Our laboratory houses a ThermoARL Advant’XP+ sequential X-ray fluorescence spectrometer purchased in 2003. Samples are received from researchers and students at other universities from both the USA and other nations as well as from WSU School of Earth & Environmental Science students and faculty. Sample preparation and analysis usually takes about 2 months.
Samples received as rock or powder are prepared for analysis by chipping, grinding to a very fine powder, weighing with di-lithium tetraborate flux (2:1 flux:rock), fusing at 1000°C in a muffle oven, and cooling; the bead is then reground, refused and polished on diamond laps to provide a smooth flat analysis surface. Advantages of the low-dilution fusion method include full correction of matrix effects for all major and trace elements, robustness (we’ve stored beads for decades and rerun them with good results), economy of sample preparation time, and cleanliness of the instrument.
The same suite of elements is analyzed on our spectrometer for all samples (averages 65 minutes per sample), which includes the 10 major and minor elements of most rocks, plus 19 trace elements.