• Korean Journal of Optics and Photonics
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• v.31 no.3
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• pp.125-133
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• 2020

An innovative method for separating overlapping latent fingerprints, using laser-induced plasma spectroscopy (LIPS) combined with multivariate analysis, is reported in the current study. LIPS provides the capabilities of real-time analysis and high-speed scanning, as well as data regarding the chemical components of overlapping fingerprints. These spectra provide valuable chemical information for the forensic classification and reconstruction of overlapping latent fingerprints, by applying appropriate multivariate analysis. This study utilizes principal-component analysis (PCA) and partial-least-squares (PLS) techniques for the basis classification of four types of fingerprints from the LIPS spectra. The proposed method is successfully demonstrated through a classification example of four distinct latent fingerprints, using discrimination such as soft independent modeling of class analogy (SIMCA) and partial-least-squares discriminant analysis (PLS-DA). This demonstration develops an accuracy of more than 85% and is proven to be sufficiently robust. In addition, by laser-scanning analysis at a spatial interval of 125 ㎛, the overlapping fingerprints were separated as two-dimensional forms.

• Analytical Science and Technology
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• v.29 no.3
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• pp.142-153
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• 2016

In crime scene investigation, fingerprint identification is regarded to be one of the most important techniques for personal identification. However, objective and unbiased evaluation methods that would compare the fingerprints with diverse available and developing methods are currently lacking. To develop an objective and quantitative method to improve fingerprint evaluation, a preliminary study was performed to extract useful research information from the analysis with densitometric image analysis (CP Atlas 2.0) and the Automated Fingerprint Identification System (AFIS) for the developed fingerprints on porous surfaces. First, inked fingerprints obtained by varying pressure (kg.f) and pressing time (sec.) to find optimal conditions for obtaining fingerprint samples were analyzed, because they could provide fingerprints of a relatively uniform quality. The extracted number of minutiae from the analysis with AFIS was compared with the calculated areas of friction ridge peaks from the image analysis. Inked fingerprints with a pressing pressure of 1.0 kg.f for 5 seconds provided the most visually clear fingerprints, the highest number of minutiae points, and the largest average area of the peaks of the friction ridge. In addition, the images of the developed latent fingerprints on thermal paper with the iodine fuming method were analyzed. Fingerprinting condition of 1.0 kg.f/5 sec was also found to be optimal when generating highest minutiae number and the largest average area of peaks of ridges. Additionally, when the concentration of ninhydrin solution (0.5 % vs. 5 %) was used to compare the developed latent fingerprints on print paper, the best fingerprinting condition was 2.0 kg.f/5 sec and 5 % of ninhydrin concentration. It was confirmed that the larger the average area of the peaks generated by the image analysis, the higher the number of minutiae points was found. With additional tests for fingerprint evaluation using the densitometric image analysis, this method can prove to be a new quantitative and objective assessment method for fingerprint development.

• Analytical Science and Technology
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• v.30 no.5
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• pp.279-286
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• 2017

Determination of the order of latent fingerprints deposition on the surface of thermal paper, often found in crime scenes, is related to the study of time course and aging of fingerprints and can provide additional information in criminal investigations. A preliminary study was performed to determine the deposition order of fingerprints left with two different conditions of deposition pressure and time (in seconds) after 1 day intervals for 7 days on thermal paper (receipt and fax thermal paper) using an iodine fuming method. The resultant images of the visualized fingerprints were analyzed with densitometric image analysis to measure the changes in the areas of the ridges, which can be correlated to the deposition order. No significant variation was found with the different types of thermal paper. The average areas of the friction ridges increased gradually or were similar to the values from day 1 for 3 days, and then a continual decrease was shown from day 4 through day 7. The area values from day 6 and day 7 were less than half of those from day 1. Furthermore, the test with overlapped fingerprints showed the possibility of differentiation between fingerprints that are 1-3 and 6-7 days old based on the clarity visible to the naked eye. Additional experiments with the deposition conditions can prove that the current method is valuable for the determining the order of fingerprint deposition on thermal paper.

• Analytical Science and Technology
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• v.20 no.4
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• pp.339-346
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• 2007

To search the ninhydrin derivatives that have high chromogenic and fluorogenic properties, molecular holographic quantitative structure property relationship (HQSPR) models on the reactivity between glycine and ninhydrin analogues as latent fingerprint detector were derived and investigated quantitatively. The ${\varepsilon}LUMO$ (e.v.) energy of ninhydrin molecule was an important factor to reactivity of ninhydrin. And, it is suggested that the nucleophilic reaction by orbital-controlled reaction from the frontier molecular orbital (FMO) interaction between glycine and ninhydrin derivatives was more superior than that of electrophilic reaction by charged controlled reaction. The analytical results in atomic contribution maps also shows that the reactivity of ninhydrin was increased by meta-substituents as strong electron withdrawing groups on the benzo ring. Therefore, it is sugested by HQSPR and QSPR model that the 5,6-dinitroninhydrin molecule would increase the reactivity as much as three times as compared to none substituted ninhydrin molecule.

