Abstract:

A glassy carbon electrode modified with hydrophobicity 1-n-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6/GCE) was fabricated. Differential pulse stripping voltammetry was used to investigate the electrochemical behavior of luteolin at the modified electrode in 0.2 mol/L phosphate buffer solution, pH 7.0 and a new method for determining total flavonoids in Flos Ionicera was established. It was found that the peak potentials for oxidation and reduction both shifted negatively by 15 mV at the modified electrode as compared with the corresponding bare electrode in 0.2 mol/L phosphate buffer solution (pH 7.0) containing 3 × 10-9 mol/L luteolin and higher oxidation and reduction peak currents of luteolin at the modified electrode were observed. Further experiments demonstrated that oxidation peak current increased linearly with increasing luteolin concentration within the range from 1.0 × 10-10 to 1.6 × 10-8 mol/L with a detection limit of 3.2 × 10-11 mol/L and the range of spike recovery at four levels was between 98.7% and 103.6%. The method is simple, fast, sensitive and accurate, thereby providing an available approach for the determination of total flavonoids in Flos Ionicera.

Key words: Flos Ionicera, luteolin, ion liquid, modified electrode, total flavonoids, electrochemistry