the identification system, the final concentration of 4-aminophenol and 2-aminophenol in the system is 50mmol / L; silver nitrate and copper nitrate are respectively prepared into 75mmol / L initial solutions, so as to ensure that when 30μL of the aforementioned solutions are added to the identification system, the final concentration of organic small molecules in the system is 25mmol / L; the solvents of the aforementioned solutions are all 53% ethanol-water solution.

[0075] Therefore, in order to obtain the above identification systems A to D, the specific method of adding samples is:

[0076] For S1: Control group: OAP (30 μL) + Ag + (30μL) + Vol52% ethanol aqueous solution (30μL), the detection group is OAP (30μL) + Ag + (30μL) + organic acid solution (30μL), the total volume of the control group and the test group was 90μL; for S2: the control group was OAP (30μL) + Cu 2+ (30μL) + Vol52% ethanol aqueous solution (30μL), the detection group is OAP (30μL) + Cu 2+ (30μL) + organic acid solution (30μL), the total volume of the control group and the test group was 90μL; for S3: the control group was PAP (30μL) + Ag + (30μL) + Vol52% ethanol aqueous solution (30μL), the detection group is PAP (30μL) + Ag + (30μL) + organic acid solution (30μL), the total volume of the control group and the test group was 90μL; for S4: the control group was PAP (30μL) + Cu 2+ (30μL) + Vol52% ethanol aqueous solution (30μL), the detection group is PAP (30μL) + Cu 2+ (30 μL) + organic acid solution (30 μL), the total volume of the control group and the test group was 90 μL.

[0077] The organic acid compounds identified in this example include: benzoic acid (A1), lactic acid (A2), acetic acid (A3), butyric acid (A4), isobutyric acid (A5), valeric acid (A6), isovaleric acid (A7), caproic acid (A8) and octanoic acid (A9).

[0078] In this embodiment, all organic acid compound solutions are prepared with Vol52% ethanol, and their original concentration range is 0.003~75mmol / L, so as to ensure that when 30μL of the above solution is added to the identification system, the final concentration of the organic acid compound in the system is 0.001mmol / L~25mmol / L. Within this range, each organic acid compound is prepared with 11 concentrations, and its final concentration in the system is: 0.001mmol / L, 0.005mmol / L, 0.010mmol / L, 0.025mmol / L, 0.05mmol / L, 0.1mmol / L, 0.5mmol / L, 1mmol / L, 5mmol / L, 10mmol / L, 25mmol / L.

[0079] After adding the organic acid compound solution or control to the identification system, the timing starts, and the visual color change of the system is recorded after 2 minutes. The visual shooting of each compound at each concentration is repeated 6 times. The color difference diagram is shown in Figure 2 As shown. By using Adobe Photoshop to extract the R, G, B mean values ​​(diameter of 25 pixels) of all pixels in each reaction hole (sensing unit) mentioned above. By subtracting the R, G, B values ​​of the reaction group from the R, G, B values ​​of the control group, the color vector matrix (ΔR, G, B) is determined. The R, G, B values ​​used in the data analysis of this embodiment are the original R, G, B differences without amplification, but for visualization purposes, the R, G, B range can be expanded 2 to 6 times to obtain a color difference map. By matlab for principal component analysis (PCA) and variable weighted based on particle swarm optimization partial least squares support vector machine analysis (PSO-VWLS-SVM).

