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Fingermarks detection by eosin-blue dye
Forensic Science International 115 (2001) 69±71
Fingermarks detection by eosin-blue dye G.S. Sodhia,*, J. Kaurb a
b
Department of Chemistry, S.G.T.B. Khalsa College, University of Delhi, Delhi 110007, India Rajguru College of Applied Sciences for Women, University of Delhi, Jhilmil Colony, Vivek Vihar, Delhi 110095, India Received 1 March 2000; received in revised form 10 May 2000; accepted 24 May 2000
Abstract Eosin-blue (I) dye, along with a phase transfer catalyst, has been used to detect latent ®ngerprints on a wide range of surfaces, including paper, glass, steel, lamination sheets, polythene, plastic and bakelite. # 2001 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Catalyst; Eosin-blue; Fingermarks
1. Introduction A latent ®ngerprint is formed when the sweat pores of the papillary ridges leave a deposit of perspiration on a surface with which the ®nger has been brought into contact [1]. Human body possesses the following three types of glands Ð viz. eccrine, apocrine and sebaceous, the secretions of which contribute to a ®ngerprint deposit [2]. Eccrine glands are widely distributed throughout the body and are particularly numerous on the palms of hands and the soles of feet. Chemicals are secreted by these glands as a result of general metabolism and catabolism. Besides water content, eccrine sweat contains up to 1% of the other substances of which inorganic salts constitute about one-half [3]. Amongst these, sodium and chloride are the most abundant ions, representing nearly 90 mM proportion. Potassium (5 mM), magnesium (0.4 mM), calcium (0.5 mM), sulphate (0.4 mM) and phosphate are also present, together with traces of iron, copper, manganese, iodide, bromide and ¯uoride. The other half is con*
Corresponding author.
stituted by organic products like amino acids, urea, creatinine, choline, lactic acid, sugars, and uric acid [4]. In addition, fatty acids are secreted by sebaceous glands. The constituents of the sweat may be selectively ®xed by different chemical reagents so as to make the latent ®ngerprints visible [5]. Various chemical reagents, such as silver nitrate, iodine and ninhydrin, are available for rendering visibility to latent prints. These reagents react with sodium chloride, fatty acid and amino acid contents, respectively, present in the sweat [6]. The powder technique of developing latent prints is the most common, but it works generally in the presence of moisture. This means that old prints developed by this method are not of optimum quality. Ninhydrin reagent may be used for developing prints as old as 15 years. However, ninhydrin gives good results after posttreatment of developed prints with zinc chloride followed by laser examination [7]. In an earlier communication [8], we devised a technique wherein the calcium content of sweat was ®xed with the help of a phase transfer catalyst. The successful development of ®ngermarks prompted us to try out the technique using a similar catalyst and
0379-0738/01/$ ± see front matter # 2001 Elsevier Science Ireland Ltd. All rights reserved. PII: S 0 3 7 9 - 0 7 3 8 ( 0 0 ) 0 0 3 0 7 - 8
70
G.S. Sodhi, J. Kaur / Forensic Science International 115 (2001) 69±71
eosin-blue reagent. The quality of developed ®ngermarks is comparable to the results obtained with other reagents, such as nitrobenzo-2-oxa-1,3-diazole [9], l,8-diaza¯uoren-9-one [10] and 1,2-indanediones [11].
