Advanced Microwave Extraction System for Environmental Applications
The overall concept of the ETHOS X for environmental applications has been developed looking at the working routine of several thousands contract laboratories around the world performing solvent extraction, with the aim of helping them, by offering an integrated solution able to render their activity easier, faster and safer. The ETHOS X processes more samples in less time and uses a fraction of the solvent required by other technologies.
It is very simple to use and, following an already established US EPA and ASTM methods, it assures consistent results with a minimal running cost. The new Milestone ETHOS X microwave cavity has a volume in excess of 70 liters, by far the largest currently available. With an installed power of 1900 Watts, the ETHOS X is the most powerful microwave platform system available for extraction. A high definition digital camera allows the chemist to monitor the progress of the extraction while fully protected by the all-stainless steel door of the instrument. Should there be a sudden over-pressurization of the cavity, the door slightly opens for rapid and safe pressure release and the microwave power is instantaneously cut off. A built-in magnetic stirrer is designed to ensure vigorous agitation of the solutions in all vessels.
The new Milestone ETHOS X is equipped with the most advanced yet easy to use reaction temperature and pressure sensors for complete quality control of the extraction conditions. It is controlled via a compact terminal with an easy-to-read, bright, full-color, touchscreen display. The terminal runs a completely new icon-driven, multilanguage software to provide easy control of the microwave run. A completely new rotor has been specifically developed by Milestone to fully accomplish the US EPA method 3546 requirements.
This new rotor consists of a 24-position carousel, which holds large pressure vessels made of an innovative and unique inert polymer material. At the core of the vessel there is a disposable and inexpensive 100 mL glass vial. A self-regulating pressure cover assures safe operations of the system. Temperature and pressure are monitored and controlled in all vessels by non-contact sensors. A fast easy-to-use automatic capping tool makes sure all vessels are properly tightened prior the microwave run.
US EPA METHOD 3546
The US EPA method 3546 is a procedure for extracting water insoluble or slightly water soluble organic compounds from soils, clays, sediments, sludges, and solid wastes. The procedure uses microwave energy to produce elevated temperature and pressure conditions (100-115°C and 4-12 bar) in a closed vessel containing the sample and organic solvents to achieve analyte recoveries equivalent to those obtained from Soxhlet extraction, using less solvent and taking significant less time than the Soxhlet procedure. This method is applicable to the extraction of semivolatile organic compounds, organophosphorus pesticides, organochlorine pesticides, chlorinated herbicides, phenoxyacid herbicides, substituted phenols, PCBs, and PCDDs/PCDFs, which may then be analyzed by a variety of chromatographic procedures. The US EPA method 3546 is applicable to solid samples with small particle sizes. The total mass of material to be prepared depends on the specifications of the determinate method and the sensitivity needed for the analysis, but an amount of 2-20 g of material is usually necessary and can be accommodated by this extraction procedure.
This method has been validated using hexane and acetone (1:1) for matrices such as soil, glass-fibers and sand. Hexane is a water-immiscible and acetone is a water-miscible solvent. The purpose of the water-miscible solvent is to facilitate the extraction of wet solids by allowing the mixed solvent to penetrate the layer of water on the surface of the solid particles. The water-immiscible solvent extracts organic compounds with similar polarities.
(In the picture, US EPA method 3546 temperature profile, suitable for the microwave solvent extraction of: Chlorinated pesticides, Semivolatile organics, PAHs, PCBs, Chlorinated herbicides, Phenols, Organophosphorus pesticides, Dioxins, Furans)