[0080] The PCA results of 8 organic acid compounds are as follows Figure 3 As shown, the quantitative results of PSO-VWLS-SVM are as follows: Figure 4 As shown in Table 1. Figure 3 , Figure 4 It can be seen from Table 1 that under 11 concentration conditions, 9 acids can obtain good PCA distinction results. Even the lowest concentration of 0.001mmol / L organic acid can still be accurately qualitatively distinguished by combining chemometrics. If you directly observe the color difference diagram, you can see that when the concentration is less than 0.05mmol / L, the color difference is not obvious enough. This shows that the use of color difference values ​​combined with principal component analysis can further expand the sensor's ability to distinguish the 9 organic acids in the experiment on the basis of visual distinction. The recovery rates of the 9 organic acids involved in the study in Table 1 are between 99.02±1.20% and 101.71±0.49%, R 2Except for butyric acid, the RMSEP of the quantitative models of the other eight organic acids is 10 -7 ~10 -8 mol / L, which is far lower than the minimum concentration value of 0.001mmol / L, reflecting the accuracy of the quantitative model. It shows that combined with PSO-VWLS-SVM, the aminophenol sensor array can quickly and accurately quantitatively detect 9 organic acids such as acetic acid, caproic acid, and lactic acid.

[0081] Table 1 Using organic acid-sensitive aminophenol-Ag + / Cu 2+ Quantitative results of 9 organic acids determined by visual sensor array (n=24 detection times)

[0082]

[0083]

[0084] Note: R 2 : linear correlation coefficient; RT: recovery rate; RMSEP: root mean square error of prediction.

[0085] Example 2

[0086] The four-channel fluorescence array sensor constructed in this embodiment can not only identify the pure substances of the above-mentioned 8 kinds of organic acid compounds, but also realize the identification of different mixed organic acid samples.

[0087] The operation of this embodiment is the same except that the pure organic acid compound solutions of different concentrations under each of the above channels are replaced with the organic acid mixed samples (final concentrations) shown in Table 2.

[0088] Similarly, all data were repeated 6 times, and their visual color differences were recorded, and their RGB values ​​were used for further chemometric analysis. The PCA analysis results are shown in Figure 5 The model established by PSO-VWLS-SVM method attempts to quantify individual acids in the mixture. The results are shown in Table 3. The recoveries of hexanoic acid and butyric acid in the 25 mixtures are close to 100%, and the RMSEP ranges from 2.87×10 -7 ~0.0011mmol / L, R 2 Not less than 0.9998.

[0089] The above phenomenon indicates that the four-channel visual array sensor constructed by the present invention can achieve good identification of mixed organic acid samples.

[0090] Table 2 Specific information of mixed acid samples

[0091]

[0092]

[0093] Table 3 Using organic acid-sensitive aminophenol-Ag+ / Cu 2+ Quantitative analysis results of 25 organic acid mixtures determined by visual sensor array (n=24 detection times)

[0094]

[0095]

[0096] Example 3

[0097] The array sensor constructed in this embodiment can identify different types of strong-flavor liquor samples based on the identification of pure organic acid and mixed organic acid components. Liquor contains abundant organic acid flavor substances. Since the content and proportion of organic acid components in each type of liquor are different, different flavors and types of liquor are formed.

[0098] In order to explore the practical application of this visual array sensor, we selected 12 major Chinese Luzhou-flavor liquors, whose specific information is shown in Table 4.

[0099] Table 4 Detailed information of 12 kinds of Luzhou-flavor liquors

[0100]

[0101] For the identification of liquor, it is only necessary to replace the organic acid compound solutions of different concentrations in Example 1 with liquor samples of the same volume (liquor does not need to be diluted, and the original liquor sample is directly added). The control under each channel is 30 μL, Vol 53% ethanol aqueous solution, and the other conditions are the same. After 2 to 5 minutes, the visualized color difference map of each sample is recorded, and its color change RGB value is extracted for further chemometric analysis.

[0102] Since liquor contains rich organic acid components, and the raw materials, processing technology, etc. of strong-flavor liquors from different flavors, origins and brands are different, the types and contents of organic acids they contain are different, thus causing changes in color rendering.

[0103] In order to obtain more accurate analysis and discrimination results, we introduced the PCA analysis method to discriminate 12 kinds of Luzhou-flavor liquor samples. The results are as follows: Figure 6 shown.

[0104] The embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments. In addition, all equivalent changes and modifications made without departing from the method and scope of the present invention should be included in the scope of the present invention.

