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Method for strengthening latent fingerprint observation on non-permeating object by adopting gold nano-material

A gold nanometer, non-permeable technology, which is applied in the analysis of materials, material analysis by optical means, and analysis by making materials undergo chemical reactions, etc., can solve the problems of inability to show old fingerprints and low sensitivity, and achieve low cost and environmental protection. friendly effect

Inactive Publication Date: 2009-06-03
CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The Achilles' heel of this method is its low sensitivity and the inability to visualize old fingerprints

Method used

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  • Method for strengthening latent fingerprint observation on non-permeating object by adopting gold nano-material
  • Method for strengthening latent fingerprint observation on non-permeating object by adopting gold nano-material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] Preparation of gold nano solution: 50ml of HAuCl with a concentration of 0.1mmol / L 4 Solution, heating and stirring to boiling, then adding 30ml concentration is the mixed solution of the sodium citrate of 1.33mmol / L and the tannic acid of 0.0025mmol / L, continues to boil for 15 minutes, is cooled to room temperature. Add 25ul Tween 20 to the above solution, stir well, and adjust the pH to 2.4 with citric acid solution. Immerse the glass to be tested in the gold nano solution for 5 minutes, take it out and rinse it with distilled water to remove the unadsorbed gold nanoparticles.

[0014] Fingerprint development: prepare 50 ml of citric acid-sodium citrate buffer solution with pH=3.8. Take 75mg of silver acetate and dissolve 210mg of hydroquinone in the buffer solution. Put the object glass to be displayed into the above solution and soak for 10 minutes. Take it out, rinse it with distilled water to remove excess silver salt, soak it in the fixer solution for 4min, ta...

Embodiment 2

[0016] Preparation of gold nano solution: 50ml of HAuCl with a concentration of 0.14mmol / L 4 Solution, heated to boiling, add 30ml concentration and be the mixed solution of the sodium citrate of 3.5mmol / L and the tannic acid of 0.0019mmol / L after stirring, continue to boil for 10 minutes, be cooled to room temperature. Add 30ul Tween 20 to the above solution, stir well, and then adjust the pH to 2.5 with citric acid solution. Immerse the aluminum foil to be tested in the gold nano solution for 13 minutes, take it out and rinse it with distilled water to remove the unadsorbed gold nanoparticles.

[0017] Fingerprint development: prepare 50 ml of citric acid-sodium citrate buffer solution with pH=3.6. Get 75mg of silver acetate, 250mg of hydroquinone dissolved in 50ml of citric acid buffer solution. Put the tinfoil of the object to be revealed into the mixture and soak for 15 minutes. Take it out, rinse it with distilled water to remove excess silver salt, soak it in the fix...

Embodiment 3

[0019] Preparation of gold nano solution: 50ml of HAuCl with a concentration of 0.6mmol / L 4 Heat the solution to boiling, add 30ml of a mixed solution of sodium citrate with a concentration of 10.0mmol / L and 0.0012mmol / L tannic acid, stir, continue to boil for 13min, stop heating and cool to room temperature. 25ul Tween 40 was added to the above solution, and after stirring for 18min, the pH was adjusted to 2.6 with citric acid solution. Immerse the plastic to be tested in the gold nano solution for 60 minutes, take it out and rinse it with distilled water to remove the unadsorbed gold nanoparticles.

[0020] Fingerprint development: prepare 50 ml of citric acid-sodium citrate buffer solution with pH=3.8. Take 80mg of silver acetate and 220mg of hydroquinone dissolved in the buffer solution, then mix the two solutions. Put the object plastic to be displayed into the mixture and soak for 15 minutes. Take it out, rinse it with distilled water to remove excess silver salt, soa...

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Abstract

The invention provides a method for strengthening latent fingerprint observation on non-permeating object by adopting gold nano-material. The method employs gold nano-particles modified by sodium citrate and tannin acid to display latent fingerprint on non-permeating objects. Under the acid condition, the gold nano-particles are absorbed on fingerprint residue of the non-permeating object by electrostatic absorption, and then are placed in silver-salt solution, and silver particles are dissolved out from silver ions by the catalysis of the gold nano-particles modified by the sodium citrate and the tannin acid. The silver particles are deposited on a fingerprint line, thus clearly displaying the latent fingerprint on the surface of the non-permeating objects. The method can better display the latent fingerprint on the surface of the non-permeating objects, and has good effect on old fingerprints. The method is simple and easy, the cost is low, and the synthesized gold nano-solution can be preserved for a long time and used repeatedly; the latent fingerprints on the surfaces of the different non-permeating objects can be clearly observed under visible light without complicated instruments. The method is environmental-friendly and causes no harm to operators.

Description

technical field [0001] The invention belongs to a method for revealing criminal technical traces, in particular to a method for revealing latent fingerprints on non-penetrating objects enhanced by using gold nanometer materials. Background technique [0002] In the middle of the 19th century, people have begun to study fingerprints in a scientific sense. Dr. Henry Faulds (1843-1930), the earliest person engaged in fingerprint research in the world, was the first master in the world to publish "Fingerprint"; Change" theory, pioneered the application of fingerprint display to crime scene identification. In 1877, the French doctor Aubert created silver nitrate display fingerprint display technology. Latent fingerprints are invisible, but they are of great significance to the detection of cases. Many advanced technologies have been applied to fingerprint display. The longest and most widely used method is the powder method. In recent years, this method has undergone major imp...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/78G01N21/84G06K9/00
Inventor 牛利许晓宇高东梅韩冬雪王晓丹
Owner CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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