Simultaneous quantitative determination of 20 active components in the traditional Chinese medicine formula Zhi‐Zi‐Da‐Huang decoction by liquid chromatography coupled with mass spectrometry: application to study the chemical composition variations in different combinations

Zhi‐Zi‐Da‐Huang decoction (ZZDHD), a classical traditional Chinese medicine (TCM) prescription composed of four herbal medicines, has been widely used in treating various hepatobiliary disorders for a long time. The objective of this study was to develop a sensitive and efficient liquid chromatography coupled with mass spectrometry (LC‐MS) method for quantitative determination of 20 active constituents, including three iridoid glycosides, 11 flavonoids, three anthraquinones and three tannins in ZZDHD. Separation was achieved on a phenomenex kinetex C₁₈ column (150 × 4.6 mm, 2.6 µm) using gradient elution with a mobile phase consisting of acetonitrile and 0.1% formic acid in water. Detection was performed with electrospray ionization source in the negative ionization and selected ion monitoring mode. The established method was validated by determining the linearity (r² ≥ 0.9983), limit of quantification (0.16–300 ng/mL), precision (RSD ≤ 4.6%), average recovery (96.0–105.6%), repeatability (RSD ≤ 3.2%) and stability (RSD ≤ 4.5%). Then, the method was successfully applied to investigate the chemical composition variations owing to the interaction between the four component herbs of ZZDHD during the extraction process. It was found that different combinations of the herbs affect the extraction efficiency of chemical constituents in different ways. The validated LC‐MS method provides a meaningful basis for quality control and further research on ZZDHD. Copyright © 2015 John Wiley & Sons, Ltd.