Supercritical fluid chromatography hyphenated with dielectric barrier discharge ionization mass spectrometry: A universal approach to analysis of complex plant extracts.

The chemical diversity of plant secondary metabolites, ranging from volatile nonpolar terpenes to polar flavonoid glycosides, often necessitates the combined use of gas chromatography and liquid chromatography for comprehensive profiling. In this study, we present a universal analytical platform based on supercritical fluid chromatography coupled with mass spectrometry (SFC-MS) that enables broad-spectrum analysis of plant extracts in a single run. A novel SFC method was developed employing a pentabromobenzyl stationary phase and a CO2-based mobile phase modified with 3 mmol/L ammonium fluoride in methanol. Separation of 62 diverse phytochemicals, including terpenes, vitamins, phenolic acids, and flavonoids, was achieved within 12 min. To address the ionization challenges posed by this chemically heterogeneous analyte panel, we evaluated both a dual ionization source combining electrospray and atmospheric pressure chemical ionization and an alternative commercially available soft ionization technique, which utilizes dielectric barrier discharge in cold plasma. This source demonstrated effective ionization of different chemical structures, enabling the detection of both functionalized polar compounds and nonfunctionalized terpenes in a single ionization mode. The method applicability was evaluated by analyzing five different plant extracts, highlighting its potential as a truly universal tool for phytochemical analysis.