J Chromatogr A. 2003 Aug; 1008(2): 167-72.

Determination of five major iridoid glucosides in Flos Lonicerae by high-performance liquid chromatography coupled with evaporative light scattering detection.

Li HJ, Li P, Ye WC.

Department of Pharmacognosy, China Pharmaceutical University, No. 24 Tongjia Lane, Nanjing 210009, China.

This study presents a new HPLC method using evaporative light scattering detection for the simultaneous determination of live major iridoid glucosides, namely 7-epi-loganin, sweroside, loganin, 7-epi-vogeloside, and secoxyloganin in Flos Lonicerae, an important traditional Chinese medicinal herb. The optimal conditions of separation and detection were achieved on a C18 analytical column with an isocratic mobile phase consisting of methanol-water (30:70, v/v) containing 0.5% acetic acid at the flow-rate of 1.0 ml/min, temperature for the detector drift tube set at 90 degrees C and the nitrogen flow-rate of 2.6 l/min. The limit of detection (S/N = 3) is less than 35.1 microg/ml and the limit of quantification (S/N = 10) is less than 140.1 microg/ml. All calibration curves show good linear regression (r2>0.996) within test ranges. This method provides good reproducibility for the quantification of the major iridoid glucosides in four Lonicera species with overall intra- and inter-day variation of less than 5% and 9%, respectively. The assay was successfully applied to quantify the main iridoid glucosides in the herb and to identify the botanical origin of Flos Lonicerae.