How does microwave extraction speed up the extraction process?

The use of Microwave Extraction using USEPA 3546 has allowed testing labs to significantly increase their throughput.  EPA 3546 is the standard method for extraction is soxhlet extraction. While this is a tried and true method, it is time and solvent consuming. Microwave extraction reduces the solvent usage significantly while also reducing the overall time. This time savings comes from the elevated temperatures reached using closed vessels as well as overall through-put compared to the Thermo ASE or Soxhlet methods (40 batch style vs 24 sequentially). In addition, the use of closed vessels allows for extraction of volatile compounds that would have been lost otherwise.

 

For instance, an analytical batch of 24 – 26 samples can be processed in the microwave in just twenty minutes.   You must filter the samples after the extraction process but you can load your next turntable and extract the second batch right away.  It is not unusual for a high throughput lab to process one hundred or more samples in a day using a single microwave.  An optional glass insert for the MARSXpress Plus vessel offers additional time savings.