Emprego de imagens hiperspectrais e espectrometria de emissão em plasma introduzido por laser na análise direta de amostras de lixo eletrônico
View/ Open
Date
2015-02-27Author
Carvalho, Rodrigo Rodrigues Victor de
Metadata
Show full item recordAbstract
In this study, laser induced breakdown spectroscopy was combined with chemometric
tools to study the chemical composition of WEEE discarded. For this, three
samples of printed circuit board were chosen for analysis: PCBs samples of mobile
phone, mouse and memory stick. The first sample with an area of 30 x 40 mm
was forwarded to the LIBS, laser pulses were made in 1200 points generating a
total of 12,000 spectra. Normalizing the data, initial exploratory analysis was conducted
in which 18 emission lines were separated corresponding to Al, Au, Ba,
Ca, Co, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Sb, Si, Sn Ti and Zn. Semi quantitative
information were acquired with scanning electron microscopy with X-ray microanalysis.
In a second step, the data were normalized by the relative intensity and
self-scaled, where principal component analysis was performed. Scores maps
were generated with PC1 containing 19 and 16% of variance explained by the
pulses 1 and 10. In the mouse sample, a small area containing 5 x 15 mm was
analyzed, and investigated the presence of Pb, the five more intense emission lines
of Pb were separated. Data were normalized by the relative intensity and self
scaled, PCA was used and scores of maps were generated, with PC1 containing
88% of the explained variance. The Pb element was quantified by Flame Atomic
Absorption Spectrometry finding a con-centration of 25% (w/w). Small areas of
10 x 10 mm were analyzed in the memory stick using laser ablation inductively
coupled plasma mass spectrometer. Data were normalized, scores were generated
and maps the elements Cr and Pb were identified and quantified by Inductively
coupled plasma optical emission spectrometry, with concentrations of 7 and 70
mg/kg, respectively