Quality evaluation of a herbal prescription through quantification of 40 components by HPLC-ESI-MS/MS.

Introduction: The Kang-nao-shuai (KNS) capsule is a combined herbal prescription used in the treatment of insomnia, amnesia, neurasthenia, age-related dementia and brain injuries. Multiple constituents are considered to be responsible for the therapeutic effects of this herbal prescription. However, the quality control of the multicomponents is limited.

Objective: To establish a liquid chromatography-electrospray ionisation-mass spectrometry method for the analysis of 40 constituents in KNS capsules.

Methodology: The optimal chromatographic conditions were achieved on an Agilent C₁₈-column with a gradient elution that consisted of methanol and 0.1% formic acid in water. The precursor and product ions of analytes were monitored on a hybrid quadrupole linear ion trap mass spectrometer in positive and negative mode respectively using multiple-reaction monitoring.

Results: A total of 40 constituents including organic acid, flavonoid, quinone, terpene, alkaloid and saponin were quantified, most of the 40 components were determined for the first time in the KNS capsule. A quantitative HPLC-ESI-MS/MS method allowing the quantification of 40 marker compounds was optimised and validated for linearity, precision, accuracy, stability, specificity and limits of detection and quantification. The method was successfully applied to analyse 10 batches of KNS capsule.

Conclusion: The established method is simple and can be used as a tool for quality evaluation and control of this natural product.