Novel silver development reagent for latent fingerprint development and preparation process of silver development reagent

A latent fingerprint and reagent technology, which is applied in the field of preparation of silver developing reagents, can solve the problems of increasing the difficulty of reagent preparation and developing operations, and achieve the effects of large molar extinction coefficient, simple operation and low cost.

Inactive Publication Date: 2016-06-01
QINGDAO AGRI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method requires the preparation of reducing agent solution and Ag + solution, and mix it in a certain proportion when using it or use two solutions to treat latent fingerprints separately, which undoubtedly increases the difficulty of reagent preparation and developing operations

Method used

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  • Novel silver development reagent for latent fingerprint development and preparation process of silver development reagent
  • Novel silver development reagent for latent fingerprint development and preparation process of silver development reagent
  • Novel silver development reagent for latent fingerprint development and preparation process of silver development reagent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Embodiment 1: The preparation of silver revealing reagent and the silver revealing reagent diluted with water to the latent fingerprint revealing experiment on the glass slide

[0026] ① Weigh 0.9g of silver acetate, dissolve it in 2.4mL of ammonia water, stir, then slowly drop in 0.15mL of formic acid solution; and keep stirring;

[0027] ②Centrifuge the obtained solution at 7000r / min for 13min, and obtain the supernatant which is the silver visualization reagent;

[0028] ③ Dilute the original silver visualization reagent with water as the diluent to obtain the visualization solution with the volume fraction of the silver visualization reagent being 0%, 20%, 40%, 60%, 80%, and 100% respectively;

[0029] ④Apply the revealing solution obtained in step ③ onto the surface of the glass with latent fingerprints printed on them, and then put them in a 60°C oven to dry to reveal the latent fingerprints.

[0030] Use a camera to record the visual display effect of different co...

Embodiment 2

[0032] Example 2: Preparation of silver visualization reagent and experiment on latent fingerprints on glass with silver visualization reagent diluted with absolute ethanol

[0033] ①Weigh 1.0g of silver acetate, add 2.5mL of ammonia water, stir, slowly drop in 0.18mL of formic acid solution; and keep stirring;

[0034] ②Place the obtained solution in a centrifuge tube and perform centrifugation at 8000r / min for 10min, and the supernatant obtained is the silver visualization reagent;

[0035] ③Use absolute ethanol as the diluent to dilute the original silver visualization reagent to obtain a visualization solution whose volume fraction of the silver visualization reagent is 20%, 40%, 60%, 80%, and 100% respectively;

[0036] ④Apply the revealing solution obtained in step ③ onto the surface of the glass with latent fingerprints printed on them, and then put them in an oven at 55°C to dry to reveal the latent fingerprints.

[0037] Use a camera to record the visual display effe...

Embodiment 3

[0039] Example 3: Preparation of silver visualization reagent and its experiment on latent fingerprints on aluminum foil paper

[0040] ①Weigh 1.2g of silver acetate, add 3.0mL of ammonia water, stir, slowly drop in 0.21mL of formic acid solution, and keep stirring;

[0041] ②Place the obtained solution in a centrifuge tube for centrifugation at 6000r / min for 15min, and the supernatant obtained is the silver visualization reagent;

[0042] ③Apply the silver visualization reagent obtained in step ② evenly on the surface of the aluminum foil paper printed with latent fingerprints, and then put it in a 65°C oven to dry to reveal latent fingerprints.

[0043] Use a camera to record the visual visualization effect of the silver visualization reagent on latent fingerprints, see image 3 .

[0044] from image 3 It can be seen that the silver developing reagent can clearly reveal the latent fingerprint pattern on the surface of the aluminum foil paper, and the pattern is relativel...

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Abstract

The invention provides a novel silver development reagent for latent fingerprint development and a preparation method of the silver development reagent. The silver development reagent solves the problems of a conventional silver mirror reaction based fingerprint detection technology which is difficult for preparation, complex to operate, short in expiration date of reaction liquid and the like. The silver development reagent, which as a reaction activity, is prepared from a mixed solution of silver acetate, ammonium hydroxide and formic acid through a chemical reduction reaction. As the reagent is heated in air and a solvent volatilizes, silver nanoparticles are generated in situ, so that the latent fingerprint development is achieved. In addition, the development reagent also has the advantages of simple preparation, convenient use, long expiration date and the like, and development of latent fingerprints can be achieved rapidly; in addition, the silver development agent shows a good latent fingerprint development effect on the surfaces of various materials, so as to provide basis for the identification of personal identity information; therefore, the silver development reagent disclosed by the invention can have a broad application prospect in the field of forensic science.

Description

technical field [0001] The invention relates to the technical field of latent fingerprint visualization, in particular to a preparation technology of a silver visualization reagent which can be used for latent fingerprint visualization. Background technique [0002] Fingerprints have the characteristics of lifelong invariance, so it is one of the most reliable methods for personal identification, and has played an important role in public security investigations. Scientific and correct discovery, extraction, display, and identification of fingerprints are very important for investigation work and punishment of crimes. It has important practical application value. Therefore, fingerprint detection technology has become one of the key research contents in the field of trace science and physical evidence technology. The basic principle of revealing latent fingerprints is to use a light or substance to act on substances such as sweat in fingerprint impressions, so that latent fi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): A61B5/117
Inventor 刘晓娟李峰范学兵
Owner QINGDAO AGRI UNIV
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