Claims

1. Aminophenol-Ag based + / Cu 2+ The method for identifying small molecules of organic acids is characterized by: The following steps are involved: A, mixing solvent, 4-aminophenol and silver ions to obtain identification system A, mixing solvent, 4-aminophenol and copper ions to obtain identification system B, mixing solvent, 2-aminophenol and silver ions to obtain identification system C, mixing solvent, 2-aminophenol and copper ions to obtain identification system D; B. Adding the organic acid small molecule solution to the identification system A to obtain sample group A, adding the organic acid small molecule solution to the identification system B to obtain sample group B, adding the organic acid small molecule solution to the identification system C to obtain sample group C, adding the organic acid small molecule solution to the identification system D to obtain sample group D, and using an equal volume of the solvent used for the organic acid small molecule solution as a control; C. Extract the average values ​​of R, G and B of sample group A, sample group B, sample group C, sample group D and the control group, and subtract the average values ​​of R, G and B of the corresponding control group from the average values ​​of R, G and B of the sample group to obtain the difference values ​​of R, G and B of the organic acid small molecules; Qualitative analysis: perform principal component analysis based on the R, G and B differences, and / or obtain a color difference map based on the R, G and B differences, and identify with the naked eye; Quantitative analysis: According to the R, G and B differences, the variable weighted particle swarm optimization partial least squares support vector machine is used for quantitative analysis; In step A, the solvent is at least one of water or ethanol; In step B, the organic acid small molecule is at least one of benzoic acid, lactic acid, acetic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, caproic acid or octanoic acid; When it is a qualitative analysis, in step B, the solvent used for the organic acid small molecule solution is at least one of water, ethanol or liquor; When quantitative analysis is performed, in step B, the solvent used for the organic acid small molecule solution is at least one of water and ethanol.

2. The method according to claim 1 based on aminophenol-Ag + / Cu 2+ The method for identifying small molecules of organic acids is characterized by: In step A, at least one of the following must be met: The silver ions are derived from silver nitrate; The copper ions are derived from at least one of copper nitrate, copper sulfate or copper chloride.

3. The method according to claim 1 based on aminophenol-Ag + / Cu 2+ The method for identifying small molecules of organic acids is characterized by: In step B, at least one of the following is met: After adding the organic acid small molecule solution to the identification system A, react for 2-5 minutes; After adding the organic acid small molecule solution to the identification system B, react for 2-5 minutes; After adding the organic acid small molecule solution to the identification system C, react for 2 to 5 minutes; After adding the organic acid small molecule solution to the identification system D, react for 2 to 5 minutes.

4. The method according to claim 1 based on aminophenol-Ag + / Cu 2+ The method for identifying small molecules of organic acids is characterized by: In step B, the concentration of organic acid small molecules in sample group A, sample group B, sample group C and sample group D is 0.001-25 mmol / L.

5. The method according to claim 1 based on aminophenol-Ag + / Cu 2+ The method for identifying small molecules of organic acids is characterized by: In step B, at least one of the following is met: The concentration of 4-aminophenol in the sample group A is 10-50 mmol / L; The silver ion concentration in the sample group A is 10-50 mmol / L; The concentration of 4-aminophenol in the sample group B is 10-50 mmol / L; The copper ion concentration in the sample group B is 10-50 mmol / L; The concentration of 2-aminophenol in the sample group C is 10-50 mmol / L; The silver ion concentration in the sample group C is 10-50 mmol / L; The concentration of 2-aminophenol in the sample group D is 10-50 mmol / L; The copper ion concentration in the sample group D is 10-50 mmol / L.

6. The method according to claim 1 based on aminophenol-Ag + / Cu 2+ The method for identifying small molecules of organic acids is characterized by: For qualitative analysis, when obtaining the color difference diagram, magnify the R, G, and B differences by 2 to 6 times.

7. Aminophenol-Ag based + / Cu 2+ The liquor identification method is characterized by: Based on the identification method steps described in any one of claims 1 to 6, the organic acid small molecule solution is replaced with white wine, and an equal volume of Vol 40-70% ethanol aqueous solution is used as a control.

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