2. Experimental The disodium salt of eosin-blue and t-tetrabutylammonium iodide were purchased from Aldrich, USA, and were used without further puri®cation. An aqueous solution containing 2.38±2.40% disodium eosin-blue and 1.25±1.30% t-tetrabutylammonium iodide was prepared in a measuring ¯ask. Over the next 1 h, the solution was periodically shaken. Alternately, it was stirred for about half an hour. This formulation was used for developing ®ngermarks on paper. For non-absorbent surfaces, an aqueous solution containing 0.31±0.35% disodium eosin-blue and 0.18± 0.20% t-tetrabutylammonium iodide was prepared. Small pieces (about 2 in.2 in.) of paper, lamination sheet, gift paper, adhesive tape, polythene or plastic surface, bearing sample latent prints, were immersed in the respective test solution for about 1 min. The paper sample was then dipped in distilled water. The other surfaces were dried with a hair dryer. For larger objects, such as polythene bottles, bakelite switches, glassware and stainless steel utensils, the test solution was sprayed onto the area containing the ®ngermark impression. The surface was dried with a hair dryer. Sharp and clear ®ngermarks developed. 3. Results Latent ®ngerprints developed by this method persist over a prolonged period of time. The impressions on
paper do not get distorted on rubbing and scratching. They can be developed over white or light coloured papers, except pink or red where the contrast with the background is low. Another limitation is that, on paper, impressions older than 1 week cannot be developed. This is probably due to the interaction of metal ions with the cellulose content of paper. However, on surfaces other than paper, prints have been obtained even after a lapse of 20±30 days. Good quality prints have been lifted from lamination sheets. Thus, the present method may be extended for obtaining ®ngerprints from laminated documents, such as archaeological scripts, certi®cates, driving licences and identity cards. Prints may also be developed on polythene bags Ð commonly used for carrying household items and polythene bottles Ð commonly used for storing household items. Normally, the cyanoacrylate fuming technique has to be employed to develop ®ngermarks on such surfaces [12]. However, the present method for rendering visibility to extent prints on a polythene surface is more convenient. Other surfaces on which an unscrupulous element is likely to leave his ®ngerprint impressions include glassware, steel handles and knobs, bakelite switches and switchboards and plastic table mats. The present technique of ®ngerprint detection gives good results on all these surfaces. 4. Discussion Although metal ions form a number of coloured complexes, but attempts to ®x these ions for developing ®ngermarks have been largely unsuccessful. The reason being that metal ions, after being deposited along the ridges, are converted into insoluble salts. Further reactions of these insoluble salts Ð if at all they occur Ð would be extremely slow to have a practical utility. On spraying with an acid buffer, the ions are, no doubt, resolubilized, but they spread out of the ridges, giving a diffused impression. To overcome this problem, we used a phase transfer catalyst which accelerates the reaction between insoluble cations and an aqueous solution of a complexing agent. A phase transfer catalyst is concerned with the conversions of chemical species present in different
G.S. Sodhi, J. Kaur / Forensic Science International 115 (2001) 69±71
phases [13]. We used t-tetrabutylammonium iodide as the phase transfer catalyst and a solution of the disodium salt of eosin-blue as a complexing agent. tTetrabutylammonium iodide acts not only as a catalyst but also as a precipitating reagent. A red-coloured complex gets deposited along the ridges within 1 min, making the latent prints visible. In the absence of the catalyst, the reaction is so slow that, by the time the complex starts getting deposited, the ridges get mingled up. Eosin-blue is a cheap, readily available and nontoxic dye. It is used for dyeing wool, cotton and paper. It is also a biological stain [14]. Acknowledgements The authors are grateful to `R.D. Birla Smarak Kosh', Medical Research Centre, Bombay Hospital Trust, Mumbai, India, for ®nancial assistance. References [1] G.L. Thomas, The physics of ®ngerprints and their detection, J. Phys. E 11 (1978) 722±731.
71
[2] A.M. Knowles, Aspects of physicochemical methods for the detection of latent ®ngerprints, J. Phys. E 11 (1978) 713±721. [3] Y. Kuno, Human Perspiration, Thomas, Spring®eld, 1956. [4] B. Scruton, B.W. Robins, B.H. Blott, The deposition of ®ngerprint ®lms, J. Phys. D 8 (1975) 714±723. [5] S. Nath, Fingerprint Identi®cation. Spectra of Anthropological Progress, University Press, Delhi, 1984, pp. 75±96. [6] S.K. Chatterjee, Finger, Palm and Sole Prints, 2nd Edition, Kosa Publishers, Calcutta, 1967, pp. 88±103. [7] D.W. Herod, E.R. Menzel, Laser detection of latent ®ngerprints: ninhydrin followed by zinc chloride, J. Forensic Sci. 118 (1981) 173±174. [8] J. Kaur, G.S. Sodhi, S. Nath, The application of phase transfer catalysis to ®ngerprint detection, Sci. Justice 36 (1996) 267± 269. [9] J. Almog, A. Zeichner, S. Shifrina, G. Scharf, Nitrobenzofurazanyl ethers, a new series of ¯uorigenic ®ngerprint reagents, J. Forensic Sci. 32 (1987) 585±596. [10] M. Stoilovic, Improved method for DFO development of latent ®ngerprints, Forensic Sci. Int. 60 (1993) 141±153. [11] D.B. Hauze, O. Petrovskaia, B. Taylor, M.J. Joullie, R. Ramotowski, A.A. Cantu, 1,2-Indanediones: new reagents for visualizing the amino acid components of latent prints, J. Forensic Sci. 43 (1998) 744±747. [12] H. Howorka, K. Kretschmer, Experimental study of using cyanoacrylate ester vapour for developing latent ®ngerprints, Forensic Sci. Int. 46 (1990) 31±32. [13] E.V. Dehmlow, S.S. Dehmlov, Phase Transfer Catalysis, 3rd Edition, VCH, New York, 1983, pp. 1±27. [14] Merck Index No. 3638, 12th Edition, Merck & Co., NJ, 1986, p. 610.
