Characterization of radix rehmanniae processing procedure using FT-IR spectroscopy through nonnegative independent...

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Chemometrics

Background:

• Radix Rehmanniae processing is crucial for its medicinal properties.
• Traditional methods for determining the processing endpoint are subjective and operator-dependent.
• Objective monitoring methods are needed for consistent quality control.

Purpose of the Study:

• To develop and validate a novel method for monitoring Radix Rehmanniae processing.
• To determine the processing endpoint using Attenuated Total Reflectance Fourier-Transform Infrared (ATR FT-IR) spectroscopy combined with nonnegative Independent Component Analysis (ICA).
• To compare the accuracy and consistency of the proposed method against traditional sensory analysis.

Main Methods:

• ATR FT-IR spectra of Radix Rehmanniae samples were collected at various steaming intervals.
• Nonnegative Independent Component Analysis (ICA) was applied to estimate pure component spectra and their concentration variations.
• The estimated independent components (ICs) were used to characterize the processing and identify the endpoint.

Main Results:

• Three independent components (ICs) were successfully estimated, correlating with key chemical constituents (catalpol/rehmaionoside, glucose, and invariant compounds).
• The IR-ICA method determined a processing endpoint of 15 hours.
• This endpoint falls within the range provided by expert sensory analysis (14-17 hours), demonstrating good agreement.

Conclusions:

• The proposed IR-ICA method provides an objective and reliable approach for monitoring Radix Rehmanniae processing.
• This technique effectively determines the processing endpoint, overcoming the significant deviations associated with traditional sensory analysis.
• The method offers potential for enhanced quality control and standardization in herbal medicine preparation.