TW201307490A - Fingerprint-displaying spray and method utilizing spray to display fingerprint - Google Patents

Abstract

The present invention is to provide a fingerprint-displaying spray, which comprises based on the total weight of (A), (B), and (C): (A) 1~10 weight parts of an amino acid reacting agent; (B) 5~30 weight parts of a dispersing agent; and (C) 50~150 weight parts of a propellant. By means of comprising the dispersing agent and the propellant, the present invention can be made to have convenience and excellent fingerprint displaying effect, reduce the use of toxic chemical substances which contaminate the environment, and achieve the purposes of low costs and sample contamination prevention, being applicable to the technological field of latent fingerprint detection.

Description

Fingerprinting spray and method for displaying fingerprint using the same

The invention relates to a fingerprint developing spray and a method for displaying a fingerprint by using the spray, in particular to a technical field for detecting a latent fingerprint.

Fingerprints are the lines formed by the uneven skin on the fingertips of the primate fingers, and may also refer to the marks printed on the objects by these lines. When a person's finger touches an item, fingerprints are usually left on the item, and these marks are most often used as evidence in criminal science and forensic science. Since many fingerprints found on crime scenes are usually invisible to the naked eye and are called latent fingerprints, research has focused on applying various techniques to make latent fingerprints visible for analysis.

At present, the methods for revealing the latent fingerprints in laboratory research mainly include the scent method, the silver nitrate method and the ninhydrin method. The scent method uses iodine or cyanoacrylate vapor to react with residual substances such as amino acids or oils on the fingerprint to make the fingerprint appear. The principle of the silver nitrate method is that the sweat discharged from the human contains a little salt, and the salt will produce white silver chloride in the case of silver nitrate. The silver chloride is sensitive to light, and it will appear black after illumination, so that the fingerprint containing sweat can be revealed. Anthracene (2,2-dihydroxyindane-1,3-dione, ninhydrin) is an organic compound widely used to detect ammonia, primary and secondary amines, especially amino acids, ninhydrin and amines on fingerprints. The base acid reacts with a deep blue or purple color called Ruhemann's purple, which is used in forensic medicine to identify fingerprints. In addition, there are also laser fingerprinting methods such as ninhydrin-zinc chloride fluorimetry, scent-dye dyeing fluorimetry, and the like.

In 1877, French doctor Aubert painted silver nitrate solution on paper to study the skin disease and glandular secretion process, showing sweat fingerprints, becoming the first person to create a fingerprint display method. Since Aubert discovered the silver nitrate display method, the fingerprint appeared from the original single and simple method, and has now become a professional technology that comprehensively uses the knowledge and technology of physics, chemistry, biology and other disciplines. In 1910, Ruhemann developed ninhydrin, which was originally used in the biomedical world to test amino acids. Many scientists then tried to synthesize analogous steroids and initially studied the effects of fingerprinting. In 1989, Pounds and Grigg found that the sensitivity of using DFO (1,8-diazafluoren-9-one) to visualize fingerprints was high. After the appearance, the specimens showed almost no traces (sometimes pale purple), only excited by argon ion laser. When the lens is observed under a specific filter, the fingerprint can be found, and the stain on the sample is small. However, DFOs are expensive, and organic solvents such as trichlorotrifluoroethane are used to seriously pollute the environment.

In addition, it has recently been found that natural light, a strong light, a blue light, and a multi-band light source can be used to detect a fingerprint. The multi-band light source is a new type of light source developed in recent years. It outputs light from different wavelengths ranging from ultraviolet light to infrared light (310 nm to 1000 nm), and has been widely used in site surveys at home and abroad. The residual material of the fingerprint produces fluorescence under the excitation of ultraviolet light, or some sweat and oil stains are processed by the fluorescent reagent to form a fluorescent fingerprint under ultraviolet light.

The fingerprint display method commonly used in criminal investigation is to use the silver powder of the aluminum series, the gold powder of the copper series, the black powder of the carbon series or other white powder, and the colored powder to cover the moisture and fat in the secretion, and use the sample. The background color and the color difference of the powder color are detected, and then the detected fingerprint is re-transferred on the adhesive film of the adhesive film. However, this method requires complicated pretreatment and requires a certain degree of operational proficiency, and there are also disadvantages such as contamination of the specimen. In addition, it is also possible to cover the sample with a yellow powder, spray water with a spray, and then use a laser to excite the fluorescent light to reveal a fingerprint. However, this method requires the use of a laser irradiation device, and the procedure is complicated and the steps are numerous. In addition, criminal investigations often use a solution containing ninhydrin to coat the sample, which has a good effect on the latent fingerprint. However, if the sample is a thermal paper, it will destroy the thermal paper to some extent. On the content.

