Microwave vs. Soxhlet for the extraction of PCDDs and PCDFs from sewage sludge samples

This study deals with a new sample preparation technique which minimizes pollution in analytical laboratories whilst reducing sample preparation time and cost. We evaluated the results of the microwave-assisted extraction (MAE) procedure for PCDDs and PCDFs. Our results show that most of these compounds can be recovered satisfactorily from the matrix investigated (sewage sludges). Recoveries ranged from 30 to 70% for the seventeen 2378-substituted isomers of PCDDs and PCDFs. These experiments indicated that MAE is a viable alternative to the conventional Soxhlet technique. The MAE technique requires smaller amounts of organic solvents and sample throughput is increased by shorter extraction times.