Pseudoperspiration and application thereof in preparation of artificial fingerprints

Abstract

The invention discloses simulated perspiration and application thereof in preparation of artificial fingerprints, and relates to the technical field of fingerprint development. Comprising amino acids and water, and the amino acids comprise at least three of serine, glycine, alanine, aspartic acid, threonine, histidine, ornithine and valine; the total concentration of amino acids in the simulated sweat is greater than or equal to 3mmol / L. The simulated sweat is obtained by compounding a plurality of amino acids, and the concentration of the amino acids in the simulated sweat is controlled, so that the simulated sweat can better simulate natural fingerprint sediments, the developing effect is achieved, a standard is provided for detecting the developing effect of the developing agent, and the developing capability of the developing agent can be efficiently and accurately evaluated.

Description

Technical Field

[0001] The invention relates to the technical field of fingerprint development, in particular to a pseudo-sweat solution and an application thereof in preparing artificial fingerprints. Background Art

[0002] Fingerprint development technology is widely used in many fields such as criminal investigation, identity recognition, security monitoring, etc. These technologies mainly enhance the visibility of fingerprints through chemical or physical methods for analysis and identification.

[0003] Common fingerprint development methods mainly use ninhydrin and its derivatives as developers to develop fingerprint deposits. However, fingerprint deposits carry a lot of chemical information, and these chemical information themselves are affected by many factors and ultimately affect the development effect. For example, intra-source differences affected by exercise, psychological state, health status, metabolism, diet and drug intake; inter-source differences affected by age, gender and race; differences in object deposition conditions affected by the depth of fingerprint deposition and the material of the background; and differences in the post-deposition environment, such as temperature and humidity changes, will affect the final development effect of fingerprints. Therefore, when using natural fingerprint samples as samples to verify the development ability of the developer, a large number of samples are required to accurately reflect the overall development ability of the developer, and the verification efficiency is low.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a pseudo sweat solution and application thereof in preparing artificial fingerprints.

[0006] The present invention is achieved in that:

[0007] In a first aspect, the present invention provides a simulated sweat solution comprising amino acids and water, wherein the amino acids comprise at least four of serine, glycine, alanine, aspartic acid, threonine, histidine, ornithine and valine; and the total concentration of the amino acids in the simulated sweat solution is ≥3 mmol / L.

[0008] In an optional embodiment, the concentration of each amino acid in the simulated sweat is 0.25-2.50 mmol / L.

[0009] In an optional embodiment, the amino acids include serine, glycine, alanine, aspartic acid, threonine, histidine, ornithine and valine, and the total concentration of the amino acids in the simulated sweat is 3 to 30 mmol / L.

[0010] Preferably, in the simulated sweat, the concentration of serine is 2.5-10.0 mmol / L, the concentration of glycine is 1.5-6.0 mmol / L, the concentration of ornithine is 1.0-4.1 mmol / L, the concentration of alanine is 0.7-3.0 mmol / L, the concentration of aspartic acid is 0.4-1.8 mmol / L, the concentration of threonine is 0.3-1.5 mmol / L, the concentration of histidine is 0.3-1.5 mmol / L and the concentration of valine is 0.2-1.0 mmol / L.

[0011] In a second aspect, the present invention provides a use of the simulated sweat according to any one of the aforementioned embodiments in preparing artificial fingerprints.

[0012] In an optional implementation, the method includes using simulated sweat to draw the fingerprint shape, and then using a developer to develop the fingerprint shape.

[0013] In an alternative embodiment, the developer is a solution of ninhydrin and its derivatives.

[0014] In an optional implementation, the fingerprint shape drawing process is printing drawing.

[0015] In an alternative embodiment, the developing method includes room temperature development or fumigation development.

[0016] In an optional embodiment, the developing temperature of the room temperature developing is 20-25° C., and the humidity is 82-88%.

[0017] In an optional embodiment, the fumigation temperature is 75-85° C., the fumigation time is 15-25 min, and the humidity is 75-85%.

[0018] The present invention has the following beneficial effects:

[0019] The present invention provides a pseudo sweat and its application in preparing artificial fingerprints. The pseudo sweat is obtained by compounding multiple amino acids, and the concentration of amino acids in the pseudo sweat is controlled, so that the pseudo sweat can better simulate natural fingerprint deposits, thereby achieving a developing effect, providing a standard for detecting the developing effect of a developer, and facilitating efficient and accurate evaluation of the developing ability of the developer. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0021] Figure 1A schematic diagram of the development results provided in Experimental Example 1 of the present invention;

[0022] Figure 2 This is a schematic diagram of the development results provided in Experimental Example 2 of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0024] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0025] The existing fingerprint development method generally uses natural fingerprints as samples, and displays the fingerprints after being treated with a developer. However, there is a lot of chemical information in natural fingerprints, and the chemical information of different fingerprints varies greatly due to various factors. Therefore, during the development process, the difference in chemical information in natural fingerprints may cause the development effect of the developer to be difficult to summarize or explain, which is not conducive to the overall evaluation of the development effect. In order to solve this technical problem, the inventor proposes the following solution.

