Complete Analyte Recovery with Microwave Evaporation
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"Microwave assisted evaporation is an effective method for the complete recovery of many analytes that have previously been documented to be volatile. . . . This capability is needed as ultratrace sample preparation procedures are required for an ever increasing number of sensitive instrumental techniques."
— Dirk Link and H.M. Kingston,
Analytical Chemistry, Vol. 72, No. 13 |
In addition to its utility for sample digestion, microwave energy can also be used for post-digestion processing, of which the most common step is evaporation. This is done to concentrate the sample when the initial analyte levels are below the instrument limit of detection, or because the matrix is incompatible with the detection method.
The use of traditional hot-plate evaporation methods can lead to losses of volatile analytes, because the sample is overheated as it approaches dryness. In contrast, the unique heating mechanism exclusive to microwave heating allows the temperature to decrease as the sample approaches dryness, preventing the loss of volatile elements.
In a recent comparative study, re-dissolution and analysis of the residue by ICP-MS showed that, while losses of several classically volatile analytes occurred using hot plate evaporation, complete recovery was achieved using Milestone's Ethos digestion labstation with MMR Evaporation Rotor.
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Milestone offers two modules for effective sample evaporation:
- Our MMR Rotor (pictured in labstation cavity) is an advanced labstation component for conveniently heating materials in a microwave field under controlled vacuum conditions. When connected to an external vacuum supply, it is used for rapid sample volume reduction, acid removal, and acid neutralization.
- Our VAC-1000 Module (pictured at left of labstation) is a high performance system that integrates a vacuum pump, water cooled condenser and a neutralizing module to completely recover and/or neutralize acid vapors.
For more information on these items, view our Microwave Evaporation page.
Benefits of the MMR System
- Dramatically faster than traditional hot plate evaporation (typical time savings: about 50%)
- Prevents contamination because evaporation is performed in a closed system
- No loss of volatiles
Clean Chemistry: Continue to trace cleaning, acid purification, closed-vessel digestion, or vessel inserts.
General: Go to the Milestone front page, or send us an inquiry.