J . Fore~ls.Sci. Soc. j 1Y 7 8 ) , 18, 233
Received,fiom (;'AC, 13 April, 1978
The Use of Ortho-phthalaldehyde for Superior Fluorescent Visualization of Latent Fingerprints S. W. MAYEK, C. P. MEILLEUK arid P. F. JONES T h e Ivan A. Get!irl,o Laboraiories, T h e Aerospace Corfiora/ion, El Segurzdo, Cal$ornia 90245, U.S.A.
In /his nole we repar[ the etlcouragirlg restllts oj" a preliminary rualuatiotl of the use of ortho-~htltalaldehyde and a BabirrgLur~ nebulizer to create a spray fur the j7uorescent visualization o f latent jingcrprints on large area surfaces at crime scenes. T h e spray can provide very good resolution yf minutiae in u i ~ u a l i t i n glatent ~ f i r ~ ~ ~ e r p run i t ~Puper ts with advantagw over ,fluorescarnine i n rapidily, cost, nnd corlvenience. Further work needed to establish the best procedure for its use is identijied.
Introduction Ninhydrin spray reagents are corrnnonly used fbr the visualizatiorl of latent fingerprint ridge detail on absorbent materials and surfaccs (Soderman and O'Corinell, 1962; Mooney, 1973; and Linde, 1973). Niilhydrin reacts with amino acids and other ainir~espresent in skin oils and perspiration to produce a deep hlue-purple compound (Moenssens, 1971). Over the past few years, several new, more sensitive reagents have been developed for the detection of amines, which offer the potential of improved, or at least alternative, methods for latent fin~erorint visualization. The use of the fluorescarnine reagent. for I example, improves the sensitivity of alnine detection by about 10 fold (Udenfriend, et al., 1972; Weigele, et al., 1972). This enhanced sensitivity and the convenience of fluorescence detection of the adducts motivated the recent evaluation by 11s and others (Meiss, 1975) of'fluorescamine as a spray reagent for fingerprint visualization. I n this report, we describe the use of a second new amine detecting reagent, ortho-phthalaldehyde, for the visualization of latent fingerprints. I t has recently been shown that ortho-phthalaldehyde reacts rapidly with NH, groups to produce a fluorescence five times more intense than that obtained with fluoreqcamine (Benson and Hare, 1975). Because the cost of ortha-phthalaldehyde is a factor of 100 less than that of an equal weight o l fluorescarnine, the ovcrall cost advantage of ortho-phthalaldehyde compared with fluorescarnine is \ignificant. Additional advantages in the use of ortho-phthalaldehyde are: it is rtable in water for at leaqt 2 rnnnths when kept under nitrogen; the reaction with primary amines proceeds rapidly at normal room temperatures; and only one step is required for latent fingerprint visualization. A difliculty in the previous use of fingerprint development sprays is that it has been necessary to make surfaces such as walls almost soaking wet in order to obtain adequate visualization of the latent fingerprints, and as a result discolorations are sometimes produced. Use ol'the Kabington nebulizer recently developed by McGaw Laboratorics (Hunter, 1975) for producing sprays composed of extremely 3mall droplets inay obviate this problem. In this nebulizer, the liquid flows as a thin surface film over a small hollow bulb. Air transmitted through the interior of the bulb is forced through a narrow slot in the bulb to break the liquid into a very fine spray that can extend to more than 180cm. Evnprirnre in hosoitals has shown that the droulet size is so - small that even ab3orbcnt surfaces do not become wet. U
U
--1
I
,
These advantages of the combined use of ortho-phthalaldehyde and a Babington nebulizer suggest that it should be practical to use ortho-phthalaldehyde solutions for spraying relatively large surfaces to detect latent fingerprints that otherwise might require considerably more time to locate with conventional dusting techniques. We report here the results of a preliminary study of the feasibility of this concept. Most of the work involved the development of latent fingerprints on paper, and the results are very encouraging, but further work is still required to optimize the technique and establish its limitations.
