Liquid chromatography separation of α- and γ-linolenic acid positional isomers with a stationary phase based on covalently immobilized cellulose tris(3,5-dichlorophenylcarbamate).

•α- and γ-Linolenic acids (ALA and GLA) are involved in several metabolic processes.•ALA and GLA-rich oils hold a potential as source of nutrition or in cosmetics field.•An immobilized cellulose-based CSP allows the RP separation of ALA/GLA.•The separation method was optimized and transferred to a LC–MS/MS platform.•The proposed innovative method was applied to analyze edible oils and human plasma.