Therefore, how to invent a fingerprint-exposure spray, which has the convenience and good fingerprint display effect, and achieves the purpose of low cost and no pollution of the sample, can be applied to the technical field of latent fingerprint detection, and will be actively disclosed by the present invention. Where.

In view of the shortcomings of the above-mentioned prior art, the inventor felt that he had not perfected it, exhausted his mind and carefully studied and overcome it, and based on his accumulated experience in the industry for many years, he developed a fingerprint development spray for convenience. Sexuality and good fingerprints show the effect, and achieve the purpose of low cost and no pollution of the sample.

The main object of the present invention is to provide a fingerprint developing spray which comprises a dispersing agent and a propelling agent so as to have convenience and good fingerprint display effect, and achieve the purpose of low cost and no pollution of the sample, thereby achieving It is used in the technical field of latent fingerprint detection.

To achieve the above object, the present invention provides a fingerprint developing spray comprising: (A) 1 to 10 parts by weight of an amino acid reactant, based on the total weight of components (A), (B) and (C); And 5 to 30 parts by weight of a dispersing agent; and (C) 50 to 150 parts by weight of a propellant.

The fingerprinting agent described above, wherein the amino acid reactant is ninhydrin or an analogous thereof.

The fingerprinting spray described above, wherein the ninhydrin homolog is 5-methylthioninhydrin.

The fingerprinting agent described above, wherein the amino acid reactant is DFO (1,8-diazafluoren-9-one) or 1,2-dihydroindoledione (1,2-indandione).

The fingerprint developing spray described above, wherein the 1,2-dihydroindoledione homolog is 5-methoxy-1,2-indanedione or 5, 6-Dimethoxy-1,2-indenedione (5,6-dimethoxy-1, 2-indanedione).

The above-mentioned fingerprint developing spray, wherein the dispersing agent is an alcohol, an ether, an acid, an ester, a ketone, an aliphatic hydrocarbon or an aromatic hydrocarbon.

The fingerprint described above exhibits a spray, wherein the spray is a liquefied petroleum gas (LPG).

The fingerprinting agent described above, wherein the propellant further comprises dimethyl ether, compressed air, carbon fluorocarbon gas, carbon dioxide or nitrogen.

Another object of the present invention is to provide a method of visualizing a fingerprint which uses the above-described fingerprint to develop a spray.

In the above method, the vacuum metal plating method is further used to enhance the fingerprint development effect.

Thereby, the fingerprint developing spray of the present invention comprises a dispersing agent and a propelling agent, so that the convenience and good fingerprint display effect can be obtained, and the use of the toxic chemical substance which pollutes the environment is reduced, and the cost is low and not The purpose of polluting the specimen is to achieve the purpose of being applicable to the technical field of latent fingerprint detection.

In order to fully understand the objects, features and effects of the present invention, the present invention will be described in detail by the following specific examples and the accompanying drawings. The content of the base acid reactant is from 1 to 10 parts by weight, and if the content of the amino acid reactant is too low, the fingerprint may appear pale and unclear. The amino acid reactant may use ninhydrin or an analogous thereof such as 5-(methylthio)ninhydrin; or DFO (1,8-diazafluoren-9) -one), 1,2-indandione or a homologue thereof, which reacts with a fingerprint to form a fluorescent compound, and its chemical structure is as follows.

The content of the dispersing agent in the fingerprint developing spray of the present invention is 5 to 30 parts by weight, the purpose of which is to effectively and uniformly adhere the spray to the surface of the sample. The dispersant may be a solvent such as an alcohol, an ether, an acid, an ester, a ketone, an aliphatic hydrocarbon or an aromatic hydrocarbon, and is preferably used from the viewpoint of reducing the use of a toxic chemical substance that pollutes the environment. Methanol, ethanol, propanol, acetic acid, ethyl acetate, acetone, and the like.

The fingerprint-forming spray of the present invention must not contain a nitrogen-containing compound, i.e., the amount of the nitrogen-containing compound is insufficient to undergo a color reaction with the amino acid reactant. Such nitrogen-containing compounds mainly include ammonia, amine salts, amine compounds, guanamine compounds, isocyanates, urethanes, and various urea derivatives.

