dc.description.abstract |
Jewellery has attracted humans of all cultures and civilization since
times immemorial. Silver for example, has a beautiful colour, excellent
corrosion and oxidation resistance, superior malleability, and ease of
fabrication. Its limited availability together with these other characteristics is
collectively responsible for the unique place silver has in the family of metals.
As a consequence much thought and extensive research have been devoted to
develop non destructive method for analyzing silver metal in general materials
and from Jewellery in particular.
In the present research, the application of X- ray fluorescence, which is
classified as non-invasive technique, to analysis two kinds of silver samples in
two silver parcels have been undertaken. The two silver samples used in this
experiment were purchased from Sudan. As a result of radiation X-ray
fluorescence (XRF) spectroscopy, only three elements, silver, zinc and copper
were observed in XRF spectrum of both silver parcel samples. The peak
intensity showed good correlation with the concentration of silver in the
samples. The analytical line for analysis silver which is Kα is fully resolved
from the other lines within the sample components. Nevertheless, there are
spectral interferences within the other sample component, copper and zinc.
This could be due to similarity in the X- ray energy since they have closely
atomic number (Cu = 29, Zn = 30).
In addition, the variation of silver peak intensity for sample 1
(designated as Carat 925) were sufficiently higher compared with
corresponding one in sample -2 (designated as Carat 800). Therefore, the
comparison of the intensity can be effective method to discriminate different
silver samples originating from different type of silver parcel. The silver
III
concentration (w/w%) in sample -1 (Carat 925) and sample -2 (Carat 800) were
found to be 94.79% and
84.45%, respectively.
In order to validate the over mention method, other wet analysis was
performed by atomic absorption spectroscopy (AAS). The obtained result from
XRF analysis and the one from AAS were correlated using statistical method
(t-test). The results indicate that there is no significant different between the
results obtained by the two methods. Therefore, XRF can be successfully
utilized for analyzing material containing silver, particularly Jewellery objects. |
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