ABSTRACT
The provenance study of archaeological materials is an important step in understanding the cultural and economic life of ancient human communities. One of the most popular approaches in provenance studies is to obtain the chemical composition of material and process it with chemometric methods. In this paper, we describe a combination of the total-reflection X-ray fluorescence (TXRF) method and chemometric techniques (PCA, k-means cluster analysis, and SVM) to study Neolithic ceramic samples from eastern Siberia (Baikal region). A database of ceramic samples was created and included 10 elements/indicators for classification by geographical origin and ornamentation type. This study shows that PCA cannot be used as the primary method for provenance purposes, but can show some patterns in the data. SVM and k-means cluster analysis classified most of the ceramic samples by archaeological site and type with high accuracy. The application of chemometric techniques also showed the similarity of some samples found at sites located close to each other. A database created and processed by SVM or k-means cluster analysis methods can be supplemented with new samples and automatically classified.
ABSTRACT
Tea is a popular drink around the world and contains essential minerals and trace elements for human health. In this study, the analytical capabilities of the total-reflection X-ray fluorescence method (TXRF) were considered for the analysis of tea. Different sample preparation techniques, e.g. suspension, open vessel acid digestion, and microwave acid digestion were examined. The influence of particle size was investigated in the analysis of the suspension of tea samples. Mass-absorption coefficients for the tea matrix and the critical surface density of the specimen were calculated. The data obtained explain the presence of absorption effects in the determination of P, S, Cl, and K in suspensions. The digestion procedure is chosen as an optimal sample preparation technique for the TXRF analysis of tea. Nineteen real tea samples were analyzed using TXRF. The advantages of TXRF have been presented through the comparison of results with the wavelength-dispersive X-ray fluorescence spectrometry method.
Subject(s)
Analytic Sample Preparation Methods/methods , Plant Leaves/chemistry , Spectrometry, X-Ray Emission , Tea/chemistry , Humans , Trace Elements/analysisABSTRACT
Apatite group of minerals incorporates a large range of trace metals such as Sr, Y, U, Th, as well as the rare earth elements, that allows obtaining useful information on their genesis and could be used in several applications in geology and geochemistry. In this study, a new method for the multielement analysis of apatite using total-reflection X-ray fluorescence spectrometry (TXRF) was developed. The acid digestion procedure was chosen as an optimal sample preparation with the capability to analyze a low sample amount (~5-10 mg). The validation of the method passed through the combination of procedures: analysis of Durango and Otter Lake well-known apatite samples; using inductively coupled plasma mass spectrometry and wavelength-dispersive X-ray fluorescence spectrometry as reference analytical methods; assessment of the measurement uncertainty. The proposed TXRF method is advantageous in being fast, cheap and simple for the multielement analysis of apatite with high accuracy.
