JP2003061937A - Fingerprints detecting liquid and preparing method for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fingerprints detecting liquid capable of clearly coloring latent fingerprints, not exerting any influence upon thermal recording paper where it is difficult to detect fingerprints, and giving no damage to influential information other than the fingerprints on normal paper, and to provide a preparing method for the fingerprints detecting liquid and a fingerprints detecting method using the fingerprints detecting liquid. SOLUTION: The preparing method for the fingerprints detecting liquid is formed by mixing nonionic detergent in which ninhydrin is dissolved and hydrochlorofluorocarbons, hydrofluorocarbons, or hydrofluoroeters. Further, the fingerprints detecting method using the fingerprints detecting liquid is provided.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a ninhydrin-containing fingerprint detection solution for detecting a latent fingerprint from a specimen containing a fingerprint, a method for preparing the fingerprint detection solution, and the fingerprint detection solution in the field of identification technology. The present invention relates to a fingerprint detection method used.

[0002]

2. Description of the Related Art Conventionally, as a fingerprint detection method, 1) aluminum-based silver powder, copper-based gold powder, carbon-based black powder, or other white powder or colored powder is used for secretion attached to a specimen. A method in which the powder is adhered to water and fat in the substance and detection is performed by utilizing the hue difference between the background color of the sample and the color of the powder, 2) the fat in the secretion is iodine after drying the sample. There is known a method of detecting the color by reacting it with a gas and coloring it.

As a conventional method for detecting a fingerprint attached to paper or the like, 3) a method of applying ninhydrin is generally used. This utilizes the fact that amino acids contained in human sweat react with ninhydrin to develop a purple color. To detect fingerprints on plain paper such as newsprint, report paper or fine paper,
Dip the plain paper with fingerprints in a ninhydrin solution using an organic solvent such as ketones or alcohols, brush the plain paper with the solution, or spray the solution onto the plain paper to apply it evenly. The plain paper is impregnated with a sufficient amount of the solution through a procedure such as, and then the color reaction is promoted by performing a heat treatment.

According to the method using ninhydrin of 3) above, fingerprints can be clearly detected without bleeding, but the following problems are recognized. That is, ninhydrin dissolves in polar solvents such as alcohols and ketones, but does not dissolve in ordinary hydrocarbons. Therefore, in the method using ninhydrin, ninhydrin is dissolved in a hydrocarbon such as a polar organic solvent or a petroleum fraction mixed with the polar organic solvent, and a fingerprint detection solution prepared based on the ninhydrin is used. It will be.

Since the polar organic solvent is used, when characters are written on plain paper with an oil-based ballpoint pen or the like, not only does the organic solvent adversely affect the detection of fingerprints, but also other than fingerprints such as handwriting verification. It will also damage the powerful information that should be obtained. Further, in the case of paper such as heat-sensitive paper, alteration due to polar organic solvent or heat occurs, and the surface is immediately discolored blackish, which makes it difficult to detect fingerprints. In this way, with the conventional method using ninhydrin, it is difficult to detect fingerprints in the case of paper such as thermal paper, and in the case of plain paper, it is possible to obtain useful information other than fingerprints such as handwriting verification. It could be damaged.

Further, in the above method 3) using a polar organic solvent or hydrocarbon, the solvent has a flash point, which may interfere with the fingerprint detection operation involving heating in air. .

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and provide a ninhydrin-containing fingerprint detecting solution which can be easily used for detecting latent fingerprints of plain paper or thermal paper. Another object of the present invention is to provide a method capable of efficiently preparing the fingerprint detection solution. Still another object of the present invention is to provide an effective fingerprint detection method that does not have a flash point-based problem.

[0008]

[Means for Solving the Problems] Hydrochlorofluorocarbons, which are problem-free solvents based on the flash point,
Although there are fluorine-containing organic solvents such as hydrofluorocarbons and hydrofluoroethers, ninhydrin is not dissolved in the fluorine-containing organic solvent at a concentration sufficient for fingerprint detection. Therefore, when the fluorine-containing organic solvent is used, it is necessary to use together with other additive components capable of dissolving ninhydrin.

