Determination of Baicalin by High Performance Liquid Chromatography Coupling with Flow Injection Chemiluminescence Detection

Abstract

A new method for the determination of baicalin in Scutellariae Radix extract and its preparations by high performance liquid chromatography (HPLC) coupling with flow injection chemiluminescence detection (FIA-CL) has been developed. The method was based on the chemiluminescence reaction of potassium permanganate with baicalin in nitric acid medium; the CL intensity can be enhanced by formaldehyde. In this study, the conditions of chemiluminescence and chromatography were examined, and the schematic diagram of the HPLC-FIA-CL analyzer was optimized. The analytes were separated on Hypersil RP-C18 columns (100 4.6 mm, I.D., 5 mm) by equality elution with 47:53 (v/v) methanol-0.3% phosphoric acid as a mobile phase at a flow rate of 0.8 mL·min -1 and a column temperature of 40°C. Under the optimum condition, the CL intensity was proportional to the concentration of baicalin over the range of 4.10´10 -7~6 .15´10 -5 mol·L -1 . The limit of detection (S/N = 3) was 2.79´10 -7 mol·L -1 with the relative standard deviation 2.5% (Cs = 6.15´10 -6 mol·L -1 , n = 5). The method has been applied to the determination of baicalin in Scutellariae Radix extract and its preparations, and satisfactory results were obtained.

The characteristic red chemiluminescence from reactions with acidic potassium permanganate: further spectroscopic evidence for a manganese(ii) emitter

“…Many researchers have reported emission spectra consisting of a single broadly distributed band with an apparent maximum intensity between 610 nm and 750 nm. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] This red emission has often been attributed to the production of singlet oxygen, 3,[9][10][11][12][13][14][15][16][17][18][23][24][25] but the spectral distribution for singlet oxygen (bands at 633, 703 and 1268 nm) 26,27 is unlike that observed for acidic potassium permanganate chemiluminescence. 28 Many other researchers have suggested that the chemiluminescence emanates from a manganese(II) species.…”