This study reports 78 Rietveld quantitative phase analyses using Cu K 1,
Mo K 1 and synchrotron radiations. Synchrotron powder diffraction has been
used to validate the most challenging analyses. From the results for three series
with increasing contents of an analyte (an inorganic crystalline phase, an organic
crystalline phase and a glass), it is inferred that Rietveld analyses from highenergy
Mo K 1 radiation have slightly better accuracies than those obtained
from Cu K 1 radiation. This behaviour has been established from the results of
the calibration graphics obtained through the spiking method and also from
Kullback–Leibler distance statistic studies. This outcome is explained, in spite of
the lower diffraction power for Mo radiation when compared to Cu radiation, as
arising because of the larger volume tested with Mo and also because higher
energy allows one to record patterns with fewer systematic errors. The limit of
detection (LoD) and limit of quantification (LoQ) have also been established
for the studied series. For similar recording times, the LoDs in Cu patterns,
0.2 wt%, are slightly lower than those derived from Mo patterns, 0.3 wt%.
The LoQ for a well crystallized inorganic phase using laboratory powder
diffraction was established to be close to 0.10 wt% in stable fits with good
precision. However, the accuracy of these analyses was poor with relative errors
near to 100%. Only contents higher than 1.0 wt% yielded analyses with relative
errors lower than 20%.
Buscar en Dimension