To purify the organic extracts, select the appropriate dispersive SPE kit depending on the method and matrix. An aliquot of the extract from the first step is added to a 2 mL or 15 mL centrifuge tube containing the QuEChERS components to remove interfering matrix components and to bind existing water. The BEKOlut® PSA kits (with 2 or 15 mL centrifuge tubes) are filled with PSA (Primary Secondary Amine) to remove oligosaccharides and fatty acids, with magnesium sulphate to bind water and/or C18e to remove residual lipids and/or GCB (Graphitized Carbon Black) to remove colour pigments. They are therefore ready for immediate use.