Abstract: Both salvianic acid B and rosmarinicacid are water-soluble hydroxybenzene acids. They are all highly valued as medicine. 3mmol/L carbamide were added into the mobile phase(methanol:1% formic acid =40:60) to get hold of more pure salvianic acid B(omit) and rosmarinicacid. They were detected at 280 nm with the peak of rosmarinicacid much better than before(There was no carbamide in the mobile phase). We supposed that rosmarinicacid had a kind of coordination with carbamide in the mobile phase and this coordination made the structure of rosmarinicacid different from before. So this detection method seems better. The method is simple for characterizing, purifing and determinating salvianic acid B and rosmarinicacid.

Key words: rosemarinicacid, salvianic acid B, combination, carbamide, HPLC