Hexadecatrienoic acid (C16:3) and its ethyl ester (CAS 25377-56-4) are used primarily as analytical standards and reference materials in plant, algal, microbial, and marine lipid analysis by GC-FID/GC-MS, since esterification improves volatility and peak shape, enabling confident identification/quantitation of C16:3 fatty acids, calibration-curve construction, retention-index mapping, and response-factor determination; they also serve as model substrates to study oxidation of polyunsaturated lipids (autoxidation, photooxidation), to evaluate antioxidant efficacy and storage stability; as enzyme substrates in assays with lipases, esterases, lipoxygenases, and desaturase-elongase systems, and in biocatalyst screening for esterification/transesterification; in organic and lipid synthesis the C16:3 ethyl ester is used as a building block to prepare acyl derivatives (e.g., acyl chlorides, defined triacylglycerols/phospholipids) or as a source of C16:3 for isotope labeling; it also supports nutrition/biology studies on metabolic fate, chloroplast membrane incorporation, and the role of 16:3 fatty acids as a "16:3-plant" biomarker, as well as method validation for LC/GC-MS lipid quantitation.
