Rapid analysis and quantification of major neutral lipid species and free fatty acids by HPLC‐ELSD from microalgae

Abstract

A method based on normal‐phase high performance liquid chromatography combined with evaporative light‐scattering detector was developed to quantify major neutral lipids from microalgae. A binary gradient enabled a good resolution of hydrocarbons and major neutral lipids by classes in less than 13 min. A good linearity was observed from 0.9 to 30 μg. Limits of detection (LOD) and quantification (LOQ) was from 3 to 64 ng depending on the analyte. The intra‐ and inter‐run precision (% RSD) of analysis was found less than 10%. The method was successfully applied to microalgae lipid extracts from Botryococcus braunii, Chlorella vulgaris, Spirulina platensis, and Porphyridium cruentum. B. braunii was distinguished by the highest levels of lipids, triacylglycerol (TAGs), and diacylglycerol (DAGs) being the major compounds. Practical applications: Neutral lipids produced by the microalgae are an interesting way for the development of biofuel from renewable carbon. A simple quantification of these lipids is important in the implementation of oleaginous microalgae screening as well as in the bioprocess optimization of algal lipid production. Besides, determining quantitatively the major lipid classes provides information in the understanding of the biosynthetic pathways and the accumulation of these lipids in relation with algal culture conditions. Normal‐phase HPLC conditions were studied to establish a method allowing a rapid separation of TAGs, DAGs, MAGs, and FFA but also HC by classes in a single run. Their quantification through evaporative light‐scattering detector (ELSD) was performed. The developed method was applied on lipid extracts from the different algal cultures.