Simultaneous determination of various bioactive redox components in Shuang-Huang-Lian preparations using a novel three-channel isocratic elution liquid chromatography with electrochemical detection system.

A novel three-channel isocratic elution high performance liquid chromatography with electrochemical detection (3LC-ECD) system was developed for the simultaneous determination of various bioactive redox components in Shuang-Huang-Lian (SHL) preparations. This 3LC-ECD system consists of three isocratic elution flow ways, two switching valves, four columns, and three electrochemical detectors. Through alternately rotating switching valves to change the elution flow way, six caffeoylquinic acids, four flavonoids, and one phenylethanoid glycoside compound were simultaneously determined within 70 min by the present 3LC-ECD method, in which three compounds of protocatechuic aldehyde, propyl gallate, and kaempferol were used as internal standards. The results demonstrated that the present 3LC-ECD method has achieved desired linearity (r>0.999), precision (relative standard deviation <2.5%), accuracy (recovery, 95.6-103.6%), and high sensitivity (limit of detection, 0.11-0.90 ng/mL). In addition, we successfully determined the contents of these 11 bioactive redox components in 14 batches of SHL oral liquid and 12 batches of SHL lyophilized powder for injection produced by different manufacturers in China.