ABSTRACT
<p><b>OBJECTIVE</b>To establish a microemulsion liquid chromatography system with direct sample loading for determining the serum level of emodin in rats.</p><p><b>METHODS</b>The separation was performed on C₁₈ column (Hypersil BDS, 5 µm,150 mm×4.6 mm) with the microemulsion mobile phase consisting of 3.3% (w/V) SDS, 6.6% (V/V) n-butyl alcohol, and 1.0% (V/V) octane and water. The flow rate was 1.0 ml/min and the detection wavelength was 254 nm.</p><p><b>RESULTS</b>The linear range of emodin detection was 0.333-5.32 µg/ml. The average recovery was 99.65% with a RSD of 3.60%. The limit of quantification was 0.1386 µg/mL.</p><p><b>CONCLUSION</b>Microemulsion liquid chromatography system with direct sample loading allows simple, accurate and rapid determination of emodin in rat serum.</p>