A 0.5g sample is digested in aqua regia in a microprocessor controlled digestion block. The solution is diluted and analyzed by ICP-MS. One blank is run for every 68 samples. An in-house control is run every 33 samples. Digested standards are run every 68 samples. After every 15 samples, a digestion duplicate is analyzed. Instrument is recalibrated every 68 samples.
Certain elements (Ti, P and S) are analyzed by ICP-OES. This extends the dynamic range for a number of elements as well. International certified reference materials are analyzed at the beginning and end of each batch of samples. Internal control standards are analyzed every 10 samples and a duplicate is run for every 10 samples. This digestion is not total and will not dissolve silicates some oxides and resistate minerals (e.g., zircon, monazite, sphene, etc.).
Au is semi-quantitative due to the small sample size.
Extraction of each element by Aqua Regia Digestion is dependent on mineralogy.
Unaltered silicates and resistate minerals may not be dissolved.
+ Sulphide sulphur and soluble sulphates are extracted.