Chemometric resolution approaches in characterisation of volatile constituents in Plantago ovata seeds using gas chromatography-mass spectrometry: methodology and performance assessment

Abstract

Introduction: Comprehensive chemical profiling of herbal medicines (HMs) is a major challenge in chemical characterisation of source materials. Many analytical platforms such as gas chromatography-mass spectrometry (GC-MS) have been applied to the characterisation. However, the great complexity of analytical results has been an obstacle. Chemometric resolution methods as a supplementary tool for data processing are proposed for solving this problem.

Objective: To develop and demonstrate the ability of chemometric techniques in the characterisation of volatile components in herbal medicines.

Methods: The volatile components of Plantago ovata were extracted using a solvent extraction method. GC-MS analysis were performed using an Agilent HP-6890 gas chromatograph equipped with a HP-5MS capillary, interfaced with an Agilent HP- 5973 mass selective detector. Resolved spectra were identified by matching against the standard mass spectral database of the National Institute of Standards and Technology (NIST).

Results: Results of this study show that the 71 constituents that are qualitatively recognised represent 94.53% of the total relative content of constituents from Plantago ovata oil, whereas without applying the chemometric methods only 51 constituents were recognised by direct searching utilising a mass database. In addition the presence of valuable components such as thymol, 2,4-decadienal, linoleic acid and oleic acid in Plantago ovata oil has been demonstrated.

Conclusion: GC-MS combined with chemometric resolution methods, such as multivariate curve resolution-alternating least squares (MCR-ALS), will provide a reliable means for rapid and accurate analyses of unknown complicated practical systems.

Keywords: Chemometrics; GC-MS; Plantago ovata; multivariate curve resolution-alternating least squares; rotational ambiguities.