Kornerupine, (square,Mg,Fe)(Mg,Fe,Al)(9)(Si,Al,B)(5)(O,OH,F)(22), contains from 0 to 4 wt% B2O3, and is an ideal material for the evaluation of accuracy and precision of different micro-methods for boron analysis. We have analyzed 32 well-characterized crystals of kornerupine for their B content by SREF (crystal-Structure REFinement), SIMS (Secondary-Ion Mass Spectrometry) and EMPA (Electron-MicroProbe Analysis). The physical phenomena underlying these three analytical methods are entirely different, and hence there should be no systematic errors common to all three methods; this allows evaluation of the accuracy and precision of each method. In the range 0.5-4.4 wt% B2O3, the precisions of the three methods are as follows: SREF (from least-squares refinement) 1-2% relative, 0.01-0.08 wire absolute; SIMS (from reproducibility) 1-2% relative, 0.01-0.08 wt% absolute; EMPA (from counting statistics) 5-22% relative, 0.1-0.2 wt% absolute. Comparison of SREF and SIMS results shows them to agree on average within 3% relative. Hence SREF and SIMS are accurate within the limits of their assigned precision. Comparison of SREF and EMPA results shows a slight systematic difference between the two sets of results, the EMPA values being 7% higher than the SREF (and SIMS) results.
MICROANALYSIS OF MINERALS FOR BORON BY SREF, SIMS AND EMPA - A COMPARATIVE-STUDY
OTTOLINI L;
1995
Abstract
Kornerupine, (square,Mg,Fe)(Mg,Fe,Al)(9)(Si,Al,B)(5)(O,OH,F)(22), contains from 0 to 4 wt% B2O3, and is an ideal material for the evaluation of accuracy and precision of different micro-methods for boron analysis. We have analyzed 32 well-characterized crystals of kornerupine for their B content by SREF (crystal-Structure REFinement), SIMS (Secondary-Ion Mass Spectrometry) and EMPA (Electron-MicroProbe Analysis). The physical phenomena underlying these three analytical methods are entirely different, and hence there should be no systematic errors common to all three methods; this allows evaluation of the accuracy and precision of each method. In the range 0.5-4.4 wt% B2O3, the precisions of the three methods are as follows: SREF (from least-squares refinement) 1-2% relative, 0.01-0.08 wire absolute; SIMS (from reproducibility) 1-2% relative, 0.01-0.08 wt% absolute; EMPA (from counting statistics) 5-22% relative, 0.1-0.2 wt% absolute. Comparison of SREF and SIMS results shows them to agree on average within 3% relative. Hence SREF and SIMS are accurate within the limits of their assigned precision. Comparison of SREF and EMPA results shows a slight systematic difference between the two sets of results, the EMPA values being 7% higher than the SREF (and SIMS) results.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