Experimental The ortho-phthalaldehyde solution was prepared as follows. First, 2.5g boric acid was dissolved in 95ml distilled water and the p H of the solution was adjusted to 10-4k . 1 with 6M KOH. T o the borate buffer was added 0.3ml of 30% Brij 35 detergent solution and 0.2ml of 2-mercaptoethanol. (Brij 35 is a non-ionic detergent available from Aldrich Chem. Co. or Pierce Chem. Co.) The ortho-phthalaldehyde (Aldrich Chem. Co.) was added as 0.24g dissolved in 2ml methanol. Although ortho-phthalaldehyde is fairly stable in water, the solution should be stored under nitrogen (Benson and Hare, 1975). It can be kept in closed glass bottles a t 4OC for up to two weeks without an appreciable increase in background fluorescence. There is no information available to us regarding the toxicity of these reagents, however, they are used routinely in the chromatographic analysis of amino acid solutions. The ortho-phthalaldehyde solution when sprayed by the Babington technique repeatedly produced excellent visualization of latent fingerprints under ultraviolet light. As shown in Figure 1, even minutiae can be clearly resolved. This
Figure 1 . Latent fingerprint fluorrscence under ultraviolrt light after simple spray treatment
is an example of the quality of developed print obtained for a fingerprint that was formed on a piece of paper that had a porous, dull surface. Fluorescent fingerprints were photographed with Polaroid No. 107 film (ASA 3000) using a Corning CS4-75 filter (Wratten No. 44 could be used) with a 3 second exposure at F-11. The fluorescence of the ortho-phthalaldehyde reaction product is blue with a maximum at 455nm and the maximum excitation is at 340nm. I n practice the ultraviolet light was produced from the long-wavelength (366nm) tube of a Mineralight ultraviolet lamp, model UVSL-25. The lamp was held a t a 45O angle 15cm away from the fingerprint being photographed. The Polaroid camera was mounted at a 90° angle to the fingerprint. No heat
was requircd to produre the fluorescence. Only the ortho-phthalaldehyde solution was needed for visualization, and the fluorescence of the fingerprint pattern was visible in ultraviolet light within one minute after spraying. Other tests showed that lowering the concentration of ortho-phthalaldehyde in the spray solution caused an increase in the time required to produce the fluorescence-forming reaction in the fingerprint. For example, decreasing the orthophthalaldehyde concentration by a factor of three increased the fluorescenceforming reaction time to three minutes. No wetting of the porous paper was disccrnible, suggesting thc spray could also be used on documents without running of any ink present. Conclusion The speed, simplicity, and quality product achieved by the use of orthophthalaldehyde to visualize latent fingerprints with the Babington spray technique are encouraging. Other advantages are the stronger intensity of the fluorescence and lower cost of reagent as compared to fluorescarnine, and the avoidance of possible purple stains due to cxccssivc wetting using ninhydrin sprays. Further work on this nlethod should establish: the procedures for obtaining the clearest and most rapid visualization of latent fingerprints on large areas of various materials; the eflect of age of the fingerprints on the develop~rlentprocedure; the optimum procedures to permit subsequent dusting of fluorescent prints; the potential of using derivatives of ortho-phthalaldehyde to vary the color of fluorescence (Weeks et al., 1976); and the utility of other. reducing agents, such as Cleland's reagent or sodium sulfite, [or better visualization and less offcnsive odors. Although the original purpnse of this study was to develop a method for rapid location of latent fingerprinls on large surfaces, the experinlental results indicate that ortho-phthalaldehyde may have advantages relative to ninhydrin in visualizing fingerprints nn smaller objects such as docurnents. The high sensitivity obtainable with ortho-phthalaldehyde, the lack of wetting, and the absence of ninhydrin stains that can obscure portions of documents might be of' value ill soIrle cases. Acknowledgement This work was supported by The Aerospace Corporation under its Research Support Program. References BENSON, J. R. and HARE,P. E., 1975, Proc. Nut. dcad. Sci. USA 72 (2), 619. HUNTER,K., 1973, McGaw I,aboratories, Trvinc, Calif. USA. LINDE,H. G., 1975, J . Furevu. S c i . , 20, 581. MEISS,L. T., 1975, Personal Communication. MOENSSENS, A. A., 197 1 , Fingerprint Techniques, Chilton Rook Co., Philadelphia. MOONEY, D. G., 1973, I(/entiJicnliot~ Netus, 23, 9. SODERMAN, H. and O'CONNELL, J. %J., 1962, ibfuderll Criminal Invwtigation, p. 134, Funk and Wagnalls, New Tl'ork. UDENFRIEND, S., STEIN,S., BOHLEN,P., DAIRMAN, W., LETMGRURER, W. and WEIGELE,M.,1972, Science, 178, 87 1. M., BLOUNT, J. F., TENGI, J. P., C:ZAJKOWSKI, K . C. and LEIMDRUBER, WEIGELE, W., 1972, J. Amer. Chem. Suc., 94, 4052. WEEKS, R. W., YASUDA, S. K. and DEAN,B. J., 1976, A~zal.Chem., 48, 159.
