J Forensic Sci, Nov. 2005, Vol. 50, No. 6 Paper ID JFS2005055 Available online at: www.astm.org
Genyia Levinton-Shamuilov,1 B.Sc.; Yaron Cohen,2 M.Sc.; Myriam Azoury,2 M.Sc.; Alan Chaikovsky,3 B.Sc.; and Joseph Almog,1 Ph.D.
Genipin, a Novel Fingerprint Reagent With Colorimetric and Fluorogenic Activity, Part II: Optimization, Scope and Limitations
ABSTRACT: Genipin, a hydrolytic productof geniposide extracted from gardenia fruit, was thoroughly studied as a potential ﬁngerprint reagent, and optimal conditions for ﬁngerprint development have been determined. Latent ﬁngerprints on paper items that have been treated with a non-ink running formulation containing 0.17% of the reagent, showed up as both colored and ﬂuorescent images. On brown wrapping paper and on papers with highlyluminescent backgrounds, genipin developed more visible and clearer prints than did classical reagents such as ninhydrin or DFO. Another potential advantage of genipin is that it is totally harmless and an environmentally friendly reagent. KEYWORDS: forensic science, ﬁngerprint reagent, genipin, amino acid reagent, ninhydrin, DFO, 1,2-indanedione, ﬂuorogenic, colorimetric
In a previous articlewe described the potential of genipin, a natural product produced from the extract of Gardenia fruit, as a ﬁngerprint reagent for paper items (1). Fingerprints developed with genipin appear as blue impressions, which ﬂuoresce upon illumination with ca. 590 nm light. We wish to report here the search for optimal development conditions with genipin, in regard to solvents, concentration, temperature,humidity, and warming regime. Other factors that have been studied are the possibility of sequential development with DFO and with ninhydrin, the performance comparison with these two reagents, and the generation of spectroﬂuorimetric data of genipin’s products with several amino acids. We identiﬁed circumstances in which genipin could be advantageous over DFO and ninhydrin; for instance, onbrown wrapping paper, or on documents written with ﬂuorescent ink. Materials and Methods Genipin was purchased from Challenge Bioproducts Co., LTD (7 Alley 25, Lane 63, Tzu-Chiang St. 404 Taichung, Taiwan). Optimal procedures for ninhydrin (2) and DFO (0.025% solution in CFC113 containing methanol and acetic acid) were always used for comparison. After optimizing the working conditions with genipin,all further experiments were carried out under these conditions. Natural ﬁngerprints from six donors (two males and four females) were deposited on different types of paper, as described below. Solvents and Concentration The following solvents were tried as initial solvents for genipin: methanol, ethanol, isopropanol, acetone, diethyl ether, ethyl acetate, acetonitrile, methyl ethyl ketone,dichloromethane and petrol ether.
1 Casali Institute of Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel. 2 Latent Fingerprint Laboratory, Division of Identiﬁcation and Forensic Science (DIFS), Israel Police, National H.Q., Jerusalem 91906, Israel. 3 Photography Laboratory, Division of Identiﬁcation and Forensic Science. (DIFS), Israel Police, National H.Q., Jerusalem91906, Israel. Received 6 Feb. 2005; and in revised form 26 May 2005; accepted 13 June 2005; published 14 Sept. 2005.
The effect of acetic acid on the genipin reaction was also tested. Optimum concentration of genipin was determined using ethanolic solutions of 5 × 10−2 to 5 × 10−4 M on serially depleted prints. HFE 7100 solvent (3M, UK) and petrol ether were used for dilution of the concentratedsolution. Final composition of the genipin solution was determined taking into consideration solution stability, color and ﬂuorescence intensity, paper background and ink spreading. The pH Effect Alanine solution (5 × 10−3 M, in 1:1 ethanol:water) and genipin solution (5 × 10−3 M in ethanol) were prepared at different pH (4.8; 5.5; 6.8; 8.5; 9.5) using acetic acid and triethylamine for pH...
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