DYE DOPED SILICA NANOPARTICLES AS NOVEL AGENT FOR DEVELOPING LATENT FINGERPRINTS Sagar Bhowmik, Harsad Patel Institute of Research and Development, Gujarat Forensic Sciences University, Gandhinagar, Gujarat
ABSTRACT Nanotechnology contributes to forensic sciences in different ways. Since it can detect and analyze samples in the nanoscale, critical evidence that could not be collected and analyzed before. The development of latent fingerprint is one of the critical evidence of the forensic investigations. There are various methods of development of latent fingerprints. The present research presents a new nanotechnology based powder method for the development of latent fingerprint. In this study, various dyes doped silica nanoparticles have been used to develop the latent fingerprints on commonly encountered different surfaces i.e., glass, aluminum foil, paper. It is observed that these silica nanoparticles are capable to develop fingerprints on most of the substrates with clear ridge characteristics. Here, Rhodamine B doped silica nanopowder was synthesis via sol-gel route and used for the development of latent finger print. Keywords :- Latent Fingerprint, Rhodamine B, sol-gel method.
INTRODUCTION Nanotechnology have found potential applications in various fields. In case of the forensic sciences, the applications have been more widely available for the purpose of the justice administration. This is useful in the different specialties of forensic sciences. To mention a few, they are useful in fingerprints, biological applications and explosives detection. However, nanotechnology is promising to have a major impact with the latest developments in the identification of latent fingerprints. Latent fingerprints are deposits left by a combination of excretions from the sweat and sebaceous glands in the skin. They are invisible and require the use of optical techniques or, more commonly, development agents such as powders to reveal the print. Materials such as carbon black and aluminium flake have been used as latent fingerprint developers for many years as it was found that they worked well under particular circumstances, but there has been minimal activity in developing engineered materials specifically designed for fingerprint development. The ideal fingerprint powder will stick to the residues left by the finger, which give rise to the characteristic patterns that everyone identifies as a fingerprint, but not stick to anything else. Many common materials also stick to the background, making a clear identification significantly harder to achieve. Nanotechnology is being used to engineer particles to overcome this problem. In this study an attempt has been made to apply the synthesized nanopatrticles for the detection and development of latent prints. The flexible synthetic process described for preparation of developing agents as latent fingerprints represents an opportunity to expand application of nanopowders; the process is cost effective, being simple to conduct and employing cheap materials
MATERAILS AND METHOD The Tetraethoxyorthosilicate(TEOS) and Ethanol(99.5%) were purchased from Merck India Pvt. Ltd. The purity of the TEOS is 97%.Polyethylene glycol 600(PEG-600) and Hydrochloric Acid purchased from Finar Ltd. Rhodamine B purchased from Sigma-Aldaich Ltd. which has 95% of purity level.
FT-IR Analysis
. RESULTS AND DISSCUSSION Measurement of Silica NPs by using Particle Size Analyzer
FT-IR spectra of sol-gel derived silica nanoparticles
Synthesis of Dye doped Silica Nanoparticles
Wave number (cm-1)
Types of stretch
3586.95
O-H
1114.65
Si-O-Si
TEOS+ Et(OH) Add water (Drop wise) pH=2-3 Hydrolysis Vigorous stirring for 20 hrs.
UV-VIS spectrophotometer analysis FT-IR spectra of Rhodamine B doped silica nanoparticles
Gelation
Highly viscous transparent gel
Washing with ethanol
Drying at RT
UV-Vis spectra of Rhodamine B doped Silica NPs
Wave number (cm-1)
Types of stretch
3498.24
O-H
1646.91
C=O
1546.63
COO-
1419.35, 2946.70
C-H
Development of Fingerprints with Rhodamine B doped Silica Nano powder
Heat treatment at 600o C
EDXRF Elemental analysis of Si NPs Grinding of SiO2 NPs
Suspend in 100 ml of water
5% Dye Doped
Quantitative Result -----------------------------------------------------------------------------------Analyte Result -----------------------------------------------------------------------------------Si 99.893 % Sm 0.107 %
On ceramic surface with white light
On ceramics surface with UV light
Wooden Surface with UV light
CONCLUSION
Drying at 70o C
Dye Doped SiO2 NPs
Characterization of Silica Nanoparticles Characterization of nanoparticles done through Particle size analyzer (Malvern ZS-nano), UV-Visible Spectrometer (V630JASCO), FT-IR (4100 JASCO), EDXRF (Shimadzu), Fluorescence Microscopy etc.
Development of latent Fingerprint The general powder dye brushing technique for development of latent print was used to developed the fingerprint using silica nano powder doped with different dyes. These fingerprints surface were exposed with the UV light source(320-400nm).
Optical photograph of prepared dye doped silica nanoparticles.
These nanotechnology based techniques are beginning to be evaluated and used by police forces and other law enforcement agencies. It is due to the nanoscale properties of the materials that the new techniques are able to provide either improved performance over existing materials or enable information to be gleaned from a crime scene that would not otherwise have been possible. It is heartening to know that nanotechnology has the potential to make a positive social contribution in an area it is not normally associated with, by helping to solve more crimes. Sol-gel techniques is found to be easy and cost effective synthesis route for development of RhB-SiO2 NPs. The fingerprint development by nanopowder was very encouraging. It is concluded from the present investigation that silica powder combined with Rhodamine B dyes, can be used to develop the fingerprint on different surfaces and give equivalent results as those of the conventional powders. It can provide a good substitute for fingerprint visualization in comparison particularly to other powders, under the instances of scarcity
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