Received,fiom (;'AC, 13 April, 1978
The Use of Ortho-phthalaldehyde for Superior Fluorescent Visualization of Latent Fingerprints S. W. MAYEK, C. P. MEILLEUK arid P. F. JONES T h e Ivan A. Get!irl,o Laboraiories, T h e Aerospace Corfiora/ion, El Segurzdo, Cal$ornia 90245, U.S.A.
In /his nole we repar[ the etlcouragirlg restllts oj" a preliminary rualuatiotl of the use of ortho-~htltalaldehyde and a BabirrgLur~ nebulizer to create a spray fur the j7uorescent visualization o f latent jingcrprints on large area surfaces at crime scenes. T h e spray can provide very good resolution yf minutiae in u i ~ u a l i t i n glatent ~ f i r ~ ~ ~ e r p run i t ~Puper ts with advantagw over ,fluorescarnine i n rapidily, cost, nnd corlvenience. Further work needed to establish the best procedure for its use is identijied.
Introduction Ninhydrin spray reagents are corrnnonly used fbr the visualizatiorl of latent fingerprint ridge detail on absorbent materials and surfaccs (Soderman and O'Corinell, 1962; Mooney, 1973; and Linde, 1973). Niilhydrin reacts with amino acids and other ainir~espresent in skin oils and perspiration to produce a deep hlue-purple compound (Moenssens, 1971). Over the past few years, several new, more sensitive reagents have been developed for the detection of amines, which offer the potential of improved, or at least alternative, methods for latent fin~erorint visualization. The use of the fluorescarnine reagent. for I example, improves the sensitivity of alnine detection by about 10 fold (Udenfriend, et al., 1972; Weigele, et al., 1972). This enhanced sensitivity and the convenience of fluorescence detection of the adducts motivated the recent evaluation by 11s and others (Meiss, 1975) of'fluorescamine as a spray reagent for fingerprint visualization. I n this report, we describe the use of a second new amine detecting reagent, ortho-phthalaldehyde, for the visualization of latent fingerprints. I t has recently been shown that ortho-phthalaldehyde reacts rapidly with NH, groups to produce a fluorescence five times more intense than that obtained with fluoreqcamine (Benson and Hare, 1975). Because the cost of ortha-phthalaldehyde is a factor of 100 less than that of an equal weight o l fluorescarnine, the ovcrall cost advantage of ortho-phthalaldehyde compared with fluorescarnine is \ignificant. Additional advantages in the use of ortho-phthalaldehyde are: it is rtable in water for at leaqt 2 rnnnths when kept under nitrogen; the reaction with primary amines proceeds rapidly at normal room temperatures; and only one step is required for latent fingerprint visualization. A difliculty in the previous use of fingerprint development sprays is that it has been necessary to make surfaces such as walls almost soaking wet in order to obtain adequate visualization of the latent fingerprints, and as a result discolorations are sometimes produced. Use ol'the Kabington nebulizer recently developed by McGaw Laboratorics (Hunter, 1975) for producing sprays composed of extremely 3mall droplets inay obviate this problem. In this nebulizer, the liquid flows as a thin surface film over a small hollow bulb. Air transmitted through the interior of the bulb is forced through a narrow slot in the bulb to break the liquid into a very fine spray that can extend to more than 180cm. Evnprirnre in hosoitals has shown that the droulet size is so - small that even ab3orbcnt surfaces do not become wet. U
U
--1
I
,
These advantages of the combined use of ortho-phthalaldehyde and a Babington nebulizer suggest that it should be practical to use ortho-phthalaldehyde solutions for spraying relatively large surfaces to detect latent fingerprints that otherwise might require considerably more time to locate with conventional dusting techniques. We report here the results of a preliminary study of the feasibility of this concept. Most of the work involved the development of latent fingerprints on paper, and the results are very encouraging, but further work is still required to optimize the technique and establish its limitations.