[0026] In a first aspect, the present invention provides a simulated sweat solution comprising amino acids and water, wherein the amino acids comprise at least four of serine, glycine, alanine, aspartic acid, threonine, histidine, ornithine and valine; and the total concentration of the amino acids in the simulated sweat solution is ≥3 mmol / L.

[0027] The present invention provides a pseudo sweat liquid, which includes three or more amino acids, can simulate the chemical information in a natural fingerprint sample, and can produce a good development effect after being combined with a developer. The development result of the pseudo sweat liquid is similar to the development result of the natural fingerprint sample, indicating that the pseudo sweat liquid can not only provide a basis for the development standardization of the developer, but also provide an important reference for the development result of the natural fingerprint sample, and can be applied to various application scenarios requiring development standardization.

[0028] In an optional embodiment, the concentration of each amino acid in the simulated sweat is 0.25 to 2.50 mmol / L, for example, the concentration of each amino acid in the simulated sweat is 0.25 mmol / L, 0.50 mmol / L, 0.75 mmol / L, 1.00 mmol / L, 1.25 mmol / L, 1.50 mmol / L, 1.75 mmol / L, 2.00 mmol / L, 2.25 mmol / L or 2.50 mol / L, any one of the values, or a range value between any two values, or any value within the range.

[0029] In an optional embodiment, the amino acids include at least 8 kinds of amino acids including serine, glycine, alanine, aspartic acid, threonine, histidine, ornithine and valine. According to actual needs, more kinds of amino acids, such as glutamic acid, arginine, etc., can also be added to the simulated sweat.

[0030] The total concentration of amino acids in the above-mentioned simulated sweat is 3 to 30 mmol / L, for example, it can be any value among 3mmol / L, 5mmol / L, 8mmol / L, 10mmol / L, 13mmol / L, 15mmol / L, 18mmol / L, 20mmol / L, 23mmol / L, 25mmol / L, 28mml / L or 30mmol / L, or a range value between any two values, or any value within the range.

[0031] In an optional embodiment, the amino acids in the simulated sweat can be composed of any three of serine, glycine, alanine, aspartic acid, threonine, histidine, ornithine and valine. For example, the amino acids in the simulated sweat are composed of serine, glycine and alanine.

[0032] Or the amino acids in the simulated sweat can be composed of any four of serine, glycine, alanine, aspartic acid, threonine, histidine, ornithine and valine. For example, the amino acids in the simulated sweat are composed of serine, glycine, ornithine and alanine.

[0033] Or the amino acids in the simulated sweat can be composed of any five of serine, glycine, alanine, aspartic acid, threonine, histidine, ornithine and valine. For example, the amino acids in the simulated sweat are composed of serine, glycine, ornithine, histidine and alanine.

[0034] Or the amino acids in the simulated sweat can be composed of any six of serine, glycine, alanine, aspartic acid, threonine, histidine, ornithine and valine. For example, the amino acids in the simulated sweat are composed of serine, glycine, ornithine, aspartic acid, histidine and alanine.

[0035] Or the amino acids in the simulated sweat can be composed of any six of serine, glycine, alanine, aspartic acid, threonine, histidine, ornithine and valine. For example, the amino acids in the simulated sweat are composed of serine, glycine, ornithine, aspartic acid, threonine, histidine and alanine.

[0036] Preferably, the amino acids in the simulated sweat are composed of 8 kinds of amino acids, namely, serine, glycine, alanine, aspartic acid, threonine, histidine, ornithine and valine, and the concentration of each amino acid is 0.25-2.50 mmol / L, and the total concentration of amino acids in the simulated sweat is 3-30 mmol / L.

[0037] Preferably, in the simulated sweat, the concentration of serine is 2.5-10.0 mmol / L, the concentration of glycine is 1.5-6.0 mmol / L, the concentration of ornithine is 1.0-4.1 mmol / L, the concentration of alanine is 0.7-3.0 mmol / L, the concentration of aspartic acid is 0.4-1.8 mmol / L, the concentration of threonine is 0.3-1.5 mmol / L, the concentration of histidine is 0.3-1.5 mmol / L and the concentration of valine is 0.2-1.0 mmol / L.

