title: A rapid method to detect dried saliva stains swabbed from human skin using fluorescence spectroscopy.
abstract: Saliva on skin is important in forensic trace evidence. If areas where saliva is present can be outlined, this may lead to DNA analysis and identification. This study describes a rapid and non-destructive method to detect dried saliva on the surface of the skin by fluorescence spectroscopy. Eighty-two volunteers deposited samples of their own saliva on the skin of their ventral forearm. A control sample of water was deposited at three different sites on the contralateral arm. Saliva and water control were then allowed to air-dry. Swab samples were taken from dried saliva and control sites and were dissolved in 0.1M KCl solution. Emission spectra were obtained from the solution and were characterized by a principal maximum at 345-355nm with excitation at 282nm. The fluorescence emission intensity was greater than background readings obtained from the control swab site in 80 of 82 volunteers (approximately 97.6%). The fluorescence profile of saliva samples were similar to those obtained from aqueous samples of pure amylase and tryptophan, an endogenous fluorophore in alpha-amylase. The presence of an emission peak at 345-355nm with excitation at 282nm could provide a strong presumptive indication of saliva deposition.
authors.affiliation: Wellman Laboratories of Photomedicine, Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA. soukos@helix.mgh.harvard.edu
authors.forename: N S
authors.initials: NS
authors.lastname: Soukos
authors.forename: K
authors.initials: K
authors.lastname: Crowley
authors.forename: M P
authors.initials: MP
authors.lastname: Bamberg
authors.forename: R
authors.initials: R
authors.lastname: Gillies
authors.forename: A G
authors.initials: AG
authors.lastname: Doukas
authors.forename: R
authors.initials: R
authors.lastname: Evans
authors.forename: N
authors.initials: N
authors.lastname: Kollias
mesh_terms: D000328:Adult; D000681:Amylases / Q000737:chemistry; D002648:Child; D002650:Child Abuse, Sexual / Q000175:diagnosis; D016172:DNA Fingerprinting; D005554:Forensic Medicine / Q000379:methods*; D006801:Humans; D011902:Rape / Q000175:diagnosis; D012463:Saliva / Q000737:chemistry*; D012680:Sensitivity and Specificity; D012867:Skin; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013997:Time Factors; D014364:Tryptophan / Q000737:chemistry
chemical_list: D014364:Tryptophan; D000681:Amylases