The content of the propellant in the fingerprint developing spray of the present invention is 50 to 150 parts by weight, preferably liquid petroleum gas, and further mixed with dimethyl ether, compressed air, CFC gas or compressed gas (such as nitrogen, Use of carbon dioxide gas, etc. After the fingerprint is developed by using the fingerprint developing spray of the present invention, the vacuum metal plating method can be further used to enhance the fingerprint display effect, and the fingerprint lines of the combined amino acid are more clearly analyzed for identification and comparison. The principle of the vacuum metal coating method is to use a small gold wire to form a gold atom under vacuum, and quickly adhere to the surface of the sample (including the fingerprint line and the fingerprint line). After gold plating, the gold atoms on the fingerprint line will be sebum. Protection forms a protective film. When galvanizing is continued, since the zinc atoms are only combined with the gold atoms, the gold atoms on the background pattern and the lines will combine with the zinc atoms to exhibit a gray-black characteristic, and the lines may not be plated with zinc after the gold atoms are coated. The atom, and the original color of gold, makes the contrast on the evidence.

Example 1

5 g of ninhydrin was dispersed in 15 g of ethanol at room temperature, and after bottling, 85 g of liquid petroleum gas was injected to complete the sealing.

Example 2

The remainder was the same as in Example 1 except that 5-methylthioninhydrin was substituted for ninhydrin.

Example 3

The same as Example 1 except that ethanol was used instead of ethanol.

Example 4

The remainder was the same as in Example 1 except that 1,2-dihydroindoledione was substituted for ninhydrin.

Examples 1 to 4 were sprayed onto a paper having a latent fingerprint at a distance of about 30 cm, and the amino acid reagent in the fingerprint developing spray adhered to the surface of the paper in the form of fine particles, and Examples 1 to 3 immediately showed a clear blue-violet color. Fingerprint lines; and after spraying in Example 4, it is irradiated by a multi-band light source or the like to form a clear fluorescent fingerprint. Therefore, it can be confirmed that the fingerprint developing spray of the present invention can effectively display latent fingerprints.

As described above, the present invention fully complies with the three requirements of the patent: novelty, advancement, and industrial applicability. In terms of novelty and advancement, the present invention employs a dispersing agent and a propellant to make it convenient and good in fingerprinting, and to reduce the use of toxic chemicals that pollute the environment, and achieve low cost and no cost. The purpose of polluting the sample is to achieve the purpose of the technical field applicable to latent fingerprint detection; in terms of industrial availability, the products derived from the present invention can fully satisfy the needs of the current market.

The invention has been described above in terms of the preferred embodiments, and it should be understood by those skilled in the art that the present invention is not intended to limit the scope of the invention. It should be noted that variations and permutations equivalent to those of the embodiments are intended to be included within the scope of the present invention. Therefore, the scope of the invention is defined by the scope of the following claims.

Claims (10)

A fingerprint developing spray comprising: (A) 1 to 10 parts by weight of an amino acid reactant; (B) 5 to 30 parts by weight of the total weight of the components (A), (B) and (C) And (C) 50 to 150 parts by weight of a propellant. The fingerprint developing spray according to claim 1, wherein the amino acid reactant is ninhydrin or an analogous thereof. The fingerprint-exposure spray of claim 2, wherein the ninhydrin homolog is 5-methylthioninhydrin. The fingerprint developing spray according to claim 1, wherein the amino acid reactant is DFO (1,8-diazafluoren-9-one) and 1,2-dihydroindoledione (1,2- Indandione) or its homologues. The fingerprint developing spray according to claim 4, wherein the 1,2-dihydroindoledione homolog is 5-methoxy-1,2-dihydroindoledione (5-methoxy-1). , 2-indanedione) or 5,6-dimethoxy-1,2-indanedione. The fingerprint developing spray according to claim 1, wherein the dispersing agent is an alcohol, an ether, an acid, an ester, a ketone, an aliphatic hydrocarbon or an aromatic hydrocarbon. The fingerprint developing spray according to claim 1, wherein the propellant is liquefied petroleum gas (LPG). The fingerprint-exposure spray of claim 7, wherein the propellant further comprises dimethyl ether, compressed air, carbon fluorocarbon gas, carbon dioxide or nitrogen. A method of visualizing a fingerprint using a fingerprint developing spray according to any one of claims 1 to 8. The method of claim 9, further using a vacuum metal plating method to enhance the fingerprint development effect.