Improved separation and quantification of neutral and polar lipid classes by HPLC–ELSD using a monolithic silica phase: Application to exceptional marine lipids

Abstract

a b s t r a c tAn improved HPLC method is presented, which allows separation and quantification of a broad range of lipid classes of marine zooplankton with special regard to neutral lipids. Marine zooplankton species often produce high amounts of exceptional lipids, especially at high latitudes, in order to cope with the harsh environmental conditions and strong seasonality in food supply. Major neutral lipid classes are wax esters, triacylglycerols, diacylglycerol ethers, free fatty alcohols and sterols. Neutral and polar lipids were separated and identified on a monolithic silica column (Chromolith ® Performance-Si) using high performance liquid chromatography (HPLC) with an evaporative light scattering detector (ELSD). The method resolves a broad spectrum of lipids, varying in polarity from squalene to lysophosphatidylcholine in a single run. The total run time was 35 min including column re-equilibration. The calibration was made at levels of 0.1-60 g lipid/injection, but a 10-15-fold greater amount can be injected if single lipid classes need to be separated, e.g. for further determination of individual fatty acids. The method was applied to representative Arctic zooplankton species (copepods, pteropods, euphausiids and ctenophores) that are known to biosynthesize in particular neutral lipids like diacylglycerol ethers and free fatty alcohols.

The black-legged kittiwake preen gland—an overlooked organ for depuration of fat-soluble contaminants?

“…The analyses were performed at Unilab Analyse AS in Tromsø, Norway. Neutral and polar lipid classes were separated and identified on a monolithic silica column using high-performance liquid chromatography coupled to an evaporative light-scattering detector (Graeve & Janssen 2009). …”

Effects of prolonged darkness and temperature on the lipid metabolism in the benthic diatom Navicula perminuta from the Arctic Adventfjorden, Svalbard

“…The solvent dichloromethane:methanol was evaporated under nitrogen in a heat block (30 °C), the residue diluted in 50 µL cyclohexane and transferred to HPLC-vials. The lipid classes were separated with a HPLC system [monolithic silica column, 100 × 4.6 mm I.D., macropore size of 2 µm, mesopore size of 13 nm (130 Å), total porosity of >80%, drift tube temperature of 40 °C, 3.5 bar internal nitrogen pressure; Chromolith ® Performance-Si, LaChrom Elite HPLC system, VWR, Germany] using a gradient programme in combination with three Eluents after Graeve and Janssen (2009). For detection, an evaporative light scattering detector (Sedex 75, Sedere, France) was utilised.…”

Atmospheric Pressure Photoionization as a Powerful Tool for Large-Scale Lipidomic Studies

“…Normal-phase liquid chromatography was performed on an Agilent 1100 series HPLC system (Agilent, Palo Alto, CA, USA), according to a method adapted from Greave et al [30] Briefly, two Chromolith Performance Si columns (Merck, Darmstadt, Germany), 100×4.6 mm are set-up in series at fixed temperature of 40°C. Eluent flow rate was 1 mL.min -1 .…”