Survey on batch-to-batch variation in spray paints: a collaborative study

Détails

ID Serval
serval:BIB_77F7643757B1
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Survey on batch-to-batch variation in spray paints: a collaborative study
Périodique
Forensic Science International
Auteur⸱e⸱s
Muehlethaler C., Massonnet G., Deviterne M., Bradley M., Herrero A., Diaz de Lezana I., Lauper S., Dubois D., Geyer-Lippmann J., Ketterer S., Milet S., Bertrand M., Langer W., Plage B., Gorzawski G., Lamothe V., Marsh L., Turunen R.
ISSN
1872-6283
ISSN-L
0379-0738
Statut éditorial
Publié
Date de publication
06/2013
Peer-reviewed
Oui
Volume
229
Numéro
1-3
Pages
80-91
Langue
anglais
Résumé
This study represents the most extensive analysis of batch-to-batch variations in spray paint samples to date. The survey was performed as a collaborative project of the ENFSI (European Network of Forensic Science Institutes) Paint and Glass Working Group (EPG) and involved 11 laboratories. Several studies have already shown that paint samples of similar color but from different manufacturers can usually be differentiated using an appropriate analytical sequence. The discrimination of paints from the same manufacturer and color (batch-to-batch variations) is of great interest and these data are seldom found in the literature. This survey concerns the analysis of batches from different color groups (white, papaya (special shade of orange), red and black) with a wide range of analytical techniques and leads to the following conclusions.
Colored batch samples are more likely to be differentiated since their pigment composition is more complex (pigment mixtures, added pigments) and therefore subject to variations. These variations may occur during the paint production but may also occur when checking the paint shade in quality control processes. For these samples, techniques aimed at color/pigment(s) characterization (optical microscopy, microspectrophotometry (MSP), Raman spectroscopy) provide better discrimination than techniques aimed at the organic (binder) or inorganic composition (fourier transform infrared spectroscopy (FTIR) or elemental analysis (SEM - scanning electron microscopy and XRF - X-ray fluorescence)).
White samples contain mainly titanium dioxide as a pigment and the main differentiation is based on the binder composition (Csingle bondH stretches) detected either by FTIR or Raman. The inorganic composition (elemental analysis) also provides some discrimination.
Black samples contain mainly carbon black as a pigment and are problematic with most of the spectroscopic techniques. In this case, pyrolysis-GC/MS represents the best technique to detect differences. Globally, Py-GC/MS may show a high potential of discrimination on all samples but the results are highly dependent on the specific instrumental conditions used.
Finally, the discrimination of samples when data was interpreted visually as compared to statistically using principal component analysis (PCA) yielded very similar results. PCA increases sensitivity and could perform better on specific samples, but one first has to ensure that all non-informative variation (baseline deviation) is eliminated by applying correct pre-treatments. Statistical treatments can be used on a large data set and, when combined with an expert's opinion, will provide more objective criteria for decision making.
Mots-clé
Forensic, Paint, Spray, Batch, Microscopy, Microspectrophotometry, Infrared spectroscopy, Raman spectroscopy, Elemental analysis, Pyrolysis GC/MS, Chemometrics
Pubmed
Création de la notice
25/06/2013 14:31
Dernière modification de la notice
20/08/2019 15:34
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