Lösungsmittel-Extraktion im EDGE

Extraktion mit dem MARS und EDGE:

Lipids were extracted from dried soil samples using a microwave (CEM MARS5) or an Energized Dispersive Guided Extraction (CEM EDGE) system. No difference in performance was observed for the different extraction systems. Samples were processed in batches of roughly 15 to 20 g of material. For microwave extraction the samples were transferred to the extraction vessels and covered by a dichloromethane (DCM):methanol (MeOH) 9:1 (v/v, 25 ml) solvent mixture. Extraction temperature was programmed to ramp to 100 ◦C in 35 min and is subsequently held for 20 min. For EDGE extraction 25 ml DCM:MeOH 9:1105 (v/v) was used for extraction at 110 ◦C for 2 min and subsequent rinsing with 15 ml followed by a second extraction with 5 ml of solvent at100 ◦C and rinsing with35ml. The process was repeated on additional samplebatches to yield sufficient quantities of the target lipid compounds for 14C analysis. Pooled extracts were then dried under nitrogen flow.

The sediments were freeze-dried and subsequently extracted with the EDGE system. Briefly, the total lipid extract was saponified, the neutral fraction liquid – liquid extracted, and separated on a silica gel column into three fractions. The polar fraction was filtered using a polytetrafluoroethylene 0.45 μm filter prior to analysis. As GDGTs in the environment have predominantly glycosidic bounds, they are not cleaved to core GDGTs by base hydrolysis (done in this study). Hence, the fraction of GDGTs analysed in this study are mostly fossilized core GDGTs, plus a small fraction of the intact polar lipid GDGT pool.

In diesem Artikel  vergleichen die Autoren die Vorteile der EDGE-Lösemittelextraktion versus der ASE-Methode und erläutern die Zeitersparnis und die Steigerung des Probendurchsatzes.

Zusammenfassung

• An Accelerated Solvent Extraction (ASE) method for 20 pesticides was developed.
• An Energized Dispersive Guided Extraction (EDGE) method was compared.
• ASE and EDGE methods were used to extract pesticides from citrus and alfalfa leaves.
• The ASE and EDGE instruments had comparable extraction efficiency.
• The EDGE instrument extracted samples ~4.5 times faster than the ASE instrument.