Qualitative analysis and quality control of Traditional Chinese Medicine preparation Tanreqing injection by LC-TOF/MS and HPLC-DAD-ELSD

Abstract

Tanreqing injection, a classical Traditional Chinese Medicine formulation, consists of Radix Scutellariae baicalensis, Fel selenarcti, Cornu naemorhedi, Flos lonicerae and Forsythiae fructus, having a marked curative effect on the diseases of the upper respiratory tract. In order to clarify its chemical profile, a method based on liquid chromatography coupled with time-of-flight mass spectrometry was proposed, and 53 compounds were identified on a formula database of 515 known compounds with the aid of accurate mass measurement for molecular ions and characteristic fragment ions. Using the chemical fingerprints for the purpose of quality control, a high performance liquid chromatography coupled with photodiode array detection and evaporative light scattering detection (HPLC-DAD-ELSD) was developed in this study. The chromatographic fingerprints were evaluated by the dual similarities (S and S′) of an ultra-violet chromatogram, in combination with S_E of an ELSD chromatogram, reflecting the complexity of Tanreqing injection with the consideration of both large and small peaks. In addition, the established HPLC-DAD-ELSD method was successfully applied to the quantitative analysis of the five ingredients (chlorogenic acid, caffeic acid, baicalin, ursodeoxycholic acid and chenodeoxycholic acid) and fingerprint analysis in 11 batches of Tanreqing injections. The results obtained in this research will provide the basis for quality control of Tanreqing injections.