Experimental The ortho-phthalaldehyde solution was prepared as follows. First, 2.5g boric acid was dissolved in 95ml distilled water and the p H of the solution was adjusted to 10-4k . 1 with 6M KOH. T o the borate buffer was added 0.3ml of 30% Brij 35 detergent solution and 0.2ml of 2-mercaptoethanol. (Brij 35 is a non-ionic detergent available from Aldrich Chem. Co. or Pierce Chem. Co.) The ortho-phthalaldehyde (Aldrich Chem. Co.) was added as 0.24g dissolved in 2ml methanol. Although ortho-phthalaldehyde is fairly stable in water, the solution should be stored under nitrogen (Benson and Hare, 1975). It can be kept in closed glass bottles a t 4OC for up to two weeks without an appreciable increase in background fluorescence. There is no information available to us regarding the toxicity of these reagents, however, they are used routinely in the chromatographic analysis of amino acid solutions. The ortho-phthalaldehyde solution when sprayed by the Babington technique repeatedly produced excellent visualization of latent fingerprints under ultraviolet light. As shown in Figure 1, even minutiae can be clearly resolved. This
Figure 1 . Latent fingerprint fluorrscence under ultraviolrt light after simple spray treatment
is an example of the quality of developed print obtained for a fingerprint that was formed on a piece of paper that had a porous, dull surface. Fluorescent fingerprints were photographed with Polaroid No. 107 film (ASA 3000) using a Corning CS4-75 filter (Wratten No. 44 could be used) with a 3 second exposure at F-11. The fluorescence of the ortho-phthalaldehyde reaction product is blue with a maximum at 455nm and the maximum excitation is at 340nm. I n practice the ultraviolet light was produced from the long-wavelength (366nm) tube of a Mineralight ultraviolet lamp, model UVSL-25. The lamp was held a t a 45O angle 15cm away from the fingerprint being photographed. The Polaroid camera was mounted at a 90° angle to the fingerprint. No heat
was requircd to produre the fluorescence. Only the ortho-phthalaldehyde solution was needed for visualization, and the fluorescence of the fingerprint pattern was visible in ultraviolet light within one minute after spraying. Other tests showed that lowering the concentration of ortho-phthalaldehyde in the spray solution caused an increase in the time required to produce the fluorescence-forming reaction in the fingerprint. For example, decreasing the orthophthalaldehyde concentration by a factor of three increased the fluorescenceforming reaction time to three minutes. No wetting of the porous paper was disccrnible, suggesting thc spray could also be used on documents without running of any ink present. Conclusion The speed, simplicity, and quality product achieved by the use of orthophthalaldehyde to visualize latent fingerprints with the Babington spray technique are encouraging. Other advantages are the stronger intensity of the fluorescence and lower cost of reagent as compared to fluorescarnine, and the avoidance of possible purple stains due to cxccssivc wetting using ninhydrin sprays. Further work on this nlethod should establish: the procedures for obtaining the clearest and most rapid visualization of latent fingerprints on large areas of various materials; the eflect of age of the fingerprints on the develop~rlentprocedure; the optimum procedures to permit subsequent dusting of fluorescent prints; the potential of using derivatives of ortho-phthalaldehyde to vary the color of fluorescence (Weeks et al., 1976); and the utility of other. reducing agents, such as Cleland's reagent or sodium sulfite, [or better visualization and less offcnsive odors. Although the original purpnse of this study was to develop a method for rapid location of latent fingerprinls on large surfaces, the experinlental results indicate that ortho-phthalaldehyde may have advantages relative to ninhydrin in visualizing fingerprints nn smaller objects such as docurnents. The high sensitivity obtainable with ortho-phthalaldehyde, the lack of wetting, and the absence of ninhydrin stains that can obscure portions of documents might be of' value ill soIrle cases. Acknowledgement This work was supported by The Aerospace Corporation under its Research Support Program. References BENSON, J. R. and HARE,P. E., 1975, Proc. Nut. dcad. Sci. USA 72 (2), 619. HUNTER,K., 1973, McGaw I,aboratories, Trvinc, Calif. USA. LINDE,H. G., 1975, J . Furevu. S c i . , 20, 581. MEISS,L. T., 1975, Personal Communication. MOENSSENS, A. A., 197 1 , Fingerprint Techniques, Chilton Rook Co., Philadelphia. MOONEY, D. G., 1973, I(/entiJicnliot~ Netus, 23, 9. SODERMAN, H. and O'CONNELL, J. %J., 1962, ibfuderll Criminal Invwtigation, p. 134, Funk and Wagnalls, New Tl'ork. UDENFRIEND, S., STEIN,S., BOHLEN,P., DAIRMAN, W., LETMGRURER, W. and WEIGELE,M.,1972, Science, 178, 87 1. M., BLOUNT, J. F., TENGI, J. P., C:ZAJKOWSKI, K . C. and LEIMDRUBER, WEIGELE, W., 1972, J. Amer. Chem. Suc., 94, 4052. WEEKS, R. W., YASUDA, S. K. and DEAN,B. J., 1976, A~zal.Chem., 48, 159.
