Comparing extraction methods for analyzing n-alkyl lipids in shelf sediments from the China Sea

•Four different extraction methods were evaluated.•Bligh-Dyer is best for simultaneous extraction of free n-alkanoic acids with intact polar lipids.•Bligh-Dyer + ultrasound-assisted extraction is suitable for n-alkanes extraction.•Accelerated solvent extraction is optimal for free n-alkanols extraction.•Odd-even effect and chain length impact different extraction methods.