Problems of Forensic Sciences 2001 Vol. 47 (XLVII) 144-146
A DIFFERENTIATION OF GLASS MICROTRACES OF THE SAME QUALITATIVE COMPOSITION
Grzegorz ZADORA1,2, Zuzanna BROŻEK-MUCHA1, Andrzej PARCZEWSKI2
1Institute of Forensic Research, Cracow, Poland
2Faculty of Chemistry, Jagiellonian University, Cracow, Poland
Streszczenie
Analysis of glass microtraces by means of SEM-EDX method provides an information about their main elemental content. The lack of information on the trace elements becomes a difficulty in the case of differentiation of glass objects revealing a similar chemical contents, e.g. vehicle windows and ordinary window sheets. Moreover, chemometric analysis of the analytical results obtained with this method for several glass microtraces originating from the same glass item usually does not allow to treat it as a homogenous object. A satisfactory solution of the problem of differentiation of two glass objects revealing the same qualitative contents determined with SEM-EDX method was obtained when considering the following model. Several fragments were selected from two glass items of the same qualitative composition being compared. Mean values of the elements concentration were determined for each fragment. Each of the microtraces was treated as a point in a multidimensional space, described by the mean values of the elements concentrations. Distances between defined in this manner points were calculated. It was assumed that microtraces originating from the same glass item created one cluster. Distances between points in such cluster were smaller than distances between points (microtraces) originating from the two compared items. The formulated in this way problem was statistically tested.
Słowa kluczowe
SEM-EDX; Glass microtraces differentiation; Multivariable analysis.