Article ID Journal Published Year Pages File Type
97228 Forensic Science International 2009 10 Pages PDF
Abstract

In this study, the colour of 23 sediment samples collected in different Portuguese beaches in the North (Entre-Douro and Minho) and 33 in the South (Algarve) was tested. Spectral colour parameters (L*a*b*) were measured after several presentation/pre-treatment methods: drying at 40 °C, sieving (<150 and <63 μm) and ashing at 850 °C, using a Konica Minolta CM-2600d spectrophotometer. A descriptive statistical analysis with L*a*b* values for each presentation/pre-treatment method was performed to ascertain within-sample reproducibility followed by a hierarchical cluster analysis to obtain significant discrimination between samples using colour analysis. The samples analysed presented a colour closest to red and yellow continuums and a lightness close to the pale side of the L*a*b* system colour sphere with samples collected in the North presenting analysis on average darker L values than the samples collected in the South. The cluster analysis, dried, unsieved bulk samples L*a*b* values gave the best discrimination between samples. The clusters analysis dried, unsieved bulk samples–dried, sieved <150 μm fraction set allowed better discrimination between samples compared with the dried, sieved <63 μm fraction set or dried, unsieved bulk samples–ashed bulk, unsieved samples set and even with dried, unsieved bulk samples/dried, sieved <150 μm fraction/dried, sieved <63 μm fraction/ashed bulk, unsieved samples considered all together.

Related Topics
Physical Sciences and Engineering Chemistry Analytical Chemistry
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