Latent fingerprint detection method based on red fluorescent carbon dot material

A technology of red fluorescence and detection method, which is applied in the direction of luminescent materials, material analysis through optical means, and analysis of materials, etc., can solve the problem of damaging fingerprints and imprints, and achieve the effect of improving accuracy, suitable for popularization and application, and low equipment requirements

Inactive Publication Date: 2017-07-25
FUDAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Finally, water as the most commonly used dispersion medium for carbon dots is difficult to evenly adhere to many smooth surfaces, and organic solvents generally damage fingerprints

Method used

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  • Latent fingerprint detection method based on red fluorescent carbon dot material
  • Latent fingerprint detection method based on red fluorescent carbon dot material
  • Latent fingerprint detection method based on red fluorescent carbon dot material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] (1) Preparation of red carbon dots:

[0025] Weigh 0.1 g of p-phenylenediamine and ultrasonically dissolve it in 40 ml of water, add 1 ml of concentrated phosphoric acid (85%), mix well, seal it in a polytetrafluoroethylene reactor, and heat the system to 180°C for 24 hours. After the system was cooled to room temperature, a clear solution was obtained by filtration. The clear solution was neutralized with sodium hydroxide to obtain a suspension, centrifuged to collect the bottom precipitate, and washed with ethanol and water several times. The washed sample was dissolved in 10 ml of dilute hydrochloric acid (0.1 mol / L), and then freeze-dried to obtain red light carbon dots;

[0026] (2) The red light carbon dot solution is applied to the display of latent fingerprints:

[0027] Dissolve 0.1 g of red light carbon dots in 100 ml of dilute hydrochloric acid (0.1 mol / L) to obtain a red light carbon dot solution. Pour 10ml of this red light carbon dot solution into a spr...

Embodiment 2

[0029] The preparation method is the same as that in Example 1, but the heating at 180°C for 24 hours in step (1) is changed to heating at 200°C for 20 hours, and other conditions remain unchanged. Dissolve 0.1 g of synthesized red carbon dots in 100 ml of dilute hydrochloric acid (0.1 mol / L), use the spray method to detect latent fingerprints on the surface of glass, metal, leather, plastic, ceramics, etc., and take pictures with a camera.

Embodiment 3

[0031] The preparation method is the same as in Example 1, but the amount of p-phenylenediamine used in step (1) is changed to 0.2 g, and other conditions remain unchanged. Dissolve 0.1 g of synthesized red carbon dots in 100 ml of dilute hydrochloric acid (0.1 mol / L), use the spray method to detect latent fingerprints on the surface of glass, metal, leather, plastic, ceramics, etc., and take pictures with a camera.

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Abstract

The invention belongs to the technical field of fingerprint detection and particularly provides a latent fingerprint detection method based on a red fluorescent carbon dot material. Red fluorescent carbon dots are prepared by adopting a hydrothermal method, and then a solid uniform in particle size is obtained through filtration, neutralization, washing and freeze-drying. The carbon dots show positive electricity under the acidic condition, can be bonded with negatively charged sebum and the like in fingerprint residues through an electrostatic interaction and is coated by the sebum, and fluorescence quenching of the carbon dots in the drying process is prevented. The carbon dots which are not bonded with the sebum produce fluorescence quenching due to drying agglomeration. Finally, the morphology of latent fingerprints is rapidly and accurately shown under an ultraviolet lamp or blue light. By adopting the method, fingerprints can be simply, conveniently and rapidly shown in a fluorescence emitting mode, and the method can be applied to a variety of material surfaces such as glass, metal, leather, plastic and ceramic. The carbon dots are safe and non-toxic themselves, high in quality, low in price, convenient to manufacture and suitable for popularization and application.

Description

technical field [0001] The invention belongs to the technical field of fingerprint detection, in particular to a method for detecting latent fingerprints. Background technique [0002] Everyone has different fingerprints. In accident or criminal scene investigations, fingerprint analysis provides reliable evidence of identification. When a person's fingers touch a solid surface, substances such as sweat and sebum on the hand will leave a unique imprint on the surface. Usually, these imprints cannot be seen by the naked eye and are called latent fingerprints. The goal of fingerprint detection is to enhance the visibility of latent fingerprints. So far, many nano-luminescent materials have been applied to the display of latent fingerprints. Including zinc sulfide quantum dots, zinc oxide quantum dots, cadmium sulfide quantum dots, lanthanide metal complexes, gold nanoclusters, etc. [0003] In the past ten years, carbon dots, as an excellent fluorescent material, have rec...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): A61B5/1172C09K11/65B82Y20/00B82Y40/00G01N21/64
CPCA61B5/1172B82Y20/00B82Y40/00C09K11/65G01N21/6428G01N2021/6432G01N2201/102
Inventor 熊焕明朱泽阳陈杰
Owner FUDAN UNIV
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