Fingermarks detection by eosin-blue dye G.S. Sodhia,*, J. Kaurb a
b
Department of Chemistry, S.G.T.B. Khalsa College, University of Delhi, Delhi 110007, India Rajguru College of Applied Sciences for Women, University of Delhi, Jhilmil Colony, Vivek Vihar, Delhi 110095, India Received 1 March 2000; received in revised form 10 May 2000; accepted 24 May 2000
Abstract Eosin-blue (I) dye, along with a phase transfer catalyst, has been used to detect latent ®ngerprints on a wide range of surfaces, including paper, glass, steel, lamination sheets, polythene, plastic and bakelite. # 2001 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Catalyst; Eosin-blue; Fingermarks
1. Introduction A latent ®ngerprint is formed when the sweat pores of the papillary ridges leave a deposit of perspiration on a surface with which the ®nger has been brought into contact [1]. Human body possesses the following three types of glands Ð viz. eccrine, apocrine and sebaceous, the secretions of which contribute to a ®ngerprint deposit [2]. Eccrine glands are widely distributed throughout the body and are particularly numerous on the palms of hands and the soles of feet. Chemicals are secreted by these glands as a result of general metabolism and catabolism. Besides water content, eccrine sweat contains up to 1% of the other substances of which inorganic salts constitute about one-half [3]. Amongst these, sodium and chloride are the most abundant ions, representing nearly 90 mM proportion. Potassium (5 mM), magnesium (0.4 mM), calcium (0.5 mM), sulphate (0.4 mM) and phosphate are also present, together with traces of iron, copper, manganese, iodide, bromide and ¯uoride. The other half is con*
Corresponding author.
stituted by organic products like amino acids, urea, creatinine, choline, lactic acid, sugars, and uric acid [4]. In addition, fatty acids are secreted by sebaceous glands. The constituents of the sweat may be selectively ®xed by different chemical reagents so as to make the latent ®ngerprints visible [5]. Various chemical reagents, such as silver nitrate, iodine and ninhydrin, are available for rendering visibility to latent prints. These reagents react with sodium chloride, fatty acid and amino acid contents, respectively, present in the sweat [6]. The powder technique of developing latent prints is the most common, but it works generally in the presence of moisture. This means that old prints developed by this method are not of optimum quality. Ninhydrin reagent may be used for developing prints as old as 15 years. However, ninhydrin gives good results after posttreatment of developed prints with zinc chloride followed by laser examination [7]. In an earlier communication [8], we devised a technique wherein the calcium content of sweat was ®xed with the help of a phase transfer catalyst. The successful development of ®ngermarks prompted us to try out the technique using a similar catalyst and
0379-0738/01/$ ± see front matter # 2001 Elsevier Science Ireland Ltd. All rights reserved. PII: S 0 3 7 9 - 0 7 3 8 ( 0 0 ) 0 0 3 0 7 - 8
70
G.S. Sodhi, J. Kaur / Forensic Science International 115 (2001) 69±71
eosin-blue reagent. The quality of developed ®ngermarks is comparable to the results obtained with other reagents, such as nitrobenzo-2-oxa-1,3-diazole [9], l,8-diaza¯uoren-9-one [10] and 1,2-indanediones [11].
2. Experimental The disodium salt of eosin-blue and t-tetrabutylammonium iodide were purchased from Aldrich, USA, and were used without further puri®cation. An aqueous solution containing 2.38±2.40% disodium eosin-blue and 1.25±1.30% t-tetrabutylammonium iodide was prepared in a measuring ¯ask. Over the next 1 h, the solution was periodically shaken. Alternately, it was stirred for about half an hour. This formulation was used for developing ®ngermarks on paper. For non-absorbent surfaces, an aqueous solution containing 0.31±0.35% disodium eosin-blue and 0.18± 0.20% t-tetrabutylammonium iodide was prepared. Small pieces (about 2 in.2 in.) of paper, lamination sheet, gift paper, adhesive tape, polythene or plastic surface, bearing sample latent prints, were immersed in the respective test solution for about 1 min. The paper sample was then dipped in distilled water. The other surfaces were dried with a hair dryer. For larger objects, such as polythene bottles, bakelite switches, glassware and stainless steel utensils, the test solution was sprayed onto the area containing the ®ngermark impression. The surface was dried with a hair dryer. Sharp and clear ®ngermarks developed. 3. Results Latent ®ngerprints developed by this method persist over a prolonged period of time. The impressions on