[0038] In an optional embodiment, the method for preparing the pseudo-sweat solution provided by the present invention comprises mixing and dissolving amino acids with water.

[0039] In a second aspect, the present invention provides a use of the simulated sweat according to any one of the aforementioned embodiments in preparing artificial fingerprints.

[0040] In an optional embodiment, the pseudo-sweat provided by the present invention can ensure the relative consistency of fingerprint information, so that the pseudo-sweat can be used to prepare artificial fingerprints for accurate evaluation of the development effect.

[0041] In an optional embodiment, the use of the pseudo sweat in preparing an artificial fingerprint includes drawing a fingerprint shape using the pseudo sweat, and then developing the fingerprint shape using a developer.

[0042] In an optional embodiment, the developer is a solution of ninhydrin and its derivatives, for example, it can be any one of ninhydrin solution, 5-methoxyninhydrin, 5-methylninhydrin, 5-methylaminoninhydrin or 5-dimethylaminoninhydrin, preferably a ninhydrin solution.

[0043] In an optional implementation, the fingerprint shape drawing process is printing drawing.

[0044] In an optional embodiment, the printing and drawing process includes: first preparing a fingerprint template, then injecting pseudo sweat into a printer, and the printer uses the pseudo sweat as ink according to the fingerprint template to print the fingerprint on paper.

[0045] The fingerprint template can be obtained by taking a photo of the developed natural fingerprint sample and then processing it through an image processor, such as Adobe Photoshop, etc., to retain only the shape of the fingerprint.

[0046] Preferably, the size of the fingerprint template can also be adjusted to be consistent with the size of the natural fingerprint sample.

[0047] Preferably, the process of printing fingerprints includes: injecting pseudo sweat as ink into the printer, turning on the printer's deep cleaning function for cleaning to replace all the ink inside the printer with pseudo sweat, and then printing to print a fingerprint pattern formed by the pseudo sweat on paper.

[0048] In other implementations, the shape of the fingerprint may also be hand-drawn.

[0049] In an optional embodiment, the developing method includes room temperature developing or fumigation developing. Specifically, the fingerprint pattern formed by the pseudo sweat obtained by printing is combined with a developer and developed or fumigated at room temperature.

[0050] In an optional embodiment, in order to ensure the development effect, the development temperature of the room temperature development is 20-25° C. and the humidity is 82-88%.

[0051] Preferably, the developing temperature of the room temperature developing is 24° C. and the humidity is 85%.

[0052] In an optional embodiment, in order to ensure the development effect, the fumigation temperature is 75-85° C., the fumigation time is 15-25 min, and the humidity is 75-85%.

[0053] Preferably, the fumigation temperature is 80° C., the fumigation time is 20 min, and the humidity is 80%.

[0054] Example 1

[0055] This embodiment provides a simulated sweat liquid composed of amino acids and water, wherein the amino acids are serine, glycine, ornithine, alanine, aspartic acid, threonine, histidine and valine.

[0056] The preparation method of the pseudo sweat provided in this embodiment includes: weighing 1.051g of serine, 0.751g of glycine, 1.322g of ornithine, 0.891g of alanine, 1.331g of aspartic acid, 1.192g of threonine, 1.552g of histidine and 1.172g of valine, respectively, and then adding the above 8 amino acids into 8 100mL volumetric flasks, respectively, adding distilled water to 100mL, and standing for 24h to obtain 8 amino acid mother solutions, respectively, and the concentration of amino acid in each amino acid mother solution is 0.1mol / L.

[0057] Use a pipette to transfer 10.0 mL of serine mother solution, 6.0 mL of glycine mother solution, 4.1 mL of ornithine mother solution, 3.0 mL of alanine mother solution, 1.8 mL of aspartic acid mother solution, 1.5 mL of threonine mother solution, 1.5 mL of histidine mother solution and 1.0 mL of valine mother solution, add them into a 100 mL volumetric flask, add distilled water to make up to 100 mL, let stand for 24 h, and obtain the simulated sweat solution.

[0058] The concentration of serine in the simulated sweat provided in this embodiment is 10.0 mmol / L, the concentration of glycine is 6.0 mmol / L, the concentration of ornithine is 4.1 mmol / L, the concentration of alanine is 3.0 mmol / L, the concentration of aspartic acid is 1.8 mmol / L, the concentration of threonine is 1.5 mmol / L, the concentration of histidine is 1.5 mmol / L and the concentration of valine is 1.0 mmol / L, and the total concentration of amino acids in the simulated sweat is 28.9 mmol / L.

