oa μSARA-HPLC: Slicing Through Petroleum Fractions with Unmatched Precision and Speed

Saturate, aromatic, resin, and asphaltene (SARA) fractionation is fundamental to petroleum fluid characterization. However, most traditional approaches are slow, labor-intensive, and inconsistent across laboratories. This study presents µSARA-HPLC, a rapid and fully reproducible high-performance liquid chromatography method that completes SARA separation in under 35 minutes using standard commercial equipment. The technique employs micro-volume injections and dual detection via evaporative light scattering (ELSD) and diode-array detectors (DAD), consistently achieving less than 1% relative standard deviation across a wide range of crude oils and bitumen extracts. Baseline separation of all four SARA fractions is achieved through an optimized gradient program and dedicated column setup. A mid-run flow reversal maintains clean elution and reduces carryover. Fraction identity and purity were confirmed using GC-MS and ultrahigh-resolution FT-ICR-MS. The method also benefits from reduced solvent use, minimal sample preparation, and longer column lifetime. Calibration with a certified reference oil ensures consistency across applications. µSARA-HPLC provides a robust, scalable solution for routine SARA profiling, offering improved speed, reproducibility, and sustainability. It is well-suited for both research laboratories and operational environments, enabling more efficient workflows in geochemistry, reservoir studies, and petroleum quality monitoring.