Lipidyzer

C. elegans samples were analyzed as described by [91 (link)] and completed at the Northwest Metabolomics Research Center. Briefly, Quantitative lipidomics was performed with the Sciex Lipidyzer platform consisting of a Sciex QTRAP® 5500 mass spectrometer equipped with SelexION® for differential mobility spectrometry (DMS). 1-propanol was used as the chemical modifier for the DMS. Samples were introduced to the mass spectrometer by flow injection analysis at 8 μL/min. Each sample was injected twice, once with the DMS on (PC/PE/LPC/LPE/SM), and once with the DMS off (CE/ CER/DAG/DCER/FFA/HCER/ LCER/TAG). The lipid molecular species were measured using multiple reaction monitoring (MRM) and positive/negative polarity switching. A total of 1070 lipids and fatty acids were targeted in the analysis. Using 54 internal standards previously used and described in [92 (link)], quantities (in μmol/g) of each lipid species could be calculated. Data were acquired and processed using Analyst 1.6.3 and Lipidomics Workflow Manager 1.0.5.0.

Lipids were extracted from 100 μL of serum by the methyl-tert-butylether method and analyzed using Lipidyzer, a direct infusion-tandem mass spectrometry (DI-MS/MS)-based platform (Sciex, Redwood City, California). Lipid concentrations were expressed as nmol/g of serum.

The mass spectrometry analysis was performed on a Lipidyzer™ Platform, including the Sciex QTRAP® (SCIEX, Darmstadt, Germany) 4500 system. Multiple reaction monitoring (MRM) was used to target and quantitate several hundreds of lipids molecular. All samples were first measured in positive and negative polarity with SelexION separation, followed by measurement without SelexION separation. Lipids were identified based on their retention time, and mass spectral information. We provide this information (filename-identification method.xlsx). All data were acquired and processed automatically using the Lipid Manager Workflow software (SCIEX, Darmstadt, Germany).

Lipidomic analysis was carried out with a triple quadrupole mass spectrometer (QTRAP 5500; AB SCIEX, Framingham, MA, USA) equipped with a differential mobility spectrometer (DMS) interface operating with SelexION technology [58 (link)]. This device was coupled to an ultra-high pressure liquid chromatography system (Nexera X2, Shimadzu, Kyoto, Japan). The lipidomics platform (Lipidyzer^TM) was operated with lipidomics algorithms (Analyst version 1.6.8 and Lipidomics workflow manager; AB SCIEX, Framingham, MA, USA). The Lipidyzer^TM Platform was tuned with a SelexION Tuning Kit (AB SCIEX, Framingham, MA, USA), and a system suitability test was performed with a System Suitability Kit (AB SCIEX, Framingham, MA, USA), both according to the manufacturer’s instructions. The Lipidyzer^TM Platform used 10 mM ammonium acetate in dichloromethane : methanol (50:50 (v/v)) as the running buffer, dichloromethane : methanol (50:50 (v/v)) as rinses 0 and 1, 2-propanol as rinses 2 and 3, and 1-propanol as a DMS modifier. 50 µL samples were injected for both multiple reaction monitoring (MRM) methods: one with DMS on and one with DMS off. A detailed description of this shotgun approach has been reported previously [59 (link)]. Data processing and quantification were performed automatically by the Lipidyzer^TM lipidomics workflow manager; lipid concentrations are given in nmol/mL.

The SPLASH LIPIDOMIX Mass Spec Standard was from AVANTI. Chromatographic grade methanol and methyl tert-butyl ether (MTBE) were purchased from the CNW Technologies, Shanghai, China. The Lipidyzer TM was from the AB Sciex Pte. Ltd., Massachusetts, United States. Chromatographic grade ammonium acetate, dichloromethane and isopropanol were obtained from the Merck Company, Darmstadt, Germany. The SCIEX ExionLC system was coupled to a SCIEX QTrap 6500+ (AB Sciex Pte. Ltd., Massachusetts, USA). ACQUITY UPLC HSS T3 (2.1 ∗ 100 mm, 1.8 μm, Waters Corporation, Milford, MA, USA) was used for lipidomics analysis.