RESUMEN
Objective::Near infrared spectroscopy was used to detect the concentration density (25 ℃), solid-containing content, rhein content and glycyrrhizic acid content of compound Dahuang decoction. Method::The concentrated liquid of compound Dahuang decoction was determined by near infrared optical fiber transmission spectrometry. The contents of rhein and glycyrrhizic acid were determined by HPLC. Fifty-one samples were used for internal cross-validation, and partial least square regression was used to establish correction models between near-infrared spectrum and density, solid-containing content, rhein content and glycyrrhizic acid content, respectively. Ten unknown concentrated liquid samples were collected for external validation and prediction. Result::The external validation complex correlation coefficients between near-infrared spectra and density, solid-containing content, rhein content and glycyrrhizic acid content of the concentrated liquid of compound Dahuang decoction were 0.995 9, 0.999 6, 0.997 0 and 0.992 2, and the root mean square error of prediction (RMSEP) values were 2.50×10-3, 0.17, 7.57 and 67.10, respectively. Conclusion::The near infrared spectroscopy is suitable for the determination of evaluation indexes of the concentrated liquid index of compound Dahuang decoction, and has the characteristics of rapid, simple, stable and reliable.