Methods using reversed-phase high-performance liquid chromatography (RP-HPLC) with ELSD were investigated to quantify enzymatic reactions of flavonoids with fatty acids in the presence of diverse room temperature ionic liquids (RTILs). A buffered salt (preferably triethylamine-acetate) was found essential for separation of flavonoids from strongly polar RTILs, whereby RTILs were generally visible as two major peaks identified based on an ion-pairing/exchanging hypothesis. C8 and C12 stationary phases were optimal while mobile phase pH (3-7) had only a minor influence on separation. The method developed was successfully applied for primary screening of RTILs (> 20), with in depth evaluation of substrates in 10 RTILs, for their evaluation as reaction media.
- reversed-phase high-performance liquid chromatography
- evaporative light scattering detection (ELSD)
- enzymatic esterification
- room temperature ionic liquids (RTIL)