paper do not get distorted on rubbing and scratching. They can be developed over white or light coloured papers, except pink or red where the contrast with the background is low. Another limitation is that, on paper, impressions older than 1 week cannot be developed. This is probably due to the interaction of metal ions with the cellulose content of paper. However, on surfaces other than paper, prints have been obtained even after a lapse of 20±30 days. Good quality prints have been lifted from lamination sheets. Thus, the present method may be extended for obtaining ®ngerprints from laminated documents, such as archaeological scripts, certi®cates, driving licences and identity cards. Prints may also be developed on polythene bags Ð commonly used for carrying household items and polythene bottles Ð commonly used for storing household items. Normally, the cyanoacrylate fuming technique has to be employed to develop ®ngermarks on such surfaces [12]. However, the present method for rendering visibility to extent prints on a polythene surface is more convenient. Other surfaces on which an unscrupulous element is likely to leave his ®ngerprint impressions include glassware, steel handles and knobs, bakelite switches and switchboards and plastic table mats. The present technique of ®ngerprint detection gives good results on all these surfaces. 4. Discussion Although metal ions form a number of coloured complexes, but attempts to ®x these ions for developing ®ngermarks have been largely unsuccessful. The reason being that metal ions, after being deposited along the ridges, are converted into insoluble salts. Further reactions of these insoluble salts Ð if at all they occur Ð would be extremely slow to have a practical utility. On spraying with an acid buffer, the ions are, no doubt, resolubilized, but they spread out of the ridges, giving a diffused impression. To overcome this problem, we used a phase transfer catalyst which accelerates the reaction between insoluble cations and an aqueous solution of a complexing agent. A phase transfer catalyst is concerned with the conversions of chemical species present in different
G.S. Sodhi, J. Kaur / Forensic Science International 115 (2001) 69±71
phases [13]. We used t-tetrabutylammonium iodide as the phase transfer catalyst and a solution of the disodium salt of eosin-blue as a complexing agent. tTetrabutylammonium iodide acts not only as a catalyst but also as a precipitating reagent. A red-coloured complex gets deposited along the ridges within 1 min, making the latent prints visible. In the absence of the catalyst, the reaction is so slow that, by the time the complex starts getting deposited, the ridges get mingled up. Eosin-blue is a cheap, readily available and nontoxic dye. It is used for dyeing wool, cotton and paper. It is also a biological stain [14]. Acknowledgements The authors are grateful to `R.D. Birla Smarak Kosh', Medical Research Centre, Bombay Hospital Trust, Mumbai, India, for ®nancial assistance. References [1] G.L. Thomas, The physics of ®ngerprints and their detection, J. Phys. E 11 (1978) 722±731.
71
[2] A.M. Knowles, Aspects of physicochemical methods for the detection of latent ®ngerprints, J. Phys. E 11 (1978) 713±721. [3] Y. Kuno, Human Perspiration, Thomas, Spring®eld, 1956. [4] B. Scruton, B.W. Robins, B.H. Blott, The deposition of ®ngerprint ®lms, J. Phys. D 8 (1975) 714±723. [5] S. Nath, Fingerprint Identi®cation. Spectra of Anthropological Progress, University Press, Delhi, 1984, pp. 75±96. [6] S.K. Chatterjee, Finger, Palm and Sole Prints, 2nd Edition, Kosa Publishers, Calcutta, 1967, pp. 88±103. [7] D.W. Herod, E.R. Menzel, Laser detection of latent ®ngerprints: ninhydrin followed by zinc chloride, J. Forensic Sci. 118 (1981) 173±174. [8] J. Kaur, G.S. Sodhi, S. Nath, The application of phase transfer catalysis to ®ngerprint detection, Sci. Justice 36 (1996) 267± 269. [9] J. Almog, A. Zeichner, S. Shifrina, G. Scharf, Nitrobenzofurazanyl ethers, a new series of ¯uorigenic ®ngerprint reagents, J. Forensic Sci. 32 (1987) 585±596. [10] M. Stoilovic, Improved method for DFO development of latent ®ngerprints, Forensic Sci. Int. 60 (1993) 141±153. [11] D.B. Hauze, O. Petrovskaia, B. Taylor, M.J. Joullie, R. Ramotowski, A.A. Cantu, 1,2-Indanediones: new reagents for visualizing the amino acid components of latent prints, J. Forensic Sci. 43 (1998) 744±747. [12] H. Howorka, K. Kretschmer, Experimental study of using cyanoacrylate ester vapour for developing latent ®ngerprints, Forensic Sci. Int. 46 (1990) 31±32. [13] E.V. Dehmlow, S.S. Dehmlov, Phase Transfer Catalysis, 3rd Edition, VCH, New York, 1983, pp. 1±27. [14] Merck Index No. 3638, 12th Edition, Merck & Co., NJ, 1986, p. 610.