Purification of extracted fatty acids from the microalgae Spirulina

The fatty acid (FA) analysis of microalgae Spirulina was studied by applying accelerated solvent extraction (ASE) and followed by purification using solidphase extraction (SPE). The objective was to develop a sensitive and reliable purification procedure to remove pigment in lipids co-extracted from Spirulina. Four extraction solvents were used for the ASE lipids extraction. The extraction efficiency was ranked in the following order: chloroform:methanol > dichloromethane:methanol > ethanol > hexane. The major composition of fatty acids were examined. Hexane and chloroform:methanol were compared for the purification step. The amounts of sorbent (Silica gel H), sample, and the volume of eluent were optimized during SPE procedure. This purification step can successfully remove the pigments from extracted lipids. For 0.1 g algae sample, chloroform:methanol (2:1, v/v) was the optimal extraction solvent, 0.3 g silica gel was the optimal amount of sorbent, with 7 mL for the volume of eluent. For hexane as the extraction solvent, 0.5 g algae sample, 0.3 g silica gel was the optimal amount of sorbent, 5 mL was the optimal volume of eluent. The calibration curve was produced comprised from five samples that contained FAME concentrations which was ranged from 0.1 to 10 mg/L (R2 > 0.99). The recoveries of fatty acids were 67.97-134.37%, 74.20-99.13% and 98.34-115.42%, with standard deviations (SD) of three replicate detections ranged from 1.09 to 8.41%. © AOCS 2011.