Comparison of high-resolution and dynamic reaction cell ICP-MS capabilities for forensic analysis of iron in glass

Abstract

Forensic laboratories routinely conduct analysis of glass fragments to determine whether or not there is an association between a fragment(s) recovered from a crime scene or from a suspect to a particular source of origin. The physical and optical (refractive index) properties of the fragments are compared and, if a "match" between two or more fragments is found, further elemental analysis can be performed to enhance the strength of the association. A range of spectroscopic techniques has been used for elemental analysis of this kind of evidence, including inductively coupled plasma mass spectrometry (ICP-MS). Because of its excellent sensitivity, precision, and accuracy, several studies have found that ICP-MS methods (dissolution and laser-ablation) provide the best discrimination between glass fragments originating from different sources. Nevertheless, standard unit-resolution ICP-MS instruments suffer from polyatomic interferences including (40)Ar(16)O(+), (40)Ar(16)O(1)H(+), and refractory oxide (40)Ca(16)O(+) that compromise measurements of trace levels of Fe(56+) and Fe(57+), for example. This is a drawback in the analysis of glass fragments because iron has been previously identified as a good discriminating element. Currently, several techniques are available that enable reduction of such interferences. However, there are no data comparing detection limits of iron in glass using those techniques. The aim of this study was to compare, the analytical performance of high-resolution sector field inductively coupled plasma mass spectrometry (HR-SF-ICP-MS) and quadrupole ICP-MS equipped with a dynamic reaction cell (DRC-ICP-MS), for the detection of iron in glass, in terms of accuracy, precision, and method detection limits (MDLs). Analyses were conducted using conventional acid-digestion and laser-ablation methods. For laser-ablation analyses, carrier gases were compared to assess the effect on detection limits in the detection of iron isotopes. Iron polyatomic interferences were reduced or resolved by using a dynamic reaction cell and high-resolution ICP-MS. MDLs as low as 0.03 microg g(-1) and 0.14 microg g(-1) were achieved in laser-ablation and solution-based analyses, respectively. Use of helium as carrier gas improved detection limits for both iron isotopes in medium-resolution HR-SF-ICP-MS and in DRC-ICP-MS.

Dynamic reaction cell ICP-MS for determination of total As, Cr, Se and V in complex matrices: Still a challenge? A review

“…On the other hand, these modern instruments have some limitations, one of the major disadvantages of ICP-MS is the occurrence of mass interferences, caused by atomic or polyatomic species having the same mass/charge ratio of the analyte [8,9]. Interferences in ICP-MS do not occur so frequently, but when they are present they can affect the analytical results if they are not properly removed or at least corrected.…”

Application of laser ablation (LA-ICP-SF-MS) for the elemental analysis of bone and teeth samples for discrimination purposes

“…The use of a sector field based inductively coupled plasma mass spectrometry (ICP-SF-MS) system has the capability of resolving polyatomic/isobaric interferences improving the detection of trace elements in complex matrices such as bone and teeth in addition to improving the detection limits when compared to a quadrupole based ICP-MS device [51]. By coupling a LA system for solid sampling, sample preparation steps are reduced significantly.…”

Inductively Coupled Plasma Mass Spectrometry

“…Multielement analysis of materials and objects in the context of forensic studies or provenance determination has been described in literature as well. [107][108][109][110] The use of LA-ICP-SFMS for the forensic study of glass was described comprehensively by Latkoczy et al 111 Determination of Fe in glass for forensic purposes by LA-ICP-SFMS was performed by Castro et al 112 Polyatomic interferences such as 40 57 Fe 1 , are resolved at a mass resolution of 4000. Ancient glass, for instance, was characterised using LA-ICP-SFMS (single collector) in order to determine the provenance of glass from an excavation in Ephesos/Turkey and to investigate the secret production processes of Art Nouveau glass.…”