The present inventors (a) that the above-mentioned fluorine-containing organic solvent does not affect the characters written on plain paper.
(B) The fluorinated organic solvent hardly dissolves ninhydrin, but it can be dissolved at a sufficient concentration by using a nonionic surfactant as an additive component, and (c) contains the nonionic surfactant. It has been found that the fluorine-containing organic solvent does not affect the thermal paper and does not damage the powerful information other than the fingerprint even in the case of plain paper.

The present invention has been completed based on the above findings,
(1) Contain at least one fluorine-containing organic solvent (A) selected from the group consisting of hydrochlorofluorocarbons, hydrofluorocarbons and hydrofluoroethers, ninhydrin (B) and a nonionic surfactant (C) A fingerprint detection solution is provided. Further, the present invention provides (2) at least one selected from the group consisting of hydrochlorofluorocarbons, hydrofluorocarbons and hydrofluoroethers, and a nonionic surfactant (C) in which ninhydrin (B) is dissolved. There is provided a method for preparing a fingerprint detection solution, which is characterized by mixing with the fluorine-containing organic solvent (A). Furthermore, the present invention provides (3) a fingerprint detection method using the solution for fingerprint detection of (1) above. (3) The fingerprint detecting method of the present invention comprises: (3-1) immersing the subject in the fingerprint detecting solution according to (1) above;
(3-2) The method of immersing the subject in the solution for fingerprint detection of (1) above, and then further immersing the subject in the fluorine-containing organic solvent of (A), or (3-3) )
The method is characterized in that the solution for fingerprint detection described in (1) is sprayed onto a subject.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The fluorine-containing organic solvent (A) in the present invention is at least one selected from the group consisting of hydrochlorofluorocarbons, hydrofluorocarbons and hydrofluoroethers.

The above-mentioned hydrochlorofluorocarbons are compounds containing hydrogen atoms, chlorine atoms, fluorine atoms and carbon atoms, and are liquid compounds at room temperature.
The carbon number of the hydrochlorofluorocarbons is 2
6, especially 2-4 is preferable. Specific examples of the hydrochlorofluorocarbons are not particularly limited and various examples can be given. 3,3-dichloro-1,1,1,2,2-pentafluoropropane, 1,3-dichloro-1,1,
2,2,3-pentafluoropropane, and 1,1-
It is preferably at least one selected from the group consisting of dichloro-1-fluoroethane.

The hydrofluorocarbons are compounds containing a hydrogen atom, a fluorine atom and a carbon atom,
Moreover, it is a liquid compound at room temperature. The hydrofluorocarbons preferably have 4 to 8 carbon atoms, and particularly preferably 4 to 6 carbon atoms.
Specific examples of the hydrofluorocarbons are not particularly limited and various examples can be given. 1,1,1,3,3-pentafluorobutane, 1,1,1,2,2,3,4
5,5,5-decafluoropentane, 1,1,1,2,
At least 1 selected from the group consisting of 2,3,3,4,4,5,5,6,6-tridecafluorohexane and 1,1,2,2,3,3,4-heptafluorocyclopentane It is preferably a seed.

The hydrofluoroethers are ether compounds containing hydrogen atoms, fluorine atoms, carbon atoms and oxygen atoms, and are liquid compounds at room temperature.
As the hydrofluoroethers, polyfluoroalkyl (alkyl) ethers are preferable, and the carbon number thereof is preferably 3 to 12, and particularly preferably 4 to 10. Specific examples of the hydrofluoroethers are not particularly limited, and can be variously exemplified, but (perfluorobutoxy) methane, (perfluorobutoxy) ethane, 1-ethoxy-1,1,
It is preferably at least one selected from the group consisting of 2,2-tetrafluoroethane.

