We conducted research related to Microwave Digestion in hope it would lead to the improvement of analytical procedures used to characterise metal and mineral samples. In particular, this research is directed to the reduction in time, complexity, and expense of sample dissolution for chemical and instrumental analysis.
The rapid development of automated instrumentation has enabled the analytical chemist to perform an ever-increasing number of analyses. Unfortunately, sample preparation has not kept pace with the development of analytical instrumentation.
The Bureau previous investigated a method for the rapid, low-cost dissolution of samples in plastic pressure vessels. The method consisted of acid digestion in sealed plastic bottles that were heated in a boiling water bath. After digestion the samples were water cooled. Boric acid solution was then added to each bottle, and the solutions were reheated in the boiling water bath to dissolve any precipitated fluorides.
Because dissolution was carried out in closed plastic vessels, contamination was avoided and volatile gases such as SiF4 were retained. Samples could be prepared for analysis in less than an hour, and many elements could be analyzed from this single dissolution. In an effort to speed up dissolution time even further, the Bureau has introduced a significant improvement by