Method for developing latent finger prints using zinc sulphide and zinc oxide nanoparticles

A latent fingerprint and zinc sulfide technology is applied in the detection field to achieve the effects of simple method, low cost, easy preparation and preservation

Inactive Publication Date: 2009-07-22
NORTHEAST NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] As the preparation and application of nanomaterials show more and more irreplaceable advantages of other materials, the use of nanomaterials to display fingerprints will also become an important research topic. P.J.Maynard, a famous scholar in this field, predicted that although nanomaterials are showing fingerprints There are still many limitations in imprinting, but nanotechnology may lead to the development of new materials and reagents with superior properties

Method used

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  • Method for developing latent finger prints using zinc sulphide and zinc oxide nanoparticles
  • Method for developing latent finger prints using zinc sulphide and zinc oxide nanoparticles
  • Method for developing latent finger prints using zinc sulphide and zinc oxide nanoparticles

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] (1) 5ml of ethanol and 0.1mol of sodium sulfide are placed in a mortar and ground;

[0049] (2) After the ethanol volatilizes, add 0.1 mol of zinc acetate and continue to grind until the ground powder turns from colorless to white;

[0050] (3) Ethanol is added to transfer the product, centrifuged, then alternately washed with ethanol and water for several times, filtered with suction, and vacuum-dried to obtain a white powder of nano-ZnS.

[0051] Appearance method:

[0052] (1) When using, dip a small amount of powder with a brush, and gently brush various surfaces with latent fingerprints, including glass sheets, plastic bottles, cans, copper sheets, aluminum foil, tables or the surface of laboratory benches, and the appearance can be observed The fingerprint pattern can be taken with a digital camera (attached figure 1 , 2 ). In the case where the surface and powder contrast are similar, after using ZnS powder to develop, under the irradiation of ultraviolet lig...

Embodiment 2

[0055] (1) Add 0.5 mol of zinc acetate solid powder into a mortar containing 0.5 mol of thioglycolic acid and grind thoroughly for about 30 minutes, wash with water, filter, and vacuum-dry to obtain a white solid that is zinc thioglycolate.

[0056] (2) After grinding it with a small amount of ethanol, add 0.4mol of Na 2 S, continue to grind for 30 minutes to obtain a light pink colloid, dissolve it in water to obtain a transparent solution, add acetone to obtain a white precipitate, filter it with suction, wash it with ethanol and dry it to obtain a water-soluble thioglycolic acid-protected ZnS nano powder.

[0057] Appearance method:

[0058] (1) When using, dip a small amount of powder with a brush, and gently brush various surfaces with latent fingerprints, including glass sheets, plastic bottles, cans, copper sheets, aluminum foil, tables or the surface of laboratory benches, and the appearance can be observed The fingerprint pattern can be taken with a digital camera (...

Embodiment 3

[0061] (1) Add 35uL of thioglycolic acid to 50mL, 5.0mmol / L, ZnCl 2 Mix well in the solution;

[0062] (2) Then adjust the pH value of the mixed solution to about 8.0 with 0.5mol / L NaOH solution, and feed nitrogen gas for 30 minutes to remove the oxygen in the mixed solution container;

[0063] (3) Under magnetic stirring and nitrogen protection, slowly drop 50mL, 6mmol / L Na 2 S solution, continue stirring for 24 hours to obtain ZnS nanoparticle sol, and thioglycolic acid is modified on the surface of ZnS. Under a UV lamp with a wavelength of 365nm, the solution emits yellow-green light.

[0064] When showing fingerprints, just soak the latent fingerprint sample in the ZnS quantum dot solution for 10-40 minutes, take it out and dry it to take pictures.

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Abstract

The invention belongs to the technical field of detection, and in particular relates to a method for applying ZnS, ZnO and functionalized nano granules thereof in revealing latent fingerprints on different surfaces. The invention provides a method for revealing latent fingerprints on surfaces including glass, plastics, metal, clad plate (lacquer wood), paper and the like by means of ZnS, ZnO and functionalized nano granules thereof, wherein ZnS is prepared by two methods of a grinding method and a solution method, while ZnO nano powder is prepared by a sol-gel method; during revealing, the method for revealing the latent fingerprints on different object surfaces is realized by means of a dry powder brushing revealing method and a wet revealing method. The method has the advantages of simplicity, quickness, easy operation, no toxic and side effects on an operator and visualized result.

Description

technical field [0001] The invention belongs to the technical field of detection, and in particular relates to a method for displaying latent fingerprints of ZnS, ZnO and functionalized nanoparticles thereof. Background technique [0002] Fingerprints are different from person to person, remain unchanged for life and leave traces on objects. Therefore, by extracting fingerprints, it can often provide accurate identification in the investigation and handling of accidents; it plays an important role in forensic science and criminal proceedings. important evidence. In recent years, DNA detection and analysis techniques have been widely used, but fingerprint identification is still one of the most reliable methods for personal identification. And with the popularization of computer technology and the continuous development and application of fingerprint automatic identification systems, fingerprint technology is becoming more and more closely integrated with people's modern lif...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): A61B5/117C09K11/56C09K11/54A61B5/1172
Inventor 柴芳苏忠民马占芳王春刚王婷婷
Owner NORTHEAST NORMAL UNIVERSITY
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