Copper nano-cluster sweat latent fingerprint developing reagent preparation method and sweat latent fingerprint developing method

Abstract

The invention provides a copper nano-cluster sweat latent fingerprint developing reagent preparation method and a sweat latent fingerprint developing method. Branched polyethyleneimine is taken as a template, ascorbic acid is taken as a reducing agent, copper sulfide is taken as a raw material to reduce a copper nano-cluster with smaller particle size and variable fluorescence through controllingthe heating condition during the reaction. A solution drop developing method is adopted to develop sweat latent fingerprints and an autonomously built latent fingerprint developing observation systemis used for observing, shooting and fixing the fingerprints. The prepared nanoparticles have the advantages of being small in size, good in stability and strong in fluorescence. The drop developed fingerprints are clear in streak line and obvious detail features under stimulation of natural light and multiband light sources. The drop developed fingerprints can emit different fluorescent lights under the multiband light sources, so as to eliminate the interferences of background colors. Compared with the traditional method, the method provided by the invention is capable of solving the defect that the traditional reagent is low in fingerprint developing sensitivity, weak in binding capacity and difficult to remove the interferences of background colors; and the fingerprint developing methodis high in sensitivity, strong in fluorescence, non-toxic and economic.

Description

technical field [0001] The invention relates to the field of identification of public security criminal technology fingerprints, in particular to a preparation method of a copper nano-cluster sweat latent fingerprint display reagent and a sweat latent fingerprint display method. Background technique [0002] Fingerprints are formed by the joint action of heredity and environment, and have characteristics that vary from person to person and remain unchanged throughout life. Due to the influence of many factors such as genetic material, skin tissue structure, pathology and trauma, the mastoid lines of fingerprints have specificity, diversity and stability. Personal identification and identification provide a scientific basis. At the same time, due to the characteristics of leaving traces on objects, the fingerprints left on the object can truly reflect the fingerprint characteristics of the person left behind. basis plays an important role. [0003] In the fingerprint displ...

AI Technical Summary

Problems solved by technology

In the prior art, as described in the patent application number 201610384933.4, the preparation method of the gold nanocluster sweat latent fingerprint display reagent and the sweat latent fingerprint display method use nano gold particles as seeds, and the surface is coated with a layer of bovine serum albumin BSA. In the phase, BSA is used as a template to reduce gold nanoclusters on the surface of nano-gold particles, and after separation, drying and grinding, gold nanocluster powder display reagents are obtained; gold particles are used as heavy metals, which are relatively expensive, and are widely used in synthesis and use. The process is very likely to cause harm to the health of the operator

[0007] In addition, the existing fingerprint display technology still has the following shortcomings: 1. It is difficult to eliminate the interference of the background color: in actual cases, the shooting of some fingerprints will be interfered by the background pattern of the left object, such as cigarette cases, bank cards, beverage bottles, etc. At present, the materials used to display latent fingerprints generally include gold powder, silver powder, magnetic powder, ninhydrin, etc., but the displayed color is single and easily affected by complex background colors; 2. It is difficult to display latent fingerprints of objects with rough fingerprint display technology: For a rough object, when the depth of the concave part on the surface of the object is relatively greater than the height of the papillae on the surface of the finger, when the human touches the object part and interacts, no matter how great the pressure is, there will not be too much value left on the concave part of the object surface. High fingerprint shape, there is no condition for appearance; in addition, the unevenness of the surface of the rough object determines the inconsistency of the sweat fingerprint lines, resulting in difficulties in the appearance, extraction, and analysis of fingerprints

[0008] In summary, the prior art has the following deficiencies: 1. The heavy metals used are relatively expensive, and are likely to cause harm to the health of operators during the synthesis and use process; 2. It is difficult to exclude background metals during use. 3. Difficulty in displaying latent fingerprints of objects with rough fingerprint display technology

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