This protocol provides a step-by-step guide to shotgun sphingolipid analysis of aqueous humor. We describe the Bligh and Dyer crude lipid extraction method and electrospray ionization tandem mass spectrometry (ESI-MS/MS) coupled with MZmine 2.21 data processing for identification and ratiometric quantitation of sphingosine, sphingosine-1-phosphate, sphingomyelin, and ceramide.
Keywords: Aqueous humor; Ceramide; Electrospray ionization-tandem mass spectrometry (ESI-MS/MS); MZmine 2.21; Shotgun lipidomics; Sphingolipids; Sphingomyelin; Sphingosine; Sphingosine-1-phosphate.