Quantitative determination of F:O ratios in rare earth oxide fluorides by energy dispersive X-ray analysis

Abstract

The F:O ratio in homogeneous and inhomogeneous rare earth oxide fluoride systems of compositions RO(1+x)F(1-2x) with -0.1</=x</=0.1 can be determined by energy dispersive X-ray (EDX) analysis with an accuracy of +/-0.5% if an appropriate background modelling procedure is applied and if the EDX signals of the light elements are free of overlap from the accompanying rare earth element. The latter condition holds true for R=Tb-Lu and it is shown that the calibration of the method with well-defined samples of YbO(1+x)F(1-2x) can be transferred with only a moderate loss of accuracy to the determination of oxygen and fluorine in DyOF and ErOF. Increasing signal overlap in case of GdOF, EuOF, SmOF and especially PrOF necessitates the choice of different channels for background modelling, and the accuracy of the method is hence decreasing to +/-4% for these systems.

Subcellular Quantitative Determination of K and Ca in Phloem, Cambium, and Xylem Cells of Spruce(Picea abies[L.] Karst.) During Earlywood and Latewood Formation

“…Marx et al 1996) 1994). In our study, the TEM-EDXS system was calibrated for quantitative analysis by proper reference materials for xylem tissues of latewood tracheids of spruce with an accuracy of 66 to 87 % for Κ and 84 to 87 % for Ca.…”

“…However, methods available for the characterization of the subcellular distribution of mineral elements in tissue samples work only semiquantitatively (Schröder et al 1988;Tolstogouzov 1997). However, recent studies (Fritz and Jentschke 1994;Marx et al 1996) using both, EDXS and scanning electron microscopy (SEM), indicated that the usual resolution of conventional microprobe analyses (MA) can be significantly expanded to a resolution much below 1 . Encouraged by these results, we studied our samples also with a transmission electron microscope by quantitative EDXS from selected areas <30nm after calibration with wood tissues of known and Ca compositions.…”