Optimisation of ultra-performance LC conditions using response surface methodology for rapid separation and quantitative determination of phenolic compounds in Artemisia minor

A method that couples rapid, sensitive, reproducible and accurate ultra-performance LC (UPLC) with quadrupole-TOF-MS was established for the first simultaneous qualitative and quantitative analysis of phenolic compounds in Artemisia minor. Box-Behnken designs (BBDs) were applied as an effective tool to optimise major parameters that influence the resolution of UPLC, including three gradient steps and column temperature. Under optimal UPLC conditions, a total of 23 phenolic compounds in the crude methanol extracts of A. minor were well separated on a Waters Acquity UPLC BEH C₁₈ column (100×2.1 mm, 1.7 μm particle size) within 16.5 min, and the compounds were unequivocally or tentatively identified via comparisons with authentic standards and literature. In this study, a total of six major phenolic compounds were quantified in A. minor and the method was validated to be sensitive, precise and accurate within the LOD from 1.24 to 5.27 μg/mL, and the overall intra- and inter-day variations in detection were less than 3.76%. The recovery of the method ranged from 97.9 to 103.8% with RSDs that were less than 5.8%. These results demonstrate that this approach has the potential for quality control of A. minor and other Tibetan herbal medicines.