Microwave offers greener approach to SVOC extraction
Microwave offers greener approach to SVOC extraction
Environmental NEWS - Fall 2009
Microwave offers greener approach to SVOC extraction
In the process of helping clients monitor and maintain environmental safety, Lancaster Laboratories believes it also has a responsibility to be a good steward of the environment. Choosing testing technologies that minimize laboratory waste is one of the ways that Lancaster Labs can meet this goal, and the recent implementation of microwave extraction for semivolatile organic compounds (SVOCs) in soil is a good example of this practice. In addition to using less solvent, the new method is more rugged than the ultrasonic extraction technique that has been the mainstay technique at Lancaster Labs for many years.
Kerrie Freeburn, chemist in the Organic Extractions Department,
performs microwave extraction for semivolatile organic compounds.
Microwave extraction using EPA method 3546 is an approved method for preparing soil, sludge, tissue and other solid wastes for SVOC analysis. In this relatively new method, the sample and solvent are sealed in a Teflon extraction vessel, which is then placed in a microwave. The microwave energy raises the temperature of the solvent, and the closed vessel causes the pressure to rise so that the solvent remains a liquid at temperatures above its boiling point. The resulting extraction is very efficient at separating SVOCs from solid matrices, requiring only 10 percent of the solvent used in the traditional ultrasonic approach. The extraction is useful to prepare samples for many different chromatographic tests, including EPA methods 8082, 8081 and 8270.
Analysts at Lancaster Labs have validated the microwave extraction by performing precision, accuracy and method detection limit (MDL) studies, yielding results that are very similar to earlier techniques. Currently, regulatory certifications are being updated as needed based on the data generated so that all clients can take advantage of the benefits offered by microwave extraction.
As manager of the Organic Extraction Laboratory, Rick Karam believes that there are many reasons why clients will appreciate the new technology. “The extraction efficiency of the microwave is comparable to the sonicators that we used in the past, but the microwave is more automated, which means there’s less opportunity for error in the extraction. This translates to greater consistency in the data that clients receive from Lancaster Labs,” he says. In addition, the microwave extraction takes less time than traditional methods, and this should translate to increased laboratory capacity and improved turnaround time.