Simultaneous determination of nine bioactive constituents of Caulis Lonicerae Japonicae by high-performance liquid chromatography coupled with mass spectrometry

A new high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS) method has been developed for the simultaneous determination of nine major compounds, namely chlorogenic acid (1), caffeic acid (2), sweroside (3), loganin (4), secoxyloganin (5), 3,5-di-O-caffeoyl quinic acid (6), luteolin-7-O-glucoside (7), rutin (8) and 3,4-di-O-caffeoyl quinic acid (9), in Caulis Lonicerae Japonicae (CLJ), a commonly used traditional Chinese medicinal herb. The separation was achieved on a C-18 column (250 x 4.6 mm, 5.0 mu m) with a column temperature of 30 degrees C and a flow-rate of 0.8 mL/min. The mobile phase was composed of (A) aqueous formic acid (0.1%, v/v) and (B) methanol, using a gradient elution of 30% B for 0-13 min, 30-40% B for 13-17 min, and 40-49% B for 17-30 min. The limit of detection (S/N= 3) ranged from 0.8 to 5.1 ng/mL and the limit of quantification (S/N = 10) varied from 3.4 to 16.9 ng/mL. All calibration curves showed good linear regression (r(2) > 0.9976) within the test ranges. The intra- and inter-day precisions, as determined from sample solutions, were below 2.2 and 4.3%, respectively. The recoveries for nine compounds were within 91.3 and 104.2%. This proposed method has been successfully applied to evaluation of commercial samples of CLJ from different markets in China, which provides a new basis of assessment of the quality of the herbal drug.