Determination of coumarin via a two-step chromogenic reaction coupled with capillary electrophoresis

Our result showed that alkaline hydrolysis of coumarin at pH 12.1 produced the strongest color response in the presence of 8.3 mM borate. In the chromogenic phase, after adjusting the pH to 8.8 with boric acid, the reaction efficiency remained high, and the stability of the colored product was superior compared to other pH conditions.

We further established a capillary electrophoresis (CE) analytical condition for the colored product. This method exhibited a strong linear correlation within the coumarin concentration range of 10-200 mg L–1. Using this method, coumarin concentrations in Medicago sativa and Trifolium pratense seeds were successfully determined.