Microwave-Assisted Digestion
Definition
Closed-vessel digestion in PTFE or quartz bombs at 1200 to 1800 W, reaching 200 degrees Celsius and 1500 psi in 30 to 60 minutes.
- Vessel type
- Closed PTFE or quartz bombs
- Power range
- 1200 to 1800 W
- Peak temperature
- Up to about 200 degrees Celsius
- Peak pressure
- Up to about 1500 psi
- Digestion time
- 30 to 60 minutes
Common questions
Why use a closed pressurised vessel instead of open-beaker digestion?+
Sealing the sample prevents loss of volatile elements such as mercury or arsenic species that would otherwise escape as vapour during heating, and the higher pressure and temperature achievable in a closed bomb digest tissue more completely and faster.
What advantage does this give over traditional wet digestion on a hotplate?+
It cuts digestion time from hours to under an hour, reduces reagent volume and contamination risk from open handling, and gives more consistent, complete sample breakdown before instrumental analysis for metallic poisons.
Related terms
- Acid Blank
- A parallel digestion of reagents in an empty vessel, subtracted from the sample to correct for trace metal contamination in the acids.
- Ashing Aid
- A salt (typically magnesium nitrate) added before dry ashing to fix volatile elements as less volatile salts that survive the furnace.
- Dry Ashing
- Viscera or hair is dried and incinerated in a muffle furnace at 450 to 550 degrees Celsius. Inorganic ash is dissolved in...
- Matrix Destruction
- Breakdown of organic tissue into water, CO2 and mineral residue so bound metals are released as free ions. Without it, AAS reads...
- Wet Digestion
- Viscera is digested with HNO3 + H2SO4 + HClO4 (or HNO3 + H2O2) at controlled temperature. Closed-vessel microwave-assisted digestion in Teflon bombs...