Analytical inconsistencies in the measurement and reporting of IP25, IPSO25 and related biomarkers for paleo sea ice reconstruction

• Phytosterol concentrations in Arctic sediments dependent on extraction method. • Analytical inconsistences found in many published papers on sea ice biomarkers. • Recommendations for measurement and reporting of sea ice biomarker concentrations. • Recommendations useful for future peer-reviewing and dataset selection. IP 25 and related biomarkers are commonly used for Arctic and Antarctic sea ice reconstruction. With a growing number of laboratories performing their measurement, we reviewed many publications spanning the period 2007–2024 in order to assess analytical rigour. We found a number of common shortfalls in analytical protocols, or at least how they are reported, which may have important implications for future synthesis studies and meta-data analyses. Here, we outline some of these shortcomings and provide suggestions of how to improve both data acquisition and reporting.