TY - JOUR
T1 - Identification of firearms handling by the [Fe(PDT)3] 2+ complex
T2 - Chemical and time-dependent factors
AU - Avissar, Yaniv Y.
AU - Sagiv, Assaf E.
AU - Mandler, Daniel
AU - Almog, Joseph
PY - 2005/8/15
Y1 - 2005/8/15
N2 - Handling of a gun results in the formation of invisible impressions, caused by transfer of iron traces to the skin surface. Visualization of these impressions is possible by spraying the palms with a solution of 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine (PDT), which forms a magenta complex with iron(II) residues. Hence, mark intensity is directly related to the amounts of iron transferred to the palm. Palmar sweat plays a major role in iron transfer from the firearm to the hand. More factors, however, are involved in this process. Three time-dependent factors have been studied with relation to their effect on the developed mark: the gripping duration of the weapon; the time elapsed from the contact; and the rate of iron dissolution in aqueous solutions containing sweat components in physiological concentrations. We found that the amounts of iron transferred to the palm depend on both, the gripping period and the levels of palmar moisture. Thus, only a few seconds of gripping were required for developing good marks (corresponding to 80 ng cm-2 of iron) on highly-moistured hands, much longer gripping periods were necessary for developing marks of similar intensity on relatively dry hands. Experiments that aimed at studying the effect of sweat components on metallic iron dissolution were carried out in aqueous solutions. It was found that chloride ions in physiological concentrations remarkably enhanced the dissolution, while l-serine, the major amino acid in palmar sweat, had a detrimental effect on this process. Urea, another sweat component, had only a minor effect on the dissolution rate.
AB - Handling of a gun results in the formation of invisible impressions, caused by transfer of iron traces to the skin surface. Visualization of these impressions is possible by spraying the palms with a solution of 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine (PDT), which forms a magenta complex with iron(II) residues. Hence, mark intensity is directly related to the amounts of iron transferred to the palm. Palmar sweat plays a major role in iron transfer from the firearm to the hand. More factors, however, are involved in this process. Three time-dependent factors have been studied with relation to their effect on the developed mark: the gripping duration of the weapon; the time elapsed from the contact; and the rate of iron dissolution in aqueous solutions containing sweat components in physiological concentrations. We found that the amounts of iron transferred to the palm depend on both, the gripping period and the levels of palmar moisture. Thus, only a few seconds of gripping were required for developing good marks (corresponding to 80 ng cm-2 of iron) on highly-moistured hands, much longer gripping periods were necessary for developing marks of similar intensity on relatively dry hands. Experiments that aimed at studying the effect of sweat components on metallic iron dissolution were carried out in aqueous solutions. It was found that chloride ions in physiological concentrations remarkably enhanced the dissolution, while l-serine, the major amino acid in palmar sweat, had a detrimental effect on this process. Urea, another sweat component, had only a minor effect on the dissolution rate.
KW - 3-(2-Pyridyl)-5,6-diphenyl-1,2,4-triazine (PDT)
KW - Dissolution rate
KW - Firearms handling
KW - Forensic science
KW - Iron determination
KW - Palmar sweat
KW - Serine
KW - Urea
UR - http://www.scopus.com/inward/record.url?scp=23344432001&partnerID=8YFLogxK
U2 - 10.1016/j.talanta.2005.01.032
DO - 10.1016/j.talanta.2005.01.032
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AN - SCOPUS:23344432001
SN - 0039-9140
VL - 67
SP - 328
EP - 333
JO - Talanta
JF - Talanta
IS - 2
ER -