Simultaneous determination of andrographolide and dehydroandrographolide in Andrographis paniculata and Chinese medicinal preparations by microemulsion electrokinetic chromatography

The present paper describes the development of a microemulsion electrokinetic chromatographic (MEEKC) method for simultaneous determination of andrographolide and dehydroandrographolide in traditional Chinese medicines and Chinese medicinal preparations. The MEEKC method involved the use of sodium dodecyl sulfate (SDS) as surfactant, heptane as organic solvent and butan-1-ol as co-solvent. The effect of temperature and pH of running buffers on separation were examined. The optimized conditions (heptane 0.81% (w/w), SDS 3.31% (w/w), butan-1-ol 6.61% (w/w) and 10 mM sodium tetraborate buffer, pH 9.2) allowed a useful and good reproducible separation of the studied analytes to be achieved.