In the present invention, the fluorine-containing organic solvent (A) containing a nonionic surfactant (C) (hereinafter,
Sometimes referred to as NSF-containing solvent. ) Is important. By using the NSF-containing solvent, the ninhydrin (B) can be dissolved at a sufficient concentration, and the latent fingerprint can be clearly colored by the obtained fingerprint detection solution.
Further, the solution for fingerprint detection of the present invention does not affect the thermal paper even though it contains the nonionic surfactant, and even in the case of plain paper, it damages important information other than the fingerprint. Absent.

As the nonionic surfactant (C) in the present invention, a) alkyl or alkylallyl polyoxyethylene ether, alkylallyl formaldehyde condensed polyoxyethylene ether, glycerin ether or its polyoxyethylene ether, polyoxypropylene. A block polymer having a lipophilic group,
Ether type such as alkylthiopolyoxyethylene ether, b) polyoxyethylene ether of propylene glycol ester, polyoxyethylene ether of glycerin ester, ether ester type of sorbitan ester such as polyoxyethylene ether, c) polyoxyethylene fatty acid ester, Examples thereof include ester type such as glycerin ester and sorbitan ester, d) nitrogen-containing type such as fatty acid alkanolamide and polyoxyethylene fatty acid amide, and e) fluorinated fluorine-containing type of the above a) to d).

The content of the nonionic surfactant (C) in the fingerprint detection solution of the present invention (hereinafter sometimes simply referred to as the total solution) is not particularly limited, but 1 k of the total solution is used.
100-100,000 mg per g is preferred. By adopting the content within the range, the ninhydrin (B) can be uniformly dissolved or dispersed in the entire solution, it does not take a long time to dry at the time of fingerprint detection, and further, the fingerprint Does not reduce clarity.

The content of the ninhydrin (B) in the fingerprint detection solution of the present invention is not particularly limited, but it is preferably 100 to 10,000 mg per kg of the total solution. By setting the content of the ninhydrin (B) within the above range, the latent fingerprint can be vividly colored, and the coloration of the fingerprint can be accelerated.

In the present invention, in order to further increase the solubility of ninhydrin (B), another polar organic solvent can be added at a concentration that does not discolor the thermal paper and does not affect the handwriting written with ink or the like. Examples of other polar organic solvents include ketones and alcohols, and the addition amount thereof is preferably 5,000 mg or less per 1 kg of the total solution,
It is particularly preferably 500 mg or less. It is desirable that the fingerprint detection solution of the present invention usually does not contain other polar organic solvent.

Ninhydrin (B) is almost insoluble in the above-mentioned fluorine-containing organic solvent (A), but is soluble in the nonionic surfactant (C). In the present invention, a nonionic surfactant (C) in which ninhydrin (B) is dissolved
And a method for preparing a fingerprint detection solution, which comprises mixing at least one fluorine-containing organic solvent (A) selected from the group consisting of hydrochlorofluorocarbons, hydrofluorocarbons and hydrofluoroethers, The fingerprint detection solution of the present invention can be efficiently prepared.

As a method of detecting a fingerprint using the fingerprint detecting solution of the present invention (hereinafter sometimes simply referred to as the solution), a test object such as a thermal paper to which the fingerprint is attached is immersed in the solution. Examples include a method, a method of applying the solution to a subject with a brush or the like, a method of uniformly applying the solution to the surface by spraying such as a spray, and the like. (3-1) Immersing the subject in the solution (3-2) After immersing the subject in the solution, further immersing the subject in the fluorinated organic solvent (A), or (3-3) A method characterized by spraying the solution onto a subject is desirable.

In the dipping methods (3-1) and (3-2), a method is used in which a sample such as a thermal paper having fingerprints is dipped in the solution and then pulled up and dried. Immersion time of about 5 to 30 seconds is sufficient. It may take time to dry depending on the material of the subject. In that case, it is desirable to adopt the method of (3-2). For example, the test sample is dipped in the solution, pulled up, dipped in the fluorine-containing organic solvent (A), and then dried. It is possible to adopt the method of making. The (3
By the method (2), the nonionic surfactant (C) remaining on the surface of the non-analyte can be removed.
According to the method (3-2), it is possible to shorten the drying time of the specimens and eliminate the adhesion between the specimens.

