Comparison of supercritical fluid extraction and Soxhlet extraction for the determination of aliphatic hydrocarbons in seaweed samples

Supercritical fluid extraction (SFE) and Soxhlet extraction methods were compared in a study of the aliphatic hydrocarbon profiles of seaweed samples. Method precision for Soxhlet extraction (⩽7.58%) was slightly better than that for SFE (⩽9.28%) except for C28. The SFE method is a good alternative for the routine determination of alkanes in seaweed samples; however, for a complete study of shorter-chain n-alkanes, the Soxhlet extraction is a more suitable method. To evaluate the SFE and Soxhlet methods developed, three diverse Undaria pinnatifida samples collected at different dates and areas of the Galician coast were analyzed. n-Alkanes C18, C20, C22, C24, and C28 were found in all samples, with values lower than 7.9 μg g−1 d.w. The total hydrocarbon content was within the range of 13.6–21.7 μg g−1 d.w. C18 was found to be the most abundant.