[0059] Example 2

[0060] This embodiment provides a simulated sweat liquid, the composition of which is the same as that of Embodiment 1, except that the simulated sweat liquid of this embodiment is obtained by diluting the simulated sweat liquid of Embodiment 1 by 4 times.

[0061] Specifically, 25 mL of the simulated sweat solution of Example 1 was taken with a pipette and added into a 100 mL volumetric flask, and distilled water was added to make the volume to 100 mL, and the solution was allowed to stand for 24 hours to obtain a simulated sweat solution diluted 4 times.

[0062] The concentration of serine in the simulated sweat provided in this embodiment is 2.5 mmol / L, the concentration of glycine is 1.5 mmol / L, the concentration of ornithine is 1.025 mmol / L, the concentration of alanine is 0.75 mmol / L, the concentration of aspartic acid is 0.45 mmol / L, the concentration of threonine is 0.375 mmol / L, the concentration of histidine is 0.375 mmol / L and the concentration of valine is 0.25 mmol / L, and the total concentration of amino acids in the simulated sweat is 7.225 mmol / L.

[0063] Example 3

[0064] This embodiment provides a pseudo sweat solution, which is composed of amino acids and water. The preparation method is similar to that of Example 2, except that it does not contain valine.

[0065] Example 4

[0066] This embodiment provides a pseudo sweat solution, which is composed of amino acids and water. The preparation method is similar to that of Example 2, except that it does not contain histidine and valine.

[0067] Comparative Example 1

[0068] This comparative example provides a pseudo sweat liquid, the composition of which is the same as that of Example 1, except that the pseudo sweat liquid of this comparative example is obtained by diluting the pseudo sweat liquid of Example 1 by 20 times.

[0069] Specifically, 5 mL of the simulated sweat solution of Example 1 was taken with a pipette and added into a 100 mL volumetric flask, and distilled water was added to make the volume to 100 mL, and the solution was allowed to stand for 24 hours to obtain a simulated sweat solution diluted 20 times.

[0070] The total concentration of amino acids in the simulated sweat provided in this comparative example is 1.445 mmol / L.

[0071] Comparative Example 2

[0072] This comparative example provides a pseudo sweat liquid, the composition of which is the same as that of Example 1, except that the pseudo sweat liquid of this comparative example is obtained by diluting the pseudo sweat liquid of Example 1 40 times.

[0073] Specifically, 2.5 mL of the simulated sweat solution of Example 1 was taken with a pipette and added into a 100 mL volumetric flask, and distilled water was added to make the volume to 100 mL, and the solution was allowed to stand for 24 hours to obtain a simulated sweat solution diluted 40 times.

[0074] The total concentration of amino acids in the simulated sweat provided in this comparative example is 0.725 mmol / L.

[0075] Comparative Example 3

[0076] This comparative example provides a pseudo sweat solution, which consists of amino acids and water, wherein the amino acid is serine with a concentration of 10.0 mmol / L.

[0077] Comparative Example 4

[0078] This comparative example provides a pseudo sweat solution, which consists of amino acids and water, wherein the amino acids consist of 10.0 mmol / L of serine and 6.0 mmol / L of glycine.

[0079] Example 5

[0080] This embodiment provides an application of pseudo sweat in preparing artificial fingerprints, wherein the pseudo sweat can be any of the pseudo sweat provided in Examples 1 to 4 and Comparative Examples 1 to 4, including using the pseudo sweat as ink for a printer to prepare an artificial fingerprint, and then developing the artificial fingerprint, the specific method is as follows:

[0081] S01. Prepare fingerprint template

[0082] The developed natural fingerprint sample was photographed and then edited in Adobe Photoshop software to remove the background color and retain the fingerprint morphology to obtain a binary fingerprint template photo (2489×3449 pixels). The above fingerprint template photo was then inserted into Word, and the size of the fingerprint template photo was adjusted to be the same as that of the natural fingerprint sample, and then it was used as the fingerprint template required for printing.

[0083] S02, Printing Artificial Fingerprints

[0084] The pseudo sweat liquids provided in Examples 1 to 4 and Comparative Examples 1 to 4 were respectively injected into the printer as the ink of the printer, and the fingerprint templates were printed under the same printing parameters using the same model of printer to obtain a plurality of artificial fingerprint samples.

[0085] S03, Development

[0086] The above multiple artificial fingerprint samples were developed and smoked at room temperature respectively.

[0087] Among them, the room temperature development method is: in an environment of 23°C and 85% humidity, use a disposable dropper to absorb 0.1 mol / L ninhydrin solution, and drop the ninhydrin solution to the position corresponding to the artificial fingerprint. The amount of ninhydrin solution should be enough to soak the paper. After dropping, dry it naturally in the shade for 8 hours indoors and observe the development situation.

