microwave digestion

Microwave digestion is dissolving a sample in acid inside a sealed, microwave-heated vessel — using the same waves that cook your dinner to drive a fierce, fast breakdown in a tightly closed container. Because the lid is sealed, the acid can be pushed well past its normal boiling point under pressure, attacking tough samples far faster than an open beaker on a hotplate.

Concretely, a weighed sample and a measured volume of acid go into a strong, sealed vessel, which is heated in a microwave system. The trapped pressure and high temperature speed the reaction enormously, so a digestion that took hours in an open vessel finishes in minutes, with the whole batch of vessels processed together under controlled conditions.

It is now the standard way to digest samples for trace-metal analysis, prized for speed, low reagent use, and a critical advantage: the sealed vessel keeps volatile elements like mercury and arsenic from escaping, which open dry ashing or open digestion would lose. The caveats are the cost of the instrument and the genuine hazard of high-pressure acid, which demands careful, vented, well-maintained equipment.