Glass‐bead/X‐ray fluorescence analysis of earthenware body – sampling from heterogeneous earthenware

Abstract

Samples of ancient earthenware were prepared in 1 : 10 glass beads for the X-ray fluorescence quantitation of 10 major elements (Na, Mg, Al, Si, P, K, Ca, Ti, Mn, and Fe). Calibration standards of the glass beads were used with a mixture of reagents in an arbitrary ratio instead of rock standards. The calibration curves were constructed using the reported values of Japanese wares and clay materials. The adequacy of conventional sampling methods was statistically evaluated by examining the homogeneities of two shards (112 g of Jomon ware and 92 g of Yayoi ware) with respect to their crystalline phases and 10 major constituents. Both shards were found to be heterogeneous. An important finding is that in the sampling from a shard, unless at least half of the shard is homogenized, small sampling cannot represent the whole shard. The sampling was found to be only marginally reliable because the K/Ca scatter diagram for determination of provenance showed regional characteristics, and the measured analytical values showed normal (or Gaussian) distributions. Furthermore, taking eight samples or above from a shard enhances the reliability of small sampling.

Determination of tungsten in tantalum–tungsten alloy by X-ray fluorescence spectrometry using fusion, thin layer, and pressed powder pellet techniques

“…The standard deviation (SD) and the relative standard deviation (RSD) of pressed powder pellet were found very high, suggesting that pressed powder pellet would give poor reproducibility in spite of the using of matrix correction and, consequently, was unsuitable for the accurate analysis of tungsten. The poor reproducibility may mainly result from the particle size effects and matrix effects [22,23]. For borate fusion and filter paper disk, the SD and RSD of both methods were lower than 0.1% and 1.0%, respectively, suggesting that their precision could meet the requirement of tungsten assay.…”

“…For borate fusion and filter paper disk, the SD and RSD of both methods were lower than 0.1% and 1.0%, respectively, suggesting that their precision could meet the requirement of tungsten assay. The main reason for their good reproducibility was that, compared with pressed powder pellet, borate fusion and filter paper disk could eliminate particle size effects and reduce or eliminate matrix effects [21,23].…”

Development of undersized (12.5 mm diameter) low‐dilution glass beads for X‐ray fluorescence determination of 34 components in 200 mg of igneous rock for applications with geochemical and archeological silicic samples

“…The intervals optimized evenness for ten major oxides and bias toward low concentration for 24 minor elements. The composition of the calibration standard set was constructed by reference to recommended values of Geological Survey of Japan geochemical references and calibration ranges of igneous rock and ancient pottery …”

Undersized (12.5 mm diameter) glass beads with minimal amount (11 mg) of geochemical and archeological silicic samples for X‐ray fluorescence determination of major oxides

“…collection date and location) and sample pretreatment (e.g. amounts, pulverization conditions) were reported elsewhere …”