Effective recovery and high purity of lipid biomarkers are essential for compound-specific stable isotope analysis in a variety of fields ranging from hydrocarbon research, paleoclimatology, food and drug analysis and medicine. Solid-phase extraction (SPE) is the most common method for purifying organic compounds from complex mixtures. SPE constitutes the most labor-intensive part of laboratory work often limiting the number of samples that can be analyzed. Reliable, easy-to-use, automated methods could increase sample throughput as well as reproducibility. Here we introduce such a method using a Gilson ASPEC GX-271 system and test the separation quality, reproducibility, and efficiency in comparison to a classical manual SPE lipid purification procedure. Using multiple extractions of the same natural soil sample we show that the automated SPE is comparable in overall quality and slightly superior in reproducibility to a manual SPE. We demonstrate that stable hydrogen isotope measurements of n-alkanes purified using an automated SPE extraction showed significantly lower standard errors. Furthermore, the unattended operation of the system eases the purification of large sample sets. Generally, the automated SPE using the Gilson ASPEC GX-271 for lipid biomarker separation provides qualitatively and quantitatively accurate and reproducible results with more efficient purification of compounds than the manual method.