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    Determination of Antimony in Gunshot Residues Using GFAAS and SEM/EDX
    (Atomic Spectroscopy Press Ltd, 2013) Aksoy, Cagdas; Akman, Yusuf; Ergun, Zeynep Omca; Uzek, Ugur; Aydin, Firat
    Transferring gunshot residue via adhesive tape is a very applicable technique for the collection of firearm discharge residue from the surface of hands and face. In this study, antimony was determined in 15 types of adhesive tape and the false positive possibility in the results was investigated. Adhesive tapes, which were provided by crime scene investigators and from a regional market, were analyzed with a graphite furnace atomic absorption spectrometer as used in Police Criminal Laboratories. In two samples, the measured antimony concentrations were 9.2 and 43.7 lig L-1, respectively, and high enough to cause false positives although most of the samples were clean. The source of antimony was detected via imaging and detailed elemental analysis of the samples. In addition, a simple method is proposed to prevent false positives. The method described is simpler, less costly, and faster than the modem approaches used for gunshot residue analysis and is based on the determination of antimony using GFAAS and SEM/EDX.
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    Öğe
    Determination of trace elements in illicit spice samples by using ICP-MS
    (Elsevier Science Bv, 2015) Bora, Taner; Aksoy, Cagdas; Tunay, Zeki; Aydin, Firat
    The narcotic and toxic effects of synthetic cannabinoids have been intensely investigated by scientists in recent years. Most of these studies have been about the effects of synthetic cannabinoid compounds on the human body. However, in this study, we aimed to determine trace element concentrations in seized spice products and observe whether they were above the limit values. The investigated spice product plants contained brooklime, which was the most popular raw material in illicit spice drugs in Turkey. The synthetic cannabinoid contents of the samples were identified by GC-MS. All samples were analyzed by ICP-MS after microwave digestion. The concentration values of Ba, Be, Co, Cr, Cu, Ni, Li, Pb, U, and Zn in three brooklime samples and twenty-nine spice samples containing brooklime were reported. Certified standard reference material CRM SRM 1573a tomato leaves were used to assess the accuracy of the method. After checking the accuracy, excess amounts of the digested CRM were also used to check the precision of the method. Trace element contents in the analyzed samples were likely to be of negligible concern. Barium was the only distinctive element determined. To our knowledge, this is the first study in this field. (C) 2015 Elsevier B.V. All rights reserved.
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    Öğe
    A new method to reduce false positives due to antimony in detection of gunshot residues
    (Elsevier Ireland Ltd, 2015) Aksoy, Cagdas; Bora, Taner; Senocak, Nilgun; Aydin, Firat
    False positives due to the presence of antimony in vehicle seat fabrics are a problem in gunshot residue (GSR) analysis, in particular, when graphite furnace atomic absorption spectrometry (GFAAS) is employed. In this study, we sought to determine the reason for the prevalence of false positive results and to propose a new approach for the analysis of GSR on vehicle seats. GFAAS was used to examine adhesive tape swabs collected from 100 seats of 50 different automobiles. Characterization of seat fabrics was carried out by using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy with energy dispersive X-ray (SEM/EDX) spectroscopy. The results of FTIR analysis indicated that all seat covers containing antimony were composed of polyester. Experimental results obtained by SEM/EDX analysis revealed that the fabrics in these seat covers contained evenly distributed antimony within the structure of polyester fibers. This study shows that the type of seat fabric should be determined by FTIR spectroscopy before elemental GSR analysis. In this way, most of the false positives caused by polyester fibers in GSR analysis can be prevented. (C) 2015 Elsevier Ireland Ltd. All rights reserved.