As many researchers are aware, some of the most demanding sample preparation procedures are called digestions. The aim of this process, like biological digestion, is to break a sample down into more basic constituents, but for analysis rather than for food use. Time, heat, and strong acids, oxidants, and bases are the agents of the process. Sample digestion is often involved in hunts for trace metals, to prepare for such analyses as atomic absorption or inductively coupled plasma spectroscopy. The Kjeldahl nitrogen determinations used by food scientists are another form of digestion.
Recently, a number of advanced microwave-based sample preparation systems have appeared on the market. These devices promise unprecedented procedural ease, greater control, and improved reproducibility of results with digestions. The new systems also make digestions--which often involve heated acids under pressure- -safer for laboratory workers. A wide range of analytical chemists, from protein analysts to chemists doing environmental ...
