Based on the outcome of an inter-laboratory investigation of the Arctic sea ice biomarker proxy IP25 initiated by Simon Belt (Belt et al., 2014) we changed the extraction method for biomarker proxies from Accelerated Solvent Extractor (ASE) to ultrasonication (US). To ensure that the new results are still comparable with previously produced data we simultaneously extracted several sediment samples with both methods. In this context we extracted the highly branched isoprenoids (IP25, C25 HBI diene, C25 HBI (Z) triene, and C25 HBI (E) triene) well as the sterols (brassicasterol, dinosterol, campesterol, and ß-sitosterol. Here we present the results from Core MSM05/3_343310-5-1.