[0088] The fumigation method is: after adding ninhydrin solution according to the above room temperature development method, the artificial fingerprint sample is placed in a fumigation cabinet for 20 minutes, the temperature is set to 80°C, the humidity is set to 80%, and the development is observed after the fumigation is completed.

[0089] When observing the development, place all the papers with artificial fingerprint samples on the same shooting stand and shoot all the developed fingerprints at once under the same lighting conditions.

[0090] Test Example 1

[0091] According to the method of Example 5, the artificial fingerprint samples prepared from the pseudo sweat provided in Examples 1 to 4 and Comparative Examples 1 to 4 were developed at room temperature to obtain the following Figure 1 Results shown.

[0092] Depend on Figure 1 It can be seen that after the pseudo sweat provided by the embodiments of the present invention is combined with the ninhydrin solution, clear fingerprint development results are shown, and the clarity of the fingerprint ridges is good; however, due to the change in the amino acid formula in the pseudo sweat in Comparative Examples 1 to 4, the fingerprint development results are poor, the clarity of the fingerprint ridges is poor, and it is not conducive to the evaluation of the development results.

[0093] It should be noted that although the amino acid concentration in the simulated sweat of the comparative example is lower than that of the embodiment, the concentration value itself has little effect on the chemical appearance of fingerprints. The reason is that the existing fingerprint appearance reagents are very sensitive and fingerprints will not be difficult to appear due to the small concentration value. The key to ensuring a good fingerprint development effect in the embodiment of the present invention lies in the compounding of multiple amino acids.

[0094] Test Example 2

[0095] According to the method of Example 5, the artificial fingerprint samples prepared from the pseudo sweat provided in Examples 1 to 4 and Comparative Examples 1 to 4 were smoked to obtain the following Figure 2 Results shown.

[0096] Depend on Figure 2 It can be seen that after the pseudo-sweat provided in the embodiment of the present invention is combined with the ninhydrin solution, clear fingerprint development results are shown under fumigation conditions, and the results are similar to those of normal temperature development, indicating that the pseudo-sweat provided in the embodiment of the present invention is suitable for a variety of development methods, and each development method can show better fingerprint development effect, and the clarity of the fingerprint ridges is good.

[0097] In Comparative Examples 1 to 4, due to the change in the amino acid formula in the simulated sweat, even after fumigation, it is difficult to obtain fingerprint ridges with high definition, and the fingerprint development results are poor, which is not conducive to the evaluation of the development results.

[0098] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A pseudo sweat solution, characterized in that: It comprises amino acids and water, wherein the amino acids include at least four of serine, glycine, alanine, aspartic acid, threonine, histidine, ornithine and valine; and the total concentration of amino acids in the simulated sweat is ≥3mmol / L.

2. The pseudo sweat solution according to claim 1, characterized in that The concentration of each amino acid in the simulated sweat solution is 0.25-10 mmol / L.

3. The simulated sweat liquid according to claim 1 or 2, characterized in that: The amino acids include serine, glycine, alanine, aspartic acid, threonine, histidine, ornithine and valine, and the total concentration of the amino acids in the simulated sweat is 3 to 30 mmol / L; Preferably, in the simulated sweat, the concentration of serine is 2.5-10.0 mmol / L, the concentration of glycine is 1.5-6.0 mmol / L, the concentration of ornithine is 1.0-4.1 mmol / L, the concentration of alanine is 0.7-3.0 mmol / L, the concentration of aspartic acid is 0.4-1.8 mmol / L, the concentration of threonine is 0.3-1.5 mmol / L, the concentration of histidine is 0.3-1.5 mmol / L and the concentration of valine is 0.2-1.0 mmol / L.

4. Use of the pseudo sweat liquid as claimed in any one of claims 1 to 3 in preparing artificial fingerprints.

5. The use according to claim 4, characterized in that: The method comprises using the pseudo sweat to draw a fingerprint shape, and then using a developer to develop the fingerprint shape.

6. The use according to claim 5, characterized in that: The developer is a solution of ninhydrin and its derivatives.

7. The use according to claim 5, characterized in that: The fingerprint shape drawing process is printing drawing.

8. The use according to claim 4, characterized in that: The developing methods include room temperature developing or fumigation developing.

9. The use according to claim 8, characterized in that: The developing temperature of the room temperature developing is 20-25° C., and the humidity is 82-88%.

10. The use according to claim 8, characterized in that: The temperature of the fumigation is 75-85° C., the fumigation time is 15-25 minutes, and the humidity is 75-85%.

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