Weinberger, M., Wobrauschek, P., Kregsamer, P., Margui, E., Jablan, J., & Streli, C. (2023, September 6). Total-reflection X-ray fluorescence analysis of coffee samples [Poster Presentation]. 19th International Conference on Total Reflection X-ray Fluorescence Analysis and Related Methods, Clausthal, Germany. http://hdl.handle.net/20.500.12708/188581
19th International Conference on Total Reflection X-ray Fluorescence Analysis and Related Methods
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Event date:
5-Sep-2023 - 8-Sep-2023
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Event place:
Clausthal, Germany
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Keywords:
coffee; TXRF; multielemental analysis
en
Abstract:
Coffee is an important, worldwide well-accepted beverage. The coffee grains have compounds containing P, K, Ca, and S as major elements and Mn, Fe, Cu, Zn, Se, Br, Rb, Sr at trace levels as well as organic compounds. The trace elements are present in the range of ng/g to ug/g [1].
Commercially available coffee powders (instant, pure and with additives) were taken from various Croatian supermarkets and prepared as digestions using a micro-wave method resulting in a clear liquid, perfectly suited for TXRF analysis. Two independent sets of digests were produced for each coffee sample.
TXRF analysis were performed at the Atominstitut using the home made, laboratory-built tabletop TXRF spectrometer based on the WOBJSTRAX design [2]. The TXRF spectrometer was calibrated with a set of 11 coffee samples excluded from the following survey using Ga as internal standard. The elemental concentrations of the empirical standards were taken from previously experimental results by ICP—OES (inductively coupled plasma optical emission spectrometry). The resulting calibration curves are the basis for the evaluation of the remaining 21 coffee samples by TXRF. The spectra were evaluated using PyMCA for deconvolution and the results found showed good agreement with the ICP measurements. Finally, the quantitation software developed at Atominstitut (ATI-QUANT), using fundamental parameters correction and detector efficiency, was applied for the available data with respect to element and evaluated counts. This is a direct approach to achieve elemental concentrations with reference to Ga as internal standard. Results of the analysis using empirically found calibration curves and ATI-QUANT are compared and show good agreement.