Analysis of flavones in Rubus parvifolius Linn by high performance liquid chromatography combined with electrospray ionization-mass spectrometry and thin-layer chromatography combined with Fourier transform surface enhanced Raman spectroscopy

Qualitative and quantitative analyses of total flavones in wild Rubus parvifolius Linn (RPL) were carried out using ultraviolet spectroscopy, and the isolation and structure determination of the main active ingredients were carried out by high performance liquid chromatography (HPLC) coupled with Electrospray ionization-mass Spectroscopy (ESI-MS), thin layer chromatography (TLC), and the Fourier transform surface enhanced Raman spectroscopy (FT-SERS). Two flavones were isolated from RPL and they were identified as herahydroxy dihydroflavanonol and quercetin. Two chromatographic spots were obtained when polyamide TLC plate was used to separate the flavones, and two strengthen bases were prepared by the reduction of silver nitrate with trisodium citrate and also by the photo-induced reduction of a mixture of silver nitrate and potassium bromide. Strong increase of characteristic Raman scatting intensity could be observed on these bases for microgram quantity of the flavones compound.