Overcome memory effect in dioxin extraction on environmental matrices

SYNLAB is one of the largest service laboratories in Europe and the largest laboratory service provider for clinics, hospitals and the environmental industry. SYNLAB has representation in more than 40 countries on four different continents around the world. They have 19,000 employees and perform around 500,000,000 analyses per year.
In 2017, SYNLAB acquired ALcontrol Group, a major European provider of environmental testing services. This allowed SYNLAB to expand to the Netherlands, Sweden, Denmark and into markets that were highly complementary to the Group’s main focus. ALcontrol had expertise in the field of environmental analysis, including testing for the clean-up and monitoring of soil, ground and drinking water, food and consumer health, oil, fuel and asbestos. SYNLAB now has laboratories in four different locations in Sweden.
The environmental department of SYNLAB Linköping carries out a large selection of organic pollutant analyses. They work to determine dioxins in soils, sludges, bottom sediments, ashes and building materials and in some food matrices, above all in fish samples.

The environmental department of SYNLAB Linköping carries out a large selection of organic pollutant analyses. They work to determine dioxins in soils, sludges, bottom sediments, ashes and building materials and in some food matrices, above all in fish samples.
They analyze about 100 samples per week, depending on the project in implementation and the large amount of the total requires an extraction process.
In particular, they are focused on the determination of the following classes of organic pollutants: Dioxins, PAH’s, PCB’s.
SYNLAB’s Laboratory performs extractions using different techniques, such as sonication, soxhlet and automated soxhlet systems. In particular, they have two (2) Accelerated Solvent Extraction systems to extract dioxins from environmental matrices.
The main issue with this technique is related to memory effect/ carryover in the extraction cells. The stability of the dioxins requires long and tedious cleaning procedures of the extraction vessels. Moreover, they have experience solvent leakage and high maintenance costs.

They decided to move their current extraction methods to microwave technology. The main reason for the change is gaining efficiency, because they can run 24 samples simultaneously. Secondly, the ETHOS X’s ease of use as the fastEX24 rotor is specifically designed to overcome the memory effect and the cleaning steps by using disposable glass vials as reaction vessels, which are placed into a pressure reactor. This approach leads to ensure great analytical blanks and completely avoid carryover between runs. This results in increasing throughput and lowering labor costs. The glass vials are inexpensive and consumable cost are negligible. They can now process up to 24 samples in 40 minutes with the fastEX-24 rotor, reducing the cost per analysis. In 2018 they approximately extracted 1500 dioxin soil samples with the ETHOS X system.
The results obtained with microwave technology show recovery of all the molecules in the range of 80-120% with great reproducibility. Even after a dioxins extraction the blanks are always below 0,065 ug/Kg, thanks to the use of disposable glass vials, which allow to completely overcome memory effect and carryover.