Different sample preparation techniques commonly used for the analyses at the Toxicological centre are described below.

Soxhlet Extraction

In Soxhlet extraction, a solid sample is extracted at a high temperature with an organic solvent. By including a reflux cooler the organic solvent continuously evaporates from a solvent container and condenses to flow into the extraction chamber (where the sample and the analytes remain). This cycling process creates a “fresh/clean” extraction solvent throughout the whole procedure. The extraction takes 2 hours (if extraction is used in hot Soxhlet mode) and is usually followed by concentration and clean-up (e.g. Solid Phase Extraction).

Solid Phase Extraction

In Solid Phase Extraction, a solution containing the target compound is loaded onto a sorbent in a cartridge. Target compounds are retained on the sorbent if their affinity for the sorbent is higher than for the solution. This technique can be applied both for extraction of drugs, drugs of abuse, and contaminants from fluids and for clean-up of extracts (after Soxhlet or liquid-liquid extraction). 

Micro Solid Phase Extraction

In micro solid phase extraction, a miniaturized solid-phase extraction (SPE) set-up is applied with a 96 well system containing different SPE sorbents for the recovery and concentration of the targeted compounds. Currently, this analytical approach is employed for the analysis of a broad range of psychoactive compounds in influent wastewater and phosphate flame retardants in human urine.

Liquid-liquid extraction

Liquid-liquid extraction employs differences in affinity of a specific compound for two immiscible solutions. Many drugs, drugs of abuse, and contaminants have a higher affinity for an organic solvent than for water and are easily extracted from blood for instance by adding a solvent. It is a quick approach for sample preparation, but can make part of a longer sample preparation protocol.


The homogenator/dissociator is a benchtop instrument for the semi-automated dissociation of tissues into single-cell suspensions or thorough homogenates. A single sample or two samples in parallel can be processed. Two types of unique tubes used with the instrument enable the time-saving and easy dissociation or homogenization of tissues in a closed system. Special protocols have been developed for various tissues, including human liver and kidney.