• Nano
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• v.13 no.11
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• pp.1850128.1-1850128.10
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• 2018

Glutathione (GSH), the protective agent and reducing agent, has been widely used to prepare gold nanoclusters (GSH-Au NCs) with stable fluorescence properties and negative charge of the surface. Meanwhile, polyethyleneimine (PEI) was used as the modification agent to synthesize magnetic ferroferric oxide nanoparticles ($Fe_3O_4$) with fantastic dispersibility and positive charge of the surface. Based on the electrostatic adsorption force, magnetic nano-$Fe_3O_4@GSH-Au$ NCs core-shell microspheres composed of magnetic $Fe_3O_4$ nanoparticles modified by PEI as the core and GSH-Au NCs as the shell were assembled. The prepared $Fe_3O_4@GSH-Au$ NCs microspheres harbored a uniform size (88.6 nm), high magnetization (29.2 emu/g) and excellent fluorescence. Due to the coordination bond action between Au atom and sulfhydryl (-SH), amino ($-NH_2$), carboxyl (-COOH) in sweat, $Fe_3O_4@GSH-Au$ NCs could combine with latent fingerprints. In addition, $Fe_3O_4@GSH-Au$ NCs with good fluorescence and magnetism could detect fingerprints on various objects. Significantly, the powders were not easy to suspend in the air, which avoided the damage to the health of forensic experts and the fingerprints by only powder contacting. Above all, $Fe_3O_4@GSH-Au$ NCs was successfully applied to the latent fingerprint visualization, which has great potential in forensic science.

• Analytical Science and Technology
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• v.33 no.3
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• pp.159-166
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• 2020

Vacuum metal deposition (VMD) is effective to develop latent fingerprints on non-porous and semi-porous surfaces. VMD can be used in cases when fingerprints that can not be developed by generalized techniques or deposited on difficult surfaces. The recommended surfaces for VMD techniques include vinyl, polymer bills, magnetic coated tickets, etc. In this study, the minimum amount of gold input was explored for developing fingerprints from at least 12 hours to up to 28 days after deposit fingerprint on the pink high density polyethylene envelope (HDPE) and low density polyethylene envelope (LDPE), which are mainly used as delivery envelopes. And the results were compared with the effects of black powder and fluorescent powder. In addition, delivery envelopes used for delivery were collected, then classified as HDPE and LDPE and pseudo-operation test was performed. As a result, VMD method developed good quality of fingerprints.

• Analytical Science and Technology
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• v.35 no.3
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• pp.129-135
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• 2022

We tested the pre-treatment of alumina, leucine, alumina mixed with leucine at ratios of 9:1 (Al-Leu (9:1)) and 5:1 (Al-Leu (5:1)), and alumina mixed with sodium lactate at a ratio of 5:1 (Al-Lac (5:1)) on aged fingerprints (1, 7, 14, and 30 days after natural fingerprinting) before cyanoacrylate (CA) fuming to improve the development efficacy. As a result of the experiment, fingerprints with pre-treatment of alumina, leucine, Al-Leu (9:1), Al-Leu (5:1), and Al-Lac (5:1) showed better development efficacy (area and minutiae) than fingerprints without pre-treatment. Therefore, this modified CA fuming method improved the development efficacy with five pretreatments.

• Analytical Science and Technology
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• v.34 no.3
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• pp.122-127
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• 2021

A mixture of polyvinylpyrrolidone and 1,2-indanedione (PVP-IND) is known to be the best reagent for developing latent fingerprints deposited on the surface of a thermal paper. However, no study has evaluated whether PVP-IND could enhance fingerprints in blood deposited on the surface of thermal paper. Therefore, in this study, the ability of PVP-IND to enhance the fingerprints in blood was investigated. Furthermore, aqueous amido black solution, which is known to be the best reagent for enhancing fingerprints in blood deposited on the surface of thermal paper, was used for comparison with PVP-IND. Therefore, while enhancing the fingerprints in diluted blood, PVP-IND enhanced the quality of fingerprints compared to aqueous amido black solution. The ridge diffused when the undiluted fingerprints in blood were enhanced with PVP-IND because PVP reacted with amino acids in blood; however, amido black solution yielded better results. When treated with PVP-IND, it is presumed that the ridge diffused due to the reaction of PVP and amino acids contained in the blood.

• The Journal of the Korea Contents Association
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• v.20 no.11
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• pp.333-341
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• 2020

Since thermal paper is widely used in daily life such as convenience store receipts, lottery tickets and ATM receipts, it is important to develop fingerprints on thermal papers because it can be easily found in crime scenes. This study compared the ability of fingerprint development between vacuum metal deposition(VMD) and 1,2-indanedione(SOON-100) in order to evaluate the effectiveness of VMD, which some literatures have stated to be effective in thermal papers. As a result, in the case of SOON-100, clear ridges of fingerprints that enable individual identification were observed after an hour of deposition, although the fresh fingerprints were faint. In the case of VMD, the fingerprints gradually spread and the quality of the ridges deteriorated rapidly after 6 hours of deposition. This results is consistent with the principle of VMD. Considering the principles of VMD and the characteristics of the surface of thermal paper, VMD is not suitable for the development of potential fingerprints on the thermal paper.

• Analytical Science and Technology
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• v.27 no.3
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• pp.147-152
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• 2014

RUVIS(Reflective Ultraviolet Imaging System) is an effective equipment that detects the location of latent fingerprint at crime scene using short wavelength ultraviolet of 254 nm. In this study, the degree of DNA damage in biological samples was compared depending on the distance and time of processing using four commonly used RUVIS. 50% of DNA was damaged by treating 10 seconds at 10 cm distance in 3 types of RUVIS such as Police RUVIS, SIRCHIE mini light and SIRCHIE RUVIS. In addition, the degree of DNA damage was increased as the distance was closer and the treatment time was longer. It showed that short wavelength UV could cause DNA damage when used close to the samples at crime scene. Therefore, it was suggested to use RUVIS at a distance of at least 1 m. The degree of DNA damage was not significant by Polilight which used long wavelength ultraviolet of 350 nm. As a result, the choice and usage of which UV light and RUVIS were critical for detection of fingerprint and successful DNA typing.