Overcome the Memory Effect in Dioxins Extraction with ETHOS X Powered by FastEX-24

Diego Carnaroglio and Matteo Volpi, Milestone Srl

Microwave extraction becomes faster and easier with the new Milestone ETHOS X with its FastEX-24. This application note shows the use of Milestone technology for extraction of dioxins from environmental matrices, with emphasis on one of the most common challenge of this application: the carryover effect. The unique design of the FastEX-24 rotor with disposable glass vials allows easy and efficient dioxin extraction, and other organic pollutants, to be performed, avoiding any memory effect. The FastEX-24 simplifies the routine pollutants extraction process and provides superior productivity at lower costs.

Figure 1: ETHOS X microwave extraction system.

Dioxin is known as one of the most toxic chemicals, a serious public health threat. According to the US Environmental Protection Agency (EPA) reports, dioxin and dioxin-like chemicals have been associated with adverse health effects in the population. 

The analysis of this class of pollutants is fundamental for environmental and human health protection, but because of the persistent nature of those compounds, the sample preparation and analysis is challenging for many extraction techniques. Many solutions are available for the extraction of dioxins such as Soxhlet, automated Soxhlet, sonication, pressurized liquid extraction (PLE), and closed microwave vessels. A common and very critical issue in all sample preparation techniques is dioxin extraction and the subsequent memory effect or carryover in the extraction cells. ETHOS X equipped with the unique FastEX-24 rotor is specifically designed to overcome the memory effect and cleaning by using disposable glass vials as reaction vessels, which are placed into a pressure reactor. This approach ensures the lowest analytical blanks and completely avoids carryover between runs.

Instrumentation

Milestone’s new ETHOS X microwave extraction system can extract organic contaminants from soils, in full compliance with EPA 3546 (100–115 °C and 50–150  psi). Disposable glass vials and contactless temperature control in all positions makes it a unique and innovative solution for the extraction of contaminants from soils, providing unmatched ease of use and low running costs. The ETHOS X is capable of processing up to 30 g of sample per vessel (up to 24 samples simultaneously), thereby improving the limit of quantitation (LOQ) for analysis. The handling is very easy because the sample is weighed directly into the disposable glass vial, 1:1 hexane–acetone or CH2Cl2–acetone is added, and the vessel is loaded into the FastEX-24 rotor. After 10–20 min of microwave heating, the sample is ready to be filtered and analyzed by gas chromatography (GC). ETHOS X provides full data traceability of the entire process.

Results

Table 1 shows recoveries of all the molecules in the range of 80–120% with great reproducibility (RSD%). It also shows the blank values of the following run with new disposable glass vials (all the blanks were below 0.065 µg/kg).

Conclusion

The ETHOS X enables simultaneous dioxins extraction of up to 24 samples (from weighing to filtration steps) in less than 1 h offering superior productivity than any other technology in the market. In addition, the use of contactless temperature control and disposable glass vials fully solves constant issues in dioxins determination by avoiding tedious cleaning, memory effect, and carryover. The ETHOS X with all its unique features fully addresses the needs of environmental laboratories in terms of productivity, ease of use, running costs, extraction quality, and is fully compliant with EPA 3546 method.

Milestone Srl
Via Fatebenefratelli, 1/5 24010 Sorisole (BG), Italy
Tel.: +39 035 573857
E-mail: marketing@milestonesrl.com 
Website: www.milestonesrl.com