Further, it is desirable to adopt the spraying method of (3-3) above for a subject that cannot be immersed in the fingerprint detection solution. For example, the solution can be evenly sprayed onto the subject. It is possible to adopt a method of applying to.

Further, by heating the subject, it is possible to shorten the time until the fingerprint is developed. However,
In the case of thermal paper, the heating temperature is set to 40 to prevent discoloration.
It is necessary to adjust the temperature up to about 60 ° C.

[0025]

EXAMPLES In each of the following examples, as the nonionic surfactant (C), a liquid nonionic surfactant such as Sunmor DB-40 (trade name: manufactured by Nika Chemical Co., Ltd. It is referred to as a mall.). Further, as the fluorine-containing organic solvent (A), 3,3-dichloro-1,1,1,2,
2-pentafluoropropane (hereinafter referred to as R225A), 1,3-dichloro-1,1,2,2,3-pentafluoropropane (hereinafter referred to as R225B),
1,1-dichloro-1-fluoroethane (hereinafter, R14
Write 1. ), 1,1,1,3,3-pentafluorobutane (hereinafter referred to as R365), 1,1,1,2,
2,3,4,5,5,5-decafluoropentane (hereinafter referred to as R4310), 1,1,1,2,2,3
3,4,4,5,5,6,6-tridecafluorohexane (hereinafter referred to as R5213), 1,1,2,2
3,3,4-heptafluorocyclopentane (hereinafter, R
It is described as 447. ), (Perfluorobutoxy) methane (hereinafter, referred to as R449), (perfluorobutoxy) ethane (hereinafter, referred to as R569), 1-ethoxy-1,1,2,2-tetrafluoroethane (hereinafter, referred to as R569). R5
It is written as 74. ), Or a mixed solvent of R225A / R225B in a mass ratio of 50/50 (hereinafter referred to as R225).
Was used.

[Examples 1 to 11] 0.6 g of ninhydrin was dissolved in 10 g of sunmol, and a fluorine-containing organic solvent shown in Table 1 below was added to make a total amount of 150 g. Fingerprints were detected from the thermal paper receipts at the cash register of a retail store. The fingerprint detection solution had a nonionic surfactant content of about 67,000 mg and a ninhydrin content of 4,000 mg per 1 kg of the total solution. The receipt with the fingerprint attached was dipped in the solution for fingerprint detection at room temperature for 10 seconds, pulled up, and then kept at 50 ° C. for 2 hours.

Table 1 shows the results obtained by visually observing the color development of the fingerprint and the color change of the thermal paper of the receipt after the color development of the fingerprint. The evaluation results in the table are represented by ◎: dark and clear, ○: clear, Δ: light color, ×: unrecognizable for fingerprint color development, and ○: no change, Δ: for thermal paper discoloration. A slight darkening is seen, and the color is represented by x: discoloration to black.

[0028]

[Table 1]

[Example 12] 10 g of sunmol at about 22 ° C
When 0.6 g of ninhydrin was added to and stirred,
The ninhydrin was immediately dissolved and completely dissolved after about 1 minute. R22 is added to the sunmol in which ninhydrin is dissolved.
When 5 was added so that the total amount was 150 g, it immediately and uniformly dissolved. On the other hand, 139.4g of R225 is 10
When g of Sanmol was mixed, it immediately and uniformly dissolved. When 0.6 g of ninhydrin was added to the obtained solution and stirred, ninhydrin was not completely dissolved 45 minutes after the start of stirring, and it was completely dissolved after about 1 hour. The same fingerprint detection as in Example 11 was performed using the fingerprint detection solution prepared by the above two methods. In the case of any of the solutions for fingerprint detection, the same results as in Example 11 were obtained with respect to the color development of the fingerprint and the color change of the thermal paper.

Example 13 A solution for fingerprint detection was prepared by adding 0.6 g of ninhydrin to 15 g of sunmol and mixing them, and further adding R225 to a total amount of 150 g. Fingerprints were detected in the same manner as in Example 10.
However, the specimen was immersed in the solution and dried at room temperature of about 22 ° C. As a result, even after 2 hours of drying, the thermal paper receipt of the register of the grocery retail store, which is the subject, was in a wet state, and was attached when the subjects were brought into contact with each other. On the other hand, after immersing the subject in the same fingerprint detection solution as described above,
When the sample was immersed in R225 for 10 seconds and pulled up without performing the drying operation, the sample was dried in about 1 minute and no adhesion between the samples was observed. The above two fingerprint detection methods gave the same results as in Example 11 with respect to both the color development of the fingerprint and the color change of the thermal paper after 4 hours of immersion in the solution for fingerprint detection.

[Examples 14 to 24] Using the fluorine-containing organic solvents shown in Table 2 below, solutions for fingerprint detection were prepared in the same manner as in Examples 1 to 11. Using each fingerprint detection solution, a thermal paper receipt of a register of a grocery store to which fingerprints are attached is used as a test object, and the solution is sprayed onto the test object to evenly wet the surface of the test object, and the temperature is kept at 50 ° C. for 3 days. I kept it warm for an hour. Example 1
The results of fingerprint detection similar to those in Example 11 are shown in Table 2 below.
Shown in.

[0032]

[Table 2]

[0033]

According to the fingerprint detecting solution of the present invention, it is possible to detect a fingerprint attached to a thermal paper such as a receipt, which has conventionally been difficult to detect a latent fingerprint. The detected fingerprints are clear enough to be observed with the naked eye, and there is no obstruction due to discoloration of the print or disappearance of evidence of police investigation due to the disappearance of the print. Further, the solution for fingerprint detection of the present invention can be easily prepared in a short time, and the fingerprint can be quickly dried even when detecting fingerprints.

Claims (8)

[Claims] 1. At least one fluorine-containing organic solvent (A), ninhydrin (B) and nonionic surfactant (C) selected from the group consisting of hydrochlorofluorocarbons, hydrofluorocarbons and hydrofluoroethers. A solution for fingerprint detection, comprising: 2. A hydrochlorofluorocarbon is
3,3-dichloro-1,1,1,2,2-pentafluoropropane, 1,3-dichloro-1,1,2,2,3-
Pentafluoropropane and 1,1-dichloro-1-
The fingerprint detection solution according to claim 1, which is at least one selected from the group consisting of fluoroethane. 3. Hydrofluorocarbons are 1,1,
1,3,3-pentafluorobutane, 1,1,1,2,
2,3,4,5,5,5-decafluoropentane, 1,
1,1,2,2,3,3,4,4,5,5,6,6-tridecafluorohexane and 1,1,2,2,3
The fingerprint detection solution according to claim 1, which is at least one selected from the group consisting of 3,4-heptafluorocyclopentane. 4. The hydrofluoroether is at least one selected from the group consisting of (perfluorobutoxy) methane, (perfluorobutoxy) ethane and 1-ethoxy-1,1,2,2-tetrafluoroethane. The solution for fingerprint detection according to claim 1, 2 or 3. 5. A nonionic surfactant (C) in which ninhydrin (B) is dissolved, and at least one selected from the group consisting of hydrochlorofluorocarbons, hydrofluorocarbons and hydrofluoroethers.
A method for preparing a fingerprint detection solution, which comprises mixing a fluorine-containing organic solvent (A) as a seed. 6. A fingerprint detecting method comprising immersing a subject in the fingerprint detecting solution according to claim 1. 7. At least one selected from the group consisting of hydrochlorofluorocarbons, hydrofluorocarbons and hydrofluoroethers after the subject is immersed in the solution for fingerprint detection according to claim 1. A fingerprint detecting method comprising immersing the subject in a fluorine-containing organic solvent (A). 8. A fingerprint detecting method, which comprises spraying the fingerprint detecting solution according to claim 1 onto a subject.