Quantifying Lipid Profiles via GCMS

Cells were broken with 0.5 mm glass beads, and then total extracted lipids were methyl esterified with a fatty acid methylation kit (Nacalai Tesque, Kyoto, Japan). The fatty acid methyl esters were identified and quantified with a capillary gas chromatograph GC-2025 (Shimadzu, Kyoto, Japan) equipped with a DB-23 capillary column (60 m, 0.25 mm internal diameter, 0.15 μm film thickness) (Agilent Technologies, Santa Clara, CA, USA) followed by the previous method [15 (link)]. Heptadecanoic acid (Sigma-Aldrich Co., St. Louis, MO, USA) was used as an internal standard; rapeseed oil (Merck KGaA, Darmstadt, Germany) was used as a quantitative standard. The changes in the contents and compositions of lipids induced by the UV-C irradiation were also evaluated, with those at 0 min used as a control.