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Silver separation technique for isotopic measurement in archaeological samples
Venhauerová, Petra ; Trubač, Jakub (advisor) ; Vaněk, Aleš (referee)
Silver isotopes nowadays present a very fast evolving system. One of the field in which this isotopic system is used is archaeology where the silver isotopes are used as a tracer of monetary and power changes between geographical regions. Through statistical analysis of measured data and their comparison with so far published values can be estimated probability of common source area of metal used for coinage. On Celtic coin samples (180-70 BC) provided by the Institute of Archaeology of the CAS, Prague (A. Danielisová) the isotopic composition of silver was measured. Silver was separated from the matrix elements by a method which uses ascorbic acid to precipitate silver. However, the weights of samples commonly used for this method are generally distinctly higher than the amounts of the obtained fragments of Celtic coins. Regarding the differences in the method and low weights of fragments, tests with variable concentrations of ascorbic acid and amounts of silver were performed. The amounts of silver used for this method are commonly ~30x-70x higher. The results showed that this method effectively separates silver from matrix elements and is sufficient for higher concentrations of silver; with lower ones the yields are reduced. The separated silver was measured using MC-ICP-MS. The adjusted...
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Silver separation technique for isotopic measurement in archaeological samples
Venhauerová, Petra ; Trubač, Jakub (advisor) ; Vaněk, Aleš (referee)
Silver isotopes nowadays present a very fast evolving system. One of the field in which this isotopic system is used is archaeology where the silver isotopes are used as a tracer of monetary and power changes between geographical regions. Through statistical analysis of measured data and their comparison with so far published values can be estimated probability of common source area of metal used for coinage. On Celtic coin samples (180-70 BC) provided by the Institute of Archaeology of the CAS, Prague (A. Danielisová) the isotopic composition of silver was measured. Silver was separated from the matrix elements by a method which uses ascorbic acid to precipitate silver. However, the weights of samples commonly used for this method are generally distinctly higher than the amounts of the obtained fragments of Celtic coins. Regarding the differences in the method and low weights of fragments, tests with variable concentrations of ascorbic acid and amounts of silver were performed. The amounts of silver used for this method are commonly ~30x-70x higher. The results showed that this method effectively separates silver from matrix elements and is sufficient for higher concentrations of silver; with lower ones the yields are reduced. The separated silver was measured using MC-ICP-MS. The adjusted...
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Variation of isotopic composition in selected natural and archeological samples, methodical approach
Venhauerová, Petra ; Trubač, Jakub (advisor) ; Magna, Tomáš (referee)
This thesis is focused on elaboration of the methodical approaches for determination silver isotope ratios by multicollector inductively coupled plasma mass spectrometry (MC-ICP- MS) from Centrum of stable and radiogenic isotopes on Science Faculty on Charles University. Therefore, this thesis describes in detail methodology of chromatographic separation and conditions of further measurement. For analysis of isotopic ratios 107 Ag/109 Ag in individual samples are used natural samples of various silver and gold deposits in Czech Republic and Poland. Also, archeological findings of fractures of silver coins from our country. The aim of this work is to find out if there is a variability among this two types of samples. Measured values are further correlated with already published works specialized on similar types of natural and archeological samples. The obtained values could be used for an interpretation of geological processes (e. g. physicochemical fractionation during ore forming processes) or as an identification source of the origin of coins and other archeological findings (e. g. silver ornaments). Gained knowledge of this work will help improve contemporary methodology in measurement of silver isotopes, such as standard calibration and tuning the stability of a signal. Key words: isotopes of...
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