Accelerated membrane-assisted clean-up as a tool for the clean-up of extracts from biological tissues

Accelerated membrane-assisted clean-up (AMAC) is a new technique to purify lipid-rich extracts of biota samples. It combines a separation of organic analytes and lipid-like matrix components using a semi-permeable membrane with the technical options provided by a Dionex ASE device which was developed for pressurized liquid extraction (PLE; Dionex trade name ASE for accelerated solvent extraction). The ASE device automates the procedure. It offers the possibility to increase the permeation of the analytes through the membrane via application of higher temperatures and automatic solvent exchange to ensure steep gradients across the membrane. The optimal operating parameters of AMAC were determined in this study. Satisfactory recoveries of over 70% for most target compounds, as well as excellent removal of lipid-like matrix components were achieved using 80 μm thick low-density polyethylene (LD-PE) membranes, at a temperature and pressure of 40 °C and 3.45 MPa, respectively, over 16 static cycles lasting 10 min each. The recoveries obtained were similar to those achieved using gel permeation chromatography (GPC), however AMAC showed a higher matrix removal capacity. AMAC removed up to 4.5 g of lipids in a single run, which was more than 98% of the original matrix content. Additionally, a 13-fold lower solvent consumption, compared with GPC, was achieved. AMAC separates analytes and matrix compounds mainly by size, making this method a beneficial tool for non-target or effect analysis. AMAC is especially applicable for processing large amounts of sample